ENERGY AND EXERGY ANALYSIS OF DOUBLE PIPE MINI TUBE HEAT EXCHANGER

Global population growth and the resulting rapid depletion of energy resources make sustainability of energy resources difficult. By reducing size, weight, and costs, more effective and sustainable systems can be developed and resource consumption reduced. Mini-channel heat exchangers ensure higher heat transfer than macro-channel heat exchangers because of the volume and surface effect factor. Furthermore, the performance of heat exchangers can be increased by suspending nano-sized particles in the base heat transfer fluids. In this study, a concentric mini-tube heat exchanger was designed, manufactured and energy-exergy analyses were made. MWCNT-Water nanofluid prepared at various volume concentrations (0.1%-0.2%-0.3%) and used as a working fluid. The heat transfer performance of the concentric mini-tube heat exchanger was evaluated using the ε-NTU method. The relationship between ε, NTU, Reynolds number, and dimensionless exergy is investigated. Effectiveness (ε), NTU, and dimensionless exergy (e) values were calculated in the range of 5 different Reynolds values (5000-25000) for water and nanofluids prepared at 3 different volumetric concentrations. The use of nanofluids as a working fluid was found to increase the ε and NTU values while decreasing the dimensionless exergy value.