In the winter heating scenario, air source products often stop heating due to the defrosting of outdoor heat exchanger, which leads to the decrease of indoor temperature and poor user experience. Therefore, improving the comfort of indoor users during defrosting operation has become an important subject for air source heat pump. Outdoor heat exchanger is divided into two parts. By controlling the saturation temperature of the refrigerant and using the latent heat of the refrigerant, the effective alternate defrosting technology of heat exchanger is developed. The experimental results show that: 1. Effective defrosting is achieved with the lowest refrigerant flow at a defrost saturation temperature from 2℃ to 8℃. 2. Under the outdoor condition of 2℃, the average heating capacity of latent heat defrosting is 75% of the rated capacity.

Forced convection heat transfer is used in the air-cooled refrigerator to make the air in the storage room flow through the evaporation room for heat and moisture exchange, and maintain the temperature of each storage space in the set range through the air circulation in the box. Takes the Indian market as the breakthrough point, combined with the local economy, environment and culture, to explore the market users' demand for flexible storage of food (such as fast ice making, energy saving, fast cooling, convertible, etc.). Especially in view of the fixed problem of the existing two door refrigerators in the market, based on the traditional function of air-cooled refrigerator, an innovative design scheme is proposed, which can realize the function of freezing to refrigeration, and at the same time can meet the rapid cooling. Through the simulation of air circulation and data analysis, a new function of air-cooled refrigerator with double fans is designed.

The consistency of the production quality of the parallel flow heat exchanger has a significant impact on the heat exchange performance of the air conditioner. The welding quality of the spacer of the parallel flow heat exchanger directly affects the performance of the heat exchanger, but there is little relevant literature to study it. Through the test and analysis of a set of abnormal cases of the refrigeration performance of the air conditioner, it is confirmed that the poor welding of the spacer of the parallel flow condenser leads to the abnormal refrigeration performance, It is suggested that the deformation caused by the processing and stamping of the collector should be considered when designing the spacer, and propose that the spacer semicircle should be designed with multi segment arcs, which can reduce the gap between the spacer and the collector after assembly, so that the solder can evenly fill the gap during brazing, and in the final inspection stage of heat exchanger production. The inspection judgment parameters need to be compared with the qualified standard parts confirmed by the high-precision plugging inspection machine.

The super hydrophobic bionic function structure is applied to the air conditioner wind deflector, used to solve the problem of air conditioner refrigeration outlet when condensation, by super hydrophobic material surface wetting properties and microstructure characteristics, analysis of the bionic function structure prevent condensation mechanism, combining with the plastic mold injection molding and processing conditions, reasonable design of bionic structure function, to verify the feasibility of the solution of anti-condensing design for air conditioner by injection mold forming of bionic functional structure.

A direct heating water heater coupled with gas and air source heat pump is developed. According to the different environmental temperature and critical temperature, different operation modes are adopted to produce the required hot water in a cascade heating mode, which can significantly improve the utilization rate of the equipment, save the operation energy consumption, and better serve people's life under the background of "double carbon".

When the air conditioner operates in the conventional dehumidification mode, dehumidification will cause human discomfort with the decrease of temperature. Therefore, it is of great significance to study the air conditioner which can realize the function of constant temperature and dehumidification to improve the living environment. The basic scheme of this study is: at the same time of dehumidification and refrigeration, turn on the electric heating element of the indoor unit, and then adjust the compressor frequency to cold and heat of the room and achieve constant temperature dehumidification. The test results show that this function can not only effectively dehumidify, but also control the room temperature fluctuation within ±1℃, so as to improve the comfort of users using the dehumidification function of air conditioning.

Household refrigerator evaporators use different heat exchange pipe diameters, which will cause differences in the heat exchange performance of the heat exchanger and the performance of the entire refrigerator. The influence of heat exchange tube diameter and evaporator heat transfer performance of air-cooled refrigerator fin evaporator under different wind speeds and different mass flow rates is studied. The heat exchanger performance test bench is used to test the 5 mm/6.35 mm/8 mm tube diameter. The performance parameters of heat transfer coefficient, heat transfer, pressure drop loss and other performance parameters under different wind speeds are compared and analyzed. The results show that: when the system mass flow is 0.5 g/s and the wind speed is 1.6 m/s, the 6.35 mm pipe diameter evaporates. The heat exchanger has better heat exchange performance, which is 9.7% higher than the 5 mm pipe diameter and 7% higher than the 8 mm pipe diameter.

The fan system based on the dual bypass design in the aviation field is applied in room air conditioners to solve the wind problem of single type fan and can effectively improve the comfort of the human body. But no relevant research on the dual engine heat exchange system design coupled with double bypass fans was found worldwide. In order to study the couple design method of dual engine heat exchange system, this paper has carried both numerical simulation and experimental research to obtain the optimal speed ratio parameters of the upper and lower fans of the double bypass fans system under different load conditions. Simultaneously, new heat exchanger structure parameters and refrigerant distribution are investigated to enhance the heat exchange efficiency and improve the energy efficiency level to meet the energy-saving needs of users.

During the cooling operation of traditional air conditioners, there are problems such as uneven heating and cooling at near and far, and insufficient circulation at local locations, which leads to poor user experience during cooling of the air conditioner. Based on the air supply range and wind perception problems of a single fan type, the coupled fan is designed with the principle of aviation double ducts. Combined with the inherent characteristics of the two fans, through the wind of two air streams to control the wind, and carry out the conversion of multiple airflow forms, so as to realize the comfortable wind feeling of breezeless and uniform wind field formation in the whole room.

Resent years, air-to-water heat pump products have developed a variety of using conditions, which can be integrated with a variety of heating sources and applications with a strong flexibility. The double temperature zone of ATW includes radiation branch and floor heating branch. The operation requirements of different inlet water temperatures can be realized in the two branches, and the water mixing unit is the core component. The water mixing mode can be divided into two types: the manual valve located on the parallel bypass branch of the water mixing valve is opened or closed. Furthermore, the relationship of water flow in double temperature circuits can be divided into several cases. The results are shown as follows: when the manual valve on the parallel bypass branch of the water mixing valve is closed, it is easy to cause large water flow fluctuation of the radiation branch, which is not recommended. When the manual valve on the parallel bypass branch of the water mixing valve is opened, the water flow fluctuation in the double temperature zone is small, which is max. 9.72% of flow variation rate in the test. During the circuit design, the circulating water flow of floor heating is equal to the water flow of floor heating branch is preferred. While for the complex situation of on-site pipeline, a larger water pump of main circuit can also be selected appropriately.

With the improvement of people requirements for a healthy indoor environment, the current indoor fresh air exchange cannot effectively improve the indoor air quality. In order to ensure effective indoor ventilation, provide sufficient fresh air volume and improve product competitiveness, wall-mounted air conditioner is taken as the research object, by optimizing the aerodynamic resistance of various components in its internal multi-blade centrifugal fan module, the low impedance air flow improvement design is carried out from the aspects of air inlet pipe, air cavity, fresh air filter and so on. By verifying the hand model, the fresh air volume is increased by about 33% at the same speed; At the same time, under the condition of sufficient fresh air rate, the internal air flow uniformity is improved and the noise quality at the same speed is guaranteed.

Among the APF weights of inverter air conditioners, low-temperature intermediate refrigeration accounts for the highest proportion which is the focus of inverter development. In the process of low-temperature intermediate refrigeration operation, the operation of the inverter compressor is greatly affected by the driving parameters. So how to optimize the driving parameters and make the compressor operation more reasonable is the focus of research. Focuses on the impact of the compressor current compensation value change on the performance of the whole machine, and analyzes its improvement effects through specific cases.

A discrete theoretical model of the internal flow in the Multi-radiation air conditioning system is established, and the control equation of the model is solved by bidirectional iterative algorithm. The uniformity of the static pressure distribution and flow distribution of the refrigerant in the system under different Re numbers is studied. The results show that under the same Re number, the distribution of refrigerant in the branch pipe presents an incremental bias distribution along the flow direction, and the increase of Re number intensifies the bias distribution of refrigerant. In order to overcome the heating inhomogeneity caused by the bias distribution of refrigerant, puts forward two solutions to improve the uniformity of refrigerant distribution from the aspects of structure design and control logic.

System leakage is one of the common faults of air conditioning system. In order to effectively control and continuously improve, this paper analyzes the typical cases of system leakage failure in the installation and design process of air conditioning system, expounds the failure mechanism and reasons from the aspects of phenomenon and principle, and puts forward the rectification scheme and preventive measures.

Hypobaric storage is a common storage method for fruits and vegetables. To evaluate the fresh-keeping effect of hypobaric storage on fruits and vegetables, three kinds of vegetables (spinach, celery and color pepper) and five kinds of fruits (strawberry, peach, green grapes, avocado and cherry) were used to evaluate the changes in weight loss and color difference under reduced pressure storage conditions (set pressure at 80 kPa) and normal pressure storage conditions. The chlorophyll content of spinach was evaluated, and the sensory quality of fruits and vegetables was evaluated by sensory evaluation. The results showed that leaf vegetables were easier to lose weight than stem and fruit vegetables during refrigeration. The weight loss of vegetables and fruits were lower in hypobaric storage, among which the weight loss of green grapes was the most significant. The weight loss of green grapes in hypobaric storage for 7 days was 8.1 times lower than that of ordinary refrigerator storage. In hypobaric storage, the surface gloss and chlorophyll were better maintained. The higher sensory scores also showed that hypobaric storage could improve the sensory quality of fruits and vegetables. In conclusion, hypobaric storage can have a better preservation effect on fruits and vegetables.

Transmitting sound is a typical noise in the abnormal noises of indoor unit. If the noise is caused by the structural vibration of the pipe, in addition to the method of installing the muffler on the pipe, the method of avoiding resonance can also be used to deal with it. Aiming at the transmitting sound problem of the indoor unit of air conditioner, avoid resonance between compressor and pipes by changing the structure of the latter. The transmitting sound of indoor unit is eliminated, the purpose of rectification has been achieved. It provides an effective method for the solution to the problem of transmitting sound in the indoor unit.

Aiming at the noise problem of range hood, the impeller structure of range hood was optimized. A range hood model was analyzed by numerical simulation and the impeller structure improvement scheme was put forward according to the simulation results, and the influence of the optimized impeller structure on the noise of the whole machine was verified through experiments, so as to solve the problem of high noise in the range hood. In addition, the experimental comparison shows that the optimized impeller structure can obviously improve the noise in the whole machine, which provides different research directions for the noise research of the range hood.

The existing high-speed blender achieves the purpose of breaking up the food through the high-speed rotation of the blade. While the motor drove the high-speed rotation of the blade, it also generated a large amount of heat and its own vibration to generate relatively large noise. Took a certain model of high-speed blender on the market as an example, and studied the temperature of the motor and the noise of the high-speed blender base under standard test conditions through experiments and numerical simulations. The test results showed that the cooling air flow of the original prototype motor is 43.59 m³/h, the maximum temperature of the motor was under its allowable operating temperature rise critical value, and the base noise is 80.35 dB at 15000 rpm. On the basis of the original prototype, reducing the gap between the motor cover and the motor, switching to a split motor cover, and reducing the distance between the fan and the base pedestal, etc., the temperature and base noise of the motor during operation were reduced. The experimental results showed that the gap between the motor cover and the motor at 3.33 mm, splitting the motor cover and raising the base pedestal can make the motor temperature meet the operating temperature requirements, while the base noise was reduced to 75.03 dB, which significantly improved the experience of the high-speed blender.

