Dimplex creates mega heat

A new college campus in Luton has used Dimplex ground source heat pumps to help meet its twin objectives of energy efficiency and sustainability in a large-scale 1.5MW installation.

As part of the Building Schools for the Future initiative, the £56 million development will see a new Luton Sixth Form College built on the site of the existing facility. Part of the brief for the new building was a commitment to sustainability, so renewable heating was a high priority.

The design consists of 28 ground source heat pumps ranging in size from 11kW to 75kW with a combined output of around 1.5MW to provide space and water heating. Some of the heat pumps are reversible, so in summer, cool liquid can be circulated through the system to draw heat out of the building; the heat pumps give a total of 712kW cooling capacity.

The Dimplex heat pump range offered solutions to all the different requirements of the