The Research On Heat Transfer Performance Of The Radiant Ceiling System

With the popularity of air-conditioning system, people have paid more and more attention on their performance. Ceiling radiant is a new air-conditioning system, and because of its energy-saving, environmental protection, and favorable thermal comfort, it has received widespread concern. The heat transfer process of the radiant ceiling is more complex, and the research of this aspect is still not enough, this paper studies the heat transfer performance of the radiant ceiling through the method of experimental research and theoretical analysis.First, the paper introduces the principle, the structure, the advantages and disadvantages of the radiant ceiling system, and mainly introduces the structure and characteristics of the three different end forms. And also it studies the heat transfer mechanism of the concrete radiant ceiling. Secondly, the experiment platform for the concrete radiant ceiling system is build up. Through changing water temperature and spacing between pipes, the experience of radiant ceiling heating has been done. And by experience, some data are obtained, which include indoor air temperature and humidity, ceiling temperature, floor temperature, and wall temperature. By analyzing data of experience, the heat storage performance, the thermal response characteristics, and the relationship between the heat transfer performance and parameters has been found.Finally, based on Fourier's law, the paper has put forward shape factor of downward heat conduct in buried pipe heated ceiling by simplifying and mirroring the structures behind the insulation layer. It has come up with equivalent heat resistance of ceiling based on shape factor and developed a new algorithm for heat gain from ceiling. By comparing the results of new algorithm with that of experiment, it shows that the new algorithm is accurate. Based on the equivalent heat resistance method, the factors influencing the heat transfer performance of the ceiling are analyzed, including heating water temperature, indoor air temperature, buried pipe diameter, buried pipe spacing and the depth of buried pipe. The results show that the ceiling surface transfer heat to the interior mainly by the way of radiation, and the indoor air quality is favorable. The ceiling temperature and the heating capacity of the ceiling become higher with the increase of water temperature; the ceiling temperature becomes higher with the increase of indoor air temperature, but the amount of heating by ceiling becomes lower; when the buried pipe spacing becomes larger, the ceiling temperature and the heating capacity of the ceiling become lower, so the buried pipe spacing should not been taken too large; the ceiling temperature and the heating capacity of the ceiling become lower with the increase of the depth of buried pipe, but the impact is not significant; the buried pipe diameter and the outdoor air temperature has little effect on the heat transfer performance of the ceiling.