Thermal Comfort Survey Research Articles

Analysis of the Thermal Comfort and Energy Performance of a Thermal Chair for Open Plan Office

The aim of this work is to analyse the thermal comfort and energy performance of a thermal heating chair for open plan office using field experiments, thermal comfort survey and energy simulations. A comprehensive review on the development of thermal chairs was carried out to highlight the present research gaps. The study developed a thermal chair prototype with controllable heating pads, incorporated into the back of the seat and back rest fabric. The field test was carried out in an office building in the UK during the winter. The study showed that the users set the thermal chair temperature between 29-45 °C. The field survey results of the thermal satisfaction survey showed that 19 out of 44 participants felt satisfied before using the device. While after using the thermal chair, the number of satisfied respondents increased to 34. The work also utilised Building Energy Simulation to further assess the thermal comfort and energy performance of the thermal chair. Three cases were simulated: non heated office chair with the zone thermostat maintained at 22 °C, non heated office chair with the zone thermostat at 16-20 °C and thermal chair with the zone thermostat at 16-20 °C.

The degree of adaptive thermal comfort in office workers in a hot-summer Mediterranean climate

This study aims to investigate occupants’ perception of feeling comfortable over different seasons in offices located in Amman, Jordan, to determine the comfort temperature zones, and to compare the results developed from this study with other adaptive models and standards. It is based on longitudinal field surveys, which were conducted in three office buildings, two mixed mode buildings and a free running building, during four seasons: April 2016 (spring), July/August 2016 (summer), October 2016 (autumn) and January/February 2017 (winter). A total of 119 occupants participated in the thermal comfort surveys and completed 659 questionnaires. The free running building experienced a variation in operative temperature during the four seasons, while median temperatures in the mixed-mode buildings stayed almost the same during all seasons. Occupants felt comfortable in a broad range of thermal sensations from ‘cool’ to ‘warm’. Thermal comfort was expressed by a high proportion of the occupants. Occupants changed their clothing insulation with season, whereby compared to winter some occupants showed a changed clothing insulation already in the spring survey and others only in the summer and autumn survey. A Loess analysis between the temperatures at which the occupants felt comfortable and the running mean outdoor temperature indicated independency between the two variables in case of the mixed-mode buildings at running mean outdoor temperatures below 22 °C, but a trend towards decreasing comfort temperature above 22 °C. The comfort temperature in both mixed mode buildings was around 23.5 °C. In the free running building, a monotonically increasing linear relation between the two variables was found at running mean outdoor temperatures below appr. 24 °C, but a constant comfort temperature of about 26 °C above this value. Compared to the adaptive comfort models in ASHRAE Standard 55 and EN 15251 the gradient in the adaptive comfort equation resulting from the free running building in Amman was higher. Although the occupants adjusted their clothing insulation level, the gradient in the comfort equation was close to zero in the mixed mode buildings.

Development of an adaptive thermal comfort model for energy-saving building design in Japan

In order to quantify the seasonal differences in the comfort temperature and to develop a domestic adaptive model for highly insulated Japanese dwellings, thermal measurements and a thermal comfort survey were conducted. We collected 19,081 thermal comfort votes from 94 residents of 69 flats. The results suggest that the residents are highly satisfied with the thermal environment of their dwellings. People are highly adapted to the thermal condition of the dwellings, and the comfort temperature has seasonal variation. An adaptive model for these dwellings was derived from the data, to relate the indoor comfort temperature to the prevailing outdoor temperature. Perhaps because of the high insulation of the condominiums, the seasonal differences of comfort temperature and the regression coefficient of the adaptive model are smaller than those of detached houses. Adaptive building design and adaptive thermal comfort of people are important for energy-saving building design.

