Experimental study of ventilation system with heat recovery integrated by pump-driven loop heat pipe and heat pump

Abstract

To improve the thermal performance of the air-to-air energy recovery devices in cold climates, especially in low temperature conditions, a novel integrated system with heat recovery combining pump-driven loop heat pipe and heat pump is proposed and studied. The energy recovery device can operate separately at three modes: pump-driven loop heat pipe mode, heat pump mode or integrated mode. Results show that the temperature effectiveness and energy efficiency ratio of the integrated system are higher than that of heat pump system in whole conditions, and the heat transfer capacity of the integrated system has a positive correlation with the fresh air load. In addition, the system can switch its operating modes according to the different outdoor temperature. In test conditions, when outdoor temperature is greater than 8.7 °C or lower than 35.8 °C, heat pump system performs better, otherwise the integrated system is more suitable. Compared with others systems, the novel integrated system has better performance in all-year, especially in low temperature conditions. The novel integrated system shows a good application prospect in energy-saving buildings.