Experimental study on passive-mixing strategy of a liquid-desiccant air-conditioning system

Abstract

In a solution recirculation-type liquid-desiccant system, small fractions of the diluted and concentrated solutions must be mixed to maintain the solution concentration. Active-mixing strategies require many moving parts such as pumps, valves, and pipelines to mix the solutions, which increase the complexity of the system structure and frequency of mechanical breakdowns. This study proposes a new passive-mixing strategy in which a diluted low-density solution and concentrated high-density solution is naturally mixed, without the need for moving parts or complex pipe structures, because of the difference in solution densities. The operating performance of the proposed strategy was experimentally investigated and compared with that of a reference active-mixing strategy. The results demonstrate the feasibility of the proposed passive-mixing strategy in terms of maintaining the solution concentration and achieving the dehumidification and regeneration performance. In addition, the proposed strategy maintained the solution levels in the absorber and regenerator sumps, thereby improving the energy performance by 4% compared with the reference active-mixing strategy. In summary, the proposed passive-mixing strategy is more applicable than the reference active-mixing strategy because of its air-conditioning performance, system durability, practicality, and energy performance.