THE PRACTICE OF ENGINEERING DESIGN IN RELATION TO ENERGY FORECASTING

emphasis on acute hospital buildings)

The reader will now be familiar with the author’s line of enquiry that it maybe the inadequate application of building engineering physics that leads to poor energy and carbon performance, as much as poor predictability of that performance during the engineering design process. This section of the literature review is thus focused on engineering design practice with particular emphasis on the application of the science through the briefing and engineering design process. This raises a question: whilst the application of the science can be appreciated for the engineering design process, it not so evident why it is applicable to the briefing process? The answer to this challenge is

as identified by Underwood and Yik, (see p56) in that it is possible that ‘appropriate values’ are not gleaned in the briefing process such that they could be used to inform the early stage analysis for the engineering design. The literature review must then seek to inform the chosen line of enquiry through a review of practice. However, to be clear, the review of practice is not concerned with opinion as to how engineering designers typically execute practice, but what the professional standards or guidance requires for practice. Consequently, the basis of this section of the literature review is to understand how practice has been codified into actionable knowledge.

3.2.1 - The challenge of accessing codified knowledge (relevant to the research questions)

Knowledge requires codification if it is to be reusable, (Nonanka and Takeuchi, 1995. Kamara et al., 2002. Bacon, 2008.). However, Kamara et al (Ibid) also acknowledge that commercial organisations in the construction industry find it very difficult to effectively manage knowledge. They point to the fact that knowledge management tends to be predominantly project focused and consequently less concerned with the generation of new knowledge. Ideally it would be the creation of new knowledge that would be codified by institutions for reuse by their associated professions. It is apparent therefore that there are two key sources of knowledge in the industry concerning practice: that which exists within commercial organisations, and that which has been codified by professional institutions or membership organisations.

The need to capture and codify new knowledge in a fragmented construction industry was discussed by the UK Government sponsored Innovation and Growth Team (IGT, Op Cit). The report asserted that there was a poor understanding of best practice as well as wide diversity of opinion as to what knowledge is required to achieve low carbon performance in the built environment in the UK. It stated:

“This will require innovation – new ways of working and the acquisition of knowledge and skills that will provide competitive advantage at home and internationally, building on the United Kingdom’s reputation as a world leader in sustainable design.”

The challenge would be to either identify sources of codified knowledge (desirable) or to codify knowledge though survey and interviews of practice (least

preferable). With divergence of opinion as to how to achieve low energy – low carbon performance in the industry a survey of practice would in all probability confirm that divergence of opinion. Recent evidence (Kershaw and Simm, 2014) (albeit with the focus being low carbon school design) confirms the findings of the IGT report. The author’s lists reasons for obstacles to low carbon performance such as: increased equipment in modern schools, complexity of building systems and the perceived extra cost of low carbon design and technologies. Interestingly and of particular relevance to this thesis the authors suggest that most barriers could be overcome by improving communication between the design team, client and end users, and that truly integrated design teams are the key to mainstream low carbon school design. The very challenges that are identified by the author’s research questions.

The argument thus leads to the need to investigate codified knowledge i.e. that which is embodied in standards and codes of practice. Yet even this has its limitations, the criticism being concerned with how it has been interpreted (Guzman and Trivelato, 2007). They cite what amounts to a constructivist predilection as a reason for this by using examples such as: assumptions, context and tacit elements as being limitations of codified knowledge. The risk here is that even codified knowledge has limitations, not least of which is its currency. The author suggests that it is commonly understood that institutions tend to lag behind industry in codifying knowledge. This presents another risk concerning the relevance of that knowledge to current practice. It is also a risk to this thesis in that it could throw doubt onto what the author would have analysed as gaps in current knowledge.

3.2.2 - Codified knowledge

Accepting the limitations of codified knowledge within institutions and membership organisations, (because it is the best that is available) the most obvious focus of study into the practice of engineering design in the UK would be the governing institute for the profession, which is the Chartered Institute of Building Services Engineers (CIBSE). Like all professional institutes it should be expected that

this institute is the focus of current knowledge too. The CIBSE web site states that its role is to18:

“…support the Science, Art and Practice of building services engineering, by providing our members and the public with first class information and education services and promoting the spirit of fellowship which guides our work.”

It also states that it is:

“…the standard setter and authority on building services engineering. It publishes Guidance and Codes which are internationally recognised as authoritative, and sets the criteria for best practice in the profession.”

Whilst other sources such as BSRIA will also provide commentary on practice CIBSE has attempted to codify knowledge into guidance and best practice. A good example of this is the CIBSE Technical Memorandum 54 (Cheshire and Menezes, 2013). In this document the authors set out to explain current knowledge concerning the performance gap, that which explains the poor forecast performance of new buildings. Considering the author’s earlier comments in this chapter, Subject Matter Expert, Bordass explains (Volume 2, p97) that codification of knowledge is often imperfect, because ‘what the industry does know’ has not been translated into the guidance – indeed he asserts that it can take years before it is consolidated:

“In the UK, we have not understood with the ‘roll back’ of the State, the role professional institutions should play and how to put sufficient horse-power into creating and revising standards and Guides”.

