Performance analysis of a liquid desiccant system with an adjustable reflux ratio of regeneration solution

Abstract

In the liquid desiccant system, the amount of the diluted solution sent to the regenerator has a great influence on the system performance. The liquid desiccant system with an adjustable reflux ratio of regeneration solution was proposed in the paper, and the effect of the solution regeneration reflux ratio on the system performance was analysed by simulation. The energy consumption, the electric coefficient of performance and the thermal coefficient of performance under different water condensation rates and varied solution regeneration reflux ratio were obtained. The results show that, the overall performance of the liquid desiccant system can be improved by reducing the solution regeneration reflux ratio; a 1% decrease in the reflux ratio leads to a 0.56–1.02% average growth rate of electric coefficient of performance and a 0.51–0.95% average growth rate of thermal coefficient of performance. Moreover, when the regeneration temperature is high and the water condensation rate of the process air is low, the improvement from decreasing the solution regeneration reflux ratio is more significant. However, the reflux ratio cannot be reduced to an unlimited extent. There is a rational optimum range of the reflux ratio to achieve high thermal coefficient of performance, the optimum range under low dehumidifying load is different from that under high load. Practical application: The performance of a liquid desiccant system can be improved by the proposed system configuration with an adjustable reflux ratio of regeneration solution, such novel system configuration could be applied for the design of air conditioning system, which is beneficial for the energy saving in building. Moreover, the rational optimum ranges of the reflux ratio to achieve high coefficient of performance under different dehumidifying loads are obtained, which could provide guidelines for the design and operation management of the liquid desiccant based building air conditioning system.

Experimental analysis and performance optimization of a counter-flow enthalpy recovery device using liquid desiccant

“…Figure 12 illustrates the effects of air and desiccant mass fluxes on the pressure drop per height of packing. Based on the experimental tests, Verschoof et al 27 proposed a general correlation to predict the loading point of structure packing at a given liquid velocity, as shown in equation (18). The curve of loading points with given desiccant velocities is drawn in Figure 12 according to this equation.…”

“…Furthermore, from the perspective of the counter-flow liquid desiccant system as a whole, there are also many researches focusing on its performance and optimization strategies. Niu et al 18 improved the performance of counterflow liquid desiccant system by decreasing the reflux ratio of regeneration solution. Ou et al 19 proposed the liquid desiccant cooling and dehumidification system (LCDC) to decrease the desiccant regeneration frequency, which can reduce the dilution rate of solution by 39.6% and save 22.3% of the energy comparing with the conventional liquid desiccant dehumidification systems (LDDS).…”