Exergetic Study of a Three-Fluid Heat Exchanger used in Solar Flat Plate Collector System

An exergetic investigation for heat transfer among different fluids in a combined three-fluid heat exchanger and solar flat plate collector system is carried out here. Present three-fluid heat exchanger (TFHE) is a modification of double pipe exchanger, where an additional helical coil is included between two concentric straight pipes for enhanced performance. The present study is an extension of previous published experimental work, where the effects of flow and thermodynamic parameter on exergetic characteristics of the TFHE are assessed in counter flow configuration. For this study, mass flow rate of different fluids and inlet temperature of hot fluid are chosen as the input parameters, whereas exergy loss and dimensionless exergy loss are considered as the performance parameters for this study. It is found out from the result that the exergetic performance of the TFHE is significantly affected by hot water and normal water mass flow rate. Inlet temperature of hot water is also other major contributing factor towards prediction of exergy loss in TFHE. It is noticed that exergy loss increases with rise in inlet temperature of hot water through helical coil in TFHE. Maximum exergy loss observed at higher mass flow rate and inlet temperature of hot water flow in TFHE.