High efficiency fresh air dehumidification and humidification heat pump air conditioning system based on desiccant-coated heat exchanger

Traditional air conditioners use condensation dehumidification to deal with the moisture load in the air, which requires very low evaporation temperature and result in low COP. Due to the existence of liquid condensate, there are risks such as bacterial breeding, device corrosion and so on. Furthermore, it can only be used to dehumidify. To utilize in low humidity conditions, it needs an additional device to realise humidification. The newly proposed desiccant-coated heat pump system uses adsorption to deal with the moisture load, eliminating the emergence of liquid water and regenerating the adsorbent by condensing waste heat, which can achieve high COP. The configuration of desiccant-coated heat pump replaces the condenser and evaporator of traditional vapor compression refrigeration system with desiccant-coated fin-tube heat exchangers. In this study, a fresh air dehumidification and humidification heat pump unit was built and its performance under Shanghai summer condition and GB winter condition was tested. Results showed that, under Shanghai summer conditions, the fresh air unit could treat the fresh air to a 24-28°C and 12-15g/kg DA supply air. The dehumidification capacity of the system could reach 2.15L/h and COP could reach 5.19. Under GB winter conditions, the fresh air unit was able to treat the fresh air to a 25-32°C and 7-15g/kg DA supply air. The humidification capacity reached 1.44L/h and COP was 5.52. The fresh air volume was designed to be 350m3/h, the average power consumption of the compressor was 700W, meaning that the system could efficiently deal with the fresh air heat and humidity loads both in summer and winter.