Investigates the proportional resonant (PR) controller to improve the acoustic noise performance in air-conditioning applications. Firstly, current harmonic in the permanent magnet synchronous machine and analyzes the PR controller parallel connected with the proportional integral (PI) controller in the synchronous rotating reference in order to reduce current harmonic in the air-conditioning fan. The model and formula of PR controller are derived in the time domain, and the parameters of PR controller are calculated in real time in the control program. Moreover, the current harmonic and noise improvement scheme of the PR controller in the air conditioning fan is proposed and verified. Finally, the effectiveness of the method on current harmonic suppression and noise dissonance elimination is verified through experiments.

In recent years, sound quality technology has been widely used in the field of household appliances, and related test methods have tended to be standardized. For example, the group standard T/CAS 341-2019 “Test Method for Sound Quality of Range Hood” provides the modeling method also gives a numerical expression of sound quality through the sound quality index, but the research on sound quality grading is still blank in our country. This paper takes the range hood as an example, combined with subjective evaluation experiments and questionnaire surveys, and uses the categorized volume ratio as the intermediate amount to construct the relationship between the sound quality index and the grading limit. Finally, the classification of range hood products is realized from the sound quality level. It provides a scientific basis for the formulation of noise perception evaluation standards or specifications, and at the same time provides a useful reference for the sound quality evaluation and classification of other household appliances.

To improve the heating effect and speed, wall-mounted air conditioners are usually equipped with PTC electric auxiliary heating to compensate for low-temperature heating. But in the case of low temperature and low speed, when the electric auxiliary heating is turned on, the indoor unit often produces abnormal noise, which affects the user's use and experience. Based on CFD numerical simulation and experimental verification, this paper verifies and analyzes different forms of electric auxiliary heating and different installation positions. Determined the influence of the shape and location of the electric auxiliary heating on the air volume, noise, condensation and other aspects. By optimizing the layout of the electric auxiliary heating, the peak value of the broadband average caused by the auxiliary heating is effectively reduced, the air volume is obviously increased, and the sound quality is improved. which has guiding significance for the subsequent design of the electric auxiliary heating position.

By studing the echo cancellation and reverberation cancellation methods of voice air conditioner in complex acoustic environment, so as to solve the problems of low recognition rate and poor robustness of far-field voice air conditioner. The frequency domain block adaptive filtering method is used for echo cancellation, the convergence speed is optimized for the large reverberation environment, and a multi-channel linear prediction method based on time-frequency mask is designed to adapt to noise reduction. Firstly, the deep learning technology is used to construct the signal time-frequency mask model, and then the multi-channel linear prediction adaptive late reverberation suppression technology is used to obtain the time-frequency mask information in combination with the mask model to suppress the reverberation components in the signal quickly and effectively. Finally, the spatial filtering technology based on transient data and eigenvalue decomposition is used in combination with the mask information, The multi-dimensional spatial signal guidance vector and noise statistics are accurately estimated, and the spatial filter is designed to effectively suppress the noise interference and improve the recognition robustness.

The heating process of boiling water cooker is accompanied by uncomfortable noise, especially when heating with high power. Reducing noise is the main research direction of boiling water cooker. By studying and analyzing the causes of noise in different stages of boiling water boiler, three main ways to reduce noise are put forward. How to reduce the bubble size and speed up the bubble separation are selected and studied. The relationship between the bubble size of noise and the shape, contact angle and surface roughness of heating surface is mainly calculated and analyzed. According to the research on the above factors related to the bubble, it is proposed to adopt the annular convex heating structure at the bottom of the cup body, and the test verifies the noise reduction effectiveness of this structure and the heating mask with small surface roughness during high-power heating. This structure has the characteristics of good production process, low cost and high heating efficiency, and has good interchangeability with the steel cup body of existing products.

With the rapid development of social economy, people's requirements for living materials and environmental protection are getting higher and higher. For the refrigeration compressor industry, improving compressor performance and reducing compressor noise are more and more in line with the development trend of the refrigeration compressor industry. Therefore, these two requirements are increasingly being valued by related companies and industry personnel. By using Ansys software to calculate and analyze the muffler characteristics of vacuum suction muffler cavity, the best muffler frequency band is about 3200 Hz, which is the most sensitive to human ear. At the same time, through the heat transfer test of the suction silencer chamber with different vacuity, it is found that the higher the vacuity is, the more obvious the heat insulation effect is. After a large number of tests, it is concluded that the higher the vacuum degree of the vacuum muffler chamber is, the more obvious the efficiency of the compressor is, and the noise is becoming more and more obvious. When the refrigerant suction temperature drops by 10℃, the efficiency can be increased by about 3%, and the noise is reduced by 1.4 dB.

Aiming at the problems of low air volume, high noise and low static pressure of range hood, redesigns the impeller of the core fan of range hood. By selecting a certain model for numerical simulation analysis, we find the problems of the existing scheme, optimize the impeller design, and verify the correctness of the new structure design scheme through numerical simulation analysis and experiments, and then find the best design parameters of the impeller. In addition, the comparison between the new impeller and the original impeller shows that the new impeller installed on the range hood has obvious improvement in the air volume and maximum static pressure performance.

An automatic drying algorithm for air vented tumble dryer is introduced, there are two NTCs to detect the temperature of air inlet and air outlet, it can reduce the influence of ambient temperature on drying and improve the accuracy of software control. The drying curve of different load components was studied, and the corresponding relationship between temperature differential and drying time was obtained. The fitting function of the 3% moisture content is preset to the software, the results show that the control of the final moisture content of all the load is within 3%±1%, and indicates the correctness and accuracy of the algorithm. This method can also be applied to different types of loads and other drying level.

Research and analysis of the characteristics of an electrolytic capacitor-less Inverter system, which voltage and current both ripple with twice the frequency of input grid voltage. Study and analysis of the corresponding control techniques for electrolytic capacitor-less Inverter system. Moreover, combining with the characteristics of electrolytic capacitor-less Inverter, most important ,flux weakening is very easy to be unstable and out of control. To solve this problem , a novel flux weakening method for electrolytic capacitor-less Inverter system is proposed. The proposed method is validated by Load experiments , test and verify the control stability of the electrolytic capacitor-less Inverter system. Accordingly, the motor efficiency is improved .

The current control strategies of constant air flow rate without external sensors have limited performance. To settle this problem, a control strategy of dynamic constant air flow rate based on load torque observer is proposed. A reduced order Luenberger load torque observer is constructed, which realizes the real time observation of fan’s load torque and air duct’s parameters, further calculating the wind pressure and air flow rate. The air flow rate calculated in real time is closed-loop controlled by PI, constructing the air flow rate-speed-current three-loop control structure. The experimental results indicate that the proposed method has high control precision for air flow rate without external sensors, which gives consideration to low cost and high performance effectively.

Based on the failure mechanism of nitrogen gas spring fracture of industrial robot, through the use of various advanced failure analysis methods, metallographic structure analysis, material composition analysis, simulation analysis, SEM morphology analysis and other aspects of analysis and verification, it is finally confirmed that the main reason for the fracture of nitrogen gas spring of industrial robot is: the preload (transverse force) on the threaded connection of nitrogen spring Under the action of alternating load stress, the biaxial high cycle fatigue fracture of nitrogen spring occurs. The research results of this paper provide a certain preventive significance for the design and installation process of nitrogen spring, and also provide a certain guiding significance for the analysis of metal material fracture parts.

The difficulties and the existing problems of the welding between aluminum liquid tank and aluminium tube are analyzed, and high frequency induction welding for production application is selected. the high frequency induction welding between the aluminum liquid tank and aluminum tube production technology is researched from the geometric shape and size of the joint to the actual production tooling. production test and production process points are summarized, the implementation of these methods, the difficult problem of welding between aluminum liquid tank and aluminum tube is solved, and good welding quality is obtained. Through the popularization and application in production practice, obvious economic benefits have been received. The solutions to the problems in practical application are of great guiding significance to the welding between products similar to aluminum tubes.

A simple and low-cost preparation method of 7075 aluminum alloy superhydrophobic surface was studied. Superhydrophobic surfaces were prepared on aluminum alloy by laser marking at laser line spacing of 50 μm, 100 μm, 150 μm and 200 μm.The surface of the pits with 50 μm spacing has excellent anti-ice, self-cleaning and anti-adhesion properties. The wettability and anti-icing performance of aluminum alloy surface were studied by surface contact Angle measuring instrument. Their morphology and chemical structure were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD).The surface contact angles of pits with different spacing (50 μm, 100 μm, 150 μm and 200 μm) are different. When the spacing is 50μm, the contact Angle is 154.1° and the slip Angle is 2.3°. The surface with high adhesion is of great significance for water collection and preservation. It can be seen that the superhydrophobic surface can be prepared by this adhesion force preparation technology, and the superhydrophobic surface has potential application prospects in the fields of fluid transport, pollution prevention, oil prevention, pollution prevention and oil transportation.

With the improvement of people’s living standards, people have higher and higher requirements for electrical equipment, such as more convenient operation and more beautiful. As human-equipment interaction interface, the touch button has the development trend of large size and super size. Through the research on the reliability of capacitive super large touch button, mainly including Electro-Static Discharge (ESD)problem, and the problem of anti-interference experiments of Electrical Fast Transient/burst (EFT) and RF induction conducted disturbances immunity test(CS), and through the application case, the expected effect is achieved. The research results shows that the design of the anti-static installation structure can completely solve the problem of touch; the software method of adding anti-interference processing can solve the problem of failure in EFT and CS experiment.

Because of its special cylindrical structure, the cushion of electric water heater is fragile during transportation and inclined during storage. Taking the packaging material of cylindrical electric water heater as the research object, the current transportation environment of the product is analyzed, and the shortcomings of the existing EPS cushion products is summarized. The compression test and fracture bending test of EPS material and EPO material are carried out respectively. It is found that EPO material is more suitable for cylindrical household appliances. The cushion structure based on EPO material is designed to replace the original EPS cushion, and the feasibility of cushion material and structure is analyzed.

With the improvement of living standards, the cleanliness of clothes has become a basic requirement, and intelligent washing has penetrated into our life, so it is particularly important for washing machines and detergent industry to analyze the smudge degree. Computer machine vision analysis is fast, objective, accurate and repeatable. Area, color, texture and so on can affect the result of the stain smudgy degree evaluation. In order to simplify the research, we putforward a kind of machine vision based on computer image analysis technology of white clothes smudgy degree analysis method, the images of the stain were got through the system. After being grayed, the smudgy degree were analyzed through the value of image grey. The results show that the gray values calculated by image method have a high consistency with the visual results, and the image analysis method can be used to analyze the degree of smudge of white clothes.

A voice priority control system in a multi-device scenario is proposed. A priority model is constructed based on information such as device functions, device status, user habits, etc., to calculate and prioritize the weights of each device. In scenarios where the target device is not clearly designated, if there exist several devices with the same name or the user does not specify the target device, this system would automatically select the device of the highest priority to respond to the user's instruction. The experimental results show that the system using the priority model greatly improves the success rate of device control, and simplifies user commands during voice interaction at the same time. Moreover, this system also solves the target decision-making problem in multi-device interaction, and further improves the smartness of voice control.