TM54 written in 2013, is an example of the concern expressed by Bordass when he claims that the ‘credibility’ gap has been understood through case studies for many years (B. Bordass et al., 2004). Another obvious institutional source of codified knowledge will be from the Royal Institute of British Architects. From a study of its web site, it is apparent the institute considers its role as a facilitator of research, and less concerned with codification of architectural knowledge, and in particular the achievement of low energy – low carbon performance. However, the significant

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exception to this concerns the investment in the RIBA Plan of Work, which received a major update in 2013. This will be discussed later in this thesis.

3.2.3 - Subject Matter Experts

For these reasons the expert opinion sought by the author from known experts on specific statements in this thesis would serve to identify leading knowledge, not yet codified by institutions. This was achieved through semi-structured interviews and these are set out in the Appendices.

Concerning a Subject Matter Expert for building engineering physics in the UK one of the most respected engineers in the industry is Professor Patrick Bellew, Royal Designer for Industry (RDI), one of only a few professionals in the construction industry that have achieved this status. As a founder of the Green Building Council and Visiting Professor at Yale University in the United States he operates at the forefront of building engineering physics. His wide international experience would provide a breadth of opinion that would challenge the author’s statements should they be deemed to be invalid.

The second Subject Matter Expert is Mr. Stephen Runicles, Engineering Director for the Building Design Partnership and also responsible for the engineering design for the 3Ts Redevelopment, which has provided the case study for this thesis. The author argues that application of building engineering physics in the project provides an objective basis for validation of the author’s findings in the literature review. Indeed as will be demonstrated later in this thesis, the case study will provide a detailed explanation of the challenges of current practice in implementing building engineering physics to achieve low energy – low carbon performance for an acute hospital.

Concerning the Subject Matter Expert for In-use, one of the most recognised experts in the UK concerning In-use is Dr. Bill Bordass who was a principal investigator in the PROBE studies carried out during the 1990’s and early years of the following decade. He was significantly involved in the research projects that led to the definition of operational rating for non-domestic buildings and now known as Display Energy Certificates. He was also co-author of the Soft Landings Framework, which helps design and building teams to focus their projects more on performance In-use.

A final consideration in the use of Subject Matter Experts was that of the ethical considerations. By including the full transcript of the interviews in the Appendices, there will be concerns of informed consent addressing such matters as anonymity, confidentiality and data protection. The author’s proposal was subject to the university Ethics Approval Process and thus the rights of the individual’s concerned were addressed through this process.

3.2.4 - Engineering design practice: application of the science

The application of the building engineering physics in practice as it applies to the energy performance of buildings is set out by (Olesen, 2007). The paper establishes the requirements for compliance with the European Directive for Energy Performance of Buildings (EPBD). Olesen (Ibid) establishes a fundamental principle at the outset:

“The energy consumption of buildings depends significantly on the criteria used for the indoor environment, which also affect health, productivity and comfort of the occupants…

There is therefore a need to specify criteria for the indoor environment for design, energy calculations, performance evaluation and display of operation conditions of the building.”

Not only are the criteria for energy consumption clearly established – particularly pertinent given the research questions, but also at the outset it establishes the need for briefing criteria. Where would an engineering designer find guidance on such criteria?

As has been explained in the UK, CIBSE has codified best engineering practice and theory into design guides. In seeking to understanding the impact of users on energy consumption in buildings, the most relevant of these is set out in CIBSE Guide F Part 2, Energy Efficiency in Buildings, (CIBSE, 2004). It describes three key factors that affect energy consumption in buildings. These are:

a) Building Services, b) Building Fabric and, c) Human Factors.

Figure 17 - The building as an integration of energy systems – based on Hensen (2000)

In studying the illustration the ‘Internal environment’ it will be observed that it is impacted by a number of factors, which are:

 The role of the occupant, which can be in terms of the number of occupants, the activity of the occupants and their physiological tolerance for example, to heat, humidity and pollutants in the air.

 This tolerance impacts their interaction with the ‘Building structure’, such as the need for fresh air, through the opening of windows for example. This action will be influenced by the ‘Outdoor environment’.  The ‘Occupants’ will react to the ‘Internal environment’ by placing

demands on the systems that condition it, and in doing so they will interact with ‘Controllers’ that will send instructions to the engineering systems to modify the ‘Internal environment’ to provide a level of comfort appropriate to their needs.

 The ‘Controllers’ can also be activated by ‘Sensors’. These detect changes in the ‘Internal environment’ and which result in them transmitting instructions to the ‘Controllers’ to modify the ‘Internal environment’ such that it is now within acceptable comfort limits that were configured in the ‘Sensor’.

 ‘Auxilliary systems’, such as fans, radiators and lighting also impact the ‘Internal environment.’ These make demands on ‘Power generation’, ‘Fuel supply’ and ‘Renewables’.

