The development of a computer program for thermal comfort analysis




Praditsmanont, Apichat

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Creating thermal comfort for building occupants is considered one of the primary goals of architectural design. It is the ultimate objective of this study to develop a useful computer program that is capable of analyzing thermal comfort in a passive environment. In order to assess thermal comfort using the Fanger thermal comfort prediction model (1970), the developed computer program must simulate not only indoor air temperature and mean radiant temperature, but also indoor air movement and humidity level. Based on the theoretical framework of a ventilation network model (Arumí-Noé, 1986), a ventilation module is developed and integrated into the DEROB thermal simulation program. The simulated results from the integrated program are compared with selected empirical data, and its thermal comfort prediction capability is tested. The ventilation module consists of two main components, the branch solution and the circuit loop solution. These solutions require the construction of the ventilation network and the circuit loops that are determined by the architectural geometry. The branch solution calculates air velocities, pressure drops, and resistances to air flow along branches in the ventilation network. The circuit loop solution uses the branches' pressure drops and resistances to calculate air mass flow rates in all circuit loops. The ventilation module is integrated into the DEROB thermal simulation program through the heat balance solution for space nodes. Consequently, the integrated thermal simulation program is able to predict all physical factors influencing thermal comfort, especially indoor air velocity and humidity level. Empirical data from Dascalaki's four experiments are selected for comparisons with simulated results. The configuration of Dascalaki's test room is digitized, and the simulation is set up and run based on the condition specified in each experiment. The simulated results are compared to Dascalaki's experimental results. A moderate agreement between these results is found. The integrated thermal simulation program tends to be more sensitive to the outdoor wind velocity than Dascalaki's experiments. The proposed computer program is also tested for its prediction of thermal comfort. The program successfully predicts thermal comfort in architectural spaces, and thus provides an alternative method for thermal comfort analysis. Further research to refine the program is suggested.




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