Chartered Institution Of Building Services Engineers Research Articles

Improving Natural and Artificial Lighting in Coastal Architecture Classrooms: Insights and Applications

This research examines the natural and artificial lighting performance comparison in an architecture classroom at a university in southern Thailand and gives principles for enhancing lighting design. The sample for the study was classroom spaces. The efficacy of natural and artificial lighting was studied using static and dynamic models, and data were obtained using a 4 in 1 multi-function environmental meter at various times of the day. The current study adopted the IESNA (Illuminating Engineering Society of North America) and CIBSE (Chartered Institution of Building Services Engineers) lighting standards for the performance comparison analysis. The results showed that the natural light in the classrooms did not satisfy the standards for lighting levels. In contrast, the artificial lighting was more effective but raised some issues with uniformity and glare. The study offers recommendations for improving lighting effectiveness, maximizing natural light, reducing energy consumption, improving the uniformity of artificial illumination, addressing issues with various classroom lighting designs, and creating more comfortable and realistic learning environments.

Enhancing Indoor Air Quality and Regulatory Compliance: An In-Depth Comparative Study on Ventilation Strategies and Their Impact on SARS-CoV-2 Transmission Risk

Enclosed-space ventilation plays a pivotal role in enhancing indoor air quality (IAQ). Various regulations and guidelines determine minimum fresh air requirements, varying by the application, country, etc. The present study employs real-time indoor CO2 measurements to calculate the actual air change rate (ACH) and models the building’s compliance with Chartered Institution of Building Services Engineers (CIBSE) guidelines to assess its impact on IAQ. The contaminant considered is the SARS-CoV-2 virus with multiple infectors, and the study calculates the virus’s transmission risk under different scenarios. Fresh air is assumed to be provided by mechanical or hybrid ventilation. The results reveal that the current building conditions are unacceptable, showing a significant gap from the recommended guideline rates. Meeting CIBSE recommendations ensures indoor air safety in terms of CO2 concentration. However, in extreme conditions with five infectors, findings show a 14% reduction in mechanical ventilation efficacy. Among the hybrid ventilation scenarios, combining CIBSE rates with natural ventilation, with a 30% door and window opening from the class outset, proves most effective in reducing the virus’s transmission risk, with a 58–70% reduction from the building’s current condition. Furthermore, implementing supplementary measures like air cleaners resulted in an additional 28–50% reduction in transmission risk.

A quantitative case study to assess the performance of UK supermarket buildings in relation to future climate change and modern construction techniques (MMCs)

This study investigates variousmethods of construction of non-domestic buildings and its effect on buildingperformance of a typical UK supermarket under the worst-case scenarios of 2080speriod of climate change. Focus is specifically on the three LIDL-approvedconstruction methods and their building materials to quantify operationalenergy usage and carbon emissions. The ThermalAnalysis Software (TAS), a dynamic building simulation package, is used toquantify the results, generating reports while Chartered Institution of BuildingServices Engineers (CIBSE) provides with the current and future weather filesto be tested. The case study is based on a newly built single-story supermarketbuilding located in Norwich and uses three models of building P1, P2 and P3with specific set of building materials. The results show that models P1 and P2have percentage increase of close to 8.80% of energy consumption and carbonemission however, P3 have less than 8.50% increase as compared to the currentconditions of the building making it a slightly better choice. It shows that aprecast concrete and glulam beam structure offer the best resistance againstthe worst climate change scenario. This investigation joins the two differentsides of built environment, construction and operation while presenting theresults.

Is indoor overheating an upcoming risk in southern Spain social housing stocks? Predictive assessment under a climate change scenario

Beyond thermal comfort, the future outlook of climate change poses a challenge for the health of the most vulnerable inhabitants of the existing residential stock. In southern Spain specifically there is extensive social housing stock that is obsolete from an energy perspective and occupied by an aging population with economic constraints for the use of energy. The main aim of this work is to evaluate the possible comfort risks in terms of overheating following the different criteria established by the Chartered Institution of Building Services Engineers (CIBSE), both under current conditions and in a climate change scenario. For this purpose, a parametric simulation model was developed to reliably evaluate the category of linear-type social housing from the postwar period, a total of more than 42,000 dwellings. The results show that around 38% of the evaluated cases are already at risk of overheating as they fail to meet two of the three adaptive criteria set in TM52. By 2050 this figure will be almost 100%. In addition, it is expected that global warming will result in an increase of up to 40% in the percentage of Hours of Exceedance.