Characterizing Variations in the Indoor Temperature and Humidity of Guest Rooms with an Occupancy-Based Climate Control Technology

This paper characterizes variations in the indoor temperature and humidity profiles of actual guest rooms equipped with Occupancy-Based Climate Control (OBCC) systems that were used to initiate a temperature setback to 15.6 °C in the winter and to 26.7 °C in the summer in the guest rooms. Empirical knowledge of these conditions can provide useful insights for an improved field demonstration and optimization of OBCC, as well as for a more realistic temperature and occupancy input for building simulations for hotel guest rooms. As a result, one year of one minute temperatures and humidity data was characterized against outdoor climate for three different occupancy modes, which was useful to identify the observed room-to-room variations in heat losses and resultant indoor temperatures during the heating season due to the different dynamic heat balance conditions of the guest rooms. This indicated potential discomfort in the rooms that appeared to have a stronger association between outdoor and indoor temperatures, which was also identified from the thermal comfort survey indicating thermostat-related discomfort sources. Interestingly enough, the guests who stayed in these rooms tended to set their thermostat at higher setpoint temperatures when they occupied the room, which appeared to compensate for the low balance-point temperatures of these rooms.

The colours of comfort: From thermal sensation to person-centric thermal zones for adaptive building strategies

Thermal comfort research has been traditionally based on cross-sectional studies and spatial aggregation of individual surveys at building level. This research design is susceptible to compositional effects and may lead to error in identifying predictors to thermal comfort indices, in particular in relation to adaptive mechanisms. A relationship between comfort and different predictors can be true at an individual level but not evident at the building level. In addition, cross-sectional studies overlook temporal changes in individual thermal perception due to contextual factors. To address these limitations, this study applied a longitudinal research design over 8 to 21 months in eight buildings located in six countries around the world. The dataset comprises of 5,567 individual thermal comfort surveys from 258 participants. The analysis aggregated survey responses at participant level and clustered participants according to their thermal sensation votes (TSV). Four TSV clusters were introduced, representing four different thermal sensation traits. Further analysis reviewed the probability of cluster membership in relation to demographic characteristics and behavioural adaptation. Finally, the analysis at individual level enabled the introduction of a new metric, the thermal zone (Zt), which in this study ranges from 21.5 °C to 26.6 °C. The thermal sensation traits and person-centric thermal zone (Zt) are a first step into the development of new metrics incorporating individual perceived comfort into dynamic building controls for adaptive buildings.

Experimental and numerical studies on indoor thermal comfort in fluid flow: A case study on primary school classrooms

Indoor thermal comfort in primary classrooms is important to students' learning and health. The studies focusing on it, especially under the subtropical plateau monsoon climate, are scarce. In this study, the indoor thermal comfort surveys and parameter measurements were made over the period from October 2018 to December 2018 in Kunming, China. A series of indoor thermal comfort and outdoor parameters were measured each 1 h and subjective questionnaire surveys were performed on the selected 20 students every week except on holidays. A series of three-dimensional numerical simulations were carried out using ANSYS Fluent.

Determination of thermal comfort of religious buildings by measurement and survey methods: Examples of mosques in a temperate-humid climate

Thermal comfort in buildings is an important parameter affecting the physiological and psychological conditions of the users as well as their working efficiency and activity levels. Acceptable thermal comfort levels specified in the standards are created within certain limits. This raises the question whether it is appropriate to use the same acceptable comfort ranges in different building types and climatic conditions. In this study, the design-usage of the example mosques in temperate-humid climate was evaluated by using thermal comfort level measurements and survey methods. The aim of this study is to compare the indoor thermal comfort conditions measured in mosques according to standards, to determine the thermal comfort perception of the users, to evaluate the difference between the measured and perceived thermal comfort levels. In the scope of the study, two mosques with different heating and cooling systems were measured with thermal comfort devices. The thermal sensation survey was conducted with the users on Fridays of the measurement weeks. When the thermal comfort levels that measured and perceived were compared, the indoor conditions were within acceptable ranges according to the measured results whereas the user thermal sensation survey results revealed that the environment was hotter. In order to create similar thermal comfort in the interior, it was determined that design innovations or mechanical solutions should be made for the prayer zones in the entrance areas of the mosques. In light of the findings, suggestions were made for the design of the new mosques and the usage program of the existing ones.

