An Experımental Study On The Thermal Effıcıency Of An Aır-To-Aır Heat Exchanger Wıth Ethylene Glycol (Eg)-Based Hybrıd Nanofluıd Al2o3 + Tio2
Künye
Öztürk, A. (2022).An Experımental Study On The Thermal Effıcıency Of An Aır-To-Aır Heat Exchanger Wıth Ethylene Glycol (Eg)-Based Hybrıd Nanofluıd Al2o3 + Tio2. Heat Transfer Research, 53(13), 59-73.Özet
The purpose of this study is to improve the thermal performance of air-to-air heat recovery units containing heat pipes and utilizing single Al2O3/EG and TiO2/EG and hybrid Al2O3 + TiO2/EG (50:50) nanofluids as various working fluids. In the experimental setup, 15 wickless and vacuumed copper pipes with a length of 100 cm, an inner diameter of 10.5 mm, and an outer diameter of 12 mm were used. Heat pipe portions of 450 mm, 400 mm, and 150 mm constitute the evaporator zone, condenser zone, and the adiabatic zone, respectively. In the experimental studies, 1/3 of the evaporator volumes of the heat pipes were filled with working fluids. The experiments were conducted by applying three different heating powers (500 W, 1000 W, and 1500 W) to the evaporator section and three different air mass flow rates (n(21) = 125 g/s, n(22) = 175 g/s, and n(23) = 215 g/s) to the condenser section. The values of thermal efficiency and thermal resistance were calculated to compare the values of single and hybrid nanofluids utilized in the system. The results indicated that single and hybrid nanofluids are more efficient than EG under all different conditions. A maximum efficiency of 82% was acquired at 1500 W and a mass flow rate of n(23) = 215 g/s by utilizing the hybrid nanofluids Al2O3 + TiO2/EG (50:50). Furthermore, it was observed all the nanofluids facilities reduced thermal resistance of heat pipes. This thus generated an improvement in the quantity of heat transfer. Under 1500 W and n(23) = 215 g/s mass flow rate conditions a maximum of 53.71% reduction in thermal resistance was also achieved by means of hybrid nanofluids.