Strategic Energy Management within Hospitals: Barriers to Energy Efficiency and the Impact of Design Margins

Jones, Darren Anthony (2022). Strategic Energy Management within Hospitals: Barriers to Energy Efficiency and the Impact of Design Margins. PhD thesis The Open University.



The original focus of the thesis looked at the barriers to effective energy management within the context of UK NHS Hospitals. As the research progressed, the overdesign of hospital building service systems emerged as a potential barrier that was considered in more detail, ultimately becoming a key focus of the research. The research revealed multiple barriers to energy efficiency; some direct, such as financial constraints, organisational limitations and poor data, and some indirect barriers, such as those leading to building services overdesign.

Oversizing of building service systems, such as heating cooling and ventilation systems has a direct impact on building energy performance and operational efficiency as oversized systems are incapable of working at their optimal efficiency point. The resultant excessive consumption affects Government’s commitment of a ‘net zero’ Carbon position by 2040. Oversizing also leads to increased capital and ongoing maintenance and repair costs and redirects funds from patient care.

This thesis addresses several research gaps on multiple levels. Whilst literature relating to energy management and its barriers is well documented in regard to private sector organisations, this is not the case for NHS hospitals. Literature relating to building services oversizing is also very limited, as is literature on design margins and oversizing within the healthcare context. The tensions between the need for resilience in hospitals and energy efficiency is also not identified in the literature.

This thesis therefore aims to answer a number of research questions – what are the barriers to energy efficiency in hospitals? What is the evidence of oversizing? What are the causes of building services overdesign? And, how can oversizing in building services be mitigated?

A multifaceted mixed methods approach has been adopted for the research of this thesis, whereby, a combination of detailed hospital case studies, supplementary interviews, research verification workshops, system modelling and elements of action research have been undertaken. The thesis is built on three in-depth case studies relating to general hospital energy management, boiler and chiller upgrades.

The research has identified a number of key findings. A significant factor to the oversizing issue is the excessive and uncoordinated design margins, that are applied during the various specification, design and installation stages of building service projects for a variety of reasons. The thesis categorises and describes the various types of margins that are applied during a building services design and the potential rational for their inclusion. It argues that care must be taken when applying margins; ensuring cumulative effects do not undermine the ability of systems to be energy efficient.

Other contributing factors to the oversizing issue include a lack of communication and transparency across the various project stakeholder groups, whereby design choices and assumptions made during an early phase of a project design are not then necessarily passed on to stakeholders during later project phases. Specific project stakeholder requirements and relationships are explored and analysed in detail to determine the various influences upon the design options chosen and the decision-making process that led to the over-dimensioned plant and equipment.

A major cause of inappropriate sizing is the lack of requirements information such as energy demand profiles and the use of vague and unreliable data for initial project requirements. The impact of these factors on system performance and cost, and how these can impede on a hospital building's ability to meet energy efficiency and carbon reduction targets are analysed and discussed in detail.

The thesis emphasises the need to develop robust processes that capture the scope and rationale for the margins applied, to communicate project assumptions and stakeholder requirements in a clear and unambiguous format and to develop systems for improved data capture and analysis. The development of flexible and alternative design solutions that apply diversity principles, such as different backup systems to provide resilience rather than the traditional ‘like-for-like’ redundancy solutions, are also explored and discussed in detail.

The thesis highlights a clear lack of systemic thinking during the specification, design and installation phases of building service systems whereby better processes, procedures and communications are necessary throughout the entire design process.

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