David Glew

Achieving Sustainability in New Build and Retrofit: Building Performance and Life Cycle Analysis

The definition of a sustainable building is not a straightforward one. There are many criteria upon which the sustainability of a building can be judged, including but not limited to energy performance, financial viability and environmental and social impact. Any determination of the sustainability of a building will be dependent upon the criteria used to assess it. Much of the work undertaken by the Leeds Sustainability Institute on building sustainability focusses on energy performance in buildings.

Accounting for refrigeration heat exchange in energy performance simulations of large food retail buildings

Heat exchange between chilled food storage and conditioned spaces in large food retail stores is not currently required as part of design stage regulatory compliance energy performance models. Existing work has identified that this exchange has a significant impact on store energy demand and subsequently leads to unrealistic assessment of building performance. Research presented in this article uses whole building dynamic thermal simulation models that are calibrated against real store performance data, quantifying the impact of the refrigeration driven heat exchange. Proxy refrigerated units are used to simulate the impact of these units for the sales floor areas. A methodology is presented that allows these models to be simplified with the aim of calculating a realistic process heat exchange for refrigeration and including this in thermal simulation models; a protocol for the measurement of chilled sales areas and their inclusion in the building models is also proposed. It is intended that this modelling approach and the calculated process heat exchange inputs can be used to improve the dynamic thermal simulation of large food retail stores, reduce gaps between predicted and actual performance and provide more representative inputs for design stage and regulatory compliance energy calculations. Practical application: The modelling methodology and research findings presented in the article are of practical use for building energy modelling engineers using dynamic simulation models to design and/or evaluate the energy performance of large food retail stores. The methodology can be used in the design of new facilities or the evaluation of large scale retrofit projects. It is also of practical interest to energy and facility managers within large food retail organisations as it will aid their understanding of applied energy performance models.

Monitoring and Measuring Building Performance

The whole-life sustainability of a building should be underpinned with a demonstration of functional value and an awareness of the direct environmental impact. While a great deal of energy and resources are consumed in the construction of buildings, this is marginal when compared to the operation costs and associated energy used during a building’s life cycle. Many reports identify the build costs and associated resources to be less than 1 % of the whole-life operation costs. The exact energy use of a building can vary widely, depending on the use, energy efficiency of the building and occupant behaviour; thus, a greater deal of attention should be given to understanding the energy used in buildings and how energy efficient operation is achieved.

Surveying and Measuring the Thermal Properties of Buildings

The energy performance of buildings and the ability to accurately predict energy demand is of global importance. As the relative cost and environmental impact of harnessing energy increases so does our need for energy efficiency. Designing, constructing and retrofitting buildings to be more energy efficient requires a thorough understanding of the way each building behaves and responds to its climatic variations. Although the measurement of a building’s energy consumption is straightforward, understanding why consumption differs from that expected requires a detailed and systematic building performance analysis. The way a building is assembled and retrofitted affects performance, and thus each aspect of a building’s makeup should be measured or monitored to understand its behaviour. When attempting to understand the performance of a building, it is important to consider each element, the components used and the way that they interface to perform as a whole. The measurement of building components in the laboratory is relatively well documented, but the testing and measuring of buildings once constructed in the field is an emerging science. This chapter presents the methods used to survey, measure and monitor building performance in the field and how the work is being used to inform the next generation of energy-efficient buildings.

Buildings that Perform: Thermal Performance and Comfort

Building performance evaluation considers the whole building system from a fabric, service and occupant perspective, as well as its response to the environment and potential integration into smart cities. There are many BPE methods used to collect building data and inform designs. Energy and environment monitoring, simulation, building surveys, post occupancy evaluation, element and whole building testing and their link to future development are discussed.

