最新刊期
卷 24 ， 期 3 ， 2003
- 摘要：The recent research development on the hot-gas defrost for air-source heat pumps was reviewed. An ideal defrost model was presented based on the fundamental conservation equations and experimental results. The distributed parameter method was served to study the details of the heat and mass transfer at the frost side and the pressure variation at the refrigerant side during the reverse cycle defrost. Good coincidence between simulation results and experimental data shows that the dynamic defrost model might be effective in the research of the heat pump especially in the study on dynamic characteristic of reverse cycle defrost.1625|347|0更新时间：2025-02-26
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- 摘要：To test control performance of the present electronic expansion valve and real-time controller developed with MCU, the experimental research of refrigeration systems was performed in cool startup or cooling load variation under a steady operating conditions. These systems were individually assembled with three kinds of expansion valves: thermostatic, electric driven by the stepmotor and electromagnetic. Results show that compared with conventional thermostatic expansion valves, electronic expansion valves are more suitable to integral controller and superheat controlled by continuous devices is more stable than that controlled by discrete devices; the integral element promotes control quantity greatly. The present electronic expansion valve and controller are of high-performance and low-cost. Compared with similar products of foreign companies, their control effectiveness is also obvious.1649|306|0更新时间：2025-02-26
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- 摘要：The heat pump cycle employing scroll compressor with an economizer was developed and its characteristics were thermodynamically analyzed. The results show that the cycle can remarkably improve the adaptability of heat pump to low ambient temperature environment. The economizer pressure is optimized by analyzing its influences on the performances of the heat pump.1491|327|0更新时间：2025-02-26
- 摘要：This paper reviews the recent development of the study on heat transfer and friction characteristics of fin-and-tube exchangers with different fin surfaces. The fin surface types involve in plain fin surface, corrugated fin surface, silt fin surface, and louver fin surface. By stating and analyzing the heat transfer and friction characteristics with different fin surfaces the feature and application with special fin surface are described and the methods of improvement are suggested.1649|345|0更新时间：2025-02-26
- 摘要：The present situation of Chinese refrigeration industry is described. Several existing problems in the refrigeration field are analyzed. The development orientation of Chinese refrigeration industry is indicated. Some suggestions are presented including building up the more perfect cold chain and market systems. In addition, it is pointed out that refrigeration should be developed in the form of intersection and mergence with the relative subjects for further energy conservation and environmental protection.1648|322|0更新时间：2025-02-26
- 摘要：Through an intermittent process (GSHP on or off), the ground temperature can be restored to enhance heat transfer in the soil and to decrease the number of wells (such as vertical boreholes) in the Ground Source Heat Pump (GSHP). In the test system of GSHP, both vertical boreholes (100m and 200m) for heat exchangers were established. Some behaviors and Characteristics were investigated, such as the ground temperature distribution in the initial case, the temperature variation in the working condition, and the temperature fluctuation in the intermittent process. Moreover, the investigation on the trend of restorative ground temperature in the intermittent process was emphasized. The intermittent time can change the trend of the temperature, prolong the underground heat transfer and result in the better working condition of GSHP. A method of using intermittent process was presented to make better use of ground source energy and the fact was pointed out that the intermittent controlling technology is very important in the utilization of ground source energy.1644|324|0更新时间：2025-02-26
- 摘要：An adsorption ice-making system driven by exhausted gas of 61610A diesel engine was designed for conserving fish on fishing boats. The system used solidified activated carbon-methanol pair. Simulation and experiments show that heat and mass recovery could enhance the performance of system greatly. The cooling power is 1.93kW when heat and mass recovery is adopted and cycle time is 50min.1690|309|0更新时间：2025-02-26
- 摘要：1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea) is a promising alternative refrigerant and its thermophysical properties have been widely studied by researchers in recent years. Research progress of the thermodynamic properties of HFC-227ea is reviewed in this paper. The available experimental data of PVT, vapor pressure, surface tension and other thermodynamic properties for HFC-227ea are also summarized here. In addition, the equation of state for HFC-227ea is described.1630|353|0更新时间：2025-02-26
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- 摘要：The pre-cooling of fruits and vegetables is an important step in the cold-chain, and a proper pre-cooling time period can assure the quality of fruits and vegetables. Here the lumped parameter method was set up to estimate the required time period after which the center temperature of the grape reaches the air temperature in the cooling store by analyzing the heat transfer of the grape in pre-cooling, and was confirmed by the experiment. The results show that adopting the qualitative size R, the method can estimate the pre-cooling time period of the grape properly when the air velocity in the cooling store is larger than 1.1m/s.2245|402|0更新时间：2025-02-26
- 摘要：Refrigerant leakage in rolling piston compressor is mainly processed by the mode that the refrigerant dissolves into the lubricant. This article used lubricant's flow model to simulate and calculate the amount of refrigerant leakage in the system. The result of calculation shows that the maximal part of the leakage occurs in the radial clearance and most of the rest leakage occurs in the axial end surface clearance which leads to the suction cavity. The effect of leakage on the rolling piston compressor can be validated indirectly through the performance experimentation for variable clearances. Moreover, the leakage losses of the rolling piston compressor can be reduced effectively by designing the value of the leakage clearance rationally.1798|334|0更新时间：2025-02-26
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