Investigating the Potential Impact of Future Climate Change on UK Supermarket Building Performance

The large-scale shifts in weather patterns and an unprecedented change in climate have given rise to the interest in how climate change will affect the carbon emissions of supermarkets. This study investigates the implications of future climatic conditions on the operation of supermarkets in the UK. The investigation was conducted by performing a series of energy modelling simulations on a LIDL supermarket model in London, based on the UK Climate Projections (UKCP09) future weather years provided by the Chartered Institution of Building Services Engineers (CIBSE). Computational fluid dynamic (CFD) simulations were used to perform the experiment, and the baseline model was validated against the actual data. This investigation ascertains and quantifies the annual energy consumption, carbon emissions, and cooling and heating demand of the supermarket under different climatic projections, which further validate the scientific theory of annual temperature rise as a result of long-term climatic variation. The maximum percentage increase for the annual energy consumption for current and future weather data sets observed was 7.01 and 6.45 for the 2050s medium emissions scenario, (90th) percentile and high emissions scenario, (90th) percentile, respectively, and 11.05, 14.07, and 17.68 for the 2080s low emissions scenario, (90th) percentile, medium (90th) percentile and high emissions scenario (90th) percentile, respectively. A similar inclining trend in the case of annual CO2 emissions was observed where the peak increase percentage was 6.80 and 6.24 for the 2050s medium emissions scenario, (90th) percentile and high (90th) percentile, respectively and 10.84, 13.84, and 17.45 for the 2080s low emissions scenario, (90th) percentile, medium emissions scenario (90th) percentile and high emissions scenario (90th) percentile, respectively. The study also analyses the future heating and cooling demands of the three warmest months and three coldest months of the year, respectively, to determine future variance in their relative values.

The impact of accurately modelling corridor thermodynamics in the overheating risk assessment of multi-residential dwellings

Prolonged overheating can have serious cumulative effects on human health, resulting in heat exhaustion, heatstroke and even death. The frequency and severity of heatwaves will increase considerably in the future as a result of accelerating climatic changes compounded by increasing urbanisation.A recent overheating risk-assessment methodology, Technical Memorandum (TM)59: 2017 was developed by the Chartered Institution of Building Services Engineers (CIBSE) to address this problem, by providing a consistent framework for the evaluation of overheating risks in new homes. TM59 has for the first time highlighted the importance of including corridor heat transfer effects in the dynamic modelling of multi-residential dwellings. This paper investigates the strengths and limitations of current approaches to the modelling of corridors, based on a case study of three energy-efficient flats located in London. The results of modelling in accordance with TM59 guidance are compared with alternative approaches, using more realistic occupancy and weather information, and compared to empirically measured data. The findings of this study indicate that current practices in Building Performance Simulation (BPS) are likely to under-estimate the actual air temperatures in corridors. This study highlights the need for further research into the way in which corridors, flats and their interconnecting ventilation and heat transfer networks are commonly discretised in BPS models.

Assessing the application and limitations of a standardised overheating risk-assessment methodology in a real-world context

Prolonged overheating has severe consequences for the future habitability of buildings. Building Performance Simulation (BPS) is increasingly used to identify the propensity of buildings to overheat, however the reliability of this approach has been repeatedly questioned. A new overheating risk-assessment methodology, Technical Memorandum (TM)59 was developed by the Chartered Institution of Building Services Engineers (CIBSE), to address this problem by providing a consistent framework for the evaluation of overheating risks in new homes. To date, little empirical research has been carried out to validate this approach in comparison to real buildings. This study aims to bridge the gap between theory and praxis by investigating the potential challenges, limitations, and implications of implementing this standardised methodology. This was achieved by comparing BPS simulations, based on the application of TM59, with empirically measured data from three recently constructed energy-efficient flats located in London. The flats were monitored during the late autumn in order to assess their propensity to chronic year-round overheating, outside of the summer season. Distinct user scenarios, based on different modes of ventilation and window/shading operation, were analysed in relation to the CIBSE TM59 overheating thresholds. The results showed that the TM59 criteria were extremely difficult to satisfy. Under a mechanical ventilation assessment mode (with windows closed) 30–67% of the total occupied hours exceeded the overheating thresholds. This analysis has highlighted the need to further improve overheating methodologies, by considering the assessment of risks in discrete temporal bands as well as incorporating methods to assess mixed-mode purge-ventilation strategies.

