Development And Experimental Investigation On Heat Pump Dehumidification System Based On Desiccant Coated Heat Exchanger

Based on the research in the field of solid desiccant at home and abroad,this paper proposes a heat pump fresh air dehumidification system based on the desiccant coated heat exchanger(SCHE),driven by condensing waste heat of heat pump,with water as a heat transfer medium between the systems.Using the heat pump circulation condensing waste heat as the driving heat source,the hydrophile and the adsorption effect of the solid desiccant on the surface of the fins are used to dehumidify the wet air flowing through the heat exchanger;Using water as the heat transfer medium between the dehumidifier system and the heat pump system;Heat pump condensing heat and regenerative hot water exchange heat are used to regenerate the dehumidified material in the channel of SCHE.The cooling water produced by heat pump is used to cool the dehumidified material to achieve the purpose of isothermal dehumidification Continuous dehumidification is achieved through the parallel structure of two internal cooling SCHE and the switching between four water valves and wind valvesThe sorption material coated heat exchanger(SCHE)is a novel solid dehumidification technology.The SCHE is fabricated by coating solid sorption material to the surface of the traditional fin-tube heat exchanger The cooling water flows through the tube to remove adsorption heat from the desiccant material,which can reduce the humidity ratio of the process air and the irreversible losses during the dehumidification process,to achieve the purpose of isothermal dehumidification.Instead,the coated desiccant material can be regenerated by hot water during the regeneration process.Considered fin-tube heat exchanger is widely used device in conventional air conditioning and refrigeration system,SCHE will has an extensive foreground of application.It has the merits of low manufacturing cost,convenient installation and low adsorption heat effectAccording the ventilation standard of Shanghai in summer,the design and calculation of the experimental units in each subsystem are carried out.The higher design requirements in moisture removal and COP are proposed through better irrigations.The system is tested under typical environmental conditions,and the experimental comparison and thermal and humidity performance analysis are carried out.SCHE has the average dehumidification capacity of 5.76 g/kg and the air return ratio of 16%.The system has a full thermal COP of 4.99,which is 21.8%higher than that of the traditional heat pump system COPBased on the experimental data,the heat and mass transfer model of the SC.HE is established.The model is fitted by Gauss-Seidel iterative algorithm,and the semi-empirical expression formula is obtained.The simulation results of heat and mass transfer in SCHE are less than 18%.The model accuracy is verified.According to the heat and mass transfer model,the desiccant performance simulation results of the SCHE in different working conditions are optimized for structural dimensions and operating parameters of the SCHE.In addition,the design calculation about the desiccant system based on SCHE technology can be summarized to provide the theoretical basis for system design.