1,721,126 research outputs found
Investigating the probability of behavioural responses to cold thermal discomfort
No full textIn buildings, occupant behaviour is recognised as a major contributing factor to energy demand and in particular to heating consumption. To achieve thermal comfort within the heating season, people report to use heat in very different ways; for example behaviours include switching on the heating system, putting on warm clothes, drawing curtains, changing rooms, making a hot drink and using a hot water bottle. While research has focused on subjective accounts using interviews, diaries and questionnaires, little is known about the frequency and probability of these behaviours. Using a mixed-method approach, this paper reports on the results of a field study in dwellings using wearable and environmental sensors. The analysis investigates the probability of these behavioural responses as a function of seven independent variables; (1) external and (2) internal monitored temperature, (3) probability of heating being on or off, (4) time of the week, (5) time of the day, (6) the three categories of the predictive thermal comfort model, and (7) the three categories of the adaptive thermal comfort model. Results show that participants were more likely to increase their clothing and activity level as internal temperature decreased, although there was no significant change in activity level throughout the course of a day. Methodologically, this paper demonstrates the effectiveness of different statistical tools in analysing occupants' behaviours. Substantively, this paper emphasises the need for future research to gather objective data on what people do
Moving beyond averages: variations in reported thermal comfort
No full textThermal comfort research characterises group thermal perception using averages. This approach overlooks the value of analysing variation as a dependent variable characterising groups’ state of comfort. In this paper, we reviewed the results of 219 surveys carried out in five schools in the UK and in Sweden between 2011 and 2016. Results show that pupils’ thermal sensation and preference votes varied more at moderate indoor operative temperature. This result suggests that pupils may have a greater range of adaptive opportunities, including clothing, in moderate environments. Substantively, reviewing the spread of the thermal comfort is critical to unpick behavioural, psychosocial and physiological mechanisms. Furthermore, results are significantly different while analysing the central tendency or spread of comfort votes. For example, there is no difference in comfort votes’ central tendency between surveys carried out during the heating seasons and the non-heating seasons but there is a significant difference in the spread, indicating the need for multilevel analysis. Methodologically, reviewing the spread of thermal comfort is also critical to establish the data analysis method. With recent advances in surveys’ tools allowing larger datasets to be gathered at individual and group levels, it is essential to review the range of analysis methods
Understanding window behaviour in a mixed-mode buildings and the impact on energy performance
No full textStudies have shown that people feel more comfortable when they can control the environment in which they live and work. In a mixed-mode office building, this control is usually through openable windows, but window opening behaviour can have a significant impact on building energy performance. This monitoring study investigated window behaviours in a mixed-mode office building during the summer of 2016 in Southampton. Applying a mixed methods approach, 31 windows and 10 offices doors, movements were monitored using accelerometers. Concurrently indoor and outdoor environments were monitored and occupants' surveys undertaken. Results show a statistical relationship between window opening behaviour and indoor ambient and radiant temperature and CO2 levels. The reasons for opening a window temperature and humidity as reported from the occupant’s survey. Observed patterns of window opening behaviour did not match the building’s design strategy as users acted differently from what BMS advised. This will have a substantial impact on energy performance in summer.<br/
Ventilation assessment and comfort implications in a student halls of residence
No full textWindow behaviour is a key driver of energy consumption and has a significant impact on occupant comfort. This study investigated patterns and drivers of window behaviour in a student halls of residence using a mixed-method approach. Twenty-one occupants of Mayflower Halls in Southampton have taken part in the study over the summer of 2017. Occupant surveys include a background interview and a weekly survey (for 6 consecutive weeks) with questions on their perception of the indoor environment as well as a self-reported use of the building controls available in occupant’s rooms (e.g. windows, curtain). The environmental monitoring recorded air temperature, relative humidity and window movement. The results showed that a large percentage of participants (67%) were dissatisfied with the ventilation, thermal conditions and noise in their rooms, and would prefer to have more air movement. To address these issues, the paper suggests a series of recommendations for building management and retrofit options
Investigating dependencies between indoor environmental parameters: thermal, air quality and acoustic perception
No full textIn buildings, occupants’ interactions with systems and their behaviour is often influenced by environmental discomfort; thermal, visual, acoustic or air quality. Many studies have investigated the relationships between occupant behaviour and one of these discomforts, but very few studies have addressed multi-stressor effects. This paper reviews the results of a field study in two office buildings (N=1,420). Questions were applied to estimate the state of seven environmental controls and three environmental parameters; thermal perception, air quality and background noise level. As the data is ordinal, linear-by-linear association tests followed by Goodman Kruskal Gamma tests were undertaken to ascertain the significance and the strength of relationships between the three environmental parameters. Most results showed no relationship between the parameters; only a modest association between air quality and background noise level. Further analysis explored the relationships between the three parameters when environmental controls were at play, e.g. state of window opening or air-conditioning. In such cases, moderate to strong relationships were uncovered, notably between thermal perception and air quality. These new insights may inform the basis for drawing causal relationships between occupant behaviour and environmental parameters in a view to re-thinking and managing behaviours in affordable comfort for all