An investigation into overheating in social housing dwellings in central England

Recent empirical studies have evidenced overheating in UK dwellings during hotter periods. Vulnerable people living in social housing dwellings may be less able to tolerate heat stress or to adapt. This study is the first large scale monitoring study to investigate overheating risk in social housing dwellings in central England against three overheating risk assessment criteria. Indoor temperature data for summer 2015 were analysed for 122 free-running social housing properties, of varying type and age, against the Chartered Institution of Building Services Engineers (CIBSE) static guidance, and the adaptive methods of TM52 and TM59. The mean bedroom and living room temperatures were 21.2 °C and 21.7 °C, respectively. Bedrooms were more likely to overheat than living rooms using the static criteria, with 42% of bedrooms exceeding 5% of occupied hours over 24 °C, and 40% exceeding 1% of occupied hours over 26 °C. 24% of living rooms exceeded 5% of occupied hours over 25 °C, and 5% exceeded 1% of occupied hours over 28 °C. Against TM52, only 1% of bedrooms and 2% of living rooms overheated. Against TM59, 5% of bedrooms and 1% of living rooms overheated. Analysis by various property categories identified those types of property which were more prone to overheating.

Time constants for understanding building dynamics

Building dynamics are key to summer overheating, plant sizing and ventilation strategies. Building designers need to consider the thermal mass of a building explicitly to understand fully a building’s response. Simulation programs readily show the dynamic responses but they are deduced from the solution of embedded intrinsic differential equations without simple understanding for initial design and appreciation. The admittance method gives such a simple understanding but the thermal mass effects are not obvious. Added to which the admittance is limited to a regular 24 h cycles of heat gains and losses. The Chartered Institution of Building Services Engineers (CIBSE) response factor is an approximation to the response of a building but it is limited to defining just slow or fast responses. Frequently, designers refer to heavyweight and lightweight buildings or even long and short time constants. The latter are simple and understandable. This paper explores the time constants and derives a simple multiple time constant equation to indicate thermal storage in a building. It is suggested that the simple time constant for building components is added to the data in the next edition of the CIBSE Guide A. This will aid designers in understanding a building’s winter heating and potential summer overheating and plant size implications.

Effects of Lighting Quality on Working Efficiency of Workers in Office Building in Tanzania.

Background In this era of Information Communication Technology, a high-quality working environment is essential to the occupants. Providing quantity rather the quality of work environments is very common in most of the least developed countries, including Tanzania. Existing research asserts that poor indoor environmental quality such as lighting has a detrimental effect on human health, and in case of the office working population, it also affects their work performance. This study aims to analyze the effects of the lighting quality on working efficiency of workers in Tanzania. Methods Four representative offices from the administration building at Mbeya University of Science and Technology were investigated from June to September 2018. The customized questionnaire survey tool was administered to the randomly selected occupants to survey their perceptions about the quality of lighting in their workplace and its influence on their health and work efficiency. Physical observation and illuminance distribution measurements were also conducted. Results The statistical analysis indicates that the majority of the occupants are less satisfied with the lighting quality in their working environment, and some respondents reported that it significantly affected their work efficiency and wellbeing. The average desk illuminance and uniformity level were found to be below the recommended values of the Chartered Institution of Building Services Engineers (CIBSE) and the International Commission on lighting (CIE). Conclusion Despite the suggested improvement measures, this research emphasizes that poorly articulated work environment can adversely affect the productivity and work efficiency of the workers. The workers in such condition are also exposed to occupational diseases. Thus, providing a healthy work environment should be a fundamental right of the workers.

