For the air-cooled refrigerator, the air duct, as a part connecting the evaporator and each chamber, conveying cold capacity, which is closely related to the refrigeration efficiency and energy consumption of the refrigerator. Through the simulation analysis of the air duct of a 380 L two-door single system air-cooled refrigerator of a certain company, the factors affecting the cooling capacity and energy consumption of the refrigerator are found. Through optimization, the original cooling air supply mode of external circulation was changed to internal circulation, so as to reduce the leakage of cooling amount of supply air and improve the cooling efficiency of supply air, thus reducing energy consumption by 1.27% and 3.38%.

The high return water temperature of CO₂ unit in this paper means that the water temperature at the inlet of the unit is higher than 35℃. If the heat generated by CO₂ unit can not be used in time, the return water temperature will rise and the energy efficiency of the unit will be decreased. Aiming at the problem of high return water temperature, puts forward an optimized frequency conversion control strategy for high return water temperature, improves the adaptability of the unit to high return water temperature, experiments are carried out to verify the control strategy. The experimental results are consistent with the control strategy, which can improve the performance and guide the application of CO₂ heat pump under high temperature return water condition.

With the emergence of application scenarios with high noise requirements such as bedroom refrigerators, semiconductor refrigerators that use mechanical fans to dissipate heat can no longer meet user needs due to rotor rotation noise and vibration noise. The ion fan uses the accelerated motion of ions generated by corona discharge to drive the air to dissipate heat. It has no moving parts and can achieve efficient and silent heat dissipation. Through design experiments on various parameters affecting the wind speed of the ion fan, when the needle electrode curvature radius is 0.05 mm, the wire diameter of the mesh electrode is 0.6 mm, the wire electrode aperture is 8 mm, and the distance between adjacent needle electrodes is 16 mm, the needle-mesh electrode When the spacing is 12 mm, the input voltage is 20 kV, and the wind speed of the ion fan can reach 2.3 m/s. It is installed on the hot end of a 90 L semiconductor refrigerator to conduct a heat dissipation experiment. The temperature inside the box is only higher than that of a semiconductor refrigerator that uses an axial fan to dissipate heat 1.22℃, the ion fan basically achieves the heat dissipation effect of an axial fan.

In order to reduce the production cost of air conditioners, an investigation on the replacement of the copper tube evaporators with aluminum counterparts was carried out based on integrated experimental comparisons of their physical properties, pressure resistance, corrosion resistance and cost. Through the experiment, first of all, the difference of heat exchange efficiency between copper tube evaporator and aluminum tube evaporator of the same specification was within 1%. Secondly, the wall thickness of the aluminum tube should be greater than 0.5 mm under the requirement of pressure resistance. Thirdly, the use of aluminum tube evaporator in strong acid and alkali environments should be avoided. Finally, taking a window air conditioner exported to North America as an example, the cost of aluminum tubes can be reduced by 30% compared to copper tubes. Meanwhile, the side plate material, flow path and pipeline of aluminum tube evaporator were analyzed. It showed that the material with the same properties as aluminum should be used instead of iron, so as to prevent the electrochemical reaction of aluminum and iron. At the same time, due to the characteristics of the melting point of the aluminum tube and the need to meet the requirements of pressure resistance, it was recommended to use two rows of aluminum tube evaporator, one in and one out for the flow path, and the pipe diameter was preferably ϕ7 and above.

The thermal comfort of floor standing air conditioners of three different outlet types was tested in the thermal comfort laboratory and the outlet types were upper air outlet, upper and lower air outlets and lengthwise air outlet respectively. The test results show that there is the best thermal comfort for the floor standing air conditioner with upper outlet; for the floor standing air conditioner with upper and lower air outlets, because its flow of air from the outlet was divided into two streams, the momentum of the single streams of air was small and it was difficult to be blown far, so the too cold or too hot air flow at near the foot of the unit was easy to be detected in the room, and the temperature at the far of the unit in the room was low and the temperature uniformity was poor during heating; for the floor standing air conditioner with lengthwise air outlet, the position of height of its outlet is in the range of that of the main activity area of human body, and the too cold or too hot air flow at near the foot of the unit was also easy to be detected in the room, and at the same time the air flow of the unit couldn’t reach the position of foot, and the temperature uniformity was poor ,and vertical temperature difference was larger during heating in the room.

