Thermal comfort in a large property portfolio: What can we do before surrendering to AC? (original) (raw)
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In Australia, the current Nationwide House Energy Rating Scheme adopts a variation of the ASHRAE 55‐2013 adaptive thermal comfort method with a criterion of 90% acceptability. It has been debated that such a high acceptability requirement may be too strict for residential buildings, and a criterion of 80% or even 70% acceptability may be adequate. This study evaluates the impact of thermal comfort criteria on space cooling energy requirement in three typical climates (Melbourne‐heating dominated, Sydney‐balanced heating and cooling, Darwin‐cooling dominated) in Australia through building simulation. The results show that under both current and future climates (assuming a global warming temperature of 2°C), the decrease from 90% to 70% in the acceptability has minor or no impact on housing cooling energy consumption in Melbourne and Sydney. However, it may have significant impact on space cooling energy consumption in Darwin (saving more than 40%). It was found that for high‐set ligh...
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International Journal of Biometeorology, 2001
Current thermal comfort standards and the models underpinning them purport to be equally applicable across all types of building, ventilation, occupancy pattern and climate zone. A recent research project sponsored by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE, RP-884) critically evaluated these assumptions by statistically analysing a large database of research results in building comfort studies from all over the world (n=22,346). The results reported in this paper indicated a clear dependence of indoor comfort temperatures on outdoor air temperatures (instead of outdoor effective temperature ET* used in RP-884), especially in buildings that were free-running or naturally ventilated. These findings encourage significant revisions of ASHRAE’s comfort standard in terms of climatically relevant prescriptions. The paper highlights the potential for reduced cooling energy requirements by designing for natural or hybrid ventilation in many moderate climate zones of the world.
Thermal comfort in residential buildings: Comfort values and scales for building energy simulation
Applied Energy, 86(5), 772-780, 2009
DOI:10.1016/j.apenergy.2008.07.011 There is evidence suggesting that subjects become accustomed to levels of warmth prevailing within buildings on time scales of weeks to months. Such exposure will influence in occupants’ expectation of their thermal environments (i.e. thermal history). This paper investigates the effects of short-term physiological acclimatization on subjects’ perception of thermal and air movement preferences. Subjective thermal perception experiments were carried out in a climate chamber to evaluate temperature and air movement acceptability across a range of simulated hot-humid conditions. Experiments were carried out during the winter season in Japan so that subjects, from different nationalities, could all be brought to comparable levels of heat acclimatization. This method consists in exposing subjects to hot-humid conditions and increasing their core temperature by means of exercise on a daily basis. The physiological monitoring of subjects in these experiments established that core temperature was increased through exercise in heat. The increment in core temperature by three consecutive days appeared to be an effective short acclimatization procedure, as demonstrated by the diminution in thermal sensation, improved thermal acceptability and thermal preferences during exposure to warm thermal environments (SET∗ varying from 25 to 31 °C). The results showed that it is possible to acclimatize such ‘air-conditioning addicts’ to warmer indoor environments without, however, compromising their thermal acceptability. In warm and humid climates, such trend for saturation of air-conditioning exposure needs to be more understood. The results presented reinforce the opportunities to use higher set-points in air-conditioning buildings, contributing to significant energy consumption cut-offs within the built environment.
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