Assessing the quality of retrofits in solid wall dwellings

Purpose The purpose of this paper is to provide a detailed appraisal of the quality of domestic retrofits. Design/methodology/approach This paper presents the results of technical surveys on 51 retrofits undertaken before, during and after the retrofits. Findings Failures are observed to be endemic and characterised into five themes: 72 per cent showed moisture issues pre-retrofit, 68 per cent had moisture risks post-retrofit, 62 per cent did not adopt a whole house approach, 16 per cent showed inadequate quality assurance protocols and 64 per cent showed evidence of insufficient design detailing. Each theme is further subcategorised with a view to identifying implications for future policy. Research limitations/implications The findings suggest the 10 per cent Ofgem retrofit failure rates predictions are an underestimate and so there may be a need for additional investigations to understand the trend across the UK. Practical implications Recommendations to reduce the failure rates may include making changes to the current inspection regime, widening understanding among installers; providing standard repeatable designs for repeated features; and empowering occupants to trigger inspections. Social implications The sample is representative of a substantial proportion of the homes in the UK suggesting that retrofit quality may in many instances be below the required standards. Originality/value Risks of moisture issues and underperformance in domestic retrofit are a concern for government industry and households. This research shows that many installation failures are the result of not implementing existing guidelines and a change to the enforcement of standards may be needed to enact a fundamental change in installer practice and process control.

Quantifying the performance of a passive deaerator in a gas-fired closed loop domestic wet central heating system

In the UK, approximately 16% of the energy use can be attributed to domestic wet central heating systems. Government financial support and advances in technology have led to boilers becoming more efficient and a range of technologies are now available that claim to be able to improve the efficiency of domestic wet central heating systems. One such low cost technology is a passive deaerator. This article presents the results obtained from installing a passive deaerator on the closed loop of a gas-fired wet central heating system, under controlled conditions in the Salford Energy House. The results indicate that although marginally less heat output was required from the boiler when the passive deaerator was operating, these savings are more or less out weighted by the boiler short cycling more frequently. Consequently, the overall reduction is gas consumption achieved by utilising the passive deaerator device is only of the order of 0.5%; this scale of savings may just be a consequence of measurement noise. The implications are that although a marginal benefit may be attributed to these products, if short cycling takes place, then these savings may become insignificant. Practical application: This article describes a test method that has been used to quantify the energy savings that could be achieved by installing a passive deaerator on the closed loop of a wet central heating system. Although the results indicate that the energy savings associated with using such a device are likely to be marginal, the test method described could be used to test a range of other devices that claim to improve the performance of domestic wet central heating systems, to directly compare before and after performance.

Switch, Don’t Save

Efforts to meet targets on carbon emission and to reduce the number of people in fuel poverty often focus on building new highly energy-efficient homes and retrofitting existing ones. However, as occupant behaviour is a major predictor of energy use, it is also valuable to provide interventions that help occupants to use less energy. Here, we report qualitative research with 26 occupants in homes retrofitted with external wall insulation and ask what influences the actions they take to reduce the energy they use. Semi-structured interviews, lasting up to one hour, were audio recorded and transcribed verbatim. Taking a social constructionist paradigm, we used a discursive approach to analyse the ways in which people construct and represent their energy consumption and the discursive practices they employ to legitimise their actions or inactions. We identified two main discourses. The dominant discourse positions savvy and responsible consumers as those who switch suppliers to obtain the best energy deals, thereby saving money and enabling them to enjoy a warm and comfortable home. Making efforts to use less energy did not feature in this discourse. Participants’ talk was of disappointment and betrayal when the anticipated savings did not materialise. They blamed suppliers and usually switched again. An alternative discourse of changing behaviour to reduce energy use was drawn upon less often, when present it accompanied other life events, such as moving home, a change in work status or a period of illness. Talk centred on trying to offset the increasing cost of energy, with the purpose of reducing energy bills rather than using less energy. Protecting the environment was not a feature of this discourse. We conclude that campaigns that encourage consumers to switch energy providers have the potential to adversely affect interventions to help them reduce the energy they use.