Under high temperature conditions, due to the large current of the whole machine and the poor heat dissipation conditions of main board components, the temperature rise of components is relatively high. In order to ensure the reliability of the whole machine, the compressor is usually controlled to operate at a lower frequency to reduce the current of the whole machine and the temperature rise of the main board. This way leads to the decline of the performance of the air conditioner and affects the comfort of users. In order to solve this problem, the causes of component temperature rise are analyzed in detail, and a solution to reduce componenttemperature rise by strengthening heat exchange and optimizing component selection is proposed. The effectiveness of the solution is proved by theoretical analysis and experimental verification.

Refrigerator noise has always been the focus of product improvement research. Refrigerator noise mainly includes compressor noise, refrigerant noise, abnormal noise, pipeline noise, and so on. Pipeline resonance caused by exhaust pipes and suction pipes is the main cause of pipeline noise. Aiming at the problem of the resonance of the refrigerator pipeline, the experimental and simulation methods are used to analyze the fixed frequency and stiffness of the suction pipe of a certain type of refrigerator machinery in our company. Optimize the suction pipe combined with the results of the experimental stress test. The low-order fixed frequency of the suction pipe effectively avoids the natural frequency of the compressor, and reduces the rigidity of the pipeline, avoids pipeline resonance during the work of the press, and provides a solution to the problem of refrigerator pipeline resonance.

Uses CFD to establish air-conditioner airflow simulation model, and evaluate the refrigeration comfort of the up air-outlet, and the evaluation model error of the wind speed simulation results and experiments in different conditions have been found within 5%. Analysis of the upper air outlet height and its airflow blowing angle, the upper air outlet height is 180 mm, and the airflow is blown out of 11°, wind speed of the upper area of human body is the highest. After the comparison of comfort experiment, it was found that the air conditioner with the upper air-outlet draft sensation and temperature hierarchical phenomenon is not obvious, which is good for the thermal comfort. The results is helpful for the research on air conditioners.

The air duct system of refrigerator is one of the core components of refrigerator products, and its flow field distribution characteristics directly affect the refrigeration efficiency of refrigerator. Taking a two door air-cooled refrigerator as an example, the initial air duct structure is simulated, optimized and tested. The results show that the new air duct structure increases the total air output by about 17.44%, and improves the air distribution ratio of the refrigeration room, so that the refrigerated compartment has better temperature uniformity, and reduces the risk of condensation in the refrigerator compartment.

Based on the 14411 documents of the WOS core collections from 2011 to 2020 in the smart home field, the paper employs CiteSpace software to map the paper author, institution, keywords, co-citation and develop the result visualization. Result shows China and the United States play a leading role in the smart home field. Smart grid, energy management system and IoT technology is the hot spots field and also get the researcher’s attention. Meanwhile, the global researcher should make a cooperation in the intelligent scene for artificial intelligence (AI) technology has few application in the smart home field. The hot research topic and industry development trend have been given to guide the enterprises and research institutes to strategic planning, technical layout and intelligence analysis better development.

The surface of plastic contacting with drinking water is prone to breeding bacteria and other microorganisms, which will lead to excessive microorganisms in drinking water and pose a huge threat to the safety of drinking water and human health. The effects of glass loaded silver, polyhexamethylene guanidine hydrochloride (PHMG), polypropylene grafted polyhexamethylene guanidine hydrochloride (PP-g-PHMG) on physical and processing properties, safety performances of contacting with drinking water, antibacterial and long-term antibacterial properties of PP plastics were studied. The results reveal that the PP material modified with PP-g-PHMG shows excellent physical and processing properties, as well as the safety performances of contacting with drinking water. Moreover, the initial antibacterial rate is greater than 99.99%, and after 81 days of continuous boiling at 80℃, the antibacterial rate is greater than 99.9%, demonstrating the excellent antibacterial and long-term antibacterial properties. Compared with glass loaded silver and PHMG, the advantages of PP-g-PHMG are obvious in health safety and long-term antibacterial properties, which has great prospects for application in antibacterial PP plastic contacting with drinking water.

In daily wear, shoes will produce moisture, odor and other problems due to sweating from sports, which will affect wearing comfort and at the same time, will breed bacteria and have a negative impact on human foot health. Consumer demand for home appliances is becoming more and more obvious, and at present, the development of shoe care machines is still in its infancy, and a complete industry chain and mature products have not yet been formed, and its market prospect is very broad. Firstly, analyzes the current situation of the domestic shoe care machine market. Secondly, combined with the research of consumer demand, to understand the basic information of domestic residents holding shoes and the current situation of daily care, it is found that the sterilization, odor removal and drying of shoes are the problems that need to be solved urgently, more than 60% of consumers say that shoe care is necessary, and 80% of consumers have the will to buy shoe care machines. Finally, the future development direction of shoe care machines is pointed out, which provides guidance suggestions for manufacturers to grasp the industry trend and fill the market gap.

