The impact of ventilation strategy on overheating resilience and energy performance of schools against climate change: the evidence from two UK secondary schools

The indoor environmental quality and energy performance of two modern secondary schools in the UK which have fundamentally different environmental strategies were investigated during building performance evaluations. The performances of these buildings against the projected weather data for future were also analysed. The results point to significant risk of future overheating as a result of climate change in the naturally ventilated building with passive measures that go well beyond the existing guidelines for schools. The other school with mechanical ventilation shows resilience to future overheating. However, shortcomings in building procurement and operation have severely compromised its energy performance. It is suggested to carry out integrated life-cycle assessment of energy performance and overheating resilience in the context of climate change during design stages and identify the corresponding risks and mitigation measures required to ensure design intents will be met in practice

A case study of the approaches used and accuracy of performance modelling for non-domestic buildings in the UK

The UK's goal of transitioning to net zero carbon buildings has led to an increasing focus on the reliability of modelling results for energy consumption. Detailed modelling of HVAC systems and controls is considered a breakthrough in improving model accuracy. This paper uses a school building as a case study. Two dynamic simulation approaches, template and detailed component level HVAC modelling, are used in the IES VE software to predict energy consumption and compare the results with measured data. The root causes of the performance gap are analysed based on the calibration of the models. At the same time, this study trades off the complexity of the performance modelling input parameters against the accuracy of the output results. Then explore the interoperability of input parameters in these two approaches to avoid additional uncertainties introduced by detailed modelling. Some insights are provided into the modelling of operational energy use for non-domestic buildings in the UK

Alternatives to air-conditioning: policies, design, technologies, behaviours

Far from being a panacea, air-conditioning is shown to create social, environmental and economic problems. Alternatives to air-conditioning are identified as a key means of reducing energy demand and carbon emissions, improving resilience to heat, and providing a healthy indoor environment. These alternatives are more than a technological issue and help to reframe coolth as an attribute and not a commodity. This editorial introduces the themes and individual papers in this special issue. It explores the implications of these alternative solutions across a range of issues: health and wellbeing; air quality; heat stress; technical/design solutions; economics and equity; climate change; social expectations and practices; policy and regulation; supply chain and procurement; education and training. Recommendations for change involve policy and regulation, construction industry business models, redefining the design decision process, improving performance and feedback, and updating workforce skills and capabilities

The impact of indoor environment quality (IEQ) on school children's overall comfort in the UK; a regression approach

Indoor Environment Quality (IEQ) is grouped into four main categories: thermal comfort, indoor air quality (IAQ), visual and acoustic comfort. Individual aspects of IEQ are investigated to examine their impact on children's overall comfort in primary schools in the UK. This study has surveyed 805 children in 32 naturally ventilated classrooms during non-heating and heating seasons. This study has calculated the proportion of comfort votes by individual aspects of IEQ, predicted comfort votes by multilinear regression model and estimated the probability of having uncomfortable votes by binary logistic regression. Results of this study highlight that the proportion of uncomfortable votes should be kept below 10%. The developed multilinear model suggests that for a unit change in Air Sensation Votes (ASVs) and operative temperatures (Top), comfort votes change by 0.28 and 0.12, respectively. Developed multilinear and logistic regression models show that ASVs have a more significant impact on overall comfort than Top. To achieve acceptable comfortable votes and keep the probability of having uncomfortable votes below 10%, ASVs and Top should be kept within these limits: [ASV = very fresh and Top = 19–27 °C], [ASV = fresh and Top = 19–24 °C], and [ASV = OK and Top = 19–22 °C]. The ranges suggest that better perception of IAQ makes up for higher temperatures. It is advised to maintain individual aspects of IEQ, however, dissatisfaction with one aspect of IEQ does not necessarily result in overall discomfort unless that aspect is extremely unacceptable. Investigating the most influential factors on occupants’ comfort suggests which building controls should be prioritized for designers

Impact of Indoor Temperature and CO2 Levels on Occupant Thermal Perception and Cognitive Performance of Adult Female Students in Saudi Arabia

Due to hot arid climate in Jeddah, Saudi Arabia, occupants rely on air conditioning (AC) to provide both ventilation requirements and thermal comfort. It is believed that this total reliance on AC have also a significant effect on thermal sensation as well as cognitive performance of building occupants. Using a multi-variable multilevel statistical analysis, the effects of classroom temperature and CO2 levels on cognitive performance were estimated. Eight neurobehavioral cognitive tests were used to evaluate cognitive performance of 499 female students (16-20 years old). In addition, thermal sensation votes were collected. All participants were exposed to nine different environmental conditions, a combination of three temperature levels 20°C, 23°C and 25°C, and three CO2 levels: 600 ppm, 1000 ppm and 1800 ppm. The baseline condition levels were set at 20°C and 600 ppm. In this paper the interrelationships between the thermal sensation votes and effects of classroom temperature and CO2 levels on vigilance (Simple Reaction Test, SRT) and memory tasks (Reversal Learning, RL) are presented. The results suggested that the ‘cold’ thermal sensations have been linked to significant increase in ‘percentage of errors’ for both memory and vigilance tasks. Also, the exposure to higher CO2 levels of 1800 ppm and 1000 ppm have led to a significant increase in the ‘percentage of errors’ for both cognitive performance tasks compared to the baseline conditions. The study has also confirmed that the significant influence of acclimatization should not be overlooked when setting up the environmental design criteria for buildings in hot arid climates

