Performance Investigation Of A Half Decoupling Dehumidification Heat Pump And FAM Coated Heat Exchanger

Dehumidification heat pump cycle built by replace conventional sensible heat exchanger(SHE)by desiccant coated heat exchanger(DCHE)have the advantages of energy saving,high thermodynamic performance and latent heat load processing ability.However,study shows that the frequent switch of hot and cold working substance and difference of heat transfer and mass transfer rate weak the overall cooling performance.To solve this problem,a half decoupling dehumidification heat pump cycle is proposed in this paper to improve the overall heat and moisture capacity by operating dehumidification evaporator and conventional sensible evaporator in series on the evaporation side.Besides,the coated material is the key to affect the system performance,and the performance of the novel FAM material coated heat exchanger(FAHE)is analyzed in this paper.Firstly,the work process of the novel half decoupling heat pump cycle is discussed and influence of the SHE on the thermodynamic performance is analyzed.Secondly,an experimental setup was built up to validate the performance of proposed concept and two different desiccant materials in terms of silica gel and composite(chloride and silica gel)were used.Performance of the system was evaluated by outlet air temperature as well as humidity ratio,cooling power and COP.Also,effects of main operation parameters on system performance were tested and discussed.Lastly,FAPO-34 zeolite-like molecular sieve is coated on the surface of SHE to manufacture FAHE.And the performance of FAHE is tested in the experimental setup under three typical outdoor environment condition.Theoretical analysis indicates that the novel cycle has better performance in dealing with sensible heat load,the cooling power is enhanced,and half decoupling treatment of thermal and moisture load lead to better accordance between the outlet temperature and humidity.The experimental results of operating DCHE and SHE in series show that with use of an auxiliary SHE,lower temperature could be obtained especially in the beginning period,the outlet temperature had good accordance with humidity ratio variable trend and then both lower supply air temperature and increased cooling power could be obtained.And two materials have similar performance in deal with sensible load,while the composite material has a larger dehumidification capacity of 20% than silica gel.Besides under experimental condition,system performance increases with increasing inlet air temperature and RH,15℃ cooling water and 40-50℃ heating water temperature are recommended to obtain enhanced system performance,suitable air velocity is above 1m/s.The results of FAHE performance test experiment show that ARI humid is the most suitable environment for the experimental system.And FAHE perform slightly better than SGCHE.Besides,15-20℃ cooling water and 40-50℃ heating water temperature is recommended to obtain enhanced system performance,suitable air velocity is above 1m/s.