Theoretical Study Of A Truncated Cone Direct Expansion Solar-assisted Heat Pump Water Heater

Energy and environment have become a focus matters of the world. Solar energy is a sort of never-failing clean energy sources; how to more effectively utilize it has increasingly become a hotspot scientists tap with efforts. A heat pump has the feature that it can transfer heat from low temperature to high temperature and improve the availability of low temperature heat sources. It will have a great future that integrating solar thermal utilization into heat pump techniques. This thesis analyzes the types and art trait of solar-assisted heat pump water heater, the development trend of direct expansion solar-assisted heat pump water heater, makes a summary of these research results from six aspects. On the basis of these works and from the point of view of receiving optimum solar radiation , the thesis develops a novel design model of direct expansion solar-assisted heat pump water heater with a truncated cone collector/evaporator, theoretically analyzes the heat that the system can absorb, compares its ability with other two types of cylinder and flat plate ones, and calculates COP and EER with computer aids. The results show that a truncated cone direct expansion solar-assisted heat pump water heater can absorb not only more solar energy but heat energy in air. It takes on favorable thermal performance. Under the average day in February which is of the worst weather throughout the year in Kunming, the COP is about 4. 2, EER is about 2.9 . The heat absorbed by the system are more than those of the other systems. The system is very great in terms of saving...