Performance analysis of a fresh air and indoor air co-treatment parallel-loop exhaust air heat pump for buildings

To reduce building energy consumption and solve the problem that the power of traditional exhaust air heat pump is limited by exhaust air volume, an innovative fresh air and indoor air co- treatment parallel-loop exhaust air heat pump (CPEAHP) was proposed, and three operating modes of the CPEAHP were studied. The results showed that the co-treatment mode not only increased the flexibility of system regulation, but also improved the heating performance of the system at low temperature in winter. When the winter outdoor temperature was higher than 0 degrees C, the temperature efficiency of the co-treatment mode was higher than 100 %, and that efficiency was higher than 100 % under all outdoor temperature conditions in summer. At a winter outdoor temperature of-15 degrees C, the co-treatment mode could increase the temperature of fresh air by 20.4 degrees C and increase the temperature of indoor air by 3.1 degrees C, the heating capacity of the system was 6.3 kW and the COP was 8.7 at this time. At an outdoor temperature of 42 degrees C in summer, the co-treatment mode could decrease the temperature of fresh air by 22.8 degrees C and decrease the temperature of indoor air by 3.1 degrees C, the cooling capacity of the system was 7.3 kW and the COP was 4.5 at this time. These results demonstrated the excellent performance of CPEAHP system, and the application of CPEAHP system was expected to reduce building energy consumption and promote carbon neutrality in the construction industry.