Heat Transfer Performance and Energy Efficiency Assessments of Nanofluids in a Compact Plate Heat Exchanger

Renato Reis Santos Thieleke da Silva

Key information

Authors:

Renato Reis Santos Thieleke da Silva (Renato Reis Santos Thieleke da Silva)

Supervisors:

Wagd Ajeeb (Wagd Ajeeb); S M Sohel Murshed (S M Sohel Murshed)

Published in

July 12, 2022

Abstract

With the advancement of industries, higher energy efficiency becomes one of the most important targets for researchers, leading to the development of compact devices and working with new fluids for better performance. This study reports experimental investigations on the heat transfer performance and energy efficiency of several types of nanofluids in a compact plate heat exchanger. Several low concentrations (0.01%-0.2vol%) of Al2O3 and TiO2 nanoparticles were selected to prepare the nanofluid samples using distilled water and ethylene glycol mixtures. The samples’ stability and thermophysical properties, namely thermal conductivity and kinematic viscosity were measured. Maximum thermal conductivity enhancements of 9.1% and 4.4% and maximum viscosity enhancements around 8% were found for Al2O3 and TiO2 nanofluids, respectively. The heat transfer coefficient, pressure drop, and energy efficiency coefficient were determined for the nanofluids and base fluids employed in CPHE. Measurements were performed at different flowrates for the nanofluids flowing in the hot loop of the heat exchanger and their performance was evaluated in comparison with the base fluid. The results indicated a heat transfer enhancement for all particle concentrations for both nanofluids, with higher enhancements for Al2O3 compared to TiO2 nanofluids. While 27% heat transfer enhancement was observed for Al2O3-DW nanofluids at 0.2vol.% concentration, the maximum enhancement for TiO2-DW nanofluid was 22% for the same concentration. The increase in pressure drop is noticed up to 8% for the highest particles’ concentration (0.2 vol.%) in comparison with the base fluids. An acceptable increase in energy efficiency was observed for the investigated nanofluids (maximum 30%).