During the developing process of a new type drying tunnel of a certain VA washing machine, early corrosion of the drying tunnel was observed. In order to figer out the reason of the corrosion, the corrosion product, microstructure and corrosion mechanism of the aluminum alloy were investigated. The results show that the die casting aluminum alloy was composed of the pre-eutectic α-Al and eutectic (Al+Si); corrosion of the die casting aluminum alloy drying tunnel mainly follows the electrochemical corrosion mechanism, produces Al(OH)₃ and a small amount of AlOOH. The corroded aluminum alloy consists of the remained Si and Fe-rich particles on the surface, which is black and loose. In terms of the reduction of the Fe and Si contents and the optimization of the die-casting technique parameters, the microstructure and the corrosion resistant property of the aluminum alloy drying tunnel could be improved.

The deformation of the refrigerator door will not only increase the production failure rate, but also increase the production cost and reduce the production efficiency. For this reason, the method of adding strengthening iron in the door is usually used to reduce the deformation. Taking the foamed refrigerator door as the research object, and uses CAE simulation to study the influence of the position and shape of the reinforced iron on the deformation of the door. The effectiveness is evaluated by the amount of deformation. The research results show that adding U-shaped reinforcing iron to both the door liner and the panel can reduce the overall deformation from 11.4 mm to 6.04 mm, and the frame deformation from 7.74 mm to 4.49 mm; while increasing the groove has the worst effect on reducing the deformation of the door. Therefore, in the initial stage of the refrigerator door design, strengthening iron should be installed in the door liner and the panel to reduce the deformation of the door.

To analysis the performance of the valve system of reciprocating compressor, a 3D fluid structure interaction model of the valve system was built using finite elements software. The lift, speed and stress distribution of the suction and discharge valve were obtained, as well as the mass flux rate and P-V diagram. Therefore, the cooling capacity, indicated power, suction loss and discharge loss were calculated and analyzed, which laid a good foundation for the optimization of valve system in the next step. This simulation model was applied to the optimization of a valve system of a mass-produced variable speed compressor. The experimental comparison between base valve system and optimized new one has showed that the new valve system significantly improved the coefficient of performance (COP) of the compressor, which effectively verify the reliability of the simulation model.

With the rapid increase of the large volume and multifunction refrigerator proportion, the improved design of the components unsteady noise has become a critical technological breakthrough. By analyzing the working principle and installation method of the electric valve, the unsteady noise in the electric valve was investigated. From the perspective of controlling the vibration and noise path, the improved methods were proposed, such as structure optimization, vibration isolation, material replacement and sound-absorbing design. In addition, the sound quality evaluation method was used to evaluate the user subjective feeling of the improved methods in noise improvement. Through evaluations, the optimal design which meets the user's demand was obtained, meanwhile the refrigerator sound quality level is improved.

The radial, axial and tangential fundamental frequency vibration distributions of compressor are obtained by operational deflection shape (ODS) method on the surface of the compressor shell. The fundamental frequency vibration of the compressor is simulated by using ANSYS harmonic response analysis by constructing the compressor model with internal structure. The calculated results are in agreement with the test results, and the accurate calculation of the fundamental frequency vibration of the compressor is realized. The average deviation is less than 12%. By using this simulation method, the variation trend of the compressor with different schemes is predicted accurately, and the tangential, radial and axial fundamental frequency vibration of the compressor are reduced by 23%, 6% and 8% respectively.

Using fluent software numerical simulation analysis and comparison of the same kind of multi-blade centrifugal fan blades and volute radial clearance on the air volume of the air duct machine, at the same time, through experiments to test the air volume and noise. It is analyzed that after increasing the radial clearance between the blades and the volute, the impact of the blade outflow and the volute is accelerated, the air volume of the duct machine will increase by 2.3% to 4.7%, and the noise of the duct machine will increase by 0.2 dB(A) to 1.5 dB(A). When designing the air duct machine, it is possible to appropriately adopt the way that the fan blades and the volute are not concentric to increase the air volume, which provides theoretical and experimental basis for the subsequent design and development of the air conditioner.

