DRAFT
Case study
Office headquarters
identifies energy savings
worth over £23,000
Disclosure Scotland is an Executive Agency of the Scottish Government operating
on behalf of Scottish Ministers. Its core function is to contribute to the safety of
vulnerable people in our society by providing criminal history information to
organisations and potential employers to assist them in making safer and more
informed recruitment decisions.
Disclosure Scotland has 500 staff at its headquarters in a three-storey office block
in Glasgow.
Background
Although the building that Disclosure Scotland
occupies in Glasgow is relatively modern, the boilers
were coming to the end of their service life and
needed to be replaced. This was seen as an
opportunity to replace the boilers with energy
efficient alternatives and carry out an energy review
of the whole building to identify further efficiency
improvements that would reduce associated costs
and carbon dioxide emissions. However, the staff did
not have the technical knowledge or experience to
identify and decide what technologies would be
most viable to help them achieve this, so it was
decided to access the free advice and support
available from Resource Efficient Scotland.
Identifying the opportunities
A Resource Efficient Scotland Implementation
Advisor visited Disclosure Scotland and carried out a
free, comprehensive review of the building. This
identified many opportunities to use energy more
efficiently and reduce costs and carbon emissions.
The recommendations ranged from inexpensive
projects with a quick payback to those requiring
larger investment and having a longer payback.
Some of the key cost-saving options available are
detailed below.
Replace boilers
Today’s gas-fired boilers are highly efficient,
particularly those that have condensing heat
exchangers. Replacing the existing boilers with
condensing boilers would be a ‘like-for-like’ project,
but with the additional requirement of providing
drainage for the condensers.
With estimated annual savings of £3,300 and an
investment of £10,000, this project would have a
payback of 3 years and reduce annual carbon
dioxide emissions by 18 tonnes.
Increase data server room temperature
The data server room had six air-conditioning units
(ACUs), each with its own thermostatic control.
During the survey, it was found that these were set
to 20°C. Increasing the temperature setting to
around 23°C would reduce the workload of the
ACUs, so cutting annual energy costs by nearly £275
and carbon dioxide emissions by 100kg. Because the
cost involved in making these adjustments is
minimal, the project would have a very quick
payback period.
“We are delighted with
the report from
Resource Efficient
Scotland. We have
already had budget
approval for the work
necessary to realise
such promising
energy savings.
”Joe Dynes
Facilities Manager,
Disclosure Scotland
www.disclosurescotland.co.uk
Case study – Office headquarters identifies energy savings worth
over £23,000
Convert to water-cooled server chillers
Each of the ACUs had an internal compressor and
external air-cooled condenser unit. A variation of
this configuration is available that incorporates a
water-cooled condenser. This allows the ACU to
operate in normal chilling mode or, when outside
temperatures are suitably low, it can be used in
‘free cooling’ mode. Free cooling mode is very
efficient because the compressor is by-passed and
the cooling is provided by the cold external air
rather than by the refrigeration system.
It was estimated that this would save nearly £5,000
per year. With an investment cost of £41,000, the
payback period would be 8.3 years. Annual carbon
dioxide emissions would be reduced by 23 tonnes.
With annual cost
savings of over
£23,000, the overall
payback would be 3.5
years. Annual carbon
dioxide emissions
would be reduced by
105 tonnes if all the
recommendations
were implemented.
Installing zone valves
While most of the building was used around the
clock, some areas were restricted to normal office
hours. However, our advisor noted that heating and
air-conditioning was being supplied as if the whole
building was occupied continuously because there
was no simple way of restricting the services to the
areas that were not used at night or at weekends. To
allow these areas to be isolated when required, our
advisor recommended that motorised zone valves
could be fitted in the heating distribution system.
It was estimated that this would cost £4,000 and
achieve annual savings of nearly £1,500, resulting in
a payback of 2.7 years. Carbon dioxide emissions
would be reduced by 8 tonnes per year.
Installing a building energy management system
The heating and air conditioning control system
relied on individual controllers for the various
functions. While these appeared to be functioning
reasonably well, they require periodic monitoring
and manual adjustment to optimise the systems.
Replacing these controls with a building energy
management system would offer more
sophisticated and flexible control, and allow remote
monitoring, adjustment and fault reporting
functions. Additional benefits would include
reduced system downtime, reduced non-planned
maintenance and better environmental control.
While this would involve a substantial investment of
over £18,000, annual cost savings of nearly £4,000
could be achieved, resulting in a payback of under 5
years. Annual carbon dioxide emissions would be
reduced by 19 tonnes.
Improvements to lighting
Our advisor noted that internal lighting was on
most of the time and individual switches controlled
large areas of the offices. Therefore, a
recommendation was made to install movement
sensors to control groups of lights and enable those
lights in areas that are unoccupied for a
predetermined length of time to switch off
automatically.
In addition, the audit showed that there were 66,
50-watt halogen GU10 lamps used in the canteen
and toilets. Replacing these with light emitting
diode (LED) equivalents was recommended as a
simple and effective way of reducing lighting costs.
An additional benefit of LED lamps is that they have
a life expectancy of around 50,000 hours – 25 times
longer than that of tungsten filament lamps. This
means they don’t need to be replaced as often,
thus reducing maintenance and purchase costs.
The audit also showed that perimeter security
lighting was on for 18 hours a day – even on sunny
days. By installing a daylight sensor and modifying
the control circuits, these lights could be switched
off automatically when there is sufficient natural
light to illuminate the surroundings of the building.
With the total investment for all these lighting
improvements estimated to be £9,600 and annual
costs savings of £9,400, the payback period would
be approximately 1 year. In addition, carbon dioxide
emissions would be reduced by 36 tonnes a year.
Implementing the cost saving projects
The total investment for the above projects at
Disclosure Scotland would be around £82,600. With
annual cost savings of over £23,000, the overall
payback would be 3.5 years. Annual carbon dioxide
emissions would be reduced by 105 tonnes if all the
recommendations were implemented.
With such a range of opportunities to reduce costs,
Disclosure Scotland is now working with Resource
Efficient Scotland to prioritise the order in which it
implements the various projects. Concentrating on
those that are relatively low cost and have short
payback periods, will generate cost savings sooner
which can then be used to help fund the more
capital intensive suggestions that have longer
paybacks.
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