Advertising: 01622 699116 Editorial: 01354 461430
By Dr Andy Lewry & Lorna Hamilton
ENERGY MANAGEMENT BSEE MIND THE GAP The difference, in performance, between design and the building ‘in‐use’
e have the ability to design good buildings and the knowledge to operate them in an effective and efficient manner – so why doesn’t it happen? The construction industry has in general been “designing for compliance” using software with “standardised driving conditions”. We know how to build good performance buildings but the issue seems to be having the design feed through to performance-in-use1
W .
This has led to what has been termed the performance gap. In reality this has two components (see figure 1): uThe compliance gap; and uActual performance gap.
The overall gap has been estimated at between 200-450%2
estimate 50-70% is the compliance gap3 of which the modellers and
can be solved with more realistic modelling mirroring the conditions in operation more closely.
However, the underpinning reasons for the second and larger actual performance gap are generally unknown. There is a lot of speculation and hypothesis but little investigation and hard evidence.
Why is the important? uFigure 2: The life costs of a building.
Management of real estate investments aimed at maximising property value and return on investment4
via
uEffective risk management uEfficient property management uIdentification and implementation of valuable improvements
However, poor operational management undermines the aims of asset management and leads to: uIncreased tenant complaints regarding comfort conditions and loss of reputation uHigher service charges uLonger void periods leading to a reduction of income uLower and shorter rental values, as a consequence of high service charges and poor comfort conditions uCapital expenditure on HVAC equipment failures, due to poor maintenance uTenants wanting to renegotiate rent values based on maintenance issues
On a pure cost basis the operation energy or the energy used in using a building is up to 50% of the operation costs or 40% of the total cost of a building; see figure 2.
If this is inflated by a multiple of 2 to 4.5 the cost to the end user is considerable. The effect on the asset and its value is just as dramatic with: uDeterioration of value uService life of plant reduced uFabric lifetime reduced uCostly remedial works to maintain value u In ‘void’ periods there is likely to be still further deterioration through lack of use uLoss of reputation
Investigating the gap BRE research5,6 and anecdotal evidence from
the asset management industry has indicated a number of possible reasons: uIssues with the management structure and governance uLack of maintenance due to resource and skills shortage uLimited data uLack of practical solutions and their costs However, the real truth is that nobody knows and this presents an opportunity for
VISIT OUR WEBSITE:
www.bsee.co.uk
whoever finds the evidence for the underpinning causes and then presents practical solutions to solve them. This has been recognised by the construction industry and priorities that were fed back from the UKGBC Delivering Building Performance task group; the UK Innovate building performance project and a BSRIA workshop on Building Performance were: uThere was data on the performance gap but no systematic investigation of the reasons why and the magnitude of the issues – what was needed was a controlled study to investigate this; not attempting to link datasets; uDesign was not an issue but operation and the associated issues seemed to be the cause, however there is only anecdotal evidence to support this. A study is needed to codify and quantify the causes of poor performance in use; uThe “gap” seems to increase with time, again anecdotal evidence is available with no quantification of the underlying reasons; with a long term study needed to identify, qualify and quantify any affect; uHealth and wellbeing is associated with this effect but as before, there is not true quantification, model or tool; as a result, a monetary value cannot be assigned to the loss/gain of productivity leading to an incomplete business case. A desk study is needed to identify knowledge gaps followed by field study producing data leading to a model/tool for quantification of productivity loss/gains. The main barrier to this is quality data from a large enough sample with full access to the building and their occupants – we have now been presented with that opportunity. What were missing are “real-life” exemplars to investigate the actual causes of the
servicing
State of Art
X Exemplar B X Exemplar E Asset Basic X Bad
performance gap and propose practical solutions.
New research project
This proposed research project is in two stages where this is the first stage which defines the methodology using trial buildings to determine the correct data to collect and the right questions to ask; with a proposed second stage rolling this out over a larger number of buildings.
The objective of this project will be: 1. Scopes proposed buildings and choose a suitable exemplar for the purpose of collection and analysis of metered, asset and energy audit data.
a. Using the results, from 1., propose reasons for the performance gap; produce operational and asset recommendations; and model the benefits.
