Prapapong Vangtook - Academia.edu (original) (raw)

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Papers by Prapapong Vangtook

This paper reports results of experiments on the application of solar regenerated desiccant for d... more This paper reports results of experiments on the application of solar regenerated desiccant for dehumidification of the ventilation air together with application of radiant cooling for thermal comfort. A set of solid desiccant (silica gel) packed beds were exposed to solar radiation during daytime. The packed beds were attached to the inlet of the ventilation duct of an experimental room in the Energy Park at AIT to dehumidify the ventilation air during night time. This dehumidification set up was used in conjunction with the use of panels supplied with cool water for cooling to achieve thermal comfort. The use of solid desiccant pack beds reduced moisture in the ventilation air resulting in the reduction of humidity in the room. This allows cold water of a lower temperature to be used in the radiant panel, thus increasing the capacity of the panel. At lower temperatures, the capacity for achieving thermal comfort is enhanced The cooling panel was able to reduce sensible heat of air...

Building and Environment, Jul 1, 2008

Building and Environment, Feb 1, 2007

In hot and humid region, air-conditioning is increasingly used to attain thermal comfort. Air-con... more 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. In a previous experimental investigation using a room equipped with radiant cooling panel, it was found that cooling water kept to 25 1C could be used to attain thermal comfort under some situations, while water at such temperature would not cause condensation of moisture from air on the panel. This paper reports 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. Admitting the inability of radiant cooling to accept latent load, chilled water at 10 1C was supplied to cooling coil to precool ventilation air while water cooled by cooling tower was used for radiant cooling in daytime application. For night-time, cooling water from cooling tower supplied for radiant cooling was found to be sufficient to achieve thermal comfort. Such applications are considered to be more amenable to residential houses. r

Energy and Buildings, 2006

This paper reports an experimental and simulation study of application of radiant cooling using n... more This paper reports an experimental and simulation study of application of radiant cooling using natural air for ventilation under 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 8C. 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 the good potential for application of radiant cooling. However, the room was served by radiant panels with a total area of 7.5 m 2 . Its capacity was grossly inadequate during the hot period, even for night time application only. 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 match experimental results very well. Using comfort criterion adopted by ASHRAE and International Standards Organization, results from experiments and simulation show that thermal comfort could be obtained with application of radiant cooling. #

Building and Environment, 2008

A field assessment of thermal comfort was conducted at Mehran University of Engineering and Techn... more A field assessment of thermal comfort was conducted at Mehran University of Engineering and Technology, situated in the subtropical region of Pakistan. The results show that people of the area were feeling thermally comfortable at effective temperature of 29.85 1C (operative temperature 29.3 1C). A comparison of this neutral effective temperature was made with the neutral effective temperature determined from adaptive models. It is found that the neutral effective temperature determined during this study closely match that of the adaptive model based on either indoor temperature or both indoor and outdoor temperatures. The results of thermal acceptability assessment show that more than 80% of occupants were satisfied at an effective temperature of 32.5 1C, which is 6.5 1C above the upper boundary of ASHRAE thermal comfort zone. Naturally ventilated classrooms and air-conditioned offices of the University were simulated using TRNSYS system simulation program for two cases, once when conventional air-conditioning is used for providing thermal comfort, and when comfort is achieved through radiant cooling. In the simulation, cooling tower was used to regenerate cooling water for the radiant cooling system. Energy consumption was estimated from simulation of both cases. The results show that it is possible to achieve thermal comfort for most of the time of the year through the use of radiant cooling without a risk of condensation of moisture from air on the radiant cooling surfaces. A comparison of the energy consumption estimates show that savings of 80% is possible in case thermal comfort is achieved through radiant cooling instead of conventional air-conditioning. r

Building and Environment, 2007

Building and Environment, Jul 1, 2008

Building and Environment, Feb 1, 2007

Energy and Buildings, 2006

Building and Environment, 2008

Building and Environment, 2007