The most significant message of this illustration is that it is the needs of Occupants that places demands on the Internal environment – in other words it is not buildings that consume energy per se – but it is the users of buildings (Janda, 2011). Clearly users have basic needs for comfort, but our expectations as users is that we have been conditioned for many years by the expectations of the consumerist society in which we live. Part of that conditioning is that we take for granted that the ‘Internal environments’ of the buildings in which we live and work can be controlled automatically with little or no occupant intervention and little regard for our actual needs. The conditioning leads us to have expectations on the systems that deliver the ‘Internal environment’ to be highly responsive (or even immediately responsive) to our ‘wants’ as distinct from our needs. For example users may want the room temperature to be 24 deg C, but we only need to it to be 21 deg C, if we were to wear appropriate clothing. Users may want hot water to be delivered at the spout within 3 seconds of turning on the faucet, but the need maybe more like 10 seconds. Both examples impact energy consumption. In their work on adaptive thermal comfort Nicol and Humphreys (2002) suggests that the human needs for thermal comfort are universal. They compare studies carried out between the UK and Pakistan to substantiate this observation. Whilst this may be so for many building types, in a hospital where patients thermal regulatory functions are compromised this cannot be the so. Indeed the wide variances of patient types suggest that the comfort range can be wide as well. A study in Swedish hospitals emphasised these distinctions through quantitative analysis techniques (Skoog and Jagemar, 2005) and also (Verheyen et al., 2011) where they carried out a study of thermal comfort of different patient types in Belgium hospitals.

In each case the sensible and latent heat gains will be different. Anecdotal evidence suggests that renal dialysis and chemotherapy patients for example are much more susceptible to variances in room temperature than healthy people. Likewise there will be variances in thermal tolerance between sedentary users and active users, and the elderly user compared to the younger user, where in each case, the former is more likely to be acutely aware of variances in temperature than the latter, a point emphasised Nicol and Humphrys (Ibid), and supported through detailed analysis (Collins et al., 1977)

Returning to Olesen (Op Cit) the author sets out the standard design criteria to be used for different types of accommodation and different types of use, based on activity. This immediately raises a question: In an era of energy conservation, how much do these ‘standards’ impact energy consumption? Olesen has already made the point that the criteria have a significant impact on consumption, and it thus follows that if those criteria could be refined (even optimised) then surely this it could be expected for forecast consumption to fall? How might this be achieved?

The ‘Sensors’ have been set up to monitor typical parameters for the ‘Internal Environment’ that are acceptable to the needs of most ‘Occupants’. These monitor the environmental parameters of what is known as Indoor Air Quality (IAQ), and are configured for heat, humidity and pollutants as described earlier. The ‘Sensors’ may or may not be configured to detect occupants in a space. They may only be configured to condition a space within the preset parameters – the very parameters cited by Olesen (Op Cit). If Sensors and Controls were not to be accurately configured for use, it would result in spaces being conditioned regardless of the occupant presence, and thus the building being effectively ‘preconditioned’ to use much more energy than is actually required. How could this situation arise? The engineers that specify the ‘Sensors’ and the ‘Controllers’ may do so in ignorance of how the building will be used. Consequently they might make assumptions concerning use, and it is these assumptions that set the operational parameters for the ‘Sensors’ and ‘Controllers’.

However, Part L2A of the UK Building Regulations 2013 Edition (NBS, 2013) sets out the requirements of control engineering services to prevent this situation arising.

In section 2.43 of the regulations it states:

Systems should be provided with appropriate controls to enable the achievement of reasonable energy efficiency in use.

It then defines what is ‘reasonable’:

The systems should be sub-divided into separate control zones to correspond with each area of the buildings that has significantly different pattern of type of use; and

Each separate control zone should be capable of independent timing and temperature control and, where appropriate, ventilation and air recirculation rate; and

The provision of the service should respond to the requirements of the space it serves. If both heating and cooling are provided, they should be controlled so as not to operate simultaneously and

Central plant should operate only as and when the zone requires it. The default position should be off.

The Building regulations are emphatic as to how the engineering systems design should be controlled. In this literature review the author will seek to understand how the engineering design briefing process implements these requirements, and how guidance from the Department of Health, Health Technical Memoranda relating to engineering services design also ensures compliance with the legislative requirement of the Building Regulations. The legislative requirement raises an important question: how does engineering practice seek to understand the impact of the building occupant on the engineering design? It is important because the legislative requirement clearly expects the use of the facility to be clearly understood as emphasised by the bold text in the above listed extracts from the Building Regulations Part L2A.

3.2.5 - The impact of the building occupant on building engineering design

(Kwok and Lee, 2009) describe how these factors (illustrated earlier in Figure 17) combine in an office building:

“In an office building occupants may use diverse electrical appliances as well as lighting appliances tending internal heat gains and the consumption of electricity. In parallel to

consumption, occupants produce waste, both in the form of solid and vapour. All of these effects resulting from occupant behaviour