Experimental study on enhanced heat transfer performances and optimized strategies of cascade sensible-latent heat storage radiator

Improving the thermal efficiency of radiator and minimizing the energy loss in distribution networks are crucial for space heating. However, existing studies primarily focused on optimizing the thermal performance or indoor environment of individual units, yet rarely revealed the enhanced heat transfer performance from initial power supply to final heat utilization. To address this gap, this study developed a cascade sensible-latent heat storage radiator, and improved the thermal performance in the following ways. Firstly, by adsorbing paraffin wax with expanded graphite, the thermal conductivity rose from 0.2 to 3.5 W/(m.K). Secondly, through cascading sensible and latent heat storage bricks, the heat charging/discharging efficiency increased by 11.9 %/14.6 %. Finally, by enhancing the airflow from 0.05 to 0.28 m/s, the heat discharging efficiency and entransy dissipation amount increased by 15.8 % and 225.8 kJ.K, respectively. The total energy utilization efficiency was improved by 7.4 %, and the dissatisfaction caused by draft and noise both met the personnel requirement. The total annual cost of developed radiator was merely 30 % and 60 % of the direct electric heating radiator and sensible heat storage radiator, respectively. Therefore, the sensible-latent heat storage radiator offered advantages in improving the energy utilization efficiency, indoor thermal environment and cost effectiveness performance.