2. Based on the learning from these trial buildings produce a methodology that can be rolled out to a larger number of buildings. 3. Propose a second phase covering more office buildings, which covers the breadth of the building stock in this sector and aims to produce a tested generic methodology for the office sector, which includes: a. Fully air-conditioned; b. Mechanical vented;
About the authors
Dr Andy Lewry (Principal Consultant and Programme Manager, BRE), has 19 years, technical, marketing and management experience within the Carbon and Energy Management Industry preceded by a further 10 years similar experience within various parts of the Environmental and Construction Sectors.
Andy is a chartered engineer and a Fellow of both the Institute of Materials (IOM3) and the Energy Managers’ Association; plus a Prince 2 qualified project manager. He has also authored and published best practice publications on energy management, energy audits, building control and building energy management systems.
Recently, he produced guidance on “Bridging the performance gap: Understanding predicted and actual energy use of buildings” and “Producing the business case for investment in energy efficiency”. Andy was also part of UK Green Building Council’s task group that produced the “Delivering Building Performance” report, on 11th May 2016, which lays out the success factors and steps required to tackle the gap between building design and building performance.
X Exemplar C Exemplar A X Exemplar D
Operational status
Good uFigure 3: Choice of exemplar buildings. BUILDING SERVICES & ENVIRONMENTAL ENGINEER MARCH 2017 33
Lorna Hamilton (Senior Statistician, BRE) currently leads on quantitative analysis aspects in BRE’s Social Research Team. She has experience of analysing and modelling a wide variety of data and specialises in the application of Generalised Linear Models for correlated data. She has worked with both large and complex data sets for a variety of Government, European Commission and commercially funded projects.
uFigure 1: The difference between design and the building “in‐use”.
Cost Years 1 - 2 2 - 5
20% Design / Build c. Naturally ventilated.
COMPLIANCE ASSET MODEL
Standardised Driving Conditions
eg: ● Set points ● Hours of occupancy ● Occupancy density ● Etc
REAL
ASSET MODEL Real Use
Occupancy hours Occupancy density
Unregulated loads:
● Lifts ● Small power ● Other services, eg: servers fire, security
OPERATIONAL (REAL) PERFORMANCE
● Issues with management structure and governance ● Lack of maintenance ● Limited data ● Lack of practical solutions and their cost ● Process loads
The first step will be to scope proposed buildings and choose a suitable exemplar. (See figure 3).
References
1. UK Green Building Council Task group report – “Delivering Building Performance”, 11th May 2016,
http://www.ukgbc.org/sites/default/files/UK- GBC%20Task%20Group%20Report%20Delivering%20 Building%20Performance.pdf
ENERGY PERFORMANCE CERTIFICATE (EPC)
METERED DATA
2. Innovate UK – “Building Performance Evaluation Programme: Getting the best from buildings - Findings from non-domestic projects”, January 2016,
https://www.gov.uk/government/publications/low- carbon-buildings-best-practices-and-what-to-avoid
COMPLIANCE GAP (50 – 70%)
PERFORMANCE GAP (150 – 400%)
3. CIBSE Building Simulation Group event, “IES Faculty: Intelligent Big Data in Building Services”, Dr Naghman Khan, IES, London, 27th April 2016.
4. Mind the Gap: Quantifying Principal-Agent Problems in Energy Efficiency, International Energy Agency (2007),
https://www.iea.org/publications/freepublications/ publication/mind_the_gap.pdf
80% (of which up to 50% are energy related) 20 - 40
Operate & maintain, renovate & revitalize
5. A. J. Lewry, J. Ortiz; A. Nabil; N. Schofield; Mr. R. Vaid, S. Hussain, and P. Davidson, “Bridging the gap between operational and asset ratings – the UK experience and the green deal tool”, BRE briefing paper KN5477,
0 - 1 reconstruct
http://www.bre.co.uk/energyguidance
6. A. J. Lewry, “Bridging the performance gap - Understanding predicted and actual energy use of buildings”, BRE IP 1/15, February 2015, IHS press, ISBN 978-1-84806-408-9,
http://www.bre.co.uk/energyguidance
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48