Energy
saving deluxe
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Click on the image for larger
version
Illustration: Jan Helge Johansen, SINTEF Media,
based on information from Arkidéco AS, Stjørdal
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Here are Norway’s most energy efficient
homes. Total energy consumption? Just over one-third of the national
average.
The buyers of these brand new apartments
outside Trondheim in Norway are about to move in to apartments featuring
insulation that is superior to that in other newly built homes.
The apartment complex also uses super insulated windows, ventilation
with heat recovery and an advanced heat pump system for domestic
hot water. All these features are controlled by a modern, user-friendly
Internet- based operating system.
But if you are thinking that all the insulation
and technical extras will be hard on the wallet, then you are wrong.
These residents will enjoy lower monthly living expenses than those
who build new, but without efficiency investments.
PROFITABLE
CUT
The property developer has calculated that construction costs
are about six percent higher than normal. However, SINTEF research
scientist Tor Helge Dokka, the building project’s specialist advisor
on energy and indoor climate, says that homeowners will be well
compensated for the extra expense by the savings from reduced energy
consumption.
The apartments have an annual energy consumption
of just 70 kilowatt hours per square metre. The average annual energy
consumption in Norwegian homes is around 200 kilowatt hours per
square metre.
On an annual basis, the low-energy apartments
require a miserly 18-20 kilowatt hours per square metre for heating
– just one-fifth of the normal level.
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ENERGY CUT: These newly constructed
lowenergy homes in Stjørdal are a result of interdisciplinary
collaboration. Architect Grete Mahlum from Arhideho, Tor Helge
Dokka, SINTEF and Bjørn Breivik, Husby Amfi Housing Co-operative
have been central in the planning.
Photo: Thor Nielsen
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HERE IS THE
RECIPE
Dokka is quick to emphasise that the energy savings are not achieved
at the expense of the indoor climate or comfort level. The recipe
for such efficient comfort comes from a host of initiatives:
- The walls, floor and roof of the apartment
complex all have greater insulation than normal.
- The windows are super insulated but, when
desirable, can allow in considerable radiation heat from the sun.
?The building structure has no air infiltration or thermal bridges.
- Each apartment has a separate ventilation
system supplying adequate fresh air. The system recovers 70-75
percent of the heat in the extracted air.
- Low-energy lighting is used where possible
to reduce energy consumption and prevent overheating.
- At any time, you can view the current
level of heat and electricity consumption on a graphic energy
tracking system designed to increase consciousness of energy use.
- When the apartment is empty, several installations
automatically switch to standby mode. Lighting, coffee percolators
and the like switch off and the ventilation level automatically
reduces.
RECORD REDUCTION
The Trondheim apartments will not reign for long as the leader
in energy saving. Several highly efficient “passive houses” are
in the process of being built or in the planning stages. To qualify
as a passive house, the annual heating requirements must be less
than 15 kilowatt hours per square metre. That is just one-seventh
to one-eighth of the heating requirements of a conventional home.
In addition, a significant percentage of
the home’s heating requirements must be provided by renewable energy.
In theory, such houses should not require heating and cooling systems.
But, in practice, on the coldest days of winter ventilated air must
be heated to some degree.
“Energy consumption in these passive houses
is so low that it will soon be possible to meet the energy requirements
exclusively from locally produced renewable energy – everything
from combinations of solar collectors, photovoltaic cell units and
wind turbines, to heat pumps and small bio-powered combined power
and heating plants,” says Dokka.
By Svein Tønseth
Contact:Tor Helge Dokka, SINTEF Technology
and Society
Tel: +47 95 75 90 40, email: tor.h.dokka@sintef.no |
