D: Paper Session_T5: Thermal Perception, Boundaries and Comfort Assessment
Performative Environments Of Alliesthesia: Thermal Perception In Solar Screened Offices Under Different Sky Conditions
University of Oregon, United States of America
Through this work, the researchers explored occupant’s thermal perception inside thermally nonuniform, indoor environments of solar screened perimeter office spaces. They examined the potential of static-fixed and dynamic-movable solar screens with geometric patterns to influence the subjective thermal perception of comfort and pleasure inside single-occupancy office set-ups. The investigation comprised of a within-subject experimental design that exposed 15 participants under sunny and 12 others under overcast sky conditions of an east-facing, static and dynamic screened, single occupancy experimental office space set-ups during the summer months in moderate climate of ASHRAE, CZ 4C. Every participant, who was exposed for an hour, carried out office-like tasks and responded to questionnaires on the thermal perception of the indoor environment. Besides the subjective responses, the indoor environmental thermal and visual data of the set-ups were recorded during the experimental period. Subjective data on thermal perception was correlated with indoor environmental data to understand the inconsistencies between predicted and actual thermal comfort, and to identify the thermal and visual parameters influencing thermal pleasure under different sky conditions. It was found that the thermal comfort PMV model over-predicted discomfort in the solar screened building perimeter spaces. Dynamic screens under sunny sky conditions could evoke the highest magnitude of thermal pleasure when the indoor environmental parameters indicated a move from predicted discomfort to comfort. Mean radiant temperature, relative humidity, and horizontal illuminance significantly impacted thermal pleasure perception. Moving beyond the usual practice of making architecture for visual delight, through this work the researchers followed a design approach that employed architecture to offer pleasurable thermal experiences for occupant satisfaction and well-being.
Shape-Shifters: Mobile Thermal Boundaries Achieve High-performance for Variable Occupancies in Native American Homes
University Of Minnesota, United States of America
Zero-H, a research project supported by a NSF Planning grant, integrated community focus groups to develop design concepts for affordable, high-performance single family residence design concepts for Native American communities in the Dakotas.
Per the 2010 US Census, 39.8% of Native Americans in North Dakota live below the poverty line. Poverty exacerbates the energy burden. According to the US Department of Health and Human Services (LIHEAP Case Study on Energy Burden for FY 2005), the median residential energy burden for households with income less than $10,000 was 15.9%, with 10% having energy burdens greater than 52.1% (90th percentile). To add to these problems, per the Energy Information Administration, North Dakota has the highest energy expenditure per person in the nation. Additionally, from focus group discussions, the research team learned that variable family structures that can shrink or grow rapidly in a matter of hours (range from 4-19 household occupants in the focus group), are a common phenomenon and not addressed by inadequate one-size-fits-all housing solutions. The 2013 National American Indian Housing Council report found that 40 percent of on-reservation housing in the United States is considered substandard and that nearly one-third of reservation homes are overcrowded.
The goal for the architectural team within the research group was to develop concepts of affordable high-performance housing where initial construction costs and ongoing operational costs are substantially lowered. The team used the Passive House criteria as a way to reduce operational energy costs by 80%. In addition, the architecture team developed the concept of interior, mobile, super-insulated wall systems which perform as variable internal thermal boundaries that can be adjusted to variable occupant loads, maximizing conditioned volume when there are more occupants and minimizing conditioned volume to save energy costs when there are fewer occupants. Since the mobile walls are internal boundaries that do not need the typical control layers such as moisture and vapor barriers, they can be lightweight and inexpensive. The thermal boundaries are super-insulated to meet Passive House standard in order to ensure that the body heat of occupants can be modeled as internal heat sources per the building science criteria developed by the german PassivHaus Institut’s (PHI) Dr Wolfgang Feist.
The hypothesis tested was that the Passive House design with the mobile thermal boundaries such that enclosed volume can be made proportional to the occupant load, is more efficient than the same Passive House design without mobile internal thermal boundaries. Simulation tests with WUFI energy modeling included multiple occupancy loads and volumes in design configurations with and without mobile interior thermal boundaries. The preliminary results of this research showed that the Passive House design with internal thermal boundaries which can be adjusted to occupant load performs better than the Passive House of comparable treated internal volume without internal thermal boundaries. This paper concludes with a discussion of variables that need to be tested in future research including relative R-values of internal and external thermal boundaries.
Thermal Preference and Comfort Assessment: Historic Buildings in Hot and Humid Climates
1Illinois Institute of Technology, United States of America; 2University of Texas at San Antonio, United States of America
Research on Post-Occupancy Evaluation (POE) in historic buildings has increased exponentially in recent years. Religious structures are a critical asset to the heritage building stock and a significant field of study due to the particular occupancy patterns and the impact of indoor microclimate on the occupants’ thermal comfort satisfaction. Based on recent research literature, this paper compares a quantitative and qualitative study performed to assess the thermal comfort conditions using occupants’ surveys, results of a calibrated energy simulation model, and Predicted Mean Vote (PMV) and Percentage of Dissatisfied (PD) calculations. The study was carried out in a UNESCO world heritage site over a 5-month period. Gathering over 221 questionnaires and data from a 12-data logger network logging air temperature and relative humidity values every 15 minutes, the indoor conditions of an 18th century church in San Antonio were monitored. The PMV and Predicted Percentage of Dissatisfied (PPD) were then calculated using Povl Ole Fanger’s method. Using the software IES-VE, the energy simulation model results and the PMV and PD values are compared with real occupants’ subjective opinions. The results show a difference among the three calculation methods, particularly during the summer months when the indoor-outdoor thermal leap is larger. Additionally, the comparison reveals that the thermal comfort predictions using computational energy models are more accurate than utilizing Fanger’s method. The findings will inform architects, engineers, and researchers in their efforts to promote more efficient and healthy historic spaces and to run POEs of existing religious buildings.