Investigation On Potassium Formate-Silica Gel Coated Heat Exchanger

Desiccant coated heat exchanger(DCHE)is a kind of novel solid desiccant equipment,which is manufactured by coating solid desiccant material to the surface of the traditional fin-tube heat exchanger.It has advantages of the use of low grade thermal energy and independent control of temperature and humidity.Desiccant material is key to deciding the dehumidification performance of DCHE.In this paper,potassium formate-silica gel composite desiccant with low corrosivity and good hygroscopicity is proposed,which avoids defects of the traditional haloid composite desiccant.Firstly,microcosmic characteristics and adsorption properties of the composite desiccant samples are tested.Then,a DCHE test system is built to investigate the dehumidification performance of potassium formate-silica gel coated heat exchanger(PSCHE)under a typical and other various operation conditions.Also,a silica gel coated heat exchanger(SCHE)system is built and tested to study the regeneration process of DCHE supplying indoor heating and humidification under winter condition.To further improve the humidification performance of DCHE,the tests on regeneration performance and the influencing factors of PSCHE are accomplished.Experimental results show that the composite desiccant has a better moisture adsorption performance.The saturated adsorption capacity at 25~oC is 50%higher than that of silica gel,and it increases with the salinity of composite desiccant.Under typical operation condition,the moisture removal and cooling capacity of PSCHE increase,respectively by 17.8%and 38%,compared with SCHE.In addition,the regeneration performance tests of SCHE system and PSCHE show that DCHEs have a good heating and humidification performance in winter.Compared with SCHE,the moisture addition of PSCHE increases by 13%and the outlet air temperature decreased by 0.8~oC in typical working condition.In summary,the use of potassium formate-silica gel composite desiccant brings remarkable improvements in the dehumidification and regeneration performance of DCHE,which indicates that this composite desiccant will have a good application prospect.