THERMODYNAMIC MODELING OF HYBRID DESALINATION SYSTEM INTEGRATED WITH HUMIDIFICATION DEHUMIDIFICATION SYSTEM

Abstract

One of the largest environmental problems facing today is the fresh water scarcity in the world. On earth, 97% of total water is salt water and the remaining 3% is the freshwater. Desalination is the process by which the salt water or the brackish water can be converted into potable water so that the water scarcity can be reduced. Many desalination techniques such as multi-stage flash, multi-effect distillation, and reverse osmosis have been conventionally used but, they have limitations like high energy consumption, low water productivity and cost. The main advantage of this technique is that it can produce cooling along with potable water. The present study focuses on thermodynamic modelling of hybrid solar adsorption desalination and cooling system. Initially, a numerical analysis of the adsorption desalination and the cooling system operating with silicagel-water is carried out to determine its performance. Two modifications are incorporated for the improvement of the system performance. The first method is the use of suitable composite adsorbent made of silicagel as the parent material with combinations of aluminium fumerate and PVC. The second method is the integration of the humidification dehumidification unit to the conventional adsorption desalination system. The system is analysed by varying the operating parameters such as hot water temperature, cooling water temperature, condenser temperature and salinity on the water productivity, coefficient of performance and the energy requirement. The result reveals that the water productivity obtained from adsorption desalination and the cooling system operating with silicagel-water is 1.3kg/cycle, whereas with that of composite adsorbent is 1.54kg/cycle. For the hybrid system integrated with the humidification dehumidification unit the water productivity is found to be 2kg/cycle which is 23%more than the conventional system.