The resistive heating, defrosting, and thermal performance of CFRPs as a heat transfer unit in a frozen environment

This study explored the feasibility of substituting the traditional aluminum heat exchanger units of the residual heat pump systems with carbon fiber reinforced polymers (CFRPs). The main objective was to investigate the potential advantages of employing a self-heating heatsink in frozen ambient regarding CFRPs resistive heating feature. The in-plane and through-plane thermal conductivity of PAN-based and Pitch-based carbon fiber laminates, as well as their resistive heating characteristics and surface temperature under various electrical conditions, were studied. Also, the impact of piping (fins to pipe connection) on CFRPs heat generation and defrosting performance of the heatsinks was examined. As a solution, the suggested three-point electrical connection demonstrated a positive effect on reaching uniform temperature throughout the samples, especially for the PANbased case. In general, the PAN-based laminate exhibited lower power consumption to obtain the desired average surface temperature compared to Pitch-based CFRPs. However, the higher thermal conductivity of the Pitchbased samples led to better heat dissipation and a more uniform temperature contour. Finally, the thermal performance of the Pitch-based CFRPs and aluminum heatsinks were compared in a freezing chamber. The results revealed that under the given time interval, amount of transferred heat for the Pitch-based CFRPs heatsink equipped with defrosting feature was 2260 (kJ), 2.23 times higher than the aluminum (without defrosting element) with 967 (kJ).