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Abstract: In the tropics, daylighting from a side window requires shading to intercept direct sunlight from the window whilst allowing penetration of daylight from sky. In this paper, daylighting from a double-pane glazed window with enclosed horizontal slats (slat window) was investigated for which it is situated on either north or south wall of a room. Full-scale experiments and simulations were conducted to characterize distribution of the interior daylight from the slat window under a real tropical climate. Performance of the slat window was evaluated in terms of the “useful daylight illuminance” (UDI), interior daylight availability and light power density (LPD) of an integrated dimmable lighting system. Empirical formulas were developed for determining annual average LPD values of the dimmable lighting system over its served area. The LPD value can be used with a reduced form of the energy equation of Thailand's building energy code to evaluate the reduced annual electrical energy consumption for accreditation of the daylight use in a building. The analysis of life cycle cost proved that the daylighting from the slat window integrated with the dimmable lighting system is cost effective. [Copyright &y& Elsevier]

Abstract: This paper reports results of a study on characteristics of luminous efficacies of tropical global and diffuse horizontal solar irradiances using observed data from a daylight measurement station located in the southern area of Bangkok, Thailand (latitude 13.58°N and longitude 100.44°E). Mean hourly values of the efficacies and their frequency distributions are first presented. Through scatter plots, variations of the efficacies are then presented for different sky conditions covering from cloudy to clear skies. From our results, the pattern of variation of tropical global efficacy is noticed to be distinct from those in high latitude region. In this study, two all-weather models are developed empirically for predicting values of the tropical global and diffuse efficacies. The models are evaluated for their performances against some selected existing models. The results show that the proposed models predict well the tropical efficacies and outperform all other evaluated models. [Copyright &y& Elsevier]

Abstract: This paper adopts a concept of life cycle cost (LCC) to develop a scheme suitable to rate the energy performance of air-conditioning systems for Thailand. The developed scheme arranges the performance into three levels: good, very good, and excellent by which the excellent corresponds to that that provides the minimum system life cycle cost. The lowest performance level of the scheme is assigned corresponding to the minimum performance requirements of air-conditioning systems announced in Thailand''s building energy code (BEC). In this study, the capital cost of air-conditioning equipment was obtained from the main manufacturers and distributors in the country. The operating cost was derived from the annual electrical energy consumption of the system simulated using a well-established software named “DesignBuilder”. The analysis results show that in most cases the best performance of chillers available in the market offers the minimum life cycle cost. [Copyright &y& Elsevier]