Fin-and-tube heat exchangers are widely used in refrigeration and air-conditioning appliances. Using smaller diameter tubes may help to improve the heat transfer performance and to decrease the size and the cost of the heat exchanger. In this paper, the state of art of fin-and-tube heat exchangers using small diameter tubes is reviewed. The reason of using small diameter tubes in fin-and-tube heat exchangers is elaborated, and the advantage of using small diameter tubes is qualitatively analyzed. The effects of small diameter tubes on the performance of air conditioner and on manufacture of fin-andtube heat exchangers are presented. The design of the new type of fins and the new type of distributor for fin-and-tube heat exchangers using small diameter tubes are illustrated. At last, the paper summarizes the development method of air-conditioning system using small diameter tubes.

The external condensation of refrigerator is always be concerned highly by consumers. This article is starting with condensation mechanism to discuss about the several schemes that can meet the external condensation requirement of 32℃ and 85% RH humidity environment. These schemes that based on multi-door frost-free refrigerator are validated though kinds of possible methods like: increasing contact area of anti-condensation pipe and the vertical beam, improving thermal isolation of the door gasket, strengthening heat conduction of the handle, or optimizing the intensity of air convection, meanwhile, combining these methods together.

The reliability of motor in high speed operation is one of the key points of motor design evaluation. In this paper, the mechanical strength of high speed motor rotor is designed and calculated, and the structural parameters are evaluated by the change of steel sleeve and carbon fiber structure parameters to meet the requirements of high speed operation. On this basis, the electromagnetic characteristics of the motor are simulated and analyzed, and the design parameters of the motor are evaluated.

In view of the research and application development of speech recognition technology in the field of artificial intelligence, dual microphone array technology is adopted to suppress environmental noise and carry out human voice through unique low power wake-up and recognition dual engine technology, speech recognition algorithm based on mixed depth learning model, fusion adaptive far field noise reduction technique and so on. Gain, acoustic source localization and wave velocity formation are used to achieve high accuracy far-field speech recognition and strong reliability operation.

This paper studies the cause of GFCI (ground fault circuit interrupter) trip caused by refrigerator with inverter: In addition to being sensitive to power frequency leakage current, GFCI is also sensitive to higher frequency leakage current, which can trigger GFCI trip. The common mode voltage with high dv/dt generated by the inverter circuit, through the distributed capacitance between the compressor drive line and power line, also through the distributed capacitance between the stator winding and the compressor shell, became high frequency leakage current, and GFCI tripping is triggered. Two countermeasures can solve the GFCI trip problem: One is to separate the compressor drive line and the power line in the refrigerator case. The other is to apply a filter to the power line in the compressor cabin.

This paper proposes a portable performance testing device for water- source heat pump. According to the uncertainty calculation is carried out by case analysis. The analysis results show that the device has high reliability.

This paper mainly introduces the working principle of evaporative air coolers, analyzes the main technical indexes of evaporative air coolers cooling performance, and focuses on the test methods specified by the standard and proposes improvement measures.

In this paper, the eliminating bacterial rate, the deodorization rate and ethylene elimination effect of three models were verified, the model 2 was considered to be best among and was improved. The results of improved model showed that the eliminating bacterial rate was 92%, the deodorization rate was 96%, and the removal rate of ethylene was 68%.

In this thesis, the structure feature and working principle of the existing integrated frequency converter fresh air conditioner are analyzed. Aiming at energy efficiency optimization, the integrated control mode and energy efficiency evaluation method of frequency converter fresh air conditioner are put forward.

Fruits and vegetables are still metabolizing after picked, mainly includes the metabolism of nutrients formation and consumption. Nutrient formation metabolism include photosynthesis and physiological after-ripening of respiratory variant fruit. Nutrient consumption is the main metabolism of fruits and vegetables after picked. This paper we will study photosynthesis effect on metabolizing of fruits and vegetables, the result is that: when the storage temperature is 8℃, the best preservation effect is achieved.

Through the research on the behavior of the user using the refrigerator, we can get the difference perceptions of vary customers. Noise design is very important during the designing process. This paper analyzes the regional differences by collecting a large number of user behaviors. Differences living conditions, refrigerator types, and refrigerator prices have different requirements for refrigerator noise. This result can guide the noise design for noise engineers.