Smart door locks have shown explosive growth in recent years, and their market share has increased year by year. The current standard lacks testing for the functional safety of smart door locks, in order to evaluate the reliability and safety of smart door locks more realistically and effectively, the key unlocking methods of intelligent door lock, such as IC card unlocking function, fingerprint unlocking function and electronic circuit core module are analyzed and a set of testing methods are developed. After many tests and continuous tracking, it was found that although the key unlocking of the door lock was upgraded and improved, but there is still the risk of replication and over-promotion, through the test results, it can be found that the major door lock enterprises have insufficient understanding of circuit reliability. Therefore, there is insufficient protection against circuit failures.

In recent years, with the traditional Chinese eating habits, to meet the tip of the tongue taste buds barbecue food culture is popular, have the function of baking oven flavor into the thousands, with the more mature of electromagnetic energy RF heating technology, radio frequency heating with heating rate, the application of heat penetrability strong electric oven at home has been rapid development, The market penetration rate of oven with RF heating device is greatly increased, bringing new feelings and experiences to users. Based on user experience pain points and technical bottleneck breakthrough innovation, RF heating in the oven for application principle of design, RF component selection match, the verification test, the effect of different RF heating food baking and CAE simulation analysis model is established, roasted barbecue process intelligent control logic design optimization, after repeated test validate, the results show that the the intelligent control radio frequency heating technology is applied to the electric oven, which solves the pain points and technical problems of the user's meat baking, and realizes the fast and efficient radio frequency heating cooking, improves the user's satisfaction with the experience, and promotes the healthy development of the kitchen electricity market.

Computational Fluid Dynamics (CFD) simulation and experimental study are carried out to improve the performance of the gas water heater burner. The internal flow field of the burner is simulated and compared with the experimental results. Lift-off flame as well as its inclination are observed due to the nonuniform distribution of velocity field near the outlet of the burner. A rectifying orifice plate is added inside the burner and its effects on burning are then investigated numerically and validated against the experiments. It is found that the performance of the burner is promoted with the more uniform and stable velocity field.

Micro steam roasting machine including microwave, barbecue, steam three basic functions, is currently in the field of kitchen cooking appliances in the highest technical difficulty, one of the most complex structure of the model, in a limited space to improve microwave energy efficiency is more difficult, but also the future of kitchen cooking appliances research breakthrough direction. Therefore, the research on how to improve the microwave energy efficiency of micro steam roasting machine is of practical value. In order to improve the output efficiency of micro steam roasting machine, it is necessary to increase the useful power in the process of food cooking, reduce the energy loss of other components, and give full play to the best cooking effect. The following mainly from the microwave source selection, microwave matching adjustment and optimization, furnace cavity material, electrical matching and other different directions, on the basis of the comparison of test data, summed up some methods and ways to improve the energy efficiency of microwave energy efficiency, meet the requirements of the first level of energy efficiency of the micro steam roasting machine under the condition of the new national standard.

Compared with the one-way rotating spray system, the two-way rotating spray washing system can effectively improve the washing efficiency and cleaning capability of dishwasher. Puts forward a two-way rotating spray system composed of the basic spray arm and the eccentric long satellite spray arm, then analyzes the characteristics of washing covering of this system, and compares with the two-way rotating spray system composed of two spray arms. In addition, the comparative cleaning tests are carried out in this paper and the results verify the contribution of the new spray system in improving the washing efficiency, so as to strengthen the cleaning capability and shorten the washing time, thus providing a practical reference for the development of dishwasher washing technology.

In order to ensure the positioning accuracy of the motion mechanism in the air conditioner and meet the requirements of refined design and reliability, two different positioning schemes for the motion mechanism of the cabinet air conditioner were designed in the product design stage. By means of tolerance statistics and dimensional chain calculation, the tolerance and the unqualified rate of the closed ring size of the kinematic mechanism caused by the two positioning modes are compared and analyzed. The results show that the positioning datum designed in the middle of the panel seat has the advantages of short dimension chain, small tolerance and low unqualified rate, which is an effective way to improve the positioning accuracy and operation stability. Tolerance and dimensional chain calculation can be used to guide the positioning design of key features in the structural design stage of air conditioning, improve design efficiency with lower cost, and develop high-quality products.

According to CNAS-GL007: 2020 “Guidelines for the Assessment of Uncertainty in Electrical Field”, the noise measurement uncertainty assessment program of household refrigerators is first introduced, and then the sources of noise measurement uncertainty are repeated measurement, sound level calibrator calibration, sound pressure level measurement of the measurement system, test environment (precision semi-silent chamber), envelope area and sample operating conditions. Next, the noise measurement uncertainty is calculated by analyzing these sources in combination with the actual case, in which the accuracy of the test equipment has a great influence on the uncertainty of the noise measurement of the household refrigerator.

National standards have adopted rich experience of developed countries and regions in initiation of ambient air quality and standards. The World Health Organization (WHO) standing from health perception, provides standards and judgments according to existing scientific research, and also serves as the standard basis and reference, the up-to date guidance limit adjusted by WHO in 2021 has been recorded and analyzed. Summarizes the impact of air pollutants on health, and introduces WHO standards and limit requirements for ambient air quality. Comprises four parts: histories of standards, air quality classification, types of controlled pollutants, standard limits, monitoring and detection methods, in comparison with ambient air quality of different countries, the theory fundamental basis and value evidence has been discussed, standing on the prior art GB/T 18883 “Indoor air quality” it provides a reference for the formulation of indoor air quality standards for home scenes in China.

The transparent drawers of refrigerator freezer are mostly made of general purpose polystyrene (GPPS). Although the material has high transparency, it has poor toughness and is easy to crack and damage. In the process of users' use, if there is accumulated water in the drawer, the external force will be produced by freezing at low temperature, which will easily lead to the drawer cracking and affect the user's experience. By simulating the use scenarios of drawers in air-cooled and direct cooled refrigerators, the effects of various factors on the freezing and cracking of drawers are analyzed. In order to improve the reliability of the refrigerator drawer, it is suggested that the general polystyrene drawer should be used in the refrigerator.

In order to study the influence factors of different factors on the vertical cutting force value of pork in refrigerator, this paper selected pork tenderloin as experimental sample, and compared the vertical cutting force value and cutting feeling with temperature, storage time and other factors as variables. The results show that the lower the temperature, the higher the freezing rate and the juice loss rate. The longer the pork, the greater the cutting force value. When the temperature is between -5°C and -3°C and the storage time is ≤7 days, the cutting experience is artificially acceptable. If you need long-term storage, you can choose frozen storage at ≤-18℃. If you eat it within a week, you should choose to store at -5℃~-3℃. It can be directly cut and cooked without thawing and reduces juice loss.

The direct blowing of cold air in air conditioning often causes discomfort to human body, and then causes cold and other diseases. Therefore, the research on comfortable wind feeling of air conditioning has positive practical significance. Firstly, the paper analyzes and summarizes the existing schemes to prevent the direct blowing of cold air from air conditioning, and expounds its technical characteristics. Based on the technical discussion and the author's technical level, a mass-produced split wall-mounted air conditioner was transformed, mainly based on the change of the shape and size of the air deflector, and the flow field simulation analysis of the change scheme was analyzed by using FLUENT, which preliminarily verified that the new scheme can achieve the effect of comfortable wind feeling in cooling mode and heating mode.

The cooling effect of the condenser of household air conditioner is directly related to the working efficiency of air conditioner. Using the condensate produced by air conditioner to cool the condenser can not only improve the refrigeration coefficient, but also reduce the random discharge of condensate. The developed condensing water recovery device improves the heat exchange effect of the condenser and reduces the starting times of the air conditioner. Taking the household air conditioner as an example, it can save about 220 yuan of electricity every year. It is easy to install and low in price, so it has a broad application prospect.

A circulating system of terminal heat pump system based on natural convection heat transfer is designed, and the experimental device of the system is built. The starting process characteristics, heating performance, surface temperature distribution of wire tube and indoor vertical temperature gradient of the system are tested in the environment. The results show that the heat pump system starts quickly, the surface temperature distribution of the wire tube end is relatively uniform, and the vertical temperature difference of indoor air is only 2.1℃. With the increase of outdoor temperature, the heating capacity, power consumption and COP of the system gradually increase, when the outdoor temperature is -20℃~5℃, the COP is up to 4.34.

The injection structure is one of the key factors that restrict the efficiency of injecting refrigerant oil in air conditioning system. To study the advantages and disadvantages of three commonly used oil injection structures, the experiment tested and analyzed the change of time and pressure in the whole process of vacuum oil injection. The results showed that the oil injection structures of the globe valve and the internal thread fluorine injection nozzle has the higher efficiency than the external thread fluorine injection nozzle. The globe valve generally takes more time to install and remove the joints and other preparations than the fluorine injection nozzle. The three processes of vacuum oil injection all lead to pressurizing of the system, thereby affecting the efficiency of the subsequent processes. Considering the oil injection time, operating efficiency and the pressure rise of the system after that the refrigerant oil has been injected, the internal threaded fluorine injection nozzle is the best choice for the vacuum oil injection structure. The results provide reference for the oil injection structure design of air conditioning system.

Roller rotary compressor has the characteristics of compact structure and high performance. Application of roller rotary compressor on slush dispenser is researched in this paper. Through the test, power consumption is reduced by 30.8%, the noise is reduced by 1.5 dB, and make-up time of slush is saved by 6.2%.

Temperature uniformity is a key indicator of refrigerators. Also, it is vital to preservation and store of food.There are many factors affecting the temperature uniformity of refrigerators, such as foaming effects, air-duct design, and shelf length. Therefore, the position of refrigerated temperature was taken as a single variable to investigate the relationship between parameters such as the temperature deviation and power consumption. The results show that the refrigerated sensor, located in the position where has large temperature deviation, is benefit to improve the temperature uniformity of the fresh-food compartment. Among them, the first layer of the fresh-food compartment is the largest temperature deviation, the fourth layer under the position of the original refrigeration sensor is the smallest temperature deviation; when the sensor position is adjusted to the top 7.5 cm of the first layer, we compare to the primary position of the refrigerated sensor. Then we found that the maximum temperature deviation of the fresh-food compartment was dropped from 11.6℃ to 5.8℃ at the air temperature of 16℃,and the maximum temperature deviation was dropped from 15.7℃ to 8.9℃ at the air temperature of 32℃. In addition, after adjusting the position of the refrigerator sensor, the fresh-food compartment is cooled more frequently, but the average temperature and power consumption of each compartment does not change significantly.

Compressor is the heart component of refrigerator. The performance of compressor is an important factor affecting the energy consumption of refrigerator. According to the specified test and data processing methods, according to the specified test and data processing methods, the working conditions of the refrigeration system under the actual operation of the air-cooled refrigerator are studied. It is found that the compressor load under the actual working conditions is reduced compared with the standard working conditions. Guide the compressor performance design according to the actual working conditions, and test the optimized compressor performance: although the single machine performance decreases under standard conditions, the single machine performance increases by 0.5%~4% under the actual condition of refrigerator, the energy consumption of the whole machine sample selected can be reduced by 2.2%.

