Impact of climate change on newly detached residential buildings in the UK passive mitigation and adaptation strategies

The global increase in demand for dwelling energy and implications of changing climatic conditions on buildings require the built environment to build sustainable dwellings. The aim of this thesis is to apply passive mitigation and adaptation design strategies to newly detached residential buildings in the UK with the view to identify the key building envelop and systems parameters to secure the right balance of energy consumption and thermal comfort in dwellings. In addition, currently, acceptable robust validation process for validating space temperatures is required, as existing simulation software validation is geared toward energy consumption. The thesis further aims to apply an effective validation method to the validation of building simulation indoor temperatures. This thesis comprised of six case studies. In the first study, Bland-Altman’s method of comparison is used as a validation technique in validating space temperatures in building simulation application. This is a newly developed knowledge in civil and construction engineering research in validating thermal analysis simulation software. The relevance of this approach is due to the emergent understanding that the goodness of fit measures used in current building simulation model validation are inadequate coupled with that fact that the current simulation software validation are geared toward energy consumption. In the second study, global Monte Carlo sensitivity analysis is performed on two differing weather patterns of UKCIP02 and UKCP09 weather data sets to compare their impact on future thermal performance of dwellings when use in thermal analysis simulation. The investigation seeks to ascertain the influential weather parameters which affect future dwelling indoor temperatures. The case study when compared to literature affirms the mean radiant temperature and the dry bulb air temperature as the key parameters which influence operative temperatures in dwellings. The third study, the extent of impact of climate change on key building performance parameters in a free running residential building is quantified. The key findings from this study were that the average percentage decrease for the annual energy consumption was predicted to be 2.80, 6.60 and 10.56 for 2020s, 2050s and 2080s time lines respectively. A similar declining trend in the case of annual natural gas consumption was 4.24, 9.98 and 16.1, and that for building emission rate and heating demand were 2.27, 5.49 and 8.72 and 7.82, 18.43 and 29.46 respectively. This decline is in consonance with the range of annual average temperature change predicted by the GCM based on the IPCC scenarios (IPCC, 2001) which generally shows an increase in temperature over stipulated timelines. The study further showed that future predicted temperature rise might necessitate the increasing use of cooling systems in residential buildings. The introduction of cooling to offset overheating risk, the trend of heating and cooling demand shows progressive increase variability with an average percentage increase of 0.53, 4.68 and 8.12 for 2020s, 2050s and 2080s timelines respectively. It is therefore observed that the introduction of cooling cancels out the energy gains related to heating due to future climatic variability. The fourth, fifth and sixth case studies consider the integrated passive mitigation strategies of varying future climatic conditions, variable occupant behaviour, building orientation, adequate provision of thermal mass, advance glazing, appropriate ventilation and sufficient level of external shading which influence the potential thermal performance of dwellings and a methodology that combines thermal analysis modelling and simulation coupled with the application of CIBSE TM52 adaptive overheating criteria to investigate the thermal comfort and energy balance of dwellings and habitable conservatories. In the fourth study, the impact of four standardized construction specifications on thermal comfort on detached dwellings in London, Birmingham and Glasgow are considered. The results revealed that the prime factor for the variation of indoor temperatures is the variability of climatic patterns. In addition, London is observed to experience more risk of thermal discomfort than Birmingham and Glasgow over the time period for the analysis. The total number of zones failing 2 or 3 CIBSE TM52 overheating criteria is more in London than in Birmingham and Glasgow. It was also observed that progressive increase in thermal mass of the standardized construction specifications decrease the indoor temperature swings but increase in future operative temperatures. The day ventilation scenario was seen not to be effective way of mitigating internal heat gains in London and Birmingham. The opposite was observed in Glasgow. Night ventilation coupled with shading offered the best mitigation strategy in reducing indoor temperatures in London and Birmingham. In the fifth study, Monte Carlo sensitivity analysis is used to determine the impact of standard construction specifications and UKCP09 London weather files on thermal comfort in residential buildings. Consideration of London urban heat island effect in the CIBSE TM49 weather files leading to the generation of three different weather data sets for London is analysed. The key findings of the study indicated that in the uncertainty analysis (box and whiskers plots), the medians for the day ventilation scenarios are generally higher than those of the night ventilation and further higher than the night ventilation with shading scenarios. This shows that applying mitigation scenarios of night ventilation and shading have a significant impact on reducing internal operative temperatures. In addition, the sensitivity analysis shows glazing as the most dominant parameter in enhancing thermal comfort. The sensitivity of glazing to thermal comfort increases from Gatwick, with London Weather Centre having the highest sensitivity index. This could be attributed to the urban heat island effect of central London, leading to higher internal operative temperatures. The study thus shows that more consideration should be given to glazing and internal heat gains than floor and wall construction when seeking to improve the thermal comfort of dwellings. Finally, the sixth study considers the use of passive solar design of conservatories as a viable solution of reducing energy consumption, enhancing thermal comfort and mitigating climate change. The results show that the judicious integration of the passive solar design strategies in conservatories with increasing conservatory size in elongated south facing orientation with an aspect ratio of at least 1.67 could progressively decrease annual energy consumption (by 5 kWh/m2), building emission rate (by 2.0 KgCO2/m2) and annual gas consumption (by 7 kWh/m2) when the conservatory is neither heated nor air-conditioned. Moreover, the CIBSE TM52 overheating analysis showed that the provision of optimum ventilation strategy depending on the period of the year coupled with the efficient design of awnings/overhangs and the provision of external adjustable shading on the east and west facades of the conservatory could significantly enhance the thermal comfort of conservatories. The findings from these case studies indicate that thermal comfort in dwellings can be enhanced by analysis of future climatic patterns, improved building fabric and provision of passive design consideration of improved ventilation and shading. They also confirm that the utilization of appropriate mitigation strategies to enhance thermal comfort could contribute to the reduction of the environmental implications to the built environment and facilitate the drive towards the attainment of future sustainability requirements

