Study On Heat And Mass Transfer Enhancement Of New Type Adsorber

Adsorption refrigeration technology is driven by low-temperature heat source,which can use solar energy and low-temperature industrial waste heat to provide cold load.It conforms to the current development trend of energy conservation and environmental protection and has great potential for development.As the core component of adsorption refrigeration system,adsorber is mainly composed of adsorber heat exchanger and adsorbent.The heat and mass transfer effects of adsorber directly affect the whole system.In this study,the plate fin adsorber was used to optimize the structure and study the silica gel/lithium chloride composite consolidated adsorbent.The heat exchanger structure and adsorbent of the plate fin adsorber were optimized to enhance the heat and mass transfer performance and improve the refrigeration efficiency of the adsorption refrigeration system.COP and SCP were used to evaluate the performance of adsorber with different fin structure run on different operating conditions.1.In the aspect of adsorber structural optimization,Comsol Multiphysics software was used to establish a two-dimensional mathematical model of the plate-fin adsorber,which carried out the effects of the adsorber with different structures(trapezoidal fins,triangular fins,diamond-shaped fins and hexagonal fins)and operating conditions.The effecs of fin spacing and adsorbent thickness on adsorber performance was investigated.Due to the change of adsorption bed structure,the proportion of adsorbent in adsorber changed.With the increase of adsorbent mass ratio in adsorber,the COP and SCP of adsorber increased.At the same time,the effects of different operating conditions(driving heat source temperature,cooling water temperature and heat transfer fluid velocity)on the adsorber performance was investigated.It provides a direction for developing adsorber research and improving the performance of adsorption refrigeration system in the future.2.In the aspect of new type composite consolidated adsorbent,using silica gel and lithium chloride compound preparation into new type composite consolidated adsorbent.Screening the best preparation method,study the effects of different quality of lithium chloride compound consolidated adsorbent on heat and mass transfer performance of adsorbent.The results show that lithium chloride has a higher adsorption rate and adsorption capacity,so the mass proportion of lithium chloride in the adsorbent increases,the heat and mass transfer performance of the composite consolidated adsorbent increases.When the mass ratio of lithium chloride in the composite curing adsorbent is less than 16%,the adsorption rate of the adsorbent increases with the increase of the mass ratio of lithium chloride,while when the proportion of lithium chloride in the composite consolidated adsorbent is more than 16%,the adsorption rate of the composite consolidated adsorbent decreases.In addition,in order to improve the SCP of the plate-fin adsorber,the hexagon fin-structured heat exchanger and the composite consolidated adsorbent S16(lithium chloride mass accounts for 16%)adsorber model were established,and the performance of the new adsorber was studied.Compared with the silica S0/hexagon fin adsorber,the SCP and COP of S16/adsorber were significantly improved.