With the energy efficiency upgrade of AHRI 210/240 in the United States, the calculation method of heating seasonal performance factor (HSPF2) of variable frequency air conditioners focuses more on the medium and low temperature conditions. Through the analysis on the calculation method of HSPF2 and experimental data, it is found that under the same configuration, the HSPF2 is significantly lower compared with the original heating seasonal performance factor (HSPF). The HSPF2_IV corresponding to the climate zone IV decreases by 8.0% on average, and the HSPF2_V corresponding to the zone V decreases by 17.2% on average. The COP under medium and low temperature conditions (H2_V, H3₂, H4₂) has a large proportion of influence on HSPF2. In product design, increasing compressor capacity, using efficient compressor and motor, optimizing heat exchanger structure and other solutions can be considered to improve the seasonal performance factor.

Under the background that the standard detergent material for washing machine testing (SPB4) has been discontinued, in order to solve the bottleneck, with SPB4 as a reference, the detergency and the washing performance of the reference washing machine of three kinds of domestic sodium perborate tetrahydrate were compared. The results were as follows: sample 1 and SPB4 showed the two have the best consistency in reference machine and can be used as substitutes.

Explored the changes in volatile basic nitrogen (TVB-N) of beef under different initial values, storage conditions, and thawing times, with the aim of improving the relevant standards for refrigerator preservation function-QB/T 5510—2021“ Test method for freshness preservation performance of household refrigerators” . Fresh beef tenderloin was selected, and the TVB-N content in beef was measured using an automatic Kjeldahl nitrogen analyzer during freezing (-18 ℃) and refrigeration (-4 ℃) at 0, 1, 2, 5, 6, and 7 days, with or without plastic wrap wrapping, and at different thawing times. The results showed that when the initial values of TVB-N were different, the change rate of low initial values and high initial values of the same refrigerator under the same preservation time conditions differed by 7 times; Temperature is an important factor affecting the changes in TVB-N content under the same storage conditions, and different storage states at the same temperature can also affect TVB-N content; Freezing for 6 hours can also cause a significant increase in TVB-N change rate.

During the ball pressure test for electrical and electronic products, the traditional indentation measurement method is not easy to accurately distinguish the boundary between indentation and material thermal deformation, which is prone to cause large deviations in measurement results. Additionally, the measurement of ball pressure test is limited by short measurement time, and manual measurement requires high standards. Introduces a new method for automatically measuring indentation diameter. By scanning the plane around the indentation with a laser sensor to obtain sampling points. The difference between the height of the indentation boundary points and the height of the indentation bottom is obtained after processing the sampling points. Finally, the diameter of the indentation is calculated based on the height difference. The experimental results of this method have been verified to be relatively accurate through comparison, which reduces human subjective errors and improves measurement efficiency.

The current technical standards related to the safe service life of household appliances do not include the method of determining the safe useful life, which makes it difficult to implement the relevant standards. The safe useful life is the time when the safety is about to deteriorate significantly, and it is also the time node for the implementation of preventive maintenance. By analyzing the rule that the safety of household appliances decreases with the useful time, it is pointed out that the product safety problem affected by the use time is actually the reliability problem of safety-related parts. It is proposed to use the test method to use the fault density change data of critical parts to determine the safety function failure time, and then the preventive maintenance time is specified as half of the time when the safety function failure time begins.The method of determining the preventive maintenance time of household appliances is helpful to the effective implementation of the standards related to the safe useful life of household appliances.

Formaldehyde, as a typical indoor pollutant, has carcinogenic properties. Purifying formaldehyde is important for human health. At room temperature, using catalysts to degrade formaldehyde into CO₂ and H₂O has become the preferred solution for indoor formaldehyde purification. The δ-MnO₂ is prepared by oxidation-reduction method. The appearance and structure of δ-MnO₂ are analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). Finally, the δ-MnO₂ is loaded to the aluminum honeycomb panel to form the catalyst module. And the formaldehyde removal performance is compared with the activated carbon module in the 30m³ test chamber. The results show that the δ-MnO₂ has many defect sites, which are conducive to the storage and transfer of reactive oxygen species. The δ-MnO₂ has 2D layer structure, which is conducive to the adsorption of formaldehyde on the surface and diffusion to active sites. The catalyst module load δ-MnO₂ 0.065 g/cm³, the CADR value is 171m³/h. The formaldehyde removal performance of the catalyst module is much higher than the active carbon module with the same loading capacity. After multiple repeated experiments, the δ-MnO₂ catalyst module maintains formaldehyde purification performance. And the cumulative purification amount (CCM) of formaldehyde exceeds 42000 mg, demonstrating a long-term formaldehyde purification life.

