Regeneration of liquid desiccant for solar air-conditioning and desalination using hybrid solar still

Abstract

In a global era, continuous increment in energy requisition with its associated cost and relevant climate problems is causing accentuation in exploring more efficient ways to provide cooling/air-conditioning in enclosed space without degrading the environment. In the hot and humid area, major part of conventionally produced electrical energy is consumed by air-conditioning. Also in the rapidly growing world, scarcity of clean water is dilemma as equal as green-house effect and ozone layer depletion. Thus, there is emergence of dehumidified air for human comfort with potable clean water at a same time. In the present paper, performance of the hybrid solar still has been evaluated for the regeneration of liquid desiccant and distillation of saline water for the three days in the month of March and April 2017 at the location 20.61°N, 72.91°E. For the experimentation, weak liquid desiccant (40% concentration) solution of Calcium Chloride (CaCl2) was selected whose stream flows through the upper basin and constant depth (10 mm) of saline water with 0.10% concentration of Zinc Oxide (ZnO) nanofluid, to improve the energy transfer, was maintained in the lower basin of hybrid solar still. The results show that the daily water desorption of 1417.22 ml/m2, 1253.88 ml/m2 and 1368.74 ml/m2 was found from the weak solution of CaCl2 in upper basin with yield of 757.22 ml/m2, 728.33 ml/m2 and 727.78 ml/m2 in lower basin for three days respectively. Considering still as dehumidifier/regenerator, daily average capacity obtained to absorb the latent heat from the humid air by the regenerated liquid desiccant was 0.168 kW, 0.148 kW and 0.143 kW respectively for the three days. The overall thermal efficiency of 16.74%, 25.39% and 26.19% was achieved for the three days respectively.