Indoor TVOC (total volatile organic compounds) gas is the most important component of polluted gas and affects people's health. Based on the study of the mechanism of TVOC generation in indoor gas, this paper uses metal oxide (MOX) sensor technology to accurately detect the TVOC concentration. In order to prevent excessive fluctuation deviation of TVOC detection, the aging of the sensor and the optimization of the assembly position of the air conditioner need to be carried out in advance to ensure the accuracy of the sensor detection. Finally, combined with the detected TVOC concentration value, the fresh air function of fresh air conditioner is used to introduce fresh air from outside to dilute the indoor TVOC concentration, and different fresh air quantities are introduced according to different concentration values, so as to improve the indoor air quality.

The new national energy efficiency standard has been implemented in 2020, which has greatly improved energy efficiency, improved air conditioning product configuration and cost. At the same time, in order to adapt to the national energy conservation and emission reduction effect, improve air conditioning energy efficiency and reduce air conditioning operation power. The compressor is the core component of air conditioning products and the component with the largest proportion of air conditioning cost and power consumption. By reducing the displacement and single rotor of the compressor, the pressure of larger configuration, significantly increased product cost and power consumption of the air conditioning system caused by the improvement of energy efficiency can be reduced. By mainly analyzing the differences between single and double rotor compressors, the design and application of two single rotor compressors instead of double rotor compressors in compressor vibration and reliability and comfort are given.

With the increase of truck market ownership and the improvement of driver's comfort requirements, the demand for battery-powered parking vehicle air conditioners is increasing. By conducting a performance comparison test and analysis of three different forms of parking vehicle air conditioners, including split, packaged top air outlet, and packaged rear air outlet, which exist in the mainstream of the market. And the state parameters of the system when refrigerant leakage occurs in the split parking vehicle air conditioner system are simulated experimentally. The results show that due to the limitation of the packaged structure, the split type is better than the packaged parking air conditioner in terms of refrigeration capacity, energy efficiency and air outlet temperature, which will bring better comfort experience to the drivers and passengers and longer battery life. When the split parking vehicle air conditioner leaks refrigerant, the compressor suction and discharge pressure, and the power of the whole air conditioner will decrease, and the compressor discharge, suction pipe temperature and evaporation temperature will rise, and the fault can be quickly locked according to this trend.

In order to solve the frosting problem of household air source heat pump (ASHP) operating under the condition of the low temperature environment, the most widely used defrosting method is reverse cycle defrost. However, the fundamental problem for such a method is that there is insufficient heat available for ASHP during defrosting, the heat storage defrosting mode is an ideal method. By reporting on an experimental study of the effectiveness of the heat storage defrosting mode, disodium hydrogen phosphate dodecahydrate is used as heat storage phase change material. Three factors, heating capacity, defrosting time and temperature fluctuation, to compare the difference between the heat storage defrosting system and the conventional reverse cycle defrosting system. Results indicated that the use of this PCM-based defrosting method could help increase the cycle heat, shorten defrosting time. The indoor temperature fluctuation of is reduced from the normal 7℃ to 2℃ during defrosting. The heat storage defrosting mode can greatly improve the thermal comfort of the room.

In order to study the frost mechanism of horizontal refrigerators with natural convection is analyzed. The frost reducing effect of several frosting modules is simulated by the test method. The optimization scheme of the unidirectional float valve pneumatic control system with hydrophobic melamine foam is determined, and the actual frost reducing effect of different density hydrophobic materials is verified, so as to optimize the frost reduction module. The research direction is provided.

Air conditioning product design has a great impact on air conditioning condensation. From the perspective of air conditioning product development and based on the principle of air conditioning condensation, this paper expounds that in the condensation design of some air conditioning products, due to the uneven refrigerant flow of each branch of evaporator, the refrigerant flow of each branch is too small, and the structural design of air conditioning outlet and scavenging blade parts is unreasonable. The condensation phenomenon of air conditioner caused by insufficient sealing between the assembly surface of evaporator and bottom shell. Based on the analysis of thermodynamic principle, it is proposed that the flow path design and air conditioning throttling device design should be paid attention to during development, the structural parts of air outlet should be designed based on the principle of CONDA effect, and the condensation solution of slotting scavenging blades is described. It is suggested to add labyrinth concave convex groove at the coordination between evaporator and shell, so as to increase the tightness and reduce condensation.

In order to study the influence of natural wind on air source heat pump, the air source heat pump unit was as the research object and the natural wind of pulse type was selected. Through experimental testing the actual operation data of the unit in refrigeration and heating modes, the law of the influence of natural wind on the operation of the unit was summarized and analyzed. The test results showed that: the operating parameters of air source heat pump unit fluctuated periodically due to the influence of natural wind. And in the heating mode, the suction temperature of unit was influenced mainly, which of the fluctuation amplitude can reach more than 4℃. In the cooling mode, the ambient temperature and condensing temperature were influenced mainly, the fluctuation amplitude of ambient temperature can reach more than 6℃ and the condensing temperature fluctuated within 2~4℃. Through detecting the ambient temperature and suction temperature in real time and judging of their fluctuation characteristics, it can effectively avoid the interference of natural wind on operating air source heat pump unit. The study provided a reference basis for the windproof reliability design of the air source heat pump unit.

APF is the main index to evaluate the energy saving of variable frequency air conditioner. In recent years, the air-conditioning engineer has done a lot of research work on how to improve APF, and the new energy efficiency standard GB 21455-2019 has been formally implemented on July 1, 2020. The team verified the method through simulation calculation and experiment, starting from the compressor frequency, indoor unit fan speed, outdoor unit fan speed and other operating parameters, the seven working conditions involved in the calculation of the new energy efficiency APF are analyzed one by one, and find out the main factors affecting the APF of the variable frequency air conditioner. From this, the irrationality of the mass production model in operation is pointed out, and the corresponding improvement scheme is put forward. The test results show that through the optimization design, the APF is increased by about 2%, and the purpose of improving efficiency is realized. At the same time, it also provides ideas for the continuous improvement of APF of variable frequency air conditioning.

As the alternative of R410A, the amount of R32 compressor will up to 50% of the AC market. The operation presser is similar between R32 and R410A, but the thermal properties are not. As a key component of an air conditioner, R32 compressor needs to be designed according to R32 thermal properties. In this paper, a mathematical model of R32 compressor was built to optimize the main structure parameters, and the leakage, heat transfer and friction of a R32 compressor were discussed. Finally the performance of developed R32 compressor in this paper has been increased by 3% compared with the original R32 compressor.

With the continuous improvement of people's requirements for material life, people's requirements for the comfort of the indoor environment are getting higher and higher, and the energy consumption of home appliances such as air conditioners, electric fans, and fresh air fans is also increasing. In an indoor air-conditioning environment, small changes in ambient temperature and lack of environmental stimulation will cause the body's ability to adapt to temperature or even weaken its resistance. Compared with the monotonous mechanical wind of home appliances such as air conditioners, electric fans, and fresh air blowers, natural wind is favored by people for its fresh, changeable, and soft blowing sensation. From the perspective of comprehensive energy issues and comfort, studying the characteristics of natural wind and adopting the method of simulating natural wind can better improve the indoor living environment and improve the comfort of the human body.

Electrical appliances such as air conditioners and refrigerators were considered to be the main source of noise in the indoor environment, especially noise generated by the flow of refrigerant. Use the aerated supercavitation theory to optimize the structure of the traditional electronic expansion valve. The refrigeration at the inlet of the evaporator was introduced to the outlet of the electronic expansion valve through the installation of a bypass pipe to form supercavitation, increase the local pressure of the refrigerant, and effectively suppress the bursting of bubbles in the two-phase flow. The optimization was compared and analyzed. Improved refrigerant flow state, partial pressure, turbulent kinetic energy and gas phase volume fraction. Based on various factors, it was found that the flow noise of the improved refrigerant was reduced by 3.16 dB. It showed that supercavitation caused by aeration could effectively suppress the flow noise of refrigerant, which was of great significance to engineering design to a certain extent.

There is an obvious "weng weng" noise when a refrigerator is running. After refrigerator noise and vibration spectrum was analyzed, it preliminarily judged that this abnormal noise was caused by resonance of discharge pipe which had a natural frequency around 50 Hz. The mechanism of discharge pipe resonance is analyzed in depth by using experimental modal analysis and modal simulation analysis, it was found that the middle part of discharge pipe had 50.8 Hz natural frequency mode. By adding software constraints to obvious modal part of discharge pipe, 50.8 Hz mode shape was limited. The refrigerator total noise reduced 2.6 dB(A) and single frequency noise about 20 dB(A). This "weng weng" abnormal noise almost disappeared when refrigerator was running.

The wall breaker relies on the high-speed rotation of the motor to achieve cell wall breaking. At the same time, the rotation of the motor will produce a variety of noises, among which the turbulence noise is one of the main sound sources, and the frequency is very harsh. However, there are relatively few researches on turbulence noise. The existing noise reduction schemes add a casing outside the cup, which brings inconvenience to consumers. It is concluded that two kind of creative problem solving scheme by invention principle and science effect of TRIZ innovative tools and other technical means, the scheme greatly reduces the disturbing noise, especially the proposed helmholtz resonator schemes in noise reduction, it also can filter high frequency grating noise, make a further improvement of consumer experience.

The strong pressure pulsation in the vapor-injection tube of scroll compressor is easy to resonate with the injection valve, resulting in valve body damage. To solve this problem, CFD simulation is used to study the generation and propagation mechanism of pressure pulsation in the vapor-injection tube. Based on the mechanism of pressure pulsation, the technical schemes of pressure fluctuation attenuation, such as optimization of the holes'shape and number, are put forward. Through the pressure fluctuation test, it is found that the reduction in OA value (0~1000 Hz) of ARI condition for all the proposed schemes is 30% on average, which verifies the effectiveness of the mechanism analysis and proposed CFD method. The study can provide theoretical basis and specific scheme for improving the vibration and noise caused by pressure pulsation of the vapor-injection scroll compressor, and can be applied to other scroll compressors.

In order to meet user needs and minimize the waiting time for users to receive water, the current large-flux (≥800G) reverse osmosis (RO) water purifier uses a larger water flow rate. But at the same time, it will cause the water purifier to be relatively loud, which will seriously affect the user's experience. The noise of the water purifier mainly comes from the noise produced by the water pump itself, the shell resonance caused by the vibration of the water pump, and the turbulence caused by the impact of the water flow in the pipeline. By adopting a new type of noise reduction scheme for the above noise sources, combined with simulation calculation and experimental analysis, the noise of the whole machine can be greatly reduced at low cost without affecting the flow rate of the water purifier.

The mechanism of large displacement scroll compressor injection pressure fluctuation was analyzed due to a market failure of injection hole impurity invasion, which was actually as result of the valve element breakage of a VRF enhanced vapor injection valve. Various injection hole positons and structures were also studied, in order to clarify their influence on the injection pressure fluctuation. The results show that the injection pressure fluctuation is mainly determined by the pressure difference of the upstream and downstream of the injection hole and local pressure variation. By adjusting the injection hole positon to the suction side and applying multiple hole or stepped hole structures, the scroll compressor injection pressure fluctuation can be effectively improved, which helps to enhance the reliability of the VRF system.

