Study On Multi-circuit Cycle Refrigerator-freezer

The characteristics on the security, the anti-staleness, the power consumption, the noise and the price of the refrigerator-freezer (RF) are the main items to be considered by the buyers. The RF which is very secure, and whose characteristics of the anti-staleness is excellent, and whose power consumption, noise and price are very low, is very salable. Since China joined in WTO, the export capacity of RF has been increased greatly. Because European and American are very strict on the security and power consumption, it is very important to increase the security and reduce the power consumption of the RF to promote its competitive power in the European and American markets. One hundred and thirty million RFs are used in China now, and their power consumption is about half of the resident power consumption. In the coming 15 years, the power consumption of RFs in China will be forty billions kilowatt-hour every year. If all the RFs are energy-saving models, the energy-savings will be the half of the generating capacity of Gezhou Dam Generating plant. According to the above reasons, it is necessary and is the trend to develop the energy-saving and high-security RFs. As the habits and customs change, the new requirements are put forward on RFs, such as multi-temperature zones and accurate temperature control.For the manufacturers of the RF, it not only can design the saving-energy RFs, but can quickly finish the designing of the saving-energy RFs. The traditional designing method is based on the experience and the experiments. Although the experiments can reflects the actual system, and is necessary to disclosure the characteristics of the system, the repeated-made model machines and their tests not only consume much cost but prolong the development cycle, and experimental method is different to reach the optimal results.This dissertation improves the simulating models of the RF, and takes the study and application on the multi-circuit cycle RF by experimental and simulating methods. The works and achievements are as follows.1. The natural-convection and radiation model of the RF evaporator is developed. The two-closed convex surface model is adopted for the calculation of the radiation heat transfer of the evaporator. This model simplifies the calculation of the radiation heat transfer greatly, and can be used into the simulating program in practice.