The adaptive model of thermal comfort and energy conservation in the built environment

Abstract

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.

Dynamic predictive clothing insulation models based on outdoor air and indoor operative temperatures

“…The models developed in the training dataset are reported in equations (8) and (9). The developed models have regression coefficients very similar to the model developed in the whole database and the calculated clo values have a difference that is negligible (less than 0.025 clo between the models (4) and (8) and less than 0.02 clo between the models (5) and (9)) therefore it is acceptable to use models obtained in the whole database. Figure 10 reports the graphical representation of the regression model (equation (4)) developed to predict the clothing insulation when only the outside dry bulb air temperature is known.…”

“…de Dear and Brager [8] and de Dear [9] analysed the relationship between clothing insulation and mean indoor operative temperature [8] and mean outdoor effective temperature [8] in the publicly available database developed within ASHRAE research project RP-884 [9]. To study the relationships between clothing level and indoor and outdoor temperatures they used the average building value (160 buildings) and not the value for each occupant (22,346 occupants), i.e.…”

“…They used the building and not the occupant as unit of the statistical analysis to ensure some homogeneity of conditions affecting each subset of data, but there was not an explicit verification of linear regression assumptions. In figure 5b a risk of leverage effect due to four data points (probably outliers) is visible [8]. Using the building as the statistical unit artificially reduces variance and increases the coefficient of determination (R 2 ).…”

Net-zero emission residential building in temperate weather condition

“…The aim of this paper is to investigate the possibility to achieve a net-zero emission residential building in Geelong, Australia. The weather in Geelong is temperate type according to RP-884 thermal comfort database [6]. In temperate weather region temperature fluctuation is very high in short time therefore overall energy demand is higher around the year.…”

“…Indoor comfort temperature depends on the outdoor air temperature and energy requirement can be reduced by designing natural and hybrid ventilation in many moderate climate zones of the world [6]. Modern building codes, practices and governments initiatives have improved the insulation on new houses in Australia which eventually improves the in-house heating/cooling condition.…”