Impact of Energy-Consuming Air Conditioning Systems on People's Thermal Comfort and Preferences: Comparative Study of Iraq and Gulf Cooperation Council Countries

This study investigates the impact of the intense usage of air-conditioning systems on the thermal comfort requirements of building occupants. It compares the thermal comfort requirements of building occupants in Iraq and Gulf Cooperation Council (GCC) countries. Iraqis have limited usage of air-conditioning units, whilst people in GCC countries intensely operate these systems. Research work underpinning this article involved undertaking a year-long thermal comfort survey in Iraq, and an intensive analysis of thermal comfort studies conducted in GCC countries. Results show that, in Iraq, people experience a 2–50 °C annual indoor temperature range, and their annual comfort range is 14–35 °C. In GCC countries, due to the intense usage of air-conditioning systems, the widest recorded annual indoor temperature range is 17.2–31.0 °C, and the widest annual comfort range is 20.0–27.8 °C. These results demonstrate the significant impact of air-conditioning systems on narrowing the thermal comfort limits of building occupants leading to high energy consumption. This study presents a novel comparison between two cases highlighting the impact of air-conditioning systems on the thermal comfort requirements of building occupants. The results of this study can be used to inform the development of thermal comfort standards that better consider people’s adaptation capabilities to help reduce energy consumption for heating and cooling purposes.</jats:p

Visual comfort assessment of daylit and sunlit areas: A longitudinal field survey in classrooms in Kashan, Iran

Visual comfort in schools enhances not only health and wellbeing, but also satisfaction and therefore learning and visual performance. This research aims at testing students’ evaluations on visual comfort through questionnaires in daylit and non-daylit areas in classrooms. Dynamic daylight metrics including Spatial Daylight Autonomy (sDA) and Annual Sunlight Exposure (ASE), codified in LEED v4, are calculated and compared to students’ evaluations. A typical high school in Kashan was selected in which subjective and field measurements were carried out simultaneously in two different oriented (south and north) classrooms during a school year (2014–2015). Simulation results show that 71% of the space in south facing classroom and 20% of the space in north facing classroom receives adequate amount of daylight while 29% of the space in south facing classroom and 0% of it in north facing classroom receives excessive amount of sunlight. According to simulations, each classroom has been divided into daylit and sunlit areas, in which students’ assessments about daylight and sunlight have been separately analyzed based on their position. Comparing simulation and survey results show that while students’ evaluation about daylight availability in daylit areas is mostly positive, daylight uniformity is not considered “enough” in these areas. Moreover, students’ impression about daylight availability in non-daylit areas is rather neutral and more optimistic than simulation results. More interestingly, most students in both sunlit and non-sunlit areas of classrooms do not feel much direct sunlight and glare. In fact, questionnaires’ results show a wider range of sunlight acceptance in south facing classroom and visual comfort in north facing classroom than simulation results. According to the results non-daylit areas or sun-lit areas defined by dynamic metrics would not necessarily cause visual discomfort, suggesting that some other factors (e.g., view, configurations of windows, expectations and region) can change the degree of comfort experienced in each space

Occupants’ satisfaction in BREEAM excellent certified buildings

This paper examines occupants’ satisfaction of three BREEAM excellent certified buildings at Coventry University in the UK. Occupants’ satisfaction is evaluated against passive and active sustainable approaches used in these buildings to improve Indoor Environmental Quality (IEQ). This paper adopts a quantitative approach by running a seven-point rating scale questionnaire to obtain occupants’ overall satisfaction score in each building. A total of 180 occupants were surveyed to investigate occupants’ satisfaction of the thermal environment, indoor air quality, visual and acoustic environment during summer and winter. The results show that average satisfaction scores are towards the more acceptable part of the scale in BREEAM Excellent certified buildings. The sustainable approaches towards these buildings and applied passive and active techniques improve occupants’ satisfaction of Indoor Environmental Quality. It should be highlighted that Coventry University has improved its sustainability approaches towards its buildings over time, with newer buildings showing a higher level of satisfaction

Developing a design framework to facilitate adaptive behaviours

Adaptive behaviour has a significant impact on the quality of indoor environment, comfort, and energy consumption. Therefore, facilitating positive occupant behaviours will improve these three factors. The aim of this paper is to develop a design framework that can be used as part of the design process to facilitate adaptive behaviours. This paper reviews studies that focus on reasons behind adaptive behaviours, and implication of these adaptive behaviours on the built environment. This paper highlights that ‘Context’, ‘Occupant’, and ‘Building’ (COB) have the most influence on adaptive behaviours. However, in most cases their influence is not considered holistically. This study also illustrates that adaptive behaviour has implications for the quality of Indoor environment, level of Comfort, and Energy consumption (ICE). This paper introduces a framework consisting of three stages: (1) Evaluate the relation between COB and ICE factors with adaptive behaviours holistically; (2) Design building's controls for ‘environmental behaviours’, set-up strategies for ‘personal behaviours’, and find a balance between these two; 3) Monitor the performance of adaptive behaviours through Post Occupancy Evaluation (POE)

Operations on windows and external doors in UK primary schools and their effects on indoor environmental quality

This study provides a comprehensive analysis of the predictors influencing operations on windows and external doors as well as their impact on IEQ, comfort and energy. The study was carried out in 31 naturally ventilated classrooms in eight primary schools in the UK during non-heating and heating seasons. The state of the windows and external doors was collected by time-lapse cameras and visual observations. Environmental variables impacting window operations were recorded at 10-min intervals. Correlational tests and predictive regression models were used to identify how windows open area (m2) were affected by environmental predictors. Results show that operative and outdoor temperature during the non-heating season and indoor and outdoor humidity during the heating season were the main predictors of windows open area (m2). The main driver for the operation of external doors was occupancy patterns, however, the period that they stayed open was dependent on temperature. The impact of windows and external doors' open area (m2) on operative temperature decreased after 40 min, however, its impact on CO2 level was only noticeable up to 30 min. Through opening more available windows, operative temperature (34% of the time) and CO2 levels (28% of the time) could be reduced during the non-heating season. Furthermore, energy waste could be avoided 67% of the time during the heating season by reducing the set-point temperature and training school occupants on when to operate windows. This study suggests several avenues to improve the impact of controls’ operation on IEQ, comfort and energy

The gap between automated building management system and office occupants' manual window operations: towards personalised algorithms

This paper aims to demonstrate how knowledge acquired from occupants' manual window operations can be implemented into BMS automated window operation algorithms. Ten single-occupant offices were selected in a university building in the UK. More than 28,000 hourly data points on indoor and outdoor temperature and open window area (OWA) were analysed from 2015 to 2020. The BMS had adopted nine different automated window operation algorithms during the 5 years. The automated window algorithms could be manually overridden by the office occupants. Automated algorithms were compared against manual window operations. The results showed that the slope and gradient of the regression lines for occupants' manual window operations are smaller than automated operations. OWA of automated window operations increased 20% per 1 °C increase in indoor temperature, however, occupants opened windows 6–8% per 1 °C increase. Occupants react slower to temperature changes than assumed by BMS, which could be considered in BMS automated window operations