Method comparison analysis of dwellings' temperatures in the UK

The credibility and confidence in usage of a simulation program must be underpinned by an acceptably robust validation process. Over the years, various techniques have been employed to validate thermal simulation programs of buildings to facilitate continuous improvement of software development and acceptability. This study introduces the Bland–Altman method comparison analysis as a simulation validation tool to statistically evaluate the agreement between monitored temperatures and predicted thermal analysis simulated operating temperatures of detached dwellings in the UK. The findings of this work give the indication that there is very strong agreement between the monitored temperatures and the thermal simulation analysis results

Impact of conservatory as a passive solar design of UK dwellings

The prime goal of professionals in the built environment is to build cost-effective, environmentally sustainable buildings. This work focuses on the viability of passive solar design strategies of conservatories in the UK in mitigating the impact of future climate change. It further shows that passive solar energy utilisation in building design can contribute to the reduction of dwelling energy consumption and enhancement of indoor thermal comfort. Synergetic passive design strategies that optimise solar energy gains through thermal simulation analyses of varying future climatic conditions, occupant behaviour, building orientation, thermal mass, advance glazing, appropriate ventilation and shading, which influence the potential thermal performance of the conservatory, are devised. The balanced energy benefits of reduction in energy consumption through the application of passive solar design principles for space heating in winter and the challenge of reducing excessive solar gains in summer are analysed using the Cibse TM52 adaptive thermal comfort criteria. The results show that judicious integration of passive solar design strategies in conservatories, with increasing conservatory size in elongated south-facing orientation with an aspect ratio of at least 1·67, could decrease energy consumption, enhance thermal comfort and help to mitigate the impact of climate change when the conservatory is neither heated nor air conditioned

Evaluation of Embodied Carbon Emissions in UK Supermarket Constructions: A Study on Steel, Brick, and Timber Frameworks with Consideration of End-of-Life Processes

Abstract: Buildings and the construction sector as a whole are among the chief emitters of carbon, and the structural system of a building contributes substantially to its embodied carbon emissions. Whereas extensive studies exist into carbon missions, a detailed evaluation of real multipart building systems in brick, steel, and timber (glulam) substitutes is lacking. This paper employs whole life-embedded carbon as a sustainability metric to compare a current UK supermarket building system of steel, brick, and timber. Four construction systems by the supermarket, referred to as CS1, CS2, CS3, and CS4, are used in the investigation. Comparisons are also made between two end-of life treatment methods (recycle and landfill) along with the benefits that can be realised in future construction projects. The outcome from the comparative assessment reveals that there are minor variations in the embodied carbon of building systems used by the supermarket. CS4, while currently presenting marginal gains (approximately 148,960.68 kgCO2eq.) compared to CS1, loses its advantages when recycled contents for future construction projects are considered. The result indicates that CS4 generates about 18% less carbon emission reduction potential than CS1, whilst CS3 generates approximately 16% less than CS1. The findings of this article can enhance the knowledge of embodied carbon estimation and reduction capabilities of timber, steel, and brick buildings. Also, the detailed method for quantifying embodied carbon used in this article can be adopted in similar projects around the world. Keywords: building systems; embodied carbon emissions; life-cycle assessment (LCA); material selectio

Impact of standard construction specification on thermal comfort in UK dwellings

The quest for enhanced thermal comfort for dwellings encompasses the holistic utilization of improved building fabric, impact of weather variation and amongst passive cooling design consideration the provision of appropriate ventilation and shading strategy. Whilst thermal comfort is prime to dwellings considerations, limited research has been done in this area with the attention focused mostly on non-dwellings. This paper examines the current and future thermal comfort implications of four different standard construction specifications which show a progressive increase in thermal mass and airtightness and is underpinned by the newly developed CIBSE adaptive thermal comfort method for assessing the risk of overheating in naturally ventilated dwellings. Interactive investigation on the impact of building fabric variation, natural ventilation scenarios, external shading and varying occupants` characteristics to analyse dwellings thermal comfort based on non-heating season of current and future weather patterns of London and Birmingham is conducted. The overheating analysis focus on the whole building and individual zones. The findings from the thermal analysis simulation are illustrated graphically coupled with statistical analysis of data collected from the simulation. The results indicate that, judicious integrated approach of improved design options could substantially reduce the operating temperatures in dwellings and enhance thermal comfort

