Performance optimization and comparison of two hybrid regeneration methods for absorption air-conditioning system

Abstract

Absorption air-conditioning system is considered as sustainable but its performance is limited by the low efficiency of conventional thermal boiling method. This study proposes two hybrid regeneration methods: one combines capacitive deionization (CDI) and solar steam (SS) process for regeneration, the other combines CDI and reverse osmosis (RO) process for regeneration. These two regeneration methods can overcome the inherent limitation of conventional absorption system. Absorbent is regenerated by electrosorption and refrigerant is obtained by solar interfacial evaporation or water permeation, which circumvents the inefficient separation of thermal boiling method. The processes of new systems have been designed. Models have been established to evaluate and optimize system performance and experiments have been conducted to acquire the corresponding performance indexes. Based on models and experimental results, the influence of some key parameters has been revealed. For CDI-SS system, a real-time control strategy has been developed to achieve its optimum performance. For CDI-RO system, the optimum inlet concentration of RO regenerator has been determined from energy and economic viewpoints. Both systems exhibit a better performance than conventional absorption system. Compared with CDI-SS system, CDI-RO system has advantages in operation and application but its COP is lower.