Moisture Performance Criteria for UK Dwellings

The new ventilation regulations in England and Wales have introduced performance criteria for the control of mould. The UK Government\'s Building Regulations Research Programme has funded University College London (UCL) to investigate the extent to which these are the most appropriate criteria for thecontrol of mould in UK dwellings. This paper reports on the plans for this study which involve both field and laboratory related work. Some initial early work has already been undertaken and the paper summarises the progress to date. This initial work is based on analysis of data from a national study of England\'s Home Energy Efficiency scheme (Warm Front). Surveys were undertaken of dwellings and households participating in the scheme in five urban areas. Half-hourly living room and main bedroom temperatures and relative humidity measurements were recorded for two to four weeks (in the heating season) in approximately 1600 dwellings. This data is being analysed to investigate the typical relativehumidities that exist in UK dwellings and also any relationship that exists between these levels and the mould growth that was recorded

The impact of climate change on cognitive performance of children in English school stock: A simulation study

Children in England spend around 30% of their time in schools to gain knowledge and skills. Climate change could impact schools' thermal environments and children's learning performance by impairing their cognitive ability. This study presents an evaluation approach to investigating and quantifying climate change's impact on the cognitive performance of children across English school stocks. The study also evaluates the potential of possible strategies for mitigating the impacts of climate change. The results show that future climates are projected to increase cognitive performance loss of children in school archetypes representative of school stocks, with variations based on regional climate characteristics. Increasing ventilation rates proves to be an effective means of reducing cognitive performance loss, while its effectiveness diminishes as outdoor temperatures rise in the future. Thus, the introduction of air conditioning becomes a potentially more beneficial strategy, despite the associated increase in cooling energy demand. Moreover, higher ventilation rates in air-conditioned classrooms can further improve children's cognitive performance. The use of cognitive performance loss as a Key Performance Indicator (KPI) allows for better communication and understanding of climate change risks faced by schools among building and non-building experts. The proposed evaluation approach remains adjustable and can be continuously updated and enhanced as new insights from psychological research emerge

Advancing a health-model linked smart control framework to improve occupant health and comfort in residences

Evidence for the impact on health of interventions that improve the indoor environment can take years or even decades to be identified and actionable. However, health impact modelling can be used to estimate changes in rates of morbidity and mortality due to changes to the environment, which can be simulated using physics-based models. In the past, these tools have not been used in combination to assist in real-time building controls. The work described here builds upon previous work that proposed a smart control framework that combined portable air purifiers and automatic window control systems to reduce indoor PM2.5 concentrations in residences whilst maintaining thermal comfort. The modelled changes can inform health models for better estimations of the impacts to population health due to the implementation of controls that use both thermal conditions and contaminant concentrations\ud as control targets. The IAQ modelling, which uses EnergyPlus to simulate both indoor contaminants and thermal conditions, includes different ambient pollution levels, and, importantly, different occupant behaviour profiles (e.g., cigarette smoking). The approach to quantitative health impact assessment in this work is through life-table models that predict survival patterns based on age-specific mortality figures and hazard ratios. The simulation results showed that dual control of portable home air purifiers and window openings has the potential to not only maintain thermal comfort but also achieve effective PM2.5 removal even in cases of high indoor sources which, consequently, can lead to considerable health benefits at a relatively low energy cost

Evaluating the impact of air purifiers and window operation upon indoor air quality - UK nurseries during Covid-19

Many indoor air pollutants have been demonstrated to have a negative impact on occupants and due to physiological and behavioural differences, young children are more vulnerable to these effects than adults. Millions of children in the UK spend large parts of the day in nurseries, where occupant density is high, and indoor air quality can be poor. Therefore, it is imperative to understand the quality of indoor air in nurseries and how to improve it. The aims of the research presented here were to explore the indoor air quality (IAQ) in nurseries and the impact of both the use of air purifiers and window operations on IAQ. Three nurseries in London were selected and monitored via both continuous air quality sensors and passive sampling covering a total of 21 pollutants. Key findings include that mean reduction rate of PM2.5 by using air purifier was 63% with window closed, and 46% with window open. The results also highlight the impacts of operational changes implemented during the Covid-19 pandemic. Windows were operated more frequently for ventilation needs rather than being driven by temperature alone. The increased ventilation in the monitored nurseries in London led to low levels of VOCs and aldehydes (except for formaldehyde and 2-ethylhexanol) but could bring thermal discomfort to occupants. Both temperature and noise levels were shown to be relevant factors impacting the operation of air purifiers. Air purifiers can be effective at reducing PM2.5 when combined with proper window operation and have potential to bring substantial health benefits