Research On Indoor Heat Transfer And Thermal Comfort Of Radiant And Ventilation Heating System

Low temperature radiant heating is a kind of heating which gives priority to radiant heat transfer, and it is more energy saving, environmental and comfortable compared with the traditional heating mode. Therefore, studying the heating transfer performance and indoor thermal comfort of radiant heating system can help to gradually improve the technology.In this paper, the indoor heat transfer performance, thermal comfort and application of radiant and ventilation heating system are studied by experimental and numerical method. First of all, the experimental platform of a radiant heating and ventilation system is established, and the temperature and air speed of internal surface are measured under different operating conditions, in order to study the change rule of radiant heat transfer and convective heat transfer under different temperature and flow rate of supply water. Secondly, the indoor thermal environment under different radiant heating mode is simulated calculation by using AIRPAK software, then the influence factors of indoor thermal environment and thermal comfort evaluation index are compared. Finally, taking the civil building in Beijing, Xi’an and Lhasa as the research object the operating performance of radiant floor heating system which has the solar energy and air source heat pump as the heat source is analyzed by the transient system simulation program (TRNSYS).The result show that, in radiant floor heating system the radiant heat transfer accounts for more than half of the total heat transfer, and the proportion decreases as the temperature and the flow rate of supply water increases, but the radiation ceiling heating system has a reverse rule. The indoor temperature field distribution with radiant floor heating system is uniform, and the vertical temperature difference is small, and the mean radiant temperature and thermal comfort of the radiant floor system are higher compared with other radiant heating system. The Lhasa has the highest annual energy-saving fraction which reaches30%in the regions with the radiant floor heating system which has the solar energy and air source heat pump as the heat source.The research results have a certain guiding significance to the radiant heating design and heat source selection.