Thermal mass advantages highlighted by school
smart meters
The installation of smart meters in schools to monitor energy
usage is being advocated by Ed Balls, the Schools
Secretary. Installing them in schools that feature the use of
thermal mass as part of a passive
sustainability design would prove the heating and cooling benefits
of heavyweight construction Tom DeSaulles, building physicist of
The Concrete Centre.
The announcement by Ed Balls for the
installation of smart meters is part of a £12 million campaign to
encourage schools to make savings of up to £750million. From
January 2010, primary and secondary schools across England will be able to apply for
a meter which will provide constant readings of how much
electricity a building is using and the potential savings of
turning down heating or switching off lights and electrical
equipment. Partnerships for Schools will be responsible for
overseeing the delivery of the smart meters project.
According to the Schools Secretary the
campaign will help to reach a long-term ambition for all new school
buildings to produce no carbon emissions.
“The use of thermal mass as part of a passive
design approach for new school buildings would certainly help
achieve that ambition”, said DeSaulles. “It would reduce both
heating and cooling energy requirements”.
Passive design involves taking advantage of a
building’s thermal mass as part of an integrated approach that
includes a balance between orientation, glazing, ventilation and
shading, as well as the provision of a high standard of insulation
and air tightness. Thermal mass has been found to be best achieved
using heavyweight concrete and masonry construction. Buildings with
a high level of thermal mass are characterised by their ability to
soak up and release heat at different times of the day. In the
summer, heat is absorbed on hot days which helps to prevent over
heating and reduces the requirement of energy intensive air
conditioning. Cool night air is used to ventilate the building and
purge the accumulated heat from the building’s fabric. In the
winter, heat gains from the sun and from lighting and electrical
equipment are absorbed into the thermal mass and radiated in the
evenings to reduce the need for heating. “Use of thermal mass and
passive design can considerably reduce the operation energy
requirements of a school building”, said DeSaulles.
Passive design for the summer requires
consideration of ventilation, shading and thermal mass. The
combination of concrete's thermal mass, solar shading and night
time cooling was the most popular strategy used by the DfES
Exemplar School Design teams to avoid summertime overheating.
For winter, consideration needs to be given to
orientation, window sizes and shading. Orientation is the most
critical factor in determining the amount of sun that a building
receives. A south orientation is required to maximise the benefit
of passive solar heat gains. In the middle of winter, the sun
reaches a height a maximum altitude above the horizon of about
17o in southern England. During the height of summer it
reaches 64o. During the summer shading provided by a
simple overhang will block the sun during the hottest part of the
day but will allow sunlight to pass directly in and heat the
building during the winter.
“The incorporation of these design
consideration will enable a building’s form and fabric to be used
to assist with the cooling of a school during the summer and
reduced heating requirements during the winter”, said
DeSaulles.
He continued: “Energy efficiency of schools is a high priority. The installation of
smart meters will allow monitoring the success of heavyweight
thermally efficient construction approaches”.
Ref: TCC627