Thermal comfort in naturally ventilated buildings: revisions to ASHRAE Standard 55

Abstract

Recently accepted revisions to ASHRAE Standard 55-thermal environmental conditions for human occupancy, include a new adaptive comfort standard (ACS) that allows warmer indoor temperatures for naturally ventilated buildings during summer and in warmer climate zones. The ACS is based on the analysis of 21,000 sets of raw data compiled from field studies in 160 buildings located on four continents in varied climatic zones. This paper summarizes this earlier adaptive comfort research, presents some of its findings for naturally ventilated buildings, and discusses the process of getting the ACS incorporated into Standard 55. We suggest ways the ACS could be used for the design, operation, or evaluation of buildings, and for research applications. We also use GIS mapping techniques to examine the energy-savings potential of the ACS on a regional scale across the US. Finally, we discuss related new directions for researchers and practitioners involved in the design of buildings and their environmental control systems. # 2002 Published by Elsevier Science B.V.

Indoor environmental quality assessment models: A literature review and a proposed weighting and classification scheme

“…Arens et al suggest that the EN15251-2007 categories for thermal comfort do not align with perceptible changes in occupant satisfaction and may lead to more energy intensive buildings [47]. Extensive research has shown that at least for thermal comfort and lighting, occupants can be satisfied over a wide range of conditions (thermal comfort: [60][61][62]; lighting: [63,64]). Additionally, there are potential economic implications associated with tighter levels of control, both in design and operation.…”

Numerical assessment of night ventilation impact on the thermal comfort of vernacular buildings

“…On the other hand, the adaptive model, states that factors beyond fundamental physics and physiology play an important role in building occupants' expectations and thermal preferences. The way people interact with the environment, their behaviour changes can modify their thermal expectations [36,37]. Figure 8 presents the adaptive thermal comfort levels of the master bedroom, according to EN 15251 (CYS EN 2007) [38].…”

Quantifying the relevance of adaptive thermal comfort models in moderate thermal climate zones

“…Fully air-conditioned buildings are also excluded from the standard. The comfort standard has a mean comfort zone band of 5K for 90% acceptance, and another of 7K for 80% acceptance, both centred around the optimum comfort temperature (T comf ) (Equation 3) [9].…”

“…Such local initiatives raise the question if models of adaptive thermal comfort should be introduced in moderate thermal climate zones since they obviously have most impact in hot climate zones [9]. Therefore this paper focuses on the impact of the introduction of adaptive thermal comfort evaluation criteria in moderate thermal climate regions, especially the marine climates labelled Cfb and Cfc according to the Köppen-Geiger-Pohl classification [12], in terms of usability and energy use.…”

“…Perhaps future guidelines and standards will be based on an improved PMV/PPD-model that allows for adaptation, such as a model proposed by Fanger and Toftum [24]. In periods, when mean daily outdoor temperatures range between 12°C and 28°C, outcomes of the PMV/PPD and adaptive model [9] differ less than 1K. De Dear and Brager [9] found that when mean outdoor temperatures rose above 23°C, indoor operative temperatures of naturally conditioned buildings frequently exceeded the upper comfort limits, clustering around 30°C.…”