Evaluating the impact of conservatory as a passive solar design on energy performance and internal temperatures of UK detached houses

The prime goal of professionals in the built environment is to develop cost effective sustainable buildings which contribute to the attainment of climate change mitigation goals, facilitate the achievement of indoor thermal comfort and reduction of building energy demand. This work focuses on the viability of passive solar design strategies of UK conservatories and shows that passive solar energy utilization in building design can contribute to the reduction of dwelling energy consumption and enhancement of indoor thermal comfort. Synergetic passive design strategies that seek to optimize solar energy gains through thermal simulation analysis of design criteria of varying future climatic conditions, variable occupant behaviour, building orientation, adequate provision of thermal mass, advance glazing, appropriate ventilation and sufficient level of shading which influence the potential thermal performance of conservatory is performed. The balance energy benefits of reduction of energy consumption through the application of these principles of passive solar design for space heating in winter and the challenge of reducing excessive solar gains in summer is analysed using the CIBSE adaptive thermal comfort criteria and statistical methods of the data collected from the thermal simulation. The results show that the judicious integrated of the passive solar design strategies in conservatories with increasing conservatory size in elongated south facing orientation with an aspect ratio of at least 1.67 could progressively decrease annual energy consumption, building emission rate and annual gas consumption when the conservatory is neither heated nor air-conditioned

Impact of future climate change on UK building performance

Global demand for dwelling energy and implications of changing climatic conditions on buildings confront the built environment to build sustainable dwellings. This study investigates the variability of future climatic conditions on newly built detached dwellings in the UK. Series of energy modelling and simulations are performed on ten detached houses to evaluate and predict the impact of varying future climactic patterns on five building performance indicators. The study identifies and quantifies a consistent declining trend of building performance which is in consonance with current scientific knowledge of annual temperature change prediction in relations to long term climactic variation. The average percentage decrease for the annual energy consumption was predicted to be 2.80, 6.60 and 10.56 for 2020s, 2050s and 2080s time lines respectively. A similar declining trend in the case of annual natural gas consumption was 4.24, 9.98 and 16.1, and that for building emission rate and heating demand were 2.27, 5.49 and 8.72 and 7.82, 18.43 and 29.46 respectively. The study further analyses future heating and cooling demands of the three warmest months of the year and ascertains future variance in relative humidity and indoor temperature which might necessitate the use of room cooling systems to provide thermal comfort

Government's influence on the implementation of BIM

The government's construction strategy requires construction projects for central government to implement level 2 building information modelling as a minimum by 2016. Since it was published, a number of specifications, plans and processes have been released. Government has been involved in their production through being part of steering groups and explaining what they, as construction clients and occupiers of a huge number of built assets, need from the industry. Department projects have also been used to trial new methods and provide feedback from both the client's and the project team's point of view. The government's involvement has resulted in a coordinated response from an industry that is traditionally very fragmented and introduced a real impetus for changing the way the construction industry works and embracing digital technology

The Impact of Different Weather Files on London Detached Residential Building Performance-Deterministic, Uncertainty, and Sensitivity Analysis on CIBSE TM48 and CIBSE TM49 Future Weather Variables Using CIBSE TM52 as Overheating Criteria

Though uncertainties of input variables may have significant implications on building simulations, they are quite often not identified, quantified, or included in building simulations results. This paper considers climatic deterministic, uncertainty, and sensitivity analysis through a series of simulations using the CIBSE UKCIP02 future weather years, CIBSE TM48 for design summer years (DSYs), and the latest CIBSE TM49 DSY future weather data which incorporates the UKCP09 projections to evaluate the variance and the impact of differing London future weather files on indoor operative temperature of a detached dwelling in the United Kingdom using the CIBSE TM52 overheating criteria. The work analyses the variability of comparable weather data set to identify the most influential weather parameters that contribute to thermal comfort implications for these dwellings. The choice of these weather files is to ascertain their differences, as their development is underpinned by different climatic projections. The overall pattern of the variability of the UKCIP02 and UKCP09 Heathrow weather data sets under Monte Carlo sensitivity consideration do not seem to be very different from each other. The deterministic results show that the operative temperatures of the UKCIP02 are slightly higher than those of UKCP09, with the UKCP09 having a narrow range of operative temperatures. The Monte Carlo sensitivity analysis quantified and affirmed the dry bulb and radiant temperatures as the most influential weather parameters that affect thermal comfort on dwellings