In this paper, the fluid simulation model of muffler is established, the pressure lossof three mufflers with different structures is ana-lyzed, the distribution of flow fieldand turbulent kinetic energy is investigated, and the mechanism of muffler is finallydetermined. By installing the optimized muffler in the inlet of the small high-speed fan,the experimental verification is carried out, and finally a better noise reduction effect isachieved.

It is necessary to paste a large amount of damping materials on the inner structure of household dishwasher. The vibration response of metal plate is different under constraint condition. If the maximum response position can be found and accurate damping paste can be carried out, not only the amount of damping material can be effectively reduced, but also the effectiveness of vibration and noise reduction will be greatly improved. Through simulation analysis and experimental test analysis, the position point with the largest vibration response on the top structure of the dishwasher tank is found, and the cross damping bonding method is adopted to replace all the bonding damping schemes. In the case of equivalent reduction of vibration and noise, the amount of damping material is reduced by a large proportion, and the competitive noise reduction is realized. The innovation of this paper is that, combined with the vibration theory of plate structure, modal simulation analysis and vibration response test, the vibration response characteristics of tank structure are studied, providing a reference analysis method for the accurate noise reduction of the same type of structure.

The refrigerator self-locking structures always have lots of problems, such as small locking angle, lacking of smoothness, poor reliability etc. Some optimizations are done on the hinge self-locking curve during the process of pushing and self-locking in this article. By comparison, many key parameters of the new hinge self-locking structure are obviously improved, such as self-locking angle, minimum closing force, minimum closing torque etc. And the closed noise is obviously improved.

To aim at the hidden peril of burning a washing machine in particular service conditions, forceful electric parts should pass the stringent safety standard according to Whirlpool- Global standard. Referred to the method of anti-pollution flashover by the power companies, we applied the RTV silica gel to the surface of the forceful electric parts. The result showed that after applying the RTV silica gel, the parts in particular service conditions were prevented to burn because of the flashover. Meanwhile, we discussed the positive role of the cryogenic plasma in improving the adhesive force between the RTV silica gel and the surface of the parts.

Detailed application of industrial design in the field of air energy water heaters, including project investigation, design direction determination, product PI strategy research, aesthetic effect performance, visual dynamic analysis, product implication expression, ergonomic expression, cost and safety considerations are expounded respectively, thus giving product intrinsic logic in appearance.

The emphasis of this product technology research is that the cooking apparatus is realized by the structure of an electric pottery heating plate and a stable cycle conversion constant power circuit control. Including anti-overflow precision temperature detection design, constant power conversion design, food cooking effect and other measures.

The water flow system is one of the most important part of dishwasher, which is in closely relation with main performance such as washing performance, energy consumption, and noise. The effect of pump joint outlet size and the angle between inlet and outlet on flow distribution and spray arm pressure has been analyzed in this paper. In conclusion, if the outlet size leading to bottom spray arm decreases and the angle between inlet and outlet increases, the flow leading to bottom spray arm will be decreased and the flow leading to upper spray arm will be increased. So these methods can be used to optimize design, which can make water flow system more rational.

To analyze the current situation of the commercial washing machine and the domestic washing machine, it is suggested that in the development of the business washing machine, the enterprise should improve the quality of the product to increase the market share of the business washing machine. And put forward specific measures: Commercial washing machine design concept should be different from the domestic washing machine, and that in that early stage of design, the commercial washing machine should provide more technical support to the merchant's maintenance service, so as to help the merchant to reduce the maintenance and operate cost, so that the manufacturer and the merchant can realize the mutual benefit model. Next to take a new type commercial pulsator washing machine design as an example, Innovative proposal: to add repair door design on the front side of the box; By adding two sets of rotating shaft modules, the design of upside down opening state of disc seat module can be realized. The new design content has the following advantages: the maintenance operation process is greatly simplified, the maintenance efficiency is greatly improved, and the requirements for the maintenance personnel are reduced, which can greatly reduce the operating costs of the merchants which can increase the profits for them. And next more merchants will choose the washing machines of this brand, and finally to achieve mutual benefit.

Firstly, this paper introduces the development of smart home and potential safety hazards and security threats. Secondly, it discusses the objects, contents, objectives and related standards of safety and security assessment from three aspects: device safety, functional safety and cyber security, and puts forward the evaluation system of safety and security for smart home.