Study of Effective Parameters on the Coefficient of Performance and Specific Moisture Extraction Rate in Solar Assisted Heat Pump Dryer for Three Cities of Iran

In this study, a solar assisted heat pump dryer with in direct model of evaporator- collector has been evaluated. The effective output parameters of the cycle are the coefficient of performance and the specific moisture extraction rate. In addition, the influence of different factors including condenser temperature, relative humidity of ambient air, slope angle of collector and temperature of evaporator on these parameters have been studied. For calculation of absorbed heat radiation in collector, the existing average temperature and the average daily radiation on a horizontal surface has been used. In direct expansion cycles, the absorbed heat by the collector in the evaporator case, vaporizes liquid refrigerant phase in the saturated gas phase. In this system, evaporator element is collector case, as well as the coils of evaporator. An element of collector can be used for two the first one is the absorbing heat and increasing temperature and the second the ability to be used as evaporator. In this study, a flat collector is used to absorb heat. The purpose of this study is to investigate promoting thermodynamic operation coefficient of entire cycle and humidity separation rate. The results of this study is capable of being evaluated for average radiation rate of Birjand, Tehran and Shiraz. This study also can be used for different refrigerants. The results show that the coefficient of performance of R134a refrigerant is 24% and 20%higher than R410a and R407c respectively.