Subsequent investigation showed that manual
control of circulation lighting in school B was
particularly bad – a characteristic that was repeated
to varying degrees in schools A and E. The schools
with large, connected atriums had the highest lighting
energy consumption for the following reasons:
•
Nobody ‘owned’ the atrium spaces and therefore no-
one took responsibility for switching off the lights;
•
The spaces were well day-lit, but in school B some
of the finished spaces were dark. Without lighting on
during the day, the teachers complained of a gloomy
feel to the spaces, although overall they enjoyed the
openness of the school;
•
The occupancy of the schools was complex and
varied on a daily basis and between school terms. This
meant that lights were not switched off outside core
hours; and
•
The 24-hour security required lights to be on for
security cameras and for walk-rounds.
The base load drove the energy consumption in all
schools. After lighting, the fans, pumps and controls
caused the highest consumption. This was partly due
to poor time control of systems.
Interestingly, school C has ventilation equipment
that defaults to ‘off’ when the spaces are not occupied.
Even though the academy had the highest proportion
of mechanically-ventilated spaces, it had the lowest
electrical consumption data for fans, pumps and
controls.
Design lessons
Clearly, some schools with low-energy features may
produce more carbon dioxide, not less. So what can
we learn from this? The data showed that all the IT
functions, such as computer use, servers and other
equipment – can represent as much as 20 per cent of a
school’s electricity consumption, a proportion that will
Similar schools can show very
> This revealed that gas consumption for heating was become more significant as other equipment becomes
different energy-efficiency
quite good – a consequence of using high-efficiency more energy-efficient.
outcomes. Occupancy and
condensing boilers, compensated circuits, optimum The likelihood is that the student/computer ratios
usage of facilities are key to
these discrepancies.
start-stop controls and reasonable to good U-values. will rise. We need to be aware of this and influence the
The electricity consumption is surprising – ICT consultants on our projects to procure the most
especially when compared with the benchmarks. efficient equipment.
However, the results were comparable to more recent Schools of the past were expected to be entirely
monitored data. For example, two schools were both free-running from April to October, with many rooms
reported to use around 65 Wh/m
2
, without some of the either noisy or hot. New schools come with a higher set
acoustic constraints and levels of ICT provided in the of expectations. However, designers must review the
academies. However, the high levels certainly warrant standards and determine their effect on energy. The
explanation. key lesson is: only provide high standards when they
Figure 2 shows the electrical breakdown by end-use. are required, and not as a default state.
Data was gathered using electrical profiling equipment School buildings are now used for a variety of
in the low-voltage panels and distribution boards. purposes, particularly during out-of-school hours,
Lighting consumption in academies A, B and E such as adult classes, community events and after
was up to four times higher than academies C and school lessons. This is raising the run-times of central
D. While installed loads were equivalent, the major plant and lighting systems, and needs consideration
difference was control. Figure 3 shows the control of at design stage.
manual lighting in school B and automatic lighting in Buro Happold’s research showed that the default is
school C over one month. The simple use of passive usually full power at all possible times that the school
infrared sensors saved 30 to 40 per cent, compared could be occupied. This is one of the key reasons that
with manual switching. school C performed so well – all defaults stated were
40 CIBSE Journal November 2009 www.cibsejournal.com
CIBSEnov09 pp38-41 poe.indd 40 22/10/09 17:12:48
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