When the Norfolk and Waveney Mental Health Foundation Trust decided to invest £8.2 million in a new hospital unit, it needed to ensure that the building took into account the NHS's target to be zero carbon by 2018 so it installed Dimplex ground source heat pumps.
The heating was required for Hellesdon Hospital's new Psychiatric Intensive Care and Low Secure Units and the Trust consulted Econic, one of Dimplex's heat pump installer partners, for a low carbon heating solution. Econic developed a system using two Dimplex SI50 TE 50kW heat pumps to draw heat from one of the largest ground collectors of its type in the UK to date.
As Dimplex offered grants of up to 50 per cent under Phase 2 of the Low Carbon Buildings Programme, Econic was able to secure £142,000 in grant funding for the project.
The design of the ground collector system took into account the geological conditions underlying the site, the heat yield available from the ground and the annual heat load profile of the new building.
The installation of the collectors used hydraulic pushing technology, with a 33 tonne 8 x 8 wheel truck carrying hydraulic rams pushing a steel casing into the ground, into which the collector pipes were inserted.
The steel casing was then withdrawn, leaving the pipes in the ground. A total of 120 25m-deep collectors were installed, which together are expected to produce around 75kW per hour throughout the collector system's lifetime, estimated to be around 25 years.
Rachel Newson, director of business development at the Trust, explained: 'We wanted the new facilities to incorporate best practice in low carbon building technology, in readiness for the 2018 zero carbon target, so we were looking for a partner to work with us to achieve our carbon reduction plans. We chose Dimplex, and having found our partner we were able to access grant funding. The heat pumps will help protect the Trust from any future unexpected increases in energy prices.'
In addition to the heat pumps, a variety of other energy-saving measures have been incorporated into the build, including high levels of insulation to minimise heat loss and energy consumption, low energy high frequency lighting with automatic controls and harvested rainwater for the units' WCs.