br Literature review br Design of the educator survey

Literature review
Design of the educator survey
Results and discussions
Conclusions and recommendations
Introduction As per ASHRAE 55 (RAA-C.E, 2013), thermal comfort is defined as “that condition of mind that expresses satisfaction with the thermal environment and is assessed by subjective evaluation.” The human body is in the process of constant heat exchange with the environment. This heat balance of the human body governs the thermal comfort experience of individuals. As such, many variables affect human thermal comfort, and research has organized the most prominent variables into three sets (Table 1). This section provides a short description of the concepts of thermal comfort, including the predicted mean vote (PMV) scale, often used to measure thermal comfort (Rupp et al., 2015). The PMV, which was developed by Ole Fanger, is a seven-point scale ranging from −3 to +3 and is the most commonly used thermal comfort index (Fanger, 1970). PMV is the mean vote that one would expect to obtain from averaging the thermal sensation votes of a large group of people in a given environment. The PMV is a complex mathematical expression that involves activity, clothing, and four environmental parameters, namely, air temperature, mean radiant temperature, humidity levels, and air velocity. However, thermal comfort temperature ranges are specific to types of buildings and climatic conditions of the location (Toe and Kubota, 2013). On the same lines, the predicted percentage dissatisfied (PPD) gives the percentage of people who are dissatisfied with the thermal environment. When PMV is zero, PPD is at five percentage, which means that when the sensational level of cold or hot is zero, five percentage votes are for discomfort. This study utilizes PMV as the thermal comfort indicator for an optimized layout design of buildings during the design stage. Optimum thermal comfort levels are basic requirements for any space design and research. For example, Han et al. surveyed 110 occupants in residential buildings and found that EZ Cap Reagent AG consumption could be reduced if thermal comfort conditions are considered (Han et al., 2007). However, a dearth of research in this field pertains to hot and humid climate locations. Furthermore, Barbosa et al. proposed design parameters that can help in evaluating and optimizing design options to maximize annual acceptable comfort levels in occupied space of up to 70% (Barbosa et al., 2015). As global interests turn toward energy efficiency in buildings in the wake of climate change, thermal comfort studies are gaining immense importance. A growing number of studies in the field of thermal comfort in tropical climates for indoor and outdoor spaces are evident with the increase in the number of published research and review articles. Deb and Ramachandraiah investigated thermal comfort conditions for indoor environments and concluded that occupants exhibited varying degrees of adaptability (Deb and Ramachandraiah, 2010). However, thermal comfort varies with different times within the day (Gupta et al., 2015). This effect is due to the thermal mass of building materials and the nighttime urban heat island (UHI) effect outdoors. An elaborate study on the effect of outdoor UHI on indoor thermal comfort in one of the test locations in this study (Chennai) is presented by Deb and Ramachandraiah (Deb and Ramachandraiah, 2011). Indraganti (Indraganti, 2010a; Indraganti, 2010b) conducted a field experiment in naturally ventilated apartment buildings in Hyderabad. Responses from approximately 100 subjects were collected, which generated a dataset of 3962 values. In the month of May, most of the subjects were uncomfortable due to high air temperature. Thermal comfort increased in June and July as air temperature decreased. Humidity was not an important factor because the climate was hot and dry. Clothing adaptation was impeded by many socio-cultural and economic aspects. PMV was always higher than the actual sensation vote. Singh et al. (2010) conducted detailed field studies on the thermal performances of typical conventional vernacular dwellings in different bioclimatic zones in India. A survey was conducted on 150 different vernacular dwellings, and field tests with thermal sensation vote were conducted among 300 occupants. ASHRAE thermal sensation scale was used as a benchmark for the survey. The thermal performances of these vernacular dwellings were investigated for winter, pre-summer, summer-monsoon, and pre-winter months for 2008. The study attempted to determine the variation of comfort temperature in these vernacular buildings for different seasons of the year. These vernacular dwellings performed quite comfortably throughout the year except during winter months, when occupants were slightly less comfortable.