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24
ZEB
annual report 2015
The project
Powerhouse Kjørbo
consists of
a total refurbishment of two office blocks in
Sandvika, Norway. The original buildings were
built in 1979, scenically situated close to the
outlet of the river Sandvikselva.
Powerhouse Kjørbo is the first project to be
realized by the Powerhouse Collaboration,
consisting of Entra Eiendom, Skanska,
Snøhetta, the environmental NGO ZERO, the
aluminium company Hydro, the aluminium
profile company Sapa, and the consulting
firm Asplan Viak. The main objective of the
Powerhouse Collaboration is to demonstrate
that profitable, energy-positive buildings are
possible - also in Norway.
Refurbishment work started March 18. 2013
and the project was completed and handed
over on February 5. 2014. The total heated
floor space that was renovated is 5,180 m
2
.
One of the goals of the project was to make
an energy positive building by compensating
for the energy demand for the production of
materials and components, construction, and
energy for operation. As well as end-of-life
treatment with on-site production of renewable
energy. Another important goal was the
achievement of BREEAM outstanding, with
a good indoor environment as one of several
objectives. In addition, profitability was a key
objective for all the parties involved in the
project.
Life cycle analysis was used to establish the
primary energy balance. It was used actively
throughout the interdisciplinary and iterative
design process to ensure decision making
based on a lifecycle perspective
1
.
Embodied energy as well as energy used
during construction and for transport of
materials is calculated as primary energy,
but it can be converted to average yearly
equivalent electricity through the use of
the primary energy factors throughout the
buildings’ expected lifetime
2
.
The equivalent yearly embodied electricity for
all materials used throughout the buildings’
expected 60 year lifetime (after total
refurbishment) is estimated to be 61,716 kWh/
year (11.91 kWh/m
2
/year). The equivalent
yearly embodied electricity for the construction
and transport of materials is calculated to be
7,082 kWh/year (1.37 kWh/m
2
/year).
The measured first year energy demand
for operation and the energy production
matches well with calculated values from
design. Total measured first year energy use
for ventilation, space and tap water heating,
cooling, ventilation, and circulation pumps
was 122,542 kWh (23.65 kWh/m
2
) while the
predicted first year use was 121,947 kWh
(23.54 kWh/m
2
). When adding energy use for
plug-loads, the measured energy use adds
POWERHOUSE KJØRBO
Bjørn Jenssen (SKANSKA)