Heat transfer performance analysis of nanofluids in radiator-based space heating: an experimental study

Abstract

This study experimentally investigates the heat transfer performance (HTP) of pure water and Fe/Water and Cu/Water nanofluids with different mass concentrations in a towel radiator used in room heating applications. Experiments were conducted under transient regime conditions at an inlet temperature of approximately 60 °C and an initial room temperature of 12 °C and system performance was calculated based on the parameters of total heat transfer (\({\dot{Q}}_{\text{T}}\)), stored heat (\(\dot{{Q}_{\text{D}}}\)), radiated heat (\({\dot{Q}}_{\text{Y}}\)), heat transfer coefficient (h), room temperature (\({T}_{\text{O}}\)) and HTP increase. According to the experimental results, it was observed that the (\(\dot{{Q}_{\text{T}}}\)) ̇ value decreased over time for all fluid types, but the use of nanofluids provided a significant improvement compared to pure water. While the (\(\dot{{Q}_{\text{T}}}\)) ̇value, initially approximately 564 W for pure water. decreased to 542 W at the end of the experiment. it ranged from 619 to 589 W at a 0.12% concentration in Fe/Water nanofluids. The highest value obtained with Cu/Water nanofluids was 638.8 W. Similarly, increases were observed in (\(\dot{{Q}_{\text{D}}}\)). (\({\dot{Q}}_{\text{Y}}\)). and h values with the use of nanofluids. In terms of HTP increase, increases of 6.42%, 11.10%, and 15.40% were obtained for 0.04% Fe/Water, 0.08% Fe/Water, and 0.12% Fe/Water nanofluids, respectively, while these values were determined as 660%, 12.20%, and 21.10% for 0.04% Cu/Water, 0.08% Cu/Water, and 0.12% Cu/Water nanofluids, respectively. The highest HTP increase was obtained with 0.12% Cu/Water nanofluid, at 21.10%. Thermal camera images also confirm that the use of nanofluids provides a more homogeneous temperature distribution on the radiator surface. In conclusion, it was determined that the use of nanofluids significantly increases HTP, that this effect varies depending on the nanoparticle type and concentration, and that Cu/Water nanofluids, in particular, provide the highest thermal performance.

Graphical abstract