| The application of natural refrigerant CO2 is significant to reduce CO2 greenhouse effect and ozone depletion. In this paper, the comprehensive evaluation of CO2 refrigerant is conducted in terms of environment protection, safety, thermophysical characters and so on. The basic trans-critical CO2 heat pump theory cycle is analyzed by using the first law of thermodynamics. For improving lower trans-critical CO2 heat pump system coefficient of performance, two-stage compression and expanders are discussed, the impact of middle pressure, superheat degree, and high and low pressure expanders on system performance is analyzed, and a kind of trans-critical CO2 heat pump system with expanders, compressors, and solar energy collector is proposed. An experimental apparatus is build and the experiments are conducted in order to testify the high-pressure-side regulation character of CO2 trans-critical cycle, to study the influence of"external heat source"on COPh.
|
PDF Full Text Request