Reducing hospital electricity use: an end-use perspective

Hospitals are an energy intensive building type for which high energy costs and sector carbon targets increasingly prompt attempts to reduce operational energy use. But evidence is sparse and generic one-fits all solutions are problematic due to the complexity and the differing specifications of hospitals. This study therefore focusses on departments as unit of analysis. Five department types (operating theatres, laboratories, day clinics, imaging departments and wards) with differing energy intensities, operating hours and at different stages within the patient pathway are investigated across three case study hospitals of different building age and size (11 departments in total). Detailed audits of installations and use are undertaken to attribute measured departmental electricity use to different end-uses. It is found that lighting loads are dominant in low energy intensity department types, while intensive department types have high loads for specialist ventilation and laboratory equipment. Resulting energy reduction strategies consequently need to take account of these differing challenges, for which an analysis of contributing factors as suggested for example by CIBSE TM22 proved useful. The use of floor area weighted operating hours is proposed as metric for hospitals and other complex buildings which may be beneficial in understanding end-use contributions to total energy use and in highlighting the after-hours switch off potential of building parts in otherwise continuously operating environments

Analysis work to refine fabric energy efficiency assumptions for use in developing the Sixth Carbon Budget

The Climate Change Committee (CCC) commissioned University College London to review and update the cost and savings assumptions related to energy efficiency measures in homes, including an increased focus on in-use performance. The updated assumptions incorporate in-use measured data from the National Energy Efficiency Data-framework (NEED) alongside the latest evidence published by Government on the costs of measures. Over 150 datasets, studies and published reports were considered in total. The resulting assumptions were used as an input to Element Energy’s analysis ‘Development of trajectories for residential heat decarbonisation to inform the Sixth Carbon Budget’, focusing on existing home

Assessing savings potentials from changes in energy behaviours of hospital staff: benefits and challenges of energy audits

Behaviour change is increasingly considered as potentially cost-effective measure to reduce organisational energy use, while campaign evaluation remains a major challenge. Previous research has shown that especially in complex non-domestic buildings the variability in baseline energy use may often equal campaign effect sizes. In hospitals, evaluative attempts are further complicated by a prevalent lack of sub-metering. Surveying and energy audits are common tools to obtain information on buildings and organisational processes and identify energy conservation opportunities in the face of these obstacles. This paper investigates the viability of using energy audits as explicit resource to explore the theoretical potential of energy savings obtainable through behaviour changes of healthcare staff. Detailed audits of lighting and appliance use were carried out in 11 hospital departments for which plug loads and lighting consumption were also monitored at the distribution board level. Reduction opportunities from specific changes in energy behaviours were then modelled on their basis to establish ex-ante estimations for savings potentials. The method proved useful in ranking different end-uses to guide behavioural energy conservation efforts in hospitals. Usability was however limited by uncertainties remaining for data inputs from audits, both for power ratings and more importantly for usage hours and frequencies with which behaviours were currently performed. Detailed energy audits were hence found to be a workable tool for campaigns reforming protocols and procedures to eliminate redundant energy use, while they seemed less helpful for those promoting easy standard behaviours. For the latter, it seems advisable to consider additional methods of data collection as part of evaluative strategies depending on project aims, available budget, access to technical staff and the importance of respective end-uses

Implementing multi objective genetic algorithm for life cycle carbon footprint and life cycle cost minimisation: A building refurbishment case study

Early design decisions made by architects have been shown to significantly impact the energy performance of buildings. However, designers often lack the resources or knowledge to take informed decisions that might improve building performance. The refurbishment of existing buildings is considered to significantly contribute to the reduction of the life cycle environmental impact of buildings. Building refurbishment is also seen as the most cost-effective way of achieving this goal. In assessing the life cycle impacts of constructing and usage processes of buildings, LCA (life cycle analysis) is often used. In order to simplify the decision-making process in early design, this study uses MOGA (multi objective genetic algorithms) to find optimal designs for a refurbishment of a residential complex case study, in terms of LCCF (life cycle carbon footprint) and LCC (life cycle cost) over an assumed life span of 60 years. Results show that utilizing MOGA has the potential to reduce the refurbishment LCCF and LCC. Findings emphasize the life-cycle impacts of insulating thermal bridges and the importance of using different heating systems and fuels. Finally, in comparing LCA with more commonly used performance-based decision-making design procedures, the study highlights that employing these distinctive methods can lead to different design solutions

