Experimental and simulation performance optimization of an exhaust air heat recovery heat pump unit

In order to optimize the performance of exhaust air heat recovery heat pump unit (EAHRHPU), Simulink system simulation and Simulink-M file optimization model were established in this paper to study the performance of the unit in variable outdoor air conditions by combining experiment. Finally, the optimal performance of coefficient and the corresponding optimal bypass fresh air flow rate of the unit in different outdoor temperature was obtained. The results showed that the change trend of the simulation value and the test value of the unit's performance parameters is consistent, and the maximum deviation is controlled within +/- 7.00% in the standard cooling condition and variable bypass fresh air. The simulation model can correctly reflect the performance changes of the unit during the operation. The operation performance of the unit was affected by the temperature and air flow rate of the bypass fresh air in variable outdoor conditions. The Simulink-M file optimization model can obtain the specific value of the optimal bypass air flow rate in different outdoor temperatures. As the outdoor temperature increases, the optimal bypass fresh air flow rate increases first and then decreases. With the use of variable frequency fans, the unit can achieve better energy utility effect. The research could be considered as the useful reference for improving the operation performance of the EAHRHPU.