Compressor is the main noise source of refrigeration system. At present, most of the compressors are wrapped with multi-layer sound insulation cotton to achieve the purpose of noise reduction and sound insulation. By studing the sound insulation law of different thickness of PVC and non-woven fiber. Then, different thickness of PVC and non-woven fiber are combined by bonding to study the sound insulation characteristics of the two-layer composite structure. Through the method of multi parameter nonlinear regression, the virtual digital sound insulation prediction model is established. The model can provide a fast selection method for practical application.

With the popularization of dryer products in daily life, the problem of ripping sound of dryer becomes more and more prominent. By analyzing the causes of rippling sound for the dryers and its induction motor. On the basis of mechanism research, according to the beat characteristics of the motor, the excitation source causing the beat vibration is analyzed. It is theoretically concluded that the interaction between the electromagnetic excitation generated by the fundamental magnetic field and the mechanical excitation force caused by the misalignment of the rotor is the main cause of the beat vibration. By interchanging rotor experiment and testing the rotor runout, the theoretical analysis is verified, and it is proposed that the rotor bending deformation will lead to beat vibration, which provides theoretical guidance for eliminating the rippling sound of induction motor.

The cavity resonance of the refrigerator compressor causes the coupling vibration of the shell to produce low and medium noise, which is different from the natural frequency of the shell and has important research significance. This paper first describes the vibration response mechanism of the cavity mode and the cavity-shell coupling, then the finite element method (FEM) is used to calculate the compressor cavity mode frequency, mode shape and velocity distribution. Finally, the spherical nearfield acoustic holography method is utilized to identify the vibration velocity distribution on the surface, and the reconstruction results are consistent with the calculation results of the FEM, which proves the correctness of the cavity-shell coupling resonance analysis based on the FEM and the effectiveness of the surface velocity reconstruction technique in cavity mode identification.

At present, in the noise field of the range hood, the reduction of the traditional noise level has not been able to meet the user's demand, and the total noise level of the product has been consistent with the industry level, but the quality of the sound cannot meet the user's needs. Based on the cosmoplat industrial Internet platform, this paper builds the NVH (Noise, Vibration, Harshness) development evaluation system of range hood, and apply it to production development, improve product competitiveness, and achieve product sound quality industry leading.

A certain type of air-conditioning drainage pump has a problem of beat vibration under certain working conditions. First, a two-phase flow transient simulation is used to confirm that the source of beat vibration is the pressure pulsation in the static and dynamic gap between the pump casing and the impeller. Monitoring the pressure pulsation at 14 monitoring points in the pump housing at a flow rate of 300 mL/min, 500 mL/min (pump design working point), and 700 mL/min, it is clear that there is a maximum pressure pulsation amplitude only at a flow rate of 500 mL/min. Based on this, the impeller optimization plan is proposed. The impeller wheel cover is opened near the outlet side, and the flow pattern in the pump is changed without changing the flow rate of the entire pump, and the pressure pulsation frequency of the dynamic and static gaps is changed to achieve vibration improvement. Provide a solution for the vibration problem of this kind of self-priming pump working under low flow rate.

Taking a model of permanent magnet synchronous motor and compressor as an example, the electronic force wave analysis table as the basis, combined with the electromagnetic theory to analyze electromagnetic wave and the electromagnetic force density wave simulation of electromagnetic force, put forward analysis methods and ideas to improve the electromagnetic noise of compressor. At the same time, the improvement of compressor noise is carried out by using the improved idea put forward in this paper. The result shows that the noise of compressor is obviously improved, and it is consistent with the theoretical simulation analysis. It shows that the improvement idea put forward in this paper is reliable.

The influence of rotor system resonance on motor noise cannot be ignored. Firstly, the influence of rotor system on the structure mode of motor is studied by modal simulation and test method. Considering the rotor system model can reflect the actual state of the motor better. And the low frequency modes are more abundant. Secondly, the sensitivity of rotor system resonance to the spatial order of radial electromagnetic force is analyzed by harmonic response simulation. The resonance of rotor system is very sensitive to the first order radial force. The influence of resonance of rotor system on air gap, electromagnetic force and noise is studied. When the rotor system resonates, it will cause dynamic eccentricity, and the air gap changes with time and space. Then the electromagnetic force appears near the original frequency, and the additional electromagnetic force of space order ±1 appears. Finally, the accuracy of simulation analysis is verified by test.

Research and analysis to high frequency noise suppression system based on the open-loop harmonic injection control algorithm. First introduces the basic principle of high frequency noise suppression system control algorithm, secondly analyses the harmonic injection of key parameters, to achieve reliable harmonic injection, finally through the s real-time control system harmonic analysis and experimental tests verify the effectiveness of the control algorithm. It provides theoretical basis and design guidance for the realization of the high frequency vibration and harmonic automatic compensation control system of compressor.

Most of the inside of window air conditioner use centrifugal fan blade for air supply. The current noise is generally more than 60 dB due to the existing centrifugal fan blade profile and air duct structure. In this paper, in order to study the impact of centrifugal fan blade and air duct on noise, summarize the design method, and carry out simulation analysis and experimental research on fan blade profile and air duct. By studying the influence of the blade angle of the backward inclined centrifugal fan blade on the air volume and the influence of the duct cochlear tongue on the noise of the backward inclined centrifugal fan blade, the theoretical analysis and experimental research on the blade angle and the structural design of the duct cochlear tongue are carried out. Through experimental research, the influence of blades with different inclination angles on air volume and the influence of volute tongue shape on the noise of backward inclined centrifugal blades are obtained, which reduces the total noise of the whole machine by more than 3 dB and applies it to practical production, which provides a direction for subsequent blade shape optimization and air duct optimization.

When the variable frequency compressor starts, due to the inertia of the movement, the compressor exists hysteresis and overshoot, which results in obvious noise fluctuation. In addition, the refrigeration system has a large load at the stage of start-up, the change of speed is easy to cause the abnormal noise and poor user experience. By studying the influencing factors of movement rotation inertia, on the premise of ensuring the normal start of variable frequency compressor, an optimized start-up control method of variable frequency compressor is proposed to control the instantaneous noise fluctuation within 2 dB(A). Improve the sound quality of refrigerators and freezers.

Air-cooled frost-free refrigerators have gradually become mainstream products in the market, and the noise of centrifugal fans has become the main noise source affecting the noise of the refrigerator. At present, the noise level of many centrifugal fans in use is quite different, and the operating conditions are different. Based on this problem, research on noise evaluation methods of centrifugal fans for refrigerators has been carried out. Through the fan performance air-dynamic test bench, the test of the air volume of different centrifugal fans at different speeds was completed, and a noise test bench for the centrifugal fan for refrigerators was designed to analyze the noise level of a single fan under variable speed conditions. Finally, by comparing the fan noise characteristic curve under the same air volume, the noise level of the fan is evaluated, which provides a reference for the selection of the centrifugal fan.

When the refrigerator compressor runs at high speed, the refrigerant pulsation causes low-frequency noise in the return pipe. The refrigerant pulsation, which transmit to the refrigerator through the pipe, will also cause low-frequency noise. The sound wavelength of low-frequency noise has strong penetration ability and wide influence range, which is easy to cause subjective annoyance to users. To solve this problem, firstly, the acoustic vibration coherence method was used to identify the low-frequency noise, and the main noise frequency band is 450 Hz~700 Hz. Then, the acoustic simulation and CFD simulation methods are used to design and optimize the muffler structure by controlling the regenerative noise, and the optimal muffler structure is obtained. The experimental results show that the muffler is effective, the noise fluctuation decreases by 1.6 dB and the average noise value decreases by 1.5 dB.

During the running of the motor, the vibration is caused by the unbalance of the bearing driven by the rotating blades, which is transmitted to the wall by the motor bracket, and then reverberation is produced on the wall surface of the reverberation room, and low-frequency resonance sound is produced, which causes the discomfort of consumers. The low-frequency resonance noise of outdoor motor of air-conditioner is analyzed and studied. Through noise source identification and frequency spectrum analysis, noise source is weakened, noise transmission path and noise radiation angle are optimized, such as improving the motor structure mode, speed, blade matching and other measures, effectively improve the low-frequency resonance motor noise, improve the sound quality.

In order to study the effect of outdoor unit panel thickness on NVH performance of air conditioner, a finite element analysis model was established for outdoor unit panel of a certain type of air conditioner. Firstly, the static analysis of the panel before and after thinning was carried out, and the stress nephogram and strain nephogram of the panel under the same compressive stress was obtained. Secondly, the pre-stressed modal analysis was carried out to get the effect of the thinning of the panel on the natural frequency and the vibration modes. Then the dynamic excitation was applied for harmonic response analysis, and the amplitude frequency characteristic curve of the panel under dynamic response excitation was obtained. Finally, the frequency domain response results obtained from harmonic response analysis were used as boundary conditions for acoustic boundary element analysis, and the noise distribution nephogram and frequency response curves of the front and rear panels were obtained. The results show that the radiation noise of the panel after thinning is generally common with that before thinning, but the noise at the resonance point near 380 Hz is significantly improved, which provides a basis for the feasibility of thinned outdoor unit panel.

Finned heat exchanger is widely used in air conditioning. Its fins will form an open cavity. When the fluid passes through the cavity, it is easy to produce a high-frequency whistling sound, which affects the user experience. Aiming at the problem of heat exchanger whistling sound of an embedded air conditioner with four air outlets, the air duct flow field is numerically simulated, the causes of heat exchanger whistling sound are analyzed, the spoiler is designed to optimize the heat exchanger whistling sound, and the noise experiment is carried out in the semi anechoic noise room. The effectiveness of heat exchanger whistling sound improvement is explained from the spectrum and subjective evaluation.

With the improvement of people's quality of life, air conditioners have become indispensable necessities of life. Vibration and abnormal noise are important indicators for evaluating the quality and experience of air conditioners. Based on the resonance problem of the right side plate of the outdoor unit, the basic theory of sheet metal structural resonance is introduced. Through modal simulation analysis of its natural frequency, the reason for the beat vibration is found: the right side plate multi-order frequency enters the resonance zone and the frequency is easily excited. Superimposing with the vibration source will cause abnormal sound of beat vibration. Observing the vibration shape diagram through modal analysis, it is found that the right side plate handle and valve cover installation position, side stiffener profile and rear profile are relatively weak. By increasing the number of ribs, widening and deepening the profile, etc. The scheme optimizes the weak area of the structure, and the results show that the optimized natural frequency effectively avoids the working frequency of the vibration source, solves the resonance problem, and improves the sound quality of the outdoor unit of the air conditioner.

The intelligent power module IPM is the core component of the home appliance inverter control board. The common failure mode of the IPM is that the temperature of the internal power device is too high and damaged. The built-in temperature sensor has more or less become the standard configuration of the IPM. However, the temperature output methods of different types of IPM are not the same. In order to improve the reliability of IPM temperature protection function and avoid reducing the service life of frequency conversion control board. This article analyzes, summarizes and experimentally studies the temperature output functions of the IPM series that are mainstream in the market for white appliances, and proposes targeted software and hardware design methods and key points, and passed test and mass production data prove that this method can greatly reduce the over-temperature failure rate of IPM.