The thickening effect of polyurethane thickener was not good in the water-based coating system with higher content of film forming additives, but the thickening effect of alkali swelling thickener was good in this system. At present, the research of alkali swelling thickeners mainly focused on the synthesis and properties of macromolecules study, but there were few public reports on their application in water-based coatings. The application of alkali swelling thickener in single-component waterborne plastic coatings was studied, and the effects of the amount of thickener on the viscosity, storage settlement, construction property, gloss and water resistance of the coating were discussed. The results show that the viscosity of waterborne coatings was increased from 38.3 KU to 134 KU, and the settlement degree was increased from 2 to 10 with the increase of the dosage of thickener. When the dosage is 0.8%~1.1%, the construction performance is better; Glossiness showed a trend of first increase and then decrease with the increase of the thickener. When the amount of the thickener was 0.8%, glossiness was up to 78.2 GU. Coatings boiling resistance with the increase of the thickener and then reduced, when the amount of more than 1.1%, bubbler was coming out after coatings boiled and coatings adhesion was abnormal.

With the increasing application of aluminum tubes in air conditioning systems, some companies are exploring the scheme that using the aluminum-tube and microchannel heat exchangers as replacements for conventional copper-tube heat exchangers. Aims to optimize the groove parameters of Φ5 aluminum inner-grooved tubes and provides an analytical model for refrigerant phase-change heat transfer inside the tube. The heat transfer capacity per unit material consumption is analyzed by comparing the parameter (KA/m)_e/(KA/m)₀ at equal pump power. The influence of 5 groove parameters on heat transfer performance is investigated. An aluminum-tube heat exchanger with the optimal parameters is prepared, and the results are compared with a copper-tube sample by conducting heat exchanger performance experiments. The results show that groove number and height significantly impact heat transfer performance. The optimal parameters of an aluminum tube are 0.156 mm groove base width, 0.20 mm groove height, 45 groove number, 30° groove tip angle, and 20° helical angle. After optimization, the cooling and heating capacity of the aluminum-tube heat exchanger can reach 102.1% and 99.7% compared to the copper tube sample, respectively.

Through the critical point corrosion temperature test, ferric chloride point corrosion test, metallographic test, tensile test, compared 2205 duplex stainless steel and the existing heat pump water heater water tank main application of stainless steel mechanical properties, corrosion resistance differences, 2205 duplex stainless steel has obvious advantages, can greatly improve the service life of heat pump water heater water tank, has a good application prospect. Through the experiments of molding processing performance and welding performance, it is found that the key problems need to be solved in the application of heat pump water heater water tank, and the solution is proposed through the process verification.

With the improvement of living standard, the sales volume of range hood increases year by year, and the smoke collection effect of range hood is a direct factor affecting the health of users, so it attracts the attention of users. The particle image velocimetry (PIV) method was used to measure the flow field of three sections near the side baffle of a top suction range hood, and the variation of the baffle flow field was studied when the range hood was installed with or without the side baffle. The results show that a stable large-scale vortex structure is formed inside the range hood under the action of the side baffle, which is helpful for the range hood to capture the airflow, and the wind speed at the exhaust port is obviously higher than that without the baffle.In addition, when the range hood is installed close to the wall, the wind speed at the suction opening of the range hood is reduced, the "smoke collection" effect of the baffle is weakened, and there is a risk of oil smoke leakage.