To clarify the two-phase flow characteristics in the horizontal compressor and control the oil discharge rate (ODR) at high frequency, the oil pool motion and its flow mechanism were studied. It is found the ODR of horizontal compressor is commonly higher than that of the vertical with same capacity, particularly under high rotating speed, and it is analyzed that the oil pool level is an important factor for ODR. Through CFD multiphase flow simulation and prototype test, the oil pool migration was studAied, and the key flow field information was extracted to clarify the level distribution and formation mechanism, which was also verified by experiment of a prototype compressor equipped with view-window. The oil level of motor and pump cavity is not consistent, showing the feature that oil level in pump cavity is higher than that in motor cavity. The reason is that the refrigerant is forced to flow through the long path under the effect of the guide shell. The pressure drop is large since the considerable throttling, which leads to the pressure in motor cavity significantly exceeds that of the pump cavity. Lubricants migrate to the pump cavity under the periodic pressure pulsation. The simulation results show the exhaust pressure drop is mainly proportional to the flowrate, followed by the rotational speed. Under the high flowrate or high rotating speed, the oil level of the pump cavity will be too high, resulting in severe turbulence of the oil surface, which may conduct a negative effect on ODR.

In the detection of refrigerant leakage of household air conditioner, the selection of characteristic parameters has an important influence on its judgment accuracy, so the selection of characteristic parameters and the influence of leakage amount on characteristic parameters are studied. Principal component analysis was used to select 21 characteristic parameters such as suction temperature and exhaust temperature, and six different characteristic parameters were obtained, namely, suction temperature, exhaust temperature, evaporation temperature, suction pressure, exhaust pressure and operating current, so as to determine whether the refrigerant leaks. In addition, through the experiment and simulation is obtained under different leakage six characteristic parameters change trend, on the basis of experiment for six characteristic parameters, the importance of from high to low is: the evaporation temperature, suction temperature, suction pressure, exhaust pressure, current operation, exhaust temperature, for the writing of the refrigerant leakage detection software provides the basis.

The damper, which is a strong nonlinear hysteretic system, is hard to be considered as a easy mathematical model. In order to solve this problem, the Bouc-wen model is applied to build a model to describe the characteristic of damper. The Bouc-wen model has been widely adopted to describe the responses of hysteretic materials and structures to applied force. Firstly, to determine the nonlineaer characteristic of damper, the curves of hysteretic characteristic are obtained through the physical tests with different frequencies and amplitudes. Using the data, the parameters of Bouc-wen model could be identified. To obtain the parameters, two different algorithms, genetic algorithm and neural network, are used to identified the parameters respectively. Comparing genetic algorithm and neural network, the simulation results show that neural network is able to achieve a smaller approximation error, and more efficint than genetic algorithm.

With the gradual improvement of our people's living standards, more and more families have begun to buy luxury clothing. Luxury clothing usually has a complex structure, various styles and colors, many decorative objects, and contains a variety of fiber components. It needs to be washed and treated under specific conditions, otherwise it will easily cause damage to the appearance and function of the clothing. The care label is an important reference for home appliance companies, detergent companies and consumers to understand the washing and care conditions of luxury clothing. In order to explore the care technology of luxury clothing, this article surveys a total of 331 international luxury brands with a high proportion of first and second tiers. Clothing care label, statistics and analysis of fiber composition, washing, drying, bleaching, ironing and other care label information. It is found that: (1) Cotton, wool, nylon, polyester, and mulberry silk are the five most commonly used fibers for luxury clothing. 66% of the clothing uses blended fabrics of two or more fibers, and non-filled outerwear accounts for the highest proportion in the market; (2) 51% of luxury clothing can only be dry-cleaned, 25% can only be washed with water, 98% can not be bleached; (3) 92% of luxury clothing can not be tumble dried, only 4% can be tumble dried, 12% of luxury goods Clothes are naturally dried by hanging in the shade, hanging to dry, spreading to dry in the shade, and spreading to dry; (4) 72% of luxury clothing is ironed at low temperature, 9% is ironed at medium temperature, 18% do not iron. The research results will help provide a theoretical basis for home appliance companies and detergent companies to develop high-end line care products, as well as provide consumers with cleaning and care guidance and suggestions.

In the design and testing stage of household electrical appliances, it is necessary to monitor the load action of the whole machine and analyze the abnormal data. In order to solve the above problems, a general analysis method is introduced. By formulating an analysis rule, the communication protocol is transformed into an array that can be directly called by the software program, and then the collected communication data is calculated to obtain real-time and intuitive whole machine monitoring data, so as to improve the efficiency of design and testing.