With the popularity of range hoods and the promotion of modern cooking technology, more and more families begin to use range hoods. The requirements of families on the performance of range hoods are also improving. Due to the great differences in the environment in different regions, the performance of the whole product is also greatly affected. And in the process of development of the hood, there are some common quality problems, which can be avoided for the later product development through the exploration. By mainly discussing the influence of the phase margin of the loop in the frequency compensation parameters of the display board DC-DC circuit on the performance of the whole range hood in the low temperature environment, which provides a reference for the subsequent development of the range hood to be used in some areas with abnormal working conditions.

Nowadays, many well-known brand mobile phone manufacturers have claimed that their new mobile phones are no longer equipped with power adapters and need to be purchased separately. In household and similar electrical appliances, this phenomenon that safe extra-low voltage power supply units and appliances powered by safe extra-low voltage are sold by different manufacturers is also more and more in the market, people often do not know enough about the safety risks of such products and do not understand the safety standards thoroughly. Based on the standard GB 4706.1-2005 “Household and similar electrical appliances - Safety - Part 1: General requirements”, discusses the basic insulation protection requirements of safe extra-low voltage power supply components, so as to analyze and understand the relevant safety requirements of the standard.

Compressor reliability is one of the prerequisites for refrigerator manufacturers to perform quality assurance to users. To evaluate the compressor reliability, beside overload test and lock rotor test, also includes accelerating life and starting durability test. The test items mainly refer to national standards or the standards of their respective enterprises. However, these standards do not describe the relationship between warranty period and reliability items, cycle and sample size. Based on weibull distribution and arrhenius acceleration model, the failure situation of similar products was counted. Combined with the life expectancy, target failure rate and confidence interval, the sampling scheme and the test condition of accelerated life were determined, so as to provide a demonstration method for compressor life design.

Due to the existing range hood using SCR dimming, when the brightness of the LED lamp is lowered, there is occasional flicker of light phenomenon. Because the stroboscopic flash appears suddenly when the user uses the lamp, it affects the user's experience and causes the user to worry about the product. The dimming control circuit of AC floodlight is optimized by means of theoretical analysis and experimental verification, which can effectively reduce the voltage step of the floodlight at low brightness, so that the stroboscopic phenomenon cannot be perceived.

In order to solve the problem of standardization of electromagnetic force simulation, the three-dimensional distribution of air gap magnetic field is obtained by establishing the standard model of electromagnetic force simulation, and the processing flow of 3D FFT is formulated to determine the spatial order and time frequency characteristics of electromagnetic force. In order to verify the practicability of this technology, two types of mass-produced motors are selected for electromagnetic force simulation, and the electromagnetic vibration of these two motors is tested. The accuracy of this method is confirmed by comparing with the trend of electromagnetic force simulation results. Finally, the electromagnetic force optimization was carried out in the design phase. In the end, through the comparison of electromagnetic vibration of sample preparation motor, the electromagnetic vibration of motor 2f decreased by 53%, respectively, which verified the effectiveness of the method.

In the context of the era of carbon neutrality and carbon peaks, energy conservation and emission reduction have become an important direction for the planning layout and policy deployment of the “14th Five-Year Plan”. The performance of building energy efficiency is particularly important, which is both an opportunity and a challenge for the HVAC field of major energy users. Air-conditioning is a large HVAC energy consumer, of which compressor energy consumption accounts for the largest proportion, so compressor energy-saving control technology is the top priority. This paper proposes an optimal efficiency drive control method combined with electromagnetism FEA of the motor, so that the motor obtains the phase angle of the optimal control efficiency under all working conditions, thereby improving the energy efficiency of the compressor and the air conditioner, and achieving the purpose of energy saving and emission reduction.

Induction heating has superior performance such as fast heating speed, high energy utilization, safety and reliability, and has been widely used in a large number of industries. The working principle of the half-bridge resonant circuit is analyzed in detail with a single-phase half-bridge circuit as the main topology, and the circuit design considerations are given through theoretical analysis and illustrated with simulations for the domestic field. Finally, a 3 kW prototype is fabricated for experiments, and the experiments prove the correctness of the theoretical analysis.

Aiming at the phenomenon that the motor circuit breaker trips when the combined air conditioner unit is powered on and the motor starts. Firstly, determine the cause of the circuit breaker tripping. Through the analysis of the cause of the circuit breaker tripping, analyze the influence of different power fixed-frequency motor starting methods on the starting current. Starting from the analysis of the motor parameters, the circuit breaker characteristic current is analyzed. The analysis of the current curve when the high-speed motor starts at high speed, draws the root cause of the circuit breaker tripping, and gives an effective conclusion on how to select the circuit breaker reasonably to avoid the circuit breaker tripping when the motor starts. For this kind of electrical problems, it is necessary to pay attention to the abnormal component test, which requires systematic analysis. It is not possible to analyze a certain component separately, and pay attention to the interrelationship.

In areas with poor power grid quality, ultra-low voltage input occurs frequently, which makes the communication between indoor unit and outdoor unit of traditional split variable frequency air conditioner appear data loss and frame loss and other problems. As a result, variable frequency air conditioner can not operate normally due to indoor and outdoor communication, which seriously restricts the popularity of variable frequency air conditioner in these areas. Based on the classical current loop communication circuit, proposes a voltage adaptive asynchronous communication. Through voltage adaptive asynchronous communication, according to the current AC input voltage, the communication time ratio (i.e. the ratio of single frame communication duration to single frame communication cycle) is adjusted in real time to maintain sufficient communication power supply voltage to ensure normal communication. It improves the communication reliability of the split variable frequency air conditioner, so as to ensure the reliable operation of the variable frequency air conditioner when the power grid is supplied with ultra-low AC voltage.

In the process of using air conditioning, users often feel uncomfortable when the indoor temperature reaches the set temperature and the prototype still runs. What is the reason that will affect the shutdown of the air conditioner when it reaches the temperature? In order to study this problem and make users experience well, it makes an experimental analysis and research on reaching temperature shutdown. Through comparative tests, the effects of frequency reduction speed and time, frequency shielding control anti fluctuation time and heat leakage on reaching temperature shutdown are analyzed. The results show that under the condition of setting the temperature desired by the user, changing the low-frequency residence point frequency can effectively shorten the time to reach the lowest frequency, avoid the continuous heat output caused by the long reaction time of the prototype after the environment reaches the temperature, make the user feel uncomfortable and accelerate the response time of reaching the temperature and shutdown.

As the cost of ABS commonly used for injection molding of home appliances continues to rise, many home appliance enterprises begin to use PP material to replace ABS to reduce the cost. However, PP material and ABS material have differences in performance, and the impact resistance of PP is poor. The formed ABS product is directly changed into PP material, and the product is prone to damage after the drop impact. In this paper, the properties of PP material are analyzed, and the simulation and physical experiment analysis and scheme optimization are carried out to replace ABS material with PP material for molding products. The matters that should be paid attention to when replacing ABS material with PP material are illustrated.

Based on the abnormal fracture of screw compressor screw in the whole machine operation, combined with its cross section characteristics, the paper has verified the failure reason by comprehensive analysis and verification of chemical composition analysis, hardness analysis, hydrogen embrittlement resistance test, metallographic analysis and non-metallic impurity electron microscope test. The failure reason is that the screw material contains too many inclusions, and the heat treatment process is abnormal and the leading factor is abnormal, the impact toughness and fatigue resistance of the screw are further reduced, which leads to the screw fracture. The paper has certain reference and guidance significance for the fracture analysis of the screw.

With the rise of market raw materials and labor costs, the profitability of home appliance companies has been challenged, so reducing product costs, improving product competitiveness and profitability have become the top priority. The methods for enterprises and research institutions to reduce product costs are generally: Method 1, Use direct experience to optimize the design of the structure, and then optimize it after repeated experiments. Method 2, Use the simulation software topology to achieve a lightweight and optimized structure scheme, and finally verify it with experiments. At present, method 2 is generally used for products with high experimental cost and complex structure. However, the method 2 simulation technology is only limited to the topology optimization of a single-density product. Therefore, another research idea to reduce product cost is proposed here, which is mainly to analyze the strength of the cushion performance through simulation analysis, determine the high and low density distribution area, and maximize the low density area of the bottom cushion to achieve ultra-low cost And then use the drop simulation experiment to compare the difference before and after to confirm the reliability, and finally perform the drop experiment to confirm the final feasibility verification. Through the above development ideas, the weight of the dual-density packaging bottom pad is optimized by about 25.2% compared with the previous one. At the same time, the expensive EPP inserts are optimized to maximize the cost and provide research ideas for the later development of multi-density and lower-cost products.

The heat-resistant deformation of the material of the outdoor electric control box of the air conditioner is the bottleneck of the industry. It is also one of the main factors that cause the short circuit of the inverter electronic control main board. It is also the main factor of the instability of the air conditioner. The control box's own heat dissipation scheme, optimized part structure design, rationalization of injection parameters, and optimized plastic materials can effectively improve the heat resistance of the air conditioning outdoor electric control box material, improve the operating reliability of the air conditioner, reduce the product maintenance rate, and reduce the cost.

The temperature of deflection under load, glow-wire ignition temperature and comparative tracking index and so on of halogen-free flame retardant PP materials were tested, and the glow-wire experiment, injection experiment and drop experiment were carried out. Research shows that halogen-free flame retardant PP material thermal deformation temperature under load is 105℃, glow-wire ignition temperature is 850℃, comparative tracking index is 600 V, flame retardant level of 2 mm thickness is 5VA, flame retardant performance is comparable to ABS material. The electrical control box parts made of flame retardant PP material have no burning through and deformation problems in the whole machine's heating wire and injection. In the drop test of the whole machine, the electrical control box is free of fracture, deformation and damage. It can replace flame-retardant ABS for switching application on electrical control box.

Polypropylene (PP) material is widely used in industrial engineering industry due to its advantages of low density, high chemical stability and low cost. However, PP injection parts have problems of size shrinkage, warping deformation and recrystallization during production and storage. The shrinkage mechanism of polypropylene (PP) injection parts was analyzed reasonably, and the experimental scheme was designed for verification. Finally, the experimental results are analyzed and discussed in depth, and the shrinkage rules and influencing factors of polypropylene (PP) injection molded parts are summarized.

In view of the intermelting leakage of fin and copper tube of air conditioner heat exchanger in the production process, the characteristics and mechanism of copper infiltration corrosion of aluminum are analyzed in combination with the leakage fault parts, and the inter melting phenomenon of fin and copper tube of heat exchanger is eliminated through standardized process design and operation treatment. The results show that the fin melting of heat exchanger can be significantly reduced by regulating the heating angle, adjusting the heating sequence of copper tube solder joints and designing and controlling the size of B value of heat exchanger, which provides an effective control method for the protection of aluminum copper penetration of air conditioner heat exchanger products.

As one of the necessary consumer goods in people's life, clothing's main function is to protect the human body. However, in the process of wearing, various pollutants in the environment are easily adsorbed on the surface of clothing. In the long run, it not only causes certain damage to clothing, but also becomes a potential secondary source of pollution. With the outbreak of COVID-19 in 2020, people were particularly concerned about disinfection and sterilization of clothing. The virus transmitted by aerosols was easily absorbed on the surface of the clothes outside the house, and as people returned home and the jitter of their clothes spread to the interior, it was even more important for people to pay special attention to the timely washing and cleaning of clothes in daily life, and to block the possible transmission routes of pollutants. . This paper summarizes the types and hazards of common pollutants on clothing, the principle of pathogenic microorganism sterilization and its application in clothing washing and home appliances, in order to help consumers correctly choose and scientifically use clothing washing and home appliances, improve the level of personal hygiene, and play a certain role in promoting daily protection.

