Low heating load areas require intermittent heating to create a comfortable indoor environment quickly and efficiently, and the indoor thermal environment depends strongly on the choice of indoor terminal units. In this paper, the thermal performances of traditional fan coil and floor heating are analyzed. It shows that the radiant heat transfer shows good thermal comfort, while convective heat transfer shows higher intermittency. Therefore, adding switchable convective heating to radiant heating is an effective improving means. On this basis, a novel terminal based on flat heat pipes is proposed, which can switch flexibly between radiation and convection modes and its thermal performance is analyzed. Furthermore, a comparative experiment between the novel terminal based on flat heat pipes and traditional terminals is conducted. The results show that the effect of the switchable mode of the novel terminal is equivalent to the combined effect of the traditional terminals at the key points of heating capacity and temperature rise. In addition, this novel terminal can initially heat up the space within 20-40 minutes and then stabilize the room temperature in a comfortable range of 18-22 Â°C. In areas of low heating load, this novel terminal can replace two traditional terminals, thereby reducing system complexity and initial investment.
Keywords energy conversion in buildings, heat pipe, heat pump, intermittent heating, low energy buildings