Analysis of the Indoor Thermal Environment and Passive Energy-Saving Optimization Design of Rural Dwellings in Zhalantun, Inner Mongolia, China

Zhalantun city is located in a severely cold region of China. The cold climate and long winter bring challenges to the energy-saving design of rural dwellings in this area, while the poor economic conditions restrict the application of energy-saving technology. This paper aims to propose an optimal combination of passive design parameters by investigating, testing, and analyzing simulations of Zhalantun rural dwellings, which have a particular architectural pattern. Field measurements during winter show that the indoor temperature of a traditional house is low and fluctuates greatly, and the inner surface is prone to easy condensation. Through thermal comfort surveys, neutral and acceptable temperature ranges were obtained to provide indoor calculation parameters for an energy-saving design. Numerical simulations of heating energy consumption were conducted on the typical building models using DesignBuilder. The influence of different design factors on energy consumption was evaluated. Orthogonal experiments were designed to optimize a series of design parameter combinations to reduce the energy consumption of Zhalantun rural houses and to determine the sequence and significance of the effect of these design factors on energy consumption. Results show that the optimal parameter combination based on orthogonal experiments can obviously reduce energy consumption and have better economic benefits without considering mechanical methods. This can provide a basis for improved energy-saving designs and indoor thermal environments in such rural dwellings.

Adaptation by coexistence: contrasting thermal comfort perception among individual and shared office spaces

ABSTRACT Shared office spaces represent a challenge regarding thermal comfort. They have a diversity of occupants and expectations, and they require social interaction, which could imply restriction in adaptive actions, contrary to individual areas that usually allow total control. Hence, this paper aims to identify differences in thermal comfort criteria among individual and shared offices spaces by comparing adaptive opportunities and actions performed as well as thermal perception. Fieldwork was carried out in Chile in 18 office buildings, 9 in Concepcion (36°S), and 9 in Santiago (33°S). Thermal comfort surveys with simultaneous measurements of indoor environmental conditions were performed in each of these buildings during a single day in winter, spring and summer. The findings show variations in the criteria studied, which indicate that thermal requirements differ by spatial layout. Moreover, the results suggest that occupants of shared spaces have a wider comfort range; therefore, some kind of ‘adaptation by coexistence’ might be happening.

Facilitating responsive interaction between occupants and building systems through dynamic post-occupancy evaluation

Post-occupancy evaluation (POE) is a process that can reveal the interrelations between key building performance factors and successfully integrate indoor environmental quality, thermal comfort, functionality, environmental strategy and occupants’ satisfaction. POE has become a prerequisite for several building certification systems and it is often presented as a method to improve the commissioning of buildings and as a user experience feedback mechanism. This paper is based on a POE undertaken through stages at the University of Southampton Mayflower Halls of Residence complex. The first stage included the evaluation of occupant satisfaction, indoor environment quality and energy use. Results from temperature and relative humidity monitoring and an online POE questionnaire were analysed in the context of energy use, thermal comfort and building controls’ functionality. The second part of this study monitored the air temperature in a sub-sample of 30 rooms where the residents participated in a thermal comfort survey with a “right-here-right-now” questionnaire and a portable instrument that monitored air temperature, relative humidity, globe temperature and air velocity in the rooms. This paper presents the results of the POE and discusses approaches for the improvement in the buildings’ energy performance and the environmental conditions in the living spaces of the students. Results suggest that current use of controls is not always effective, with implications for the buildings’ energy use. Large variability was found in occupants’ thermal perception and preferences, which points to a need for occupant-centric solutions. In this study, POE is approached as a dynamic process that could be used to facilitate the responsive interaction of occupants with building systems and deliver through their engagement high energy performance and comfort.

Research on Thermal Comfort of Outdoor Space in Summer Urban Park: Take Mianyang Urban Park as an Example

One of the factors for the evaluation of the space environment is the comfort of outdoor activities spaces in urban parks. The space composed of different landscape elements has different microclimate environment. In this paper, in order to evaluate the role of thermal comfort in influencing resident’s assessment of the outdoor space and activities of the park, a thermal comfort survey was conducted on the outdoor open space of Mianyang Urban Park in summer. In this article, meteorological surveys, questionnaire surveys and observation of park attendance are selected to collect data. The physiological equivalent temperature (PET) assessment was selected as the index to evaluate resident’s thermal comfort level, and the comprehensive evaluation and analysis of the spatial thermal environment of different outdoor landscape elements in the park. The overall comfort of current visitors is mainly influenced by their subjective heat perception voting (TSV). In this article, we focus on providing microclimate adjustment considerations for urban park landscape design, and may help people understand the outdoor thermal comfort of Mianyang in summer, increase the using time of outdoor activities, and promote the use of outdoor space.