Precise control of the spatial temperature field is crucial for adjusting the thermal comfort of air conditioner. To investigate the temperature distribution patterns of indoor air conditioner cooling, on-site experiments were conducted in an environmental simulation chamber. By integrating the simulation results of the air flow field distribution, the spatiotemporal evolution characteristics of the cooling temperature field for a cylindrical air conditioner in a room were obtained. The results indicate that the downward movement of high-velocity cold air is the primary cause of the temperature stratification within the room. Even when the temperature distribution at the air vent of the air conditioner is lower at the bottom and higher at the top, the indoor temperature still increases with the increase in height from the ground. The minimum temperature difference between the upper and lower parts on the same vertical plane can still reach 5.60 ℃. As the cooling duration increases, the indoor temperature gradually decreases, and the cooling rate gradually weakens with the increase in horizontal height. After 60 minutes of cooling, the temperature difference on the upper equidistant horizontal plane can reach 3.04 ℃, while it is only 0.42 ℃ for the lower level. Moreover, the temperature distribution and its variation on the room walls resemble that of the air domain, with the highest temperature and the slowest cooling rate occurring at the ceiling. These findings can provide theoretical support for the optimization design of air conditioner airflow organization and guide related enterprises in developing new energy-efficient and high-thermal-comfort air conditioners.

With the formation of global green trade barriers, China, as the world's largest producer of electronic products, has missing or incomplete data on electronic product lists, which brings challenges to analysis and evaluation. In order to solve this problem, proposes an intelligent completion method for electronic product inventory data based on support vector machine. Based on Word2Vec and support vector machine, the method uses the vectorized result of the inventory data of electronic products as the input of the support vector machine, and uses this method to predict and complete the missing or incomplete inventory data. Experimental results show that the proposed method has achieved remarkable results in improving the integrity of inventory data, and provides a more reliable data basis for the life cycle assessment of electronic products.

Preventing condensation on the exterior of a refrigerator is one of the key research issues in refrigerator design. Influenced by multiple factors such as the temperature difference between the inside and outside of the refrigerator and the external air environment, local condensation and even freezing often occur on the exterior surface, directly affecting user experience. For embedded refrigerators, the usage environment is even more complex. Therefore, it is particularly important to establish a simulation model that accurately simulates the velocity and temperature fields of the air outside the box. Through this model, the temperature distribution on the outer surface of the refrigerator can be intuitively understood, ensuring that the temperature distribution trend of the simulation results closely matches the experimental data (with a maximum error within 1.6 ℃). This provides more scientific and optimized suggestions for the form, structural design, and external airflow distribution of embedded refrigerators.

Drum washing machine through many washing modes to improve the washing degree of clothes, in addition to the washing mode, drum washing machine inner cylinder structure and water blade structure also affect the washing degree of clothes, inner cylinder components and affect the energy consumption of the whole machine. In order to improve the washing ratio of the washing machine and reduce the energy consumption of the whole machine, this study based on the principle of the fastest falling line, through theoretical analysis, innovative design and application of a new inner barrel component on the whole machine, set up a washing machine energy consumption test platform, and verified that the washing machine can realize the spray function during the washing process, and the inner barrel pressure structure is conducive to rapid drainage and drying. The cleaning ratio of the whole machine is increased to 1.10 level, far exceeding the 1.03 level energy efficiency standard stipulated by the state. The power consumption is 0.72 kW·h per cycle, which is 5.1% lower than that of similar products, and the water consumption is 56 L/(cycle·kg), which is 12.2% lower than that of similar products, which reduces the energy consumption of the whole machine and significantly improves the user experience.

The aging process of food will experience a lot of heat absorption, and heat will damage the texture of food, nutrition and other aspects. The changes in processing and nutritional characteristics of food in the aging process were investigated under different temperature conditions, and a variety of food were selected to test the suitability of low-temperature slow-cooking process. By measuring the texture, basic nutrients, color difference, artificial sensory evaluation and total number of colonies of typical recipes such as shrimp, broccoli and steak under different cooking conditions, the advanced nature and advantages of low temperature and slow cooking technology are demonstrated. The experimental results show that the nutrition retention and taste of shrimp, broccoli and steak under vacuum low temperature slow cooking conditions are better than that under ordinary cooking conditions. Based on this, a gas-electric combination stove with fixed temperature and timing function was developed. The universality of multiple ingredients was verified by further experiments. Under the same low temperature and slow cooking conditions, shrimp, broccoli and other types of ingredients were also suitable for this stove.