Daylighting Retrofit Methods as a Tool for Enhancing Daylight Provision in Existing Educational Spaces—A Case Study

Adequate illuminance has a great effect on the health, comfort, and performance of pupils. It can be achieved by either artificial lighting or daylighting. Daylighting is usually preferred due to psychological, physiological, and economic purposes. This study aims to improve the daylight provision in existing classrooms, by investigating various retrofit methods for passive daylighting techniques in northerly oriented classrooms at Jordan University of Science and Technology (JUST). Data for this research are obtained using computer simulation. The retrofit methods are evaluated in terms of illuminance levels on the desks plane and the chalkboard. The retrofit methods investigated in this study included improving the material reflectance, adding clerestory to the classroom, lightshelves, anidolic ducts, as well as various combinations between these cases. By comparing the results, and in light of the recommended lighting level by The Lighting Guide 5: Lighting for Education released by Chartered Institution of Building Services Engineers (CIBSE) in 2011, the combination of the clerestory window and the anidolic ducts result in the best results. While CIBSE recommended a target illuminance of 300 lx on desks plane and 500 lx on the board, the combination registers an average of 249 lx–300 lx on the desks plane in all sensors compared to 42 lx–105 lx in the base case, and an average of 275 lx–345 lx on the board for the tested dates compared to an average of 45 lx–115 lx in the base case.

Assessing overheating risk and thermal comfort in state-of-the-art prototype houses that combat exacerbated climate change in UK

There is growing evidence that terraced houses—thermally lightweight, well insulated, naturally ventilated with three exposed wall surfaces—are at risk of overheating, especially in south-eastern England. The aim of this study is to evaluate the building performance and develop a reliable building simulation, which will be employed in the second phase of the study: developing affordable and feasible passive design strategies to support the energy-efficient building systems of the construction industry. This paper reports on the results from the first phase of the study where a quantitative methodology, including indoor and outdoor environmental monitoring, in-situ measurements and building simulation modelling, was adopted. The performance of a case study was modelled and simulated via employing Integrated Environmental Solutions (IES) software suite.The results from the base-case were analysed according to the adaptive thermal comfort of Chartered Institution of Building Services Engineers (CIBSE) Technical Memorandum 52 guidelines: The Limits of Thermal Comfort—Avoiding Overheating in European Buildings. The spaces studied within the case study house were observed to exceed the acceptable limits of thermal comfort; particularly, the large bedroom within this zone exceeded the upper limit for overheating up to 11 h daily. Furthermore, the results from the monitoring study indicate a high risk of summertime overheating across all the case study settings, especially during short-term peaks in outdoor temperatures. The main reasons for the problematic thermal performance were identified as well-insulated and fully air-tight building fabric, the lack of sufficient ventilation through the living spaces and excessive heat gains through the composite cladding material.

Field-test of the ASHRAE/CIBSE/USGBC performance measurement protocols: Part I intermediate level energy protocols

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)/Chartered Institution of Building Services Engineers (CIBSE)/U.S. Green Building Council (USGBC) performance measurement protocols provide a standardized set of protocols for measuring and comparing the operational performance of occupied commercial buildings. The ASHRAE performance measurement protocols has been developed at three levels of cost/accuracy, Basic (Indicative), Intermediate (Diagnostic), and Advanced (Investigative), for the following six performance categories: energy use, water use, thermal comfort, indoor air quality, lighting, and acoustics. This article presents the results of an effort to develop and apply a field test to evaluate the Intermediate level of the performance measurement protocols energy protocols in a case-study office building in Central Texas. The data collected include multi-year monthly whole-building electricity use, electric demand, and natural gas data for the total and major end uses of the case-study building, as well as coincident on-site weather data. The data collected were then analyzed to calculate the corresponding performance metrics based on the Intermediate level of the performance measurement protocols energy protocols and compared with the appropriate benchmarks. The problems and issues with implementing the performance measurement protocols Intermediate level energy protocols in a case-study building were noted throughout the entire research process. The evaluation revealed five issues, for each of which recommendations were developed to improve the current version of the performance measurement protocols. The results for the performance measurement protocols Basic level applications, including all six areas, were reported in Kim and Haberl (2012a). A companion article (Kim and Haberl 2017) presents the results of applying the performance measurement protocols Advanced level energy protocols.

