INVESTIGATION OF A NOVEL CEILING PANEL FOR HEAT AND MOISTURE CONTROL IN BUILDINGS

In occupied buildings, it is important to condition the air inside the building to ensure occupant comfort. There are several aspects that affect comfort, including temperature, relative humidity (RH), air motion and thermal radiation. The main criterion for occupant comfort is the temperature of the air. Indoor temperature is often controlled using conventional all-air systems to heat or cool the supply air before it enters the space. Another method of controlling the temperature of the air that is gaining interest is the use of radiant ceiling panels. Radiant ceiling panels use water flowing through pipes to transfer heat by convection and radiation to maintain the indoor temperature. When the indoor temperature in a space is maintained with radiant panels, the flow rate of supply air to the space can be drastically reduced so that it only needs to meet ventilation and latent load requirements. This saves energy and space (in a new building) as the size of fans and ductwork can be reduced to meet the smaller airflow rates. A disadvantage of using current radiant ceiling panel technology is the lack of control of the RH (latent load) in the space. The aim of this research is to create a new ceiling panel that can transfer both heat and moisture to maintain both the temperature and RH in a space. The newly designed heat and moisture transfer panel (HAMP) will be constructed from a porous membrane and contain a flowing aqueous salt solution. This will allow for moisture transfer between the panel and the space air, helping to maintain the RH levels in the space. This research consists of three phases: experimental testing, numerical modeling and testing in TRNSYS (a commercial computer software package). The data from the experimental testing will be used to validate the numerical model. The model will then be implemented into TRNSYS to determine the effects of the panel on the indoor RH, comfort levels and energy consumption of an office building in different climates. This paper focuses on the design of the new experimental test facility and preliminary results obtained from the experiments. The test facility takes compressed dry air, which is passed through a series of water tanks to humidify the air to the desired level, and delivers the air to the test section where the HAMP is located. The temperature and RH of the air are measured before and after the HAMP. As well, the RH and temperature of the salt solution inside the HAMP are measured throughout the experiment. From these results, the heat and moisture transfer rates between the air and the salt solution in the HAMP will be determined. Tests will be run at different air RH levels to model different indoor conditions and at different salt solution temperatures to model both heating and cooling conditions.