R454B, a new refrigerant with low global warming potential, is a green refrigerant, but because of its flammability, it also has certain safety risks. It is of great significance to improve the safety of combustible refrigerant by simulating leakage. Based on the criteria and requirements of refrigerant leakage simulation experiment and refrigerant sensor positioning experiment of AHU stipulated in UL 60335-2-40 4^th. According to the structural characteristics of AHU, which are mainstream products in the North American market, for the horizontal installation, the simulation esperment of refrigerant gas leakage at dangerous points during use is carried out. Select the best refrigerant sensor installation position. The experimental results show that for R454B refrigerant, the refrigerant sensor should be installed lower; For the horizontal installation of AHU in this paper, the installation position of the leakage sensor is optimized; In the process of testing, as many leak points should be arranged to exclude abnormal mutation points to ensure the safety of the product.

According to the problem that the reverse rotation of the compressor caused by mis-operation in the reliability experiment of the variable frequency compressor leads to the wear and jamming of the parts, the research on the positive and reverse low speed pump oil of the variable frequency compressor is put forward. The two-phase flow simulation model of crankshaft oil pump based on VOF method is established by commercial fluid simulation software to study the influence of crankshaft oil path design on its oil pump capacity. Three kinds of oil path design are proposed: single-pass pipe oil path, double-helix cross oil path and double-helix non-cross oil path, and simulation and experimental test analysis are carried out. The positive rotation oil mass flow rate of the double helix non-cross oil path design running at 20 Hz is 8 g/Ts, and the reverse rotation oil mass flow rate is 6 g/Ts, which all meet the relevant oil mass flow rate standards, indicating that the double helix non-cross crankshaft structure can meet the reliability requirements of parts, and the compressor can operate at low speed and can be expanded to 20 Hz. Comparing the experimental and simulation results, the trend of simulated oil output is basically the same as that of the experiment, indicating that the crankshaft pump oil simulation model has high accuracy and could guide the crankshaft oil path design, which is of great significance for improving compressor operation and component reliability.

In single-phase AC-powered household appliance systems, EMI filters composed of X capacitors and common-mode inductors are typically used to suppress electromagnetic interference, and Boost-type Power Factor Correction (PFC) circuits are employed to improve power factor and reduce current harmonics. However, under certain conditions, the common-mode inductor may experience excessive temperature rise or even overheat and burn out due to current resonance. A high-frequency ripple current equivalent circuit model is established for the EMI filter and Boost-type PFC circuit, revealing the mechanism by which the differential mode component of the common-mode inductor induces current resonance under the excitation of PFC switching ripple current. It analyzes the critical impact of the common-mode inductor's leakage inductance and the X capacitor on current resonance and proposes strategies to reduce the resonance frequency and peak resonance current. Using an inverter air conditioning system as a case study, PSIM simulations and experiments were conducted, which validate the accuracy of the model analysis. A PFC carrier frequency design and common-mode inductor optimization scheme is proposed, thoroughly resolving the reliability issue of common-mode inductor resonance.

In order to solve the local wear problem of crankshaft in higher motor thickness and smaller crankshaft diameter rolling rotor compressors, through coupled simulations of friction dynamics and fluid dynamics, the impact on the lubrication oil film thickness of the shaft system was analyzed. Besides, the optimal mounting position of PTFE bushing on main bearings was determined. The improvement of PTFE bushings on the load pressure and oil film lubrication of main bearings was analyzed. The performance, noise and durability tests were carried out to verify the effectiveness and feasibility of PTFE bushings for the improvement of crankshaft lubrication of high motor thickness and small-diameter compressors, provided design solutions and experimental basis for addressing the problem of crankshaft wear in rolling rotor compressors.

The variable frequency refrigerator compressor has a periodic pulse load characteristic. Under heavy load conditions such as high system pressure or large pressure difference, the traditional sensorless three-stage starting method has problems such as insufficient starting ability, large starting jitter, and poor starting stability. In response to the above issues, this article conducts theoretical research on three key processes: A rotation delay positioning method was proposed in the rotor pre-positioning stage, effectively avoiding blind spots in positioning and ensuring smooth and accurate positioning. In the I-F open-loop drag section, the effects of key parameters such as open-loop drag current, reference acceleration, target speed, low voltage, and overload inductance saturation on startup were compared and analyzed. Finally, smooth state switching is achieved through the linear fitting algorithm of rotor angle. On the basis of theoretical analysis, a variable frequency compressor was installed for experimental verification, and the results showed that compared to the traditional three-stage starting method, the optimized algorithm has strong starting ability, rapid and stable starting process, and high reliability, which proves the effectiveness and advantages of the optimization algorithm.