Field-test of the ASHRAE/CIBSE/USGBC performance measurement protocols: Part II advanced level energy protocols

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)/Chartered Institution of Building Services Engineers (CIBSE)/U.S. Green Building Council (USGBC) performance measurement protocols provide a standardized set of protocols for measuring and comparing the operational performance of occupied commercial buildings. The ASHRAE performance measurement protocols have been developed at three levels of cost/accuracy, Basic (Indicative), Intermediate (Diagnostic), and Advanced (Investigative), for the following six performance categories: energy use, water use, thermal comfort, indoor air quality, lighting, and acoustics. This article presents the results of an effort to develop and apply a field test to evaluate the Advanced level of the performance measurement energy protocols in a case-study office building in Central Texas. The data collected include multi-year sub-hourly whole-building electricity data for the total and major end uses, thermal data for chillers and condensers, and coincident on-site weather data, as well as monthly utility bills of the case-study building. The data collected were then analyzed to calculate the corresponding performance metrics based on the Advanced level of the performance measurement protocols energy protocols and compared with the appropriate benchmarks. The problems and issues with implementing the performance measurement protocols Advanced level energy protocols in a case-study building were noted throughout the entire research process. The evaluation revealed four issues, for each of which recommendations were developed to improve the current version of the performance measurement protocols. The results for the performance measurement protocols Basic level applications, including all six areas, were reported in Kim and Haberl (2012a). A companion paper (Kim and Haberl 2017) presents the results of applying the performance measurement protocols Intermediate level energy protocols.

Realising Operational Energy Performance in Non-Domestic Buildings: Lessons Learnt from Initiatives Applied in Cambridge

The gap between the intended and actual energy performance of buildings is increasingly well documented in the non-domestic building sector. Recognition of this issue has led to the availability of a large range of initiatives that seek to ensure energy efficient building operation. This article reviews the practical implementation of three such initiatives in a case study building at the University of Cambridge. The notionally high-performance office/laboratory building implemented two voluntary design frameworks during building planning and construction: the voluntary rating scheme BREEAM and a bespoke Soft Landings framework called the Cambridge Work Plan. The building additionally meets the energy reporting criteria for the EU Energy Performance of Buildings Directive (EPBD), a legislative requirement for many publicly owned buildings in the UK. The relative impact of these three approaches for optimising building energy performance is reviewed through a mixed methods approach of building occupant and operator interviews, document analysis and energy performance review. The building’s core functions were revealed to consume 140% more energy than the building logbook estimate for the same needs. This difference, referred to widely as the energy performance gap, is larger than the majority of reported UK university buildings in the energy reporting database CarbonBuzz. The three implemented initiatives are demonstrated to be inadequate for reducing the energy performance gap in the case study, thus a number of alternative energy efficiency approaches are additionally reviewed. Common to the three approaches used in the case study is a lack of verification of actual building performance despite ambitious sustainability targets, due to a heavy focus on the design-stage and few follow-up mechanisms. The paper demonstrates the potential of energy efficiency initiatives that are focussed on operational performance as a core criterion (such as the Living Building Challenge) together with those that ensure the creation of realistic energy estimates at the design stage (such as the Chartered Institution of Building Services Engineers (CIBSE) Technical Memorandum 54).

Estimating overheating in European dwellings

ABSTRACTIn recent years, the urgent need to adapt our lifestyles and buildings to deal with a more extreme and a warming climate has become clear, not least through the increasing overheating of buildings. This is reflected in the rising concerns about the discomfort and heat stress to building occupants caused by the increasing indoor temperatures. European standard BS15251 and Chartered Institution of Building Services Engineers (CIBSE) guidance note TM52 are documents that address the issue. Both include a methodology predicting the probability of overheating in buildings. Despite this, many modern buildings overheat. This paper looks at the criteria from CIBSE TM52 and discusses their applicability to a single UK dwelling archetype. This was modelled and then located in a range of European cities to understand the causes of overheating and the means of reducing it. Results highlight some problems in practice using simulations tools to evaluate overheating and the fundamental assumptions on which they are based. Energy performance and thermal comfort of dwellings were assessed using morphed climates for each location for 2020, 2050 and 2080.

