Design Of 1100m~2 Solar Energy Phase-Change Regenerative Air Source Heat Pump Combined Heating System And Performance Measurement Under R417A

The traditional heating method is heating small coal-fired boilers.This way of heating consumes energy and produces pollutants.With the increasing demand for environmental protection in China,these traditional heating methods are gradually eliminated.Solar energy and air energy are two kinds of clean energy.Although solar energy is inexhaustible,it is instability according to the influence of season and weather.Air source heat pump can effectively use the heat in the environment,but there is also the problem of insufficient heat production at low temperature.The solar-assisted phase change heat storge evaporative air source heat pump heating control system can combine the two clean energy sources very well,achieving the complementary advantages of solar energy and air energy,and phase transformation technology is used to solve the contradiction between heat supply and demand at low temperature.Based on the design object of a three-storey office building in Yuanping,Shanxi Province,a 1100m2 solar energy-phase change heat storage evaporation air source compound heating system was designed.Composite heating system was mainly composed of solar collector system and air source heat pump system and parallel connection mode was adopted.According to different load,there were three operation modes: solar energy heating alone,solar energy-heat pump combined heating and heat pump heating alone.The design load of solar energy accounted for 20% of the total load.There were 4 heat pump units designed for heating,which could be started in turn according to the different heat load.Meanwhile,in order to ensure the safe and reliable operation of the compound heating system,a matching control system was developed.According to the characteristics of compound heating system,the control system adopted the distributed control structure of one master station and four slaves.In order to make the control system play a good control effect,the corresponding control strategy was studied for each control link,and the control system was debugged by setting up a simulation system.After debugging,the control system had good stability and meet the control needs of compound heating system.In addition,in view of the R22 refrigerant currently used in the heat pump system,the performance of R417 A instead of R22 was compared.R417 A belongs to the environmental protection refrigerant,and the destruction to the ozone layer is 0.Through the experiment,it could be concluded that the exhaust pressure and temperature of the compressor of the system would decrease after R417 A replaces R22 directly,which is beneficial to the safe operation of the heat pump unit.Although both heat production and COP decreased,the decrease was not obvious.At-15℃,when R22 was used as refrigerant,COP of the system was 2.0,and when R417 A was used as refrigerant,the unified COP was 1.96.