Radiant cooling for thermal comfort in tropical climate | |
| Author | Prapapong Vangtook |
| Call Number | AIT Diss. no.ET-05-02 |
| Subject(s) | Air conditioning--Climatic factors--Tropics Heat--Radiation and absorption Radiant heating--Tropics |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. ET-05-02 |
| Abstract | In hot and humid region, air-conditioning is increasingly used to attain thermal comfort. Air-conditioning is highly energy intensive and it is desirable to develop alternative low-energy means to achieve comfort. This dissertation reports on experimental and simulation studies for the application of radiant cooling using natural air for ventilation in the hot and humid climate of Thailand. To avoid condensation of moisture on the cooling panel, the temperature of water supplied to the panel was limited to 24 °C. This led to the expectation that the low heat reception capacity of the panel would limit its use only to situations when loads were low. Experiments were conducted in an experimental room over the hot and dry period of March, the humid period of May, and the cool period of December. The results generally confirm good potential for application of radiant cooling. However, the room was served by radiant panels with a total area of 7 .5 m2 . Its capacity was grossly inadequate during the hot period, even for application exclusively at night time. A special configuration was devised to achieve thermal comfort for the area served by the panel. The well-known TRNSYS program was used to simulate the use of cooling panels and conventional air-conditioning in the experimental room. Simulation results matched experimental results very well. Using comfo1t criteria adopted by ASHRAE and International Standards Organization, results from experiments and simulation show that thermal comfort could be obtained with application of radiant cooling. Results of a series of whole-year simulations using TRNSYS computer code on applications of radiant cooling to a room model that represents the actual experimental room are reported. Admitting the inability of radiant cooling to accept latent load, chilled water at 10 °C was supplied to the cooling coil to precool ventilation air in the daytime in addition to the water cooled by the cooling tower that was used for radiant cooling. At night, cooling water from the cooling tower alone supplied for radiant cooling was found to be sufficient to achieve thermal comfort. Such applications are considered to be more amenable to residential houses. Results of an experimental study on the application of solar regenerated desiccant for dehumidification and radiant cooling for thermal comfo1t are also rep01ted. A set of packed beds of solid desiccant were exposed to solar radiation during day time. The packed beds were connected to the inlet ventilation duct of an experimental room in the Energy Park at AIT for dehumidification of the ventilation air during night time. This dehumidification setup was used in conjunction with the use of a panel supplied with cool water for cooling to achieve thermal comfort. This combination enables quiet quality thermal comfort to be achieved. The use of packed beds of solid desiccant reduced moisture in the ventilation air resulting in the reduction of humidity in the room. This allows cold water of lower temperature to be used on the radiant panel, thus increasing the capacity of the panel. With the lower temperature, the capacity to achieve thermal comfort is enhanced. |
| Year | 2005 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. ET-05-02 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Energy Technology (ET) |
| Chairperson(s) | Surapong Chirarattananon; |
| Examination Committee(s) | Kumar, Sivanappan;Salokhe, Vilas M.;Roux, Jean-Jacques; |
| Scholarship Donor(s) | EGAT Public Company Limited; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2005 |