Thermally driven adsorption cooling and desalination employing multi-bed dual-evaporator system

Abstract

In this paper, an advanced adsorption cooling cum desalination system comprising four adsorption beds and two evaporators is presented. The proposed system continuously produces desalinated water in the condenser and chilled water at two different temperature levels. It employs silica gel as adsorbent and water as adsorbate pair. One evaporator is operated at low pressure for low temperature cooling (≈10 °C) while the pressure of the other evaporator is set higher for sufficient desalination and cooling water production at high temperature (≈20 °C). The proposed system is simulated with two different configurations. In the first configuration each evaporator is connected to only two beds, whereas in the second configuration, all beds are connected to both evaporators for consecutive low pressure and high pressure adsorption. Both configurations are compared with conventional system in regards of specific cooling power for the two temperature levels (SCP-L and SCP-H), specific daily water production (SDWP), performance ratio (PR), coefficient of performance (COP) and overall conversion ratio (OCR). It is found that the proposed system with the second configuration outperforms the conventional 4 bed system by 45% and 40% in terms of SDWP and OCR. Further, the flexibility of the system is proven by the variation of timing schemes, leading to an adjustment in SCP and SDWP depending on the fresh water and cooling energy demands.