Numerical simulation and experimental investigation on Phase Change Materials based energy storage system for cooling the water in process industries towards water conservation and environmental sustainability

Abstract

Water conservation is one of the significant concerns in the industrial sector in cooling processes. Water is lost predominantly in the cooling towers by evaporation, drift, and blowdown. A new Phase Change Material (PCM) based cooling system is proposed as a replacement for cooling towers to eliminate water losses completely. In the current research, the temperature drop of water known as range in the cooling tower is investigated in the proposed system by varying the process parameters such as water velocity, tube materials and tube lenght. In the present study, OM50, an organic PCM with a melting temperature of 500 C is chosen for experimental and numerical analysis as the normal operating temperature of water in the cooling towers is in this range. Based on the experiment, it is observed that the temperature range of water almost remains constant for the melt fraction values of PCM from about 0.1 to 0.8 and taking about 35 % of the total time required for completely melting the PCM. However the cooling range steeply decreases for the melt fraction variation from 0.8 to 1. Hence the designing of PCM based cooling system will be effective for the melting of the PCM from 0.1 to 0.8 leading to constant cooling range of temperature. The experimental results obtained are also validated by CFD simulation using ANSYS 18.1 and the results obtained are in close agreement with each other. The range obtained in the present research is almost in the same range of cooling tower used in the chiller plant presented in the case study. The proposed system may be able to replace cooling towers towards conservation of water and environmental sustainability.