An assessment of the potential returns of energy certificates for the UK household sector

Purpose – This article seeks to investigate the interconnections between the expectations of the impact of energy certificates issued within the UK domestic building sector through the Energy Performance of Buildings Directive (EPBD) and the actual number and financial implications of the energy saving measures (ESMs) achieved. Design/methodology/approach – The methodology uses two previously published surveys and compares these with a third independent survey by the authors focusing upon the discrepancies between planned action and implemented action, introducing the term human factor element (hfe). Findings – The article concludes that annual carbon savings arising from implementation of the Energy Performance Certificate (EPC) may be as low as 73.4?ktC over the five year term of the Kyoto Protocol even though 44 per cent of energy saving measure costs of £200 million are recouped within the same time period and savings will continue for up to 40 years. Achieving annual savings of only 14.7?ktC by 2010, such a figure represents a mere 0.3 per cent of the annual domestic 4.8?MtC savings announced by the government in its 2006 Climate Change Programme. Practical implications – Since the principal determinant in the uptake of ESMs is initial cost, it is considered that the EPBD is likely to remain an under-performing instrument in the promotion of energy sufficiency until such time as other complementary provisions are introduced. Originality/value – Sheds light upon the likely financial impact upon energy efficiency in domestic buildings by energy certificates

Parameterisation of M.R. system performance : towards optimised measures of image quality

This thesis proposes optimal measures for the inter-system comparison of signal properties when assessing the imaging performance of Magnetic Resonance Imaging (MRI) scanners. MRI has become a popular clinical imaging modality and there are many manufacturers producing systems of various quality. It is essential, therefore, that the performance of each MRI system can be measured and compared. Five criteria have been identified as being of prime importance, namely, the signal-to-noise ratio (SNR), signal non-uniformity, resolution, system induced ghost artefacts and patient induced ghost artefacts. The research concentrated directly on the derivation of performance parameters from test object images. For each criterion a specific algorithm has been developed to obtain optimal parameters. For SNR, a method of evaluation has been derived that utilises the Wiener spectrum to distinguish between random and non-random noise in the MR image. The assessment of signal non-uniformity has been improved by applying statistical parameters. The Modulation Transfer Function has been used in the evaluation and comparison of resolution of MRI systems. Crosscorrelation techniques have enabled the complete automatic location and analysis of ghost artefacts in MR test object images. An autocorrelation technique has been created to compare the degree of respiratory motion artefact present in an MR image. All the techniques, wherever possible, have been optimised for speed and automated to eliminate operator dependency. The strength of this thesis lies in the fact that the data used is not simulated, it is actual data gathered with the full support of each manufacturer in the country of origin. This enables truly applicable comparison parameters to be derived. This is a prominent deficiency for workers who mathematically create images or who work with only one system. The success of the five parameterisations is demonstrated by performing an inter-system comparison of ten commercially available scanners.Open Acces

The building energy performance gap: Up close and personal

Measurements of completed projects confirm significant gaps between the predicted and actual energy performance of buildings. This is due to: actual occupant behaviour; weather conditions; workmanship/installation errors; systems’ control settings and modelling issues. Recent developments in automated meter reading (AMR) and monitoring and targeting (M&T) make the performance gap visible to owners/operators. Bridging the gap becomes even more important if the industry intends to ‘occupant/climate change proof’ buildings. This paper reviews energy performance gap literature, the findings of a workshop on the subject, and presents ongoing work in this area. It concludes that the energy performance gap can only be bridged through better definition and joint efforts across all actors involved in the design, construction and operation of buildings/building (sub) systems

Simulation of Heritage Buildings: The Duke of Bedford’s Cottages in West Devon

Building performance simulation (BPS) is used to select and justify an energy-saving retrofit for the Duke of Bedford's cottages, aiming to improve performance sufficiently within the cottages' constraints, which include conservation concerns plus wider practical and economic constraints. Building data is passed from a building information model (BIM). Building energy simulation (BES) and hygrothermal modelling obtain results in the performance attributes of energy efficiency, thermal comfort and damp risk. Parametric analysis assesses performance ranges and sensitivity to long-term climate uncertainties. Moderate fabric upgrades, including window replacement and an insulating plaster, perform best within their constraints. Long-term, a heat pump is recommended to increase efficiency though is currently financially constrained. Ultimately, this sufficiently balances performance and heritage needs

A Discontinuous Model to Study Fracture of Brittle Materials

In this paper, the partition of the unity property of finite element shape functions is used to introduce displacement discontinuities into finite elements. The discontinuous character of the displacement field is captured with the Heaviside step function. Using the partition of unity concept, the governing equation of the continuum and the discontinuity are separated and are consequently described by different constitutive laws. Inside the discontinuity, a plasticity based constitutive law is used to describe the decrease of tractions in function of the crack opening while the continuum is assumed to remain elastic. The methodology will be described and validated with a comparison between numerical simulations and experimental results.This paper is dedicated to J. Sejnoha, TU Prague, with respect and admiration for his scientific achievement.

Improving the quality management systems for energy-efficient social housing projects

Developing and implementing quality management systems (QMS) in construction is particularly difficult because of a lack of standardization, the use of transient workforce and the many parties involved. This paper discusses the challenges faced by social housing providers in the UK when implementing quality assurance programs in their effort to provide their tenants with energy-efficient dwellings. In particular, it focuses on the quality plans defined at the early stages of a project, their impact during the construction process and on the resulting building energy performance. Based on data collected from the project team and documentation, a comparative analysis of the QMS development process of two social housing developments is presented. The key findings show that the two case studies followed different quality management approaches to deliver energy efficient dwellings. The most significant discrepancies were found in defining the energy performance targets and detailing the quality assurance procedures. The contribution of this paper is to create awareness of the importance of defining Quality Assurance Systems with a focus on energy performance from the early stages of a project

Measured indoor temperatures, thermal comfort and overheating risk: Post-occupancy evaluation of low energy houses in the UK

There is growing concern in Western Europe that higher insulation and air tightness of residential buildings leads to increased overheating risk. This paper discusses temperature monitoring from identical houses in the Southwest of the UK that were built to low energy standards (Code for Sustainable Homes Level 5). The temperature data were analysed using both established static overheating criteria (CIBSE Guide A) and an adaptive thermal comfort standard (BSEN15251). The houses can be considered uncomfortably warm during summer and are at risk of overheating. The study suggests that occupant behaviour plays an important role in reducing or increasing internal temperatures

Extending the UK's green deal with the consideration of occupant behaviour

This paper introduces a study, which extends the current UK’s Green Deal through a consideration of modifying occupant behaviour in buildings to save building energy consumption. A case study was carried out in a typical mid-terraced residential building located in the Southwest of the UK. In the study, dynamic building performance simulation was used to predict the energy saving potential of various behaviour change options so as to help occupants use the building more energy efficiently. Feedback from building occupants reveals that this approach is helpful in reducing energy demand in a real building application, but also points out the need for future work