As people's attention to the safety of agricultural products has gradually increased, pesticide residues have always been a problem to be solved urgently. Various pesticide residues in fruits and vegetables endanger the health of consumers. The existing pesticide residue reduction technologies are mainly divided into electrolytic water technology, ultrasonic technology, and ozone degradation technology. These technologies are gradually being applied to a large number of fruit and vegetable washing machine products. Different pesticide residue reduction technologies have different mechanisms and methods for pesticides. Analyze the principles and market applications of pesticide residue reduction technologies.

The new wine needs to require aging processing to achieve the mature. The conventional aging treatment includes temperature and humidity control, shock prevention, light avoidance, etc. Its flavor and color after aging are significantly improved, but the method has high labor cost, long storage time, and the price is high after aging. Early research found that the wine under the condition of the alternating substation field treatment, the wine body color and taste will change, and different electric field intensity and processing time will lead to obvious differences. In order to determine the suitable aging conditions of wine under the electric field conditions, the composition and contents of the wine control the changes under specific temperature and humidity conditions. Final treatment conditions for electric field: 5 days at 100 V~400 V at 50 Hz.

The problem of secondary pollution caused by dirt and bacteria between the inner and outer cylinders of washing machines has always been a pain point for the industry and users. Starting from the application background of the technology of no hole inner cylinder, this paper comprehensively introduces the key technologies such as water inlet mode, drainage mode, air pressure balance, positioning detection, etc. in the pollution-free washing machine, and summarizes and analyzes them, so as to provide reference for the development of the healthy pollution-free technology of the washing machine.

Formaldehyde (HCHO), one of the main indoor pollutants, has been listed as carcinogenic and teratogenic substances by the World Health Organization, which poses a serious threat on human health. The catalytic technologies for HCHO removal at room temperature can fully degrade HCHO into CO₂ and H₂O without additional energy, which is suitable for HCHO removal in home environment. Because of its variable valence state, abundant resources, low price and excellent catalytic performance, manganese oxide is often used in the study of catalytic degradation of HCHO. In this paper, δ-MnO₂ catalyst was synthesized by REDOX precipitation method, and its catalytic activity and mechanism of HCHO degradation were discussed. Finally, it was applied in air conditioning products to achieve the purification of HCHO in room.

With the impact of COVID-19 and the unprecedented improvement of consumer's attention to healthy home furnishing environment, the design of healthy materials is becoming more and more important in the design of household appliances. Mining the latest innovative achievements in products, materials and technologies to cope with the emerging global health crisis and meet the focus of consumers has become the key research direction and work content of refrigerator material design. Glass, as the appearance and interior material widely used in refrigerators, has increasingly become the main battlefield of home appliance materials. The addition of antibacterial function on its surface can greatly improve the market competitiveness of products as health appliances. By analyzing the glass surface treatment process used in the existing refrigerator, combined with the implementation technical path of adding antibacterial function to the glass, this paper selects the implementation method suitable for increasing antibacterial function to the glass surface of the refrigerator, the antibacterial process scheme suitable for the external and internal environment requirements of the refrigerator, analyzes and expounds the popularization and application of antibacterial glass as a health material in refrigerator.

With the increasingness of air pollution and people's environmental awareness is gradually strengthened, air quality has become one of the most concerned issues in everyday life. People are getting deeper with air purification. At present, the air filter is mainly used in indoor air purifiers, construction ventilation systems, clean rooms, etc., and air filter applications are also increasingly wide. There is also more and more prominent odor problems about environmentally friendly health and comfort. This paper provides comprehensive exploration of aerobic odor evaluation methods, odor ingredients and odor generating mechanisms, odor elimination techniques, etc., providing reference for activated carbon air filter development.

Designs a negative ion generator which can release negative oxygen ions and integrate into the existing air-conditioning, which introduces the working principle and structural design scheme based on limited space of the negative ion generator, analyzes the parameters affecting the concentration of negative oxygen ions, and finally tests the negative ion generator. The test results show that the negative ion generator can simulate the waterfall effect and create negative oxygen ions space which is beneficial to human health.

With the proportion of the elderly population increasing year by year, its consumption potential share is also growing rapidly. Under the guidance of the national policy of respecting the old and loving the old, elderly-oriented has become one of the application scenarios of smart home appliances. In order to construct a scenario that meets the needs of users, on the basis of a profound study of the behavior habits and characteristics of the elderly, this paper discusses the key directions of realizing the elderly-oriented for smart home appliances through the intelligent technology, in order to meet the physiological and psychological needs of the elderly, to provide maximum convenience and respect, so that more elderly enjoy digital convenience.

Intelligence has become an inevitable trend in the development of household appliances. The intelligent technology of household air conditioner in Japan has the following characteristics: in terms of monomer intelligence, it meets the needs of users in energy saving, convenience and safety through technologies such as human body detection, object detection, weather detection and APP intelligent control, combined with scene factors; In terms of smart home system, through the linkage of household air conditioner and various equipment, users can get a more comfortable experience and living environment. Referring to the practices of Japanese enterprises, China's air conditioning enterprises can improve the intelligent level of household air conditioning from the aspects of using sensing instruments, considering scene application, IoT etc.

With the improvement of material living standard and the attention to health, consumers no longer think about satiety, but also pursue how to eat delicious, nutritious and healthy. In recent years, the gourmet baking that satisfies the taste buds of the tongue has become increasingly popular. Many people have started to use the oven. In order to achieve the intelligent perception and control of food material maturity, which can not only stop when it is mature, but also lock the color, fragrance and healthy taste, has become a technical problem in the industry. On the basis of dealing with users’ problems, we have innovatively designed the control of ingredients maturity perception. Oxygen sensing device is set in cavity. It can collect the smell across the food maturation medium, and establish the CAE analysis and control logic model. After repeated tests in groups, it shows that the load of electric oven heating can be regulated through the intellisense based on the oxygen concentration change. The food can be stopped heating when it has been mature, which makes it come true. The intelligent perception and control technology that is applied to the research on the electric oven, can effectively solve the problem of baking or burning, improve the aesthetic feeling of baking experience, and lead the trend of intelligent life.

As the intelligent networking of smart home appliances becomes the mainstream, the data of smart home appliances is connected to the Internet, and a series of network security issues have been introduced, such as data eavesdropping, malicious control operations, and privacy leakage, which threaten user safety and personal information security. First introduce the network communication framework of smart home appliances. Under this framework, communication is divided into three ends, including cloud platform server, home appliance equipment, and mobile control end (application), targeting its binding scenarios, identity authentication scenarios, and communication Analysis of existing problems such as protection, we interface security, rights management, firmware security and code security. The main problems include communication security, authorization authentication, and key distribution. In order to prevent potential safety hazards, the channel should ensure the basic requirements of confidentiality, integrity, and availability, and reasonably allocate user access control permissions, and the entire system should have a certain degree of fault tolerance.

Smart home appliance connectivity has developed over the years, but it is still isolated islands, and it is difficult to realize a truly smart life. Exploring the root cause is the lack of a unified system of voluntary access between manufacturers and products. The introduction and application of Harmony OS make the smart home appliance industry see a new breakthrough. Analyzes the interconnection bottleneck of intelligent home appliance industry and the technical architecture of Harmony OS, and compares the core parameters of traditional intelligent home appliance and intelligent home appliance equipped with Harmony OS in network access speed and control convenience through experiments, demonstrates and prospects the arrival of the era of Harmony OS to help all things to integrate.

With the development of AI technology, smart home has become a hot topic. After years of development, Wi-Fi module has gradually become the main solution of IoT smart appliances. However, after smart appliances enter user’s home, how to easily connect the Wi-Fi network has become a painful point that users do not need to pay attention to, it brings a lot of trouble to users using IoT smart appliances. With the increasing popularity of NFC mobile phones in the past two years, mainstream mobile phone brands pay more and more attention to and recognize the user experience of NFC touch. In 2020, iOS system opened the appclip Developer Platform Based on NFC, and “touch” has also become one of the important experience features of HarmonyOS applications. In the field of Wi-Fi smart appliances, by comparing the characteristics of existing Wi-Fi network-config method, the dual interface passive NFC technology is adopted to achieve lower cost, higher reliability and better experience.

In the field of home appliances, there are few special studies on the value of user experience, so it is necessary to analyze the mechanism of user experience value for companies. In this paper, the definition and characteristics of user experience and value are clarified via literature research. Then, we have got the general analytical framework of value and found the dimensions and the suitable calculation formulas from a project perspective based on Cost-Benefit Analysis and experience value chain with proper assumption. The research enriches the theoretical system of user experience value analysis in the field of home appliances and it will help the managers to pay attention to the user experience and get to invest in it. It will provide a solid foundation for the improvement of user experience quality for home appliances continuously.

Gas-cooker is the main appliance of Chinese cooking, which can meet a vange of cooking forms. Users frequently remark that the cooking pan slides during the cooking process, resulting in a dangerous experience. Users' demand for household appliances is not only for their functionality, but also for their experience during use. This article analyzes the occurrence scene of “pan-sliding”, collects numerous Chinese cooking methods, finds out the influence of different methods on “pan-sliding”, and concentrates focuses on the Chinese “stir-frying” cooking scene as the research scope. In the study, the Chinese “stir-frying” cooking were decomposed, and the observation method was adopted to collect the actions of “stir-frying” and the users feelings of “pan-sliding” under different pans and pan’s racks, and the core influencing factors of “pan-sliding” in actual cooking were excavated. Then, using the previous study’s approach, the “inclination Angle” of pot sliding is taken as the dependent variable to measure the degree of “pot sliding”, so as to facilitate the subsequent conversion into laboratory measurement method. At the same time, the paper applies user experience measurement method to quantify the experience corresponding to various physical indicators, providing data support for “pan-sliding” test standard.

In order to study the effect of the relative distance between the range hood and the cooker on the oil fume capture rate, a CFD multi-component model of a range hood is established by using the computational fluid dynamics (CFD) method, and the reliability of the CFD simulation model is verified by smoke emissions experiment. Based on the model, the oil fume capture rate of a range hood at different horizontal and vertical installation positions is calculated and analyzed. The calculation results show that the capture rate decreases obviously with the increase of the horizontal installation distance of the range hood, but the vertical installation distance has little effect on the capture rate. The results can be used to standardize and guide the after-sales installation of range hood products.

In the design of a range hood, the design of a air duct is the most important. The performance of a range hood is directly determined by whether the air duct is reasonable or not. The two different sides suction range hood models are bulit, using the fluid dynamics method to simulate the air duct, the final conclusions mainly associated to the air volume, lampblack flow field, velocity flow field and negative pressure area analysis, are got.

