Performance Investigation Of The Air-source Heat-pump Integrated With Air-to-air Energy Exchanger

Air-to-air energy exchangers can recovery energy from exhaust air to improve efficiency of HVAC systems.However,the efficiency of existing air-to-air energy exchangers cannot reach 100%,and the remained energy within exhaust air can be further used by air-source heat pump（ASHP）.Existing designs for both heat pump and fresh air exchangers have limitations of providing space heating and fresh air exchange separately and the excess heat of exhaust air is not used sufficiently.To address these limitations,a novel design of air-source Heat-Pump integrated with Air-to-air Energy Exchangers（HPAEE）has been proposed in this study.It utilized the energy of exhaust air after heat recovery ventilators at the evaporator side to improve heat pump’s COP.A prototype has been built and tested under winter conditions in Beijing（China）,and the HPAEE appeared to be able to reduce system energy consumption and achieve fresh air exchange,comparing to the existing system.The COP of the proposed HPAEE has reached 2.76 while providing 803m³/h fresh air.Results demonstrated that the new solution proposed here can provide space heating with fresh air exchange or heat recovery with fresh air exchange to achieve better energy usage.To further continute the performance analysis and optimization research of the air-to-air heat exchanger intergated with the air-source heat pump,the mathematical model of the direct expansion air source heat pump and the air-to-air plate-fin type energy exchanger are established.The heat exchanger is based on the multivariate polynomial regression prediction model.The prediction model agreed with the measured data.The model assumes that the material of the heat exchanger membrane is constant,and the variation parameters are the air flow rate and the size of the heat exchange channel unit.The air flow rate and heat exchanger setting size for the target maximum operating exchange efficiency of the membrane material are obtained.The air-source heat pump model is coupled to obtain the optimal capacity matching of the fixed frequency air source heat pump and the air volume to make_HPAEE highest.