Meta-analysis of indoor temperatures in new-build housing

ABSTRACTDespite growing concerns about overheating, a lack of evidence exists on the scale of the problem, particularly in contemporary UK housing. This paper presents the results of a meta-analysis of indoor temperatures in selected low-energy housing. Temperature data recorded at five-minute intervals in 60 dwellings across 19 demonstration projects (2012–14) were collated and analysed to investigate the prevalence of overheating. Findings evidence high summertime temperatures, with 27% of living rooms exceeding 28°C during August. Based on the Chartered Institution of Building Services Engineers (CIBSE) threshold of 5% annual occupied hours > 25°C, 57% of bedrooms and 75% of living rooms were classified as having overheated. Overall, 30% of living rooms exceeded the adaptive comfort threshold of > 3% occupied hours ΔT ≥ 1 K. The results suggest a fundamental relationship between ventilation and indoor temperatures. The higher minimum and average summertime temperatures observed in mechanical ventilation with heat recovery (MVHR) homes (p < 0.05) and lower temperature range (p < 0.001) suggest the need for greater attention to adequate summertime ventilation provision in airtight homes. The results demonstrate a high prevalence of overheating in exemplary housing, indicating the need for greater efforts to ensure the effective implementation of strategies to minimize overheating and improve ventilation in low-energy homes.

Finite-element view-factor computations for radiant energy exchanges

Radiation heat transfer has very many applications within the building services sector. CIBSE (Chartered Institution of Building Services Engineers) Guide A provides the physics background and the relevant mathematical functions for radiant energy exchanges between surfaces of different configurations in chapters 2 and 5. The aim of this article is to present procedures for inter-surface radiant energy exchange that range from the most simple (macro-) to most general formulations that are based on a micromesh, finite-element approach. The justification for such detailed procedures and their applicability within the modern building energy simulation software is also covered.

A study of passive ventilation integrated with heat recovery

To meet the demand for energy demand reduction in heating, ventilation and air-conditioning systems, a novel design incorporating a heat recovery device into a wind tower was proposed. The integrated system uses a rotary thermal wheel for heat recovery at the base of the wind tower. A 1:10 scale prototype of the system was created and tested experimentally in a closed-loop subsonic wind tunnel to validate the Computational Fluid Dynamics (CFD) investigation. Wind towers have been shown to be capable of providing adequate ventilation in line with British Standards and the Chartered Institution of Building Services Engineers (CIBSE) guidelines. Despite the blockage of the rotary thermal wheel, ventilation rates were above recommendations. In a classroom with an occupancy density of 1.8m2/person, the wind tower with rotary thermal wheel was experimentally shown to provide 9L/s per person at an inlet air velocity of 3m/s, 1L/s per person higher than recommended ventilation rates. This is possible with a pressure drop across the heat exchanger of 4.33Pa. In addition to sufficient ventilation, the heat in the exhaust airstreams was captured and transferred to the incoming airstream, raising the temperature 2°C, this passive recovery has the potential to reduce demand on space heating systems.

Investigating the Process of Exporting Autodesk Ecotect Models to Detailed Thermal Simulation Software

Autodesk Ecotect^[1] is a whole building simulation software that can predict the thermal, visual and acoustic performance of buildings. It is very user-friendly software that could potentially integrate with the architectural design process. Thermal performance analysis in Autodesk Ecotect is based on the Chartered Institution of Building Services Engineers (CIBSE) admittance method and thus inherits its limitations. Hence, the need to use more detailed thermal simulation tools during the final stage of a building design or research project. This paper investigated the potential of using detailed thermal simulation software (HTB2) in conjunction with Autodesk Ecotect. Five primary classrooms built in a hot-dry climatic region were monitored. The same classrooms were modelled in Autodesk Ecotect using several modelling techniques and the internal temperatures were simulated using HTB2. Analysis of results suggested that a number of necessary measures are required to ensure the reliability and accuracy of the simulation results.