At present, the majority of fans on the market adopt a single-layer structure design. For single-layer fans, there are problems such as high noise and short air supply distance. A fan with double-layer blades is proposed, and the method of physical experiment is used, and performance analysis and research are carried out by comparing with the prototype blades. According to experimental study, at the same noise level, the air volume of the double-layer fan blade is slightly larger than that of the original fan blade, and the air volume of the double-layer fan blade is raised by around 7~8 m³/min compared with the prototype. The double-layer fan blade is less noisy than the prototype one, under the same air volume condition.

Consumers often complain that their washing machine does not drain, it accounts for a sizable proportion of all complaints. The problem is caused by three factors: pump damaged, pump blocked and gas trapped in the pump. The pump damaged and pump blocked mainly as a result of incorrectly plugged, the pump impeller was damaged by foreign matter and the impeller got stuck; and trapped gas mainly due to structural design or software beats’ unreasonable. This paper optimized and adjusted software, through the drainage pump terminal foolproof, door seal clearance control, increased filter screen, pressure difference, natural backwater, no vacuum, resolve the drainage issue.

In view of the non-supplying of softener quality incidents in the drop pump of the XQG-RBD1401Ea1 heat pump washing and protecting machine of our company. The injection pump does not operate because the reverse impulse voltage generated by the injection pump motor exceeds the withstand voltage of the solid state relay after it is turned off, according to the analysis. Without the circuit for absorbing the reverse voltage, which leads to the breakdown of the solid state relay. By adding a resistance-capacitance module to the pump wiring harness to absorb the peak voltage, the controlled solid state relay is added with a varistor at both ends for clamping voltage, so that the reverse voltage is reduced by rectification. After the rectification, the reverse voltage is within the withstand voltage range of the solid state relay, and the whole machine is qualified.

To save storage space and rational use of clamps machine, the front load washing machines with heavy weights and large volumes is normally stacked by 4 layers. Higher package requirements were proposed. So as the rationality of dimension chain. The deformation and wrinkles are not permitted to happen in gasket after long time placed. Main cause to the deformation of gasket including the rear cabinet deformation, the transportation bolts get loosing, compressional deformation of foam and irrational dimension chain of packaging. The interference of the foam stress point must allow for a 3 mm error. The transport bolt length must fully consider the error of the actual assembly system. Eventually, an effective method for resolving gasket deformation problem is presented.

The pretightening force of the screw in the cylinder head of the refrigerator compressor causes the deformation of the cylinder hole, which has a great inpact on the compressor’s performance and reliability. This paper mainly establishes a numerical method for analyzing the cylinder deformation caused by the screw force of the cylinder head’s. The numerical model of the compressor is established by the finite element method. The cylinder head screw is preloaded, and the deformation of the cylinder bore is analyzed, so as to judge whether the stiffness of the crankcase cylinder is reasonable, which has a some guiding significance for the design of the reciprocating compressor crankcase.

The drop simulation analysis refrigerator of the refrigerator is carried out in accordance with the test standard. The simulation results show that due to the unreasonable design of the original packaging structure, the support plate of the press is deformed beyond the yield stress and cannot pass the drop test. Combined with simulation analysis and dynamics theory, the optimal design scheme of the base is proposed. The simulation results of the optimization scheme show that the support plate has no obvious deformation and can pass the drop test, and the final optimization scheme can pass the test at one time. Not only is the packaging cost reduced through simulation analysis and optimization, but the packaging's ability to protection products is also improved.

New energy vehicle development is accelerating in the automotive industry. The impact of lightweight vehicle on automobile performance has long been a source of contention in the industry. The air conditioning of lightweight vehicles has become an inevitable development trend, conducting EPP material characteristics and air conditioning chassis structural analysis. Using adhesive to solve the components fixed connection strength on the chassis, as well as design suspension, chalm, stretching, destruction, loose, whole machine vibration and other series of experimental verification, verification results are significantly improved, guaranteed. Components are firmly attaches to the EPP chassis. Exploration of feasibility, resolution of difficulties, method summary, etc., the use of automotive, home appliances, logistics and transportation and other industrial products, application EPP material fixed connection applications.

As people become more concerned about healthy economy, electric massage appliances, as a product that integrates machinery, electronics, information technology and sensors, are becoming more common ordinary people’s household appliances. Electric massage chairs as a typical example of electric massage appliances, have been widely used in recent years. Based on the performance requirements of the electric massage chair, this article selects the DC brush motor that meets the requirements and designs the corresponding drive circuit to realize the forward and reverse rotation and speed control functions of the DC brush motor. It meets the performance requirements of the existing electric massage chair after testing, and can be transplanted to the existing electric massage chair for use.

The heat efficiency for electric rice cookers refers to the ratio of thermal energy produced and electric energy consumed. High efficiency means low energy consumption. In recent years, as the industry develops, the heating method of electric household appliances has been further upgraded. The induction heating rice cooker has the characteristics of uniform heating and good rice taste, which has become an inevitable trend of the development of the rice cooker industry. However, its lower heating efficiency will inevitably affect its development. Therefore, in the standard formulation process, the correction coefficient λ was introduced to increase the heating efficiency value of the IH rice cooker. By comparing the neural network linear regression algorithm and the nonlinear regression algorithm to determine a correct method to predict the heat efficiency for the electric rice cookers.

Taking Saudi duct type U-Match of 16 kW as an example, summarizes different ways of energy efficiency upgrade through theoretical analysis and experimental verification, contribute to higher technological levels and development efficiency. To be specific, it has been confirmed in this article that increasing the supercooled section of condensers can improve refrigerating capacity, and that decreasing busbar voltage serves to reduce power and increase energy efficiency.

Introduced the working principle of IPT technology applied to household appliances, analyzed the electromagnetic interference test technical requirements for IPT equipment with inductive power transmission technology in the standard CISPR 14-1: 2020, and conducted an in-depth interpretation of different types of EUT test methods. Combining the test examples, the main points of the 30 MHz~1 GHz radiation disturbance test are analyzed, and test suggestions are put forward at the same time.

The mandatory standards for light commercial freezer products stipulate the energy efficiency limits, energy efficiency grades, energy-saving evaluations, etc. of the products. The detection method adopts GB/T 21001 refrigeration display cabinet and SB/T 10794 commercial freezer. With the release of the “Green and Efficient Refrigeration Action Plan”, the energy efficiency of air conditioners is required to increase by 30% within three years, and the energy efficiency of commercial freezers and refrigerated display cabinets should be increased by 20%. Therefore, it is necessary to analyze the impact of energy efficiency standards on product energy efficiency and the factors affecting energy efficiency. Through the analysis of the actual product of the freezer, compare the influencing factors and how to improve the energy efficiency of the product.

Carbon black soiled strip as the core standard consumable for evaluating washing machine’s washing performance, its quality directly affects the evaluation results of the washing machine. By comparing the formula, production process and the test effect of the advanced and ancient carbon black soiled strip, the advanced carbon black soiled strip is more environmentally friendly and more stable, thus improves the requirements for washing machine’s washing performance and guides that the industry of the washing machine keeps the level of energy efficiency by improving technology.

Noise pollution has been regarded the important influencing factors that harm health and environment by interrupting people’s life, work, study, rest and sleep directly and has become a common problem around the world. However, though the negative effect of noise is well known the low frequency noise has attracted attention in the recent years since it is not easy to sense and not easy to determine. This article has concluded the negative effect on health and recommended the specific standards on low frequency noise from household electrical appliances. To conduct octave spectrum analysis on the noise, and then to apply the NR curve to measure whether the sound pressure level of each octave band is within the allowable range. It is recommended to use the C-level sound level method to test low-frequency noise.

GB/T 4343.2 latest revision national recommended standard for electromagnetic compatibility immunity of household appliances has been implemented since July 1st, 2021, and the technical changed greatly. Based on the main contents and implementation date, combined with the technical changes and differences between the old and new versions, integrate and interpret the main technical changes of the new revised version from the standard scope, appliance classification, test items, etc. Provide guidance for the laboratory to update and implement standards, enterprise product testing and certification, and timely adjust product technology.

The refrigerator is detected by the main control board software to judge the current when the water pump is supplying water, and then judge whether there is water in the water storage box. When it is determined that there is water in the water box, the heating wire of the water box works normally according to the startup rate; On the contrary, the heating wire of the water box is closed. The scheme can not only solve the problem of shortage of infrared sensors under the background of global epidemic, but also more accurately control the start and stop of heating wire of water box, so as to achieve the purpose of energy saving of refrigerator.

IEC 60335-2-34 Household and similar electrical appliances-Safety-Part 2-34: Particular requirements for motor-compressors version 6.0 has been published, the test contents and methods in the new standard have been greatly changed. Introduces the main differences between the newly released IEC 60335-2-34 Version 6.0 and Version 5.2. The new requirements of the standard test method are described in detail, which can provide reference for the testers and designers of motor compressor enterprises and testing institutions.

Describes the derivation process and application conditions of two linear measurement models of uncertainty. At the same time, by evaluating the uncertainty of the measurement results of the power consumption in the energy efficiency testing of washing machines, two linear measurement models of the uncertainty and their propagation formulas are applied to calculate with different analysis conditions. It can be found from the calculation results that the different forms of the linear model determine whether the uncertainty component is expressed by standard uncertainty or relative standard uncertainty in the propagation process. On the other hand, in the process of uncertainty propagation, the difference in calculation results may be caused by the existence mode (constant or variable input) of each input value of the mathematical model in the process of uncertainty analysis. Generally, the input with small uncertainty will not affect the result.

In the context of the country's vigorous efforts to promote the development of low-carbon economy, people are gradually paying attention to the energy-saving effects of household appliances. When people buy household appliances, they mainly pay attention to the power consumption or energy-saving effect in the work project, and often ignore the power consumption in the non-working mode. Due to the differences in the understanding of the standby mode and shutdown mode of the range hood energy efficiency standards by standard users, different judgments have appeared in the design and production, energy efficiency testing, and market supervision and spot checks of range hood products. This article sorts out the relevant standards for shutdown The standby and shutdown modes of different types of range hood products are analyzed and discussed to provide a reference for companies to confirm the standby mode of range hoods.

Nowadays, all kinds of household appliances are becoming more and more popular in people's homes, bringing a lot of convenience to people's lives and improving people's living standards. In daily life, after finishing work on household appliances that are frequently used, most people are accustomed to turning off household appliances with remote control functions, such as air conditioners and televisions. In the environment where the country advocates energy conservation, low carbon, environmental protection and energy shortage, the standby power consumption of household appliances has become an urgent problem that all countries in the world need to face and solve together. Standby power and shutdown power are two important indicators of the energy efficiency labeling system. Correctly testing the standby power and shutdown power of home appliances has an important role in the implementation of the energy efficiency labeling system and subsequent supervision. Discusses the test of standby power and shutdown power from the aspects of measuring instrument influence, product under test, and measuring instrument connection.

Massage appliances are very popular health care household appliances. Massage appliances are favored by many elderly consumers. The demand for massage appliances also shows an increasing trend. Massage appliances have become the first choice for young consumers give presents to their elders. Consumers have safety concerns, so it is very important to ensure the health and safety of the elderly. This paper mainly studies household massage appliances. This paper focuses on the standard system of massage household appliances. The formulation idea of core indicators such as safety, health and intelligence of massage household appliances is analyzed. It is pointed out that the intelligence, comfort and massage effect of massage equipment are the focus of research and development.