Examination of Comfort Temperature in the Traditional and Modern Building of Warm Humid Region

A Questionnaire survey to understand the Thermal Comfort of the inhabitants was carried out in the traditional and modern residential buildings in the coastal region of Nagappattinam during various seasons. The list of Questionnaire was prepared based on the Literature studies from Thermal Comfort Survey – ASHRAE 55 standards to comprehend the effect of diverse Climatic factors such as temperature, humidity, air flow and overall thermal comfort factors in the evaluation of thermal comfort in traditional and modern residential buildings. The findings of this study were based on the collection of answers from the survey. The findings of the survey are compared with the technical investigations which is included at the end of this paper. These findings reveal that people living in the traditional buildings of the coastal belts of Nagapattinam are well modified to the harsh environment of traditional houses than modern houses.

Performance evaluation of a direct ground-coupled self-regulating active chilled beam system

Active chilled beams support high temperature cooling which enables the opportunities of direct ground-coupling and self-regulation. Direct ground-coupling implies cooling through a ground heat exchanger without use of a chiller and self-regulation refers to the elimination of individual room control systems. This paper presents the operation and indoor air temperatures in such an office building located in Stockholm, Sweden, and the analysis includes the unprecedented hot summer of 2018.The results show that the system is capable of supplying the building with enough cooling to not exceed desired indoor air temperature levels. It is also concluded that the self-regulation kept the indoor air temperature satisfactory uniform. The difference between the highest and lowest temperature is 1.9 K on average and below 2.4 K during 90% of the time. Regarding stability, the least stable temperature recorded has a standard deviation of 0.8 K while the average standard deviation is less than 0.5 K. The indoor air temperature during summer is about 2 K lower than suggested by standards. This calls for conducting a thermal comfort survey and may be remedied by increasing the chilled water temperature. To increase the performance of the system, the ground is cooled during winter by preheating the supply air. During 2018, slightly more cooling was extracted in the summer than recharged during winter.

Thermal comfort of motion and stationary states for recreational spaces of colleges and universities in the cold regions of China

This study examined a representative college activity centre in China’s cold regions and conducted a field measurement study and questionnaire analysis on the indoor thermal environment in winter. Data fitting and comparative analysis were performed on the predicted mean vote (PMV) calculated from measured environmental parameters and the seven-point vote value actual mean vote (AMV) based on the questionnaire. According to the least square method, the corresponding human adaptive coefficient λm in the motion state and λs in the stationary state were obtained. Based on the research, the thermal comfort survey results were reported for the two states for recreational spaces of colleges and universities. These results suggest that the AMV and PMV do not coincide in the two states. The actual thermal sensation is less sensitive than predicted through the sensitivity analysis for the two states. The respondents’ actual thermal sensation is less sensitive when exercising than stationary state. Moreover, both PMV and AMV in motion state are higher than those in stationary state, illustrating that the state of motion has a greater influence on thermal sensation. This research provides a theoretical basis and data reference for the low energy design of recreational spaces of colleges and universities.