Researching sustainability perspectives through online ‘face-to-face’ focus groups: Sage research methods video: qualitative and mixed methods
No full textStephanie Gauthier, PhD, and Philip Turner, PhD, University of Southampton, discuss researching sustainability perspectives through online 'face-to-face' groups, including research design, ethical approval, data collection and analysis, challenges faced, lessons learned, and future recommendations
UK energy consumers acceptability of a heat deferral approach to mitigating peak electricity demands
No full textIn order to meet UK 'net zero' objectives, residential heat demand is to be decarbonised through a combination of electrification (alongside the decarbonisation of electricity generation) and energy efficiency measures. This strategy, in combination with electric vehicles, could lead to a 200-300% increase in the UK's annual electricity demand and could introduce serious capacity issues for the electricity system. In the future, residential electrical heating or electric vehicle charging loads may need to be controlled remotely and adjusted to better suit the capacity of electricity network infrastructure. Here we present part of a study examining the concept of ‘deferable heat’: the reduction of electrical load from heating appliances such as air-source heat pumps for short periods during peak times. We report the findings of an online survey with a UK energy provider’s domestic customers (N=4,100) which asks whether household approve of such a scheme and what levels of heat deferral they would be willing to accept at various times of day. The survey also gathered information on energy literacy levels, personality traits, trust in energy companies, social demographics, thermal comfort and general dwelling information. These factors were examined in the analysis to determine the extent to which they influence stated acceptance of heat deferral. The survey results helped to identify pathways for ongoing research, guiding follow-up online focus group interactions further examining the factors influencing household acceptance. Moreover, the stated preferences will be tested against actual behaviour during a field trial (active 2022 to 2024).<br/
Comparing the influence of PMV inputs on the index between naturally ventilated and air-conditioned buildings
No full textPrevious studies have shown MET and CLO are the most influential variables in the PMV model. Using the data from ASHRAE database 2 this paper performs a global sensitivity analysis of the input variables to the PMV model adopted in ISO 7730. First, this paper reviews the descriptive statistics of the six PMV inputs (M,Icl,ta,tr,RH,va) from naturally ventilated and air-conditioned buildings. Then, a global sensitivity analysis is carried out to estimate the strength of the relationships between each PMV input and the PMV index. Results show a difference between the two ventilation modes: in air-conditioned buildings the PMV index is mostly influenced by clothing insulation and metabolic rate, whereas for naturally ventilated buildings ambient and radiant temperatures have the greatest impact. This difference is explained by the difference in the inputs’ variance, which is likely to be attributed to the behavioural adjustment of occupants to achieve personal comfort. In air-conditioned buildings, thermal comfort is directly associated with personal adaptation (clothing and activity levels), therefore social and corporate codes should support this adaptation. In naturally ventilated buildings, the design of building systems and control interfaces should enable individuals to adjust their environment to their preferences
Thermal comfort and productivity – What can the chair tell us?
No full textPast research has suggested that there is a relationship between people who report dissatisfaction with their indoor environment and those that report the office environment to be affecting their productivity. Currently, there is no method to assess productivity objectively. This study develops a new method to measure productivity and thermal comfort of offices’ occupants. Mixed-method approach was used to monitor concurrently environmental conditions, office chair movements, self-assessed productivity, and thermal comfort. 3-Axis accelerometers fixed on office chairs were used to monitor occupants’ movement while sitting down. The general idea is the more 'twitchy' the chair is, the more productive a person can be. This study involves 6 participants monitored for 4 weeks. Results show that there is a significant relationship between occupants’ perceived productivity and occupants’ chair movement. Furthermore, the analysis explored the lag effect of environmental variables on perceived productivity, at the time of the survey, one hour prior to the survey, and for a whole day
The importance of sample grouping; Exploring thermal sensitivity of occupants within one building type and ventilation mode
Full text linkOccupants’ thermal response is influenced by their sensitivity to temperature variations, i.e. the rate of change in occupants’ thermal sensation per unit change in indoor temperature. Thermal sensitivity is commonly taken as constant (Griffiths constant) in the calculation of occupants’ comfort temperature. This constant is based on small differences found between buildings’ ventilation modes [naturally ventilated (NV) vs. air conditioned (AC)]. However, recent research found significant differences depending on building type, ventilation mode, age, gender and climate. This paper reviews thermal sensitivity within the same building type and main ventilation mode using longitudinal surveys and monitoring data from school buildings, two in the UK (U1 and U2) and one in Sweden (S1). Results show that in two of the schools (U1 and S1) children were half as sensitive as in school U2 and the difference is statistically significant. A similar result with slightly different thermal sensitivities was derived from comparison by clusters derived from the classrooms’ indoor temperatures. This outcome suggests that building ventilation mode (AC/NV), which is typically considered the main determinant of occupants’ thermal experience and often the only building information recorded in field surveys, is inadequate to explain this important occupant response factor
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