How useful are building energy models for policy? A UK perspective

Energy demand models are central to the efforts of many governments to reduce carbon emissions from buildings. The lack of empirical research to ensure the appropriate use of predictions from the models has implications for building regulations and evaluating policy initiatives. We present three recent examples from the UK that highlight challenges: the discovery of a heat by-pass in party walls, trends in household gas consumption and the impact of condensing boilers, and inter-model variation in the non-domestic sector. We emphasise and contrast the approach of health sciences to support policy, and suggest that a far more systematic and integrated approach between empirical research, model development, and policy evaluation is needed

Adaptive building envelope simulation in current design practice: findings from interviews with practitioners about their understanding of methods, tools and workarounds and implications for future tool developments

Adaptive building envelopes can dynamically adapt to environmental changes to improve thermal building performance. To predict the performance of design proposals with adaptive building envelopes, Building Performance Simulation (BPS) tools can be employed. However, one shortcoming of existing tools is their limited extensibility, which implies that accurately predicting adaptive building envelope performance remains a challenge and requires ad hoc approaches. This challenge has made practitioners reticent in considering adaptive building envelopes, which in turn has led to a slow uptake of them in the built environment. This study seeks to advance the understanding of the limitations of adaptive building envelope simulation in current design practice and to suggest implications for future tool developments. To this aim, the study adopts a user-centred perspective through interviews with experts in the field. Findings suggest that current BPS tools hinder the reliable prediction of adaptive building envelope performance, as accurately representing the level of detail of the building envelope is challenging. The subsequent workarounds applied are either time- and cost-intensive or do not consider the dynamic building envelope components. More flexible modelling approaches that allow for rapid prototyping and easy integration are required to enable designers to take full advantage of adaptive building envelopes

Cost optimal energy retrofit strategies for public administrative buildings: A Cairo case study

The Egyptian government is currently constructing a new governmental quarter in the New Administrative Capital City, located east of Cairo. A planned relocation for all ministerial authorities to the New Capital City will leave a vacant governmental estate in Cairo. The study of the energy retrofit options provides a unique opportunity to reduce energy use and maximize the benefit from the anticipated investment in the re-use to be implemented within this stock. However, energy retrofit was found to be under-researched in the Egyptian context. This paper presents a pilot study that aims to identify cost optimal retrofit strategies for one of the soon to be vacated buildings, the Central Agency for Public Mobilization and Statistics (CAPMAS). Using DesignBuilder, an energy modelling study was implemented to estimate the existing performance of the building, assess the projected performance after a change of use (to an office building), and evaluate the cost optimality and the savings associated with the application of retrofit measures. The study found that the feasibility of implementing retrofit can be significantly offset by the discount rates in Egypt. As such, maintaining economic stability and considering non-economic incentives can be key drivers to increasing the energy retrofit uptake in Egypt

A bootstrap method to investigate the variability of overheating risk against the future climate uncertainty in dwellings

Future overheating risk in dwellings can be potentially mitigated by minimising the variability of overheating hours against uncertainties in future climate via robust optimisation. However, the estimation of this variability value through the utilisation of percentile-based probabilistic weather data has yet to be sufficiently investigated. In this simulation-based study, the bootstrap method is used to quantify the accuracy of the variability estimation via percentilebased weather data. The results indicate significant overheating risk in regulation-compliant houses. An increased degree of difficulty is also suggested in obtaining accurate estimations when considering time periods further in the future and when assuming higher carbon emissions. In addition, the skew normal distribution can be used for a simpler and faster estimation, but the underlying uncertainties must be strengthened throughout its implementation

Investigation Into Informational Compatibility Of Building Information Modelling And Building Performance Analysis Software Solutions

There are significant opportunities for Building Information Modelling (BIM) to address issues related to sustainable and energy efficient building design. While the potential benefits associated with the integration of BIM and BPA (Building Performance Analysis) have been recognised, its specifications and formats remain in their early infancy and often fail to live up to the promise of seamless interoperability at various stages of design process. This paper conducts a case study to investigate the interoperability between BIM and BPA tools, and discusses the limitations to suggest development of Information Delivery Manual (IDM) aiming to propose potential solutions for typical issues facing professionals in architecture, engineering and construction (AEC) industry