Innovate Green office, Thorpe Park, Leeds
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A commercial building in Leeds has been awarded the highest
ever BREEAM rating - 87.55 per cent - by utilising the high
thermal mass of structural hollowcore concrete.
A sustainable wonder
The Innovate Green office, at Thorpe Park in Leeds, at first
glance does not look particularly green. There are no windmills or
solar panels. Indeed, it even has mechanical ventilation. Yet, the
building emits 80 per cent less CO2 than a typical
conventionally air-conditioned office, producing only 22kg of
carbon dioxide per m2 per year. This equates to a saving of
350 tonnes of CO2 a year.
The design and construction approach developed by the project
team was based on harnessing 'sustainable first principles' rather
than adding renewable energy systems to a conventional building
design. An engineering-led exercise produced an environmentally and
commercially sustainable prototype building design with the
sustainability credentials of each element being considered in
conjunction with the client's need for flexible, commercially
viable office space.
The building services were designed to be low carbon with low
energy lighting and heating, cooling and electricity tri-generation
provided by a 30kWe baseload CHP and matched absorption chiller.
However it is the passive design features that makes this building
The concrete structure plays a key role in the environmental
performance, with the whole building designed as a thermal store.
The structural frame consists of load bearing precast wall panels,
precast floor planks and a single, central column line. The
concrete incorporates fly ash secondary cementitious
material, Lytag aggregates and recycled reinforcement.
The concrete structure is externally insulated to
substantially exceed the requirements of Part L at 0.15W/m2°C and
exposed internally allowing its high thermal mass to regulate the
internal environment. The floor and roof planks are used as
Termodeck to further increase the thermal mass. In the Termodeck
system the hollow cores of the precast planks are cross connected
internally to create a serpentine labyrinth through which the
supply air is passed. This additional contact between the
environmental air and the interior of the floor planks engages
virtually the entire mass of the concrete, not just that exposed at
the external surfaces.
With the insulation levels achieved; the heat loss is reduced
to a point where the internal gains provide the majority of useful
heat. The building is mechanically ventilated and heat recovery
AHUs collect the heat gains from people and computers and store the
energy in the Termodeck for later beneficial re-use. Summer cooling
is provided by a combination of passive night cooling and active
cooling from the chiller using the Termodeck as a thermal store in
a strategy similar to ice storage.
Drainage and water
A vacuum drainage system utilises harvested rainwater for
flushing the toilets. This virtually eliminates use of treated
mains water to convey sewage. The overall volume of sewage
discharged from the building is reduced by 75 per cent.While the
provision of permeable paving and a natural wetland area prevents
This is a speculative office that provides real sustainability
using existing and readily-available construction techniques and
technology. Its success is due to the consideration given to the
structural and building elements as an holistic, sustainable
Architect: Rio Architects
Environmental engineer: King Shaw Associates
Termodeck supplier: Tarmac