Research on a radiant heating terminal integrated with a thermoelectric unit and flat heat pipe

A prototype radiant heating terminal utilizing a thermoelectric cooling (TEC) unit and a flat heat pipe was evaluated in an experimental study to determine its working characteristics under practical operating conditions. TEC units have the advantage of having a higher coefficient of performance (COP) than electric heating terminal and a faster thermal response than a conventional radiant heating terminal. The main barrier to using TEC units in a radiant system is the heat transfer between the TEC unit and the radiant panel. Combining a flat heat pipe with the TEC unit helps to solve this heat transfer problem, enabling rapid intermittent radiant heating. The experimental results showed a fast heating response of the terminal of under 10 min. Moreover, the COP of this terminal ranged from 1.02 to 1.53, i.e. it achieved a similar heating effect as existing convective TEC heating units. A simplified energy equilibrium model of the heating terminal was developed and the heat transfer process was analyzed. In addition, the energy balance was confirmed experimentally and an uncertainty analysis was also performed. Overall, this new radiant terminal is capable of intermittent and local radiant heating and shows potential as a supplement in space heating applications.