Use of adaptive control and its effects on human comfort in a naturally ventilated office in Alameda, California

Naturally ventilated buildings have been found to be comfortable over a wider range of indoor temperatures than in air-conditioned buildings, while using less energy. The mechanisms underlying this are not well understood. Through a longitudinal field study of a naturally ventilated office in Alameda, CA, we obtained insights into how occupants exercise various adaptive control opportunities to meet their comfort needs in the absence of a mechanical HVAC system. Continuous measurements were made of adaptive behaviors such as window state, ceiling fan usage, heater usage, and indoor and outdoor climate (dry-bulb air temperature, relative humidity, CO2, outdoor temperature). Over 1400 thermal comfort survey responses were collected, which showed that the building provided acceptable thermal conditions for 98% of the survey period, covering an indoor temperature range of 16–28 °C. Occupants wore clothing between 0.5 and 0.6 clo in summer, and 0.7–0.8 in winter. Occupants opened windows when the outdoor temperature was above 15 °C, with window opening often occurring at the occupant's arrival and proportional to outdoor temperature. Fan use was best explained by indoor temperature, typically being turned on during summer at indoor temperatures above 25 °C. Heaters were turned on in winter more than an hour after arrival and commencement of sedentary activity. With these adaptive control behaviors, occupants were thermally neutral and satisfied from 18 to 27 °C. Their satisfaction exceeded that predicted by ASHRAE Standard 55 or PMV-based ISO standards. Overall, our findings provide empirical support for adopting adaptive comfort model in office buildings.

Adaptive model and the adaptive mechanisms for thermal comfort in Japanese dwellings

In order to quantify the seasonal differences in the comfort temperature and to develop a domestic adaptive model for Japanese dwellings, thermal measurements, a thermal comfort survey, and an occupant behaviour survey were conducted for 4 years in the living and bedrooms of dwellings in the Kanto region of Japan. We have collected 36,114 thermal comfort votes from 244 residents of 120 dwellings. The results show that the residents are highly satisfied with the thermal environment of their dwellings. People are well-adapted to the thermal condition of their dwellings, and thus the comfort temperature has large seasonal differences in free running mode (FR): 9.4 K. An adaptive model for housing was derived from the data to relate the indoor comfort temperature to the prevailing outdoor temperature, and the regression coefficient in the FR mode is notably higher (0.48) than that in office buildings. Such models are useful for the control of indoor temperatures. The adaptive model of thermal comfort is strongly supported by the various adaptive actions reported by the residents.

Field Survey of Thermal Comfort and Sleep Quality in the Bedrooms with Different Cooling Strategies in Malaysia

This study aims to determine the indoor comfort temperature before sleep and after wake up in air-conditioning (AC) mode with different adaptive cooling strategies. Two units of guest rooms on the university campus were used with a total of 20 participants. The arbitrary-controlled AC setting (case 1) and control of thermostat setting by 3∘C higher than case 1 with installing of cool bed padding (case 2) were employed as cooling strategies in this study. The measurement parameters were indoor and outdoor air temperatures, globe temperature, relative humidity, air velocity, and AC electricity consumption. The questionnaire survey has also been distributed twice a day for “before going to bed” and “after waking up” during measurement simultaneously. It was observed that thermal sensation vote (TSV) indicated for both cases were within -1 ≤ TSV ≤ 1 and respondents might accept the present condition for both cases. Mean thermal preference (TP) in both cases either “before going to bed” and “after waking up” was found mostly close to “0 no change” (0.1 ≤ TP ≤ 0.3) for all cases. Overall comfort (OC) ranged between 4.7 and 4.9 for both cases, indicating for “comfortable.” However, air movement sensation (AMS) shows respondent felt weak airflow inside the room for all ventilation strategies. The skin moisture sensation (SMS) shows value pointed to neutral feeling for all cases. The comfort temperature obtained by Griffiths’ method was approximately 24∘C and 25∘C that for case 1 and case 2, respectively. Meanwhile, most of the respondents experienced calmness during sleeping and satisfied with their sleep in both cases. Sleep efficiency index (SEI) shows case 2 was higher rather than case 1. It seems the second adaptive cooling strategy might effective for reducing AC energy consumption by about 32% and increase 2% of SEI without affecting respondents’ thermal comfort.

Behavioural Adaptation for the Thermal Comfort and Energy Saving in Japanese Offices

Office workers use a variety of adaptive opportunities to regulate their indoor thermal environment. The behavioural adaptations such as window opening, clothing adjustments, and use of heating/cooling are important factors for adaptive thermal comfort. It is well-known that they are the most important contributors in the adaptive thermal comfort model. Thus, if we understand the behavioural adaptation properly, we can explain the mechanism of the adaptive model. The indoor thermal environment is often adjusted using the air conditioning in Japanese office buildings to improve thermal comfort and productivity. Thus, it is necessary to conduct research on the behavioural adaptation in the offices because the occupant behavior is different from behaviour in dwellings. In order to record the seasonal differences in behavioural adaptation and to develop an adaptive algorithm for Japanese offices, we measured temperatures in 11 office buildings and conducted the thermal comfort and occupant behaviour survey for over a year. We collected 4,660 samples from about 1,350 people. The proportion of ‘open window’ in the free running mode (neither heating nor cooling being used) is significantly higher than that of the air conditioned mode. The behavioural adaptation is related to the outdoor air temperature. The behavioural adaptations such as window-opening, heating and cooling use predicted by regression analysis are in good agreement with the measured data. These findings can be applied to building thermal simulation to predict the behavioural adaptation and energy use in office buildings.

A field investigation on the wintry thermal comfort and clothing adjustment of residents in traditional Nepalese houses

Nepal is a landlocked country with geographic variations that have led its people to develop a variety of distinctive cultures. Part of these cultures is reflected in the way that people create a suitable indoor thermal environment in residential buildings, depending on the outdoor climatic conditions. Temperature preferences may vary depending on the local climate characteristics. The aim of this study was to investigate the clothing adaptation of Nepalese residents in traditional houses during the winter. The indoor thermal conditions were examined during a winter in three regions of Nepal with different climates, including cold, temperate and sub-tropical climatic regions. A set of thermal measurements and thermal comfort survey was conducted in traditional houses of selected villages in Mustang, Kavrepalanchok, and Sarlahi districts during the winter of 2016. As part of the survey, 275 votes were collected, while the indoor and outdoor thermal conditions were being recorded in 108 houses. The mean indoor globe temperature was 12.2 °C in the cold region, which was 4.7 °C and 10.0 °C lower than that in the temperate and sub-tropical regions, respectively. The estimated mean comfort globe temperature was 13.8 °C in the cold region, which was 4.1 °C and 9.3 °C lower than that in the temperate and sub-tropical regions, respectively. The difference in the regional comfort temperature is quite large, and this is considered mainly due to differences in the adaptive behavior and particularly the clothing adaptation of the residents in these distinct climatic regions. The mean preferred temperature in the cold region was 14.7 °C, which is slightly higher than its mean comfort temperature. The mean clothing insulation was 1.63 clo in the cold region, and 1.32 clo and 1.15 clo in the temperate and sub-tropical regions, respectively. The choice of clothing and its insulation properties during the winter were mainly based on the condition of the building, indoor and outdoor climatic conditions.

Indoor comfort and adaptation in low-income and middle-income residential buildings in a Nigerian city during a dry season

This paper investigates occupants' comfort, adaptation and their responses during the dry season in low-income to middle-income residential buildings in Abuja, Nigeria. The study aims to provide empirical data on occupants' comfort through evaluating 171 households in four different locations in Abuja. The study considered a combination of different research methods for data collection. Post-occupancy surveys were used to evaluate the buildings and residents' adaptation within the thermal environment. Thermal comfort surveys were also carried out in eight low-income residential households to assess occupants' perception of the thermal environment. Based on the short duration of the physical measurements, building simulation was also used to examine thermal comfort of occupants for an extended period. The Post Occupancy Evaluation (POE) results revealed over 70% of the occupants were dissatisfied with their thermal environment. The comfort surveys reported similar results with over 65% of the responses revealed being ‘uncomfortably warm’. The results showed an overall mean temperature of all the measured case studies to be 31.7 °C and the average temperature (predicted) of 30.7 °C. The neutral temperatures were in a range of 28°C–30.4 °C compared to the preferred temperature range of 27.5°C–29.4 °C. The prevalence of thermal discomfort highlights the need to explore the possibilities of reducing internal temperatures, particularly by passive means (fabric, shading, insulation etc.) given the need to avoid or reduce the need for air conditioning to make the buildings energy-efficient for low to middle income groups.