Improvability of Thai’s Building Energy Code via Lighting Power Density Requirements

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Nichakorn Hengrasmee
Sant Chansomsak


The Thai government plans to enforce the Thai’s new Building Energy Code or BEC, which is a Ministerial Regulation in 2009 for the building to be submitted for construction or modification and it has been in forced since mid of this 2018. In order to achieve its 20-year reduction of energy intensity used in accordance with the National Energy Conservation Plan 2015-2022. BEC has been promulgated for 9 years and it has not been updated to reach the minimum standards in line with the current technology. Specifically, the lighting criteria for energy efficiency in building. Consequently, the Lighting Power Density allowance per square meter or LPD is set based on lighting technology on that day. Therefore, in order to meet the government targets, BEC should reconsider the criteria for defining the new LPD value to match with current technology for increasing the energy efficiency of buildings. This study illustrates the concept of adjusting new LPD value, to be applicable with today’s technology. Simple calculation methods and case studies, which based on standard criteria of illuminance level according to ministerial regulation no.39, are set to investigate and compare the total lighting power density per specific area between three types of current lighting technologies, which are T8 Fluorescent tube, T5 fluorescent tube and LED T8 retro-fit. Result from the comparison shows that even the least energy-efficient bulbs of selected type, which is T8 fluorescent tube, the LPD value still lower than that specified in the BEC requirement almost 19% and it can be reduced up to 31% with the advantages of LED technology. The results from the study shows the relationship between the thresholds for defining LPD according to BEC and the brightness level in accordance with the ministerial regulations, but also shows trends in upgrading LPD configuration with reference to current technology. Reducing LPD value will be the key to developing the benchmark and increase the energy efficiency of the buildings in the future.


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