Simulations And Experiments On A Solar-Assisted Heat Pump Water Heater-Comparisons Between R290 And R22

As a larger share of the world population is gaining a higher living standard and a higher energy consumption,it is increasingly important to find new,better,and more efficienct ways to meet our energy demands.A solar-assisted heat pump water heater is one way to efficiently use solar energy to produce hot water for dometic demands.There are currently few commercial applications of this technology and it has remained an idea since it was first porposed in 1955.Solar assisted heat pump can achive elevated evaporator temperature compared to a air-source heat pump and be more efficient when solar radiation is present.It also has the advatage of using a refrigerant as fluid and not water and problemes related to frost is eliminated.This thesis presents a the results from an experiment conducted on a Solar-Assisted Heat Pump Water Heater using R22 as working fluid.Further,a simulation model was built that could load the weather data from experiment and perform a simulation using a refrigerant of choice.The refrigerant data was loaded from the NIST Refprop database into a SIMULINK/Matlab model.In this thesis,the simulation compared R22 and R290 as refrigerant.The overall COP for the experiment was 3.39 under overcast conditions and 3.29 under sunny conditions.The simulation predicted a COP of 4.69 and 4.47 for R290 and R22,respectively,under sunny conditions.The simulation model was not validated and it is believed that the refrigerant charge of R22 was too low during experiments.It is proposed to better and more targeted research of SAHPs by having a test rig where different key components can easily be changed and it is easy to evaluate performance.Further it is suggested to research SAHP specify operation conditions for SAHPs and how to make it possible for SAHPs to outperform other heating technologies.SAHPs should also be developed with natural refrigerants in mind.