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Refrigerant distribution characteristics of direct-expansion solar-assisted heat pump water heater


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Refrigerant distribution characteristics of direct-expansion solar-assisted heat pump water heater
Zhang Dong1Nan Junhu1Wang Linjun2
1.School of Energy and Power Engineering; 2.School of Mechanical and Electronic Engineering,Lanzhou University of Technology,Lanzhou 730050,China
solar-assisted heat pump direct-expansion refrigerant distribution refrigerant charge
To optimize the system performance and reduce the refrigerant charge,the refrigerant conditions of the direct-expansion solar-assisted heat pump water heater(DX-SAHPWH)system are analyzed.Simulation program of the system is coded based on the main components and refrigerant charge mathematical models.Comparisons between the simulation results and experimental measurements show that the model is suitable for predicting the system.Based on calculated results,effects of the water temperature,the refrigerant charge,the compressor motor speed,the solar radiation and the environmental temperature on the refrigerant distribution and migration are obtained.The results show that the 70%~80% refrigerant charge of DX-SAHPWH mostly exists in the condenser and the collector.When system parameters change,the refrigerant redistributes mainly between the condenser and the collector.And the refrigerant mass charge in the compressor and pipes varies slightly.Smaller sizes of condensers and collectors can effectively reduce the refrigerant charge and optimize system performance.


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Last Update: 2013-10-31