Cooling and Heating performance of Ceiling Radiant Textile Air Conditioning System with PAC

There are two types of air conditioning systems, convective and radiant air conditioning system. Radiant air conditioning systems have attracted many people’s interest due to the high capabilities of energy saving and maintaining a comfortable indoor environment at the same time. However, it is difficult to install this system and maintain system performance. There is also a problem about the drought from convective air conditioning system. In this study, the authors suggest a new radiant air conditioning system, ceiling radiant textile air conditioning system with package air conditioner (Package Air Conditioner). In a room with PAC installed, we introduced the textile layer covering the ceiling below the PAC. By using existing PAC, the complexity of installation and the chance of having drought will become lower compared to the typical air conditioning system. The aim of this study is to investigate the thermal environment when operating the new radiant system and to develop an optimal method of using this system. This system controls the indoor environment utilizing the radiant effect of textile and the airflow through textile. In order to clarify the actual phenomenon, we conducted several experiments under 6 conditions, changing the supply airflow angle, pre-set temperature of PAC, airflow rate from PAC or heat generation rate. We also set up a "guide" below the inlet of PAC which prevents supply air from being drawn into the inlet of PAC and is made of non-flammable corrugated carton. Moreover, in order to increase the airflow rate through textile, we cut the part of textile under the guide and made an opening. Experiments in a total of 18 cases were carried out and compared under three conditions, "no guide", "guide on textile" and "guide with opening", combined with previous 6 conditions, thus we conducted the experiment in 18 cases. 
In this study, the temperature, concentration of carbon dioxide as a tracer gas, and heat transfer rate by radiation were measured. Airflow rate through textile is calculated by tracer gas method. The heat transfer was also modelled considering exchange air through membrane. A new coefficient to quantify the heat transfer was introduced and performed by experiment. In addition, the representative temperatures of experimental room were calculated using the new coefficient and compared with the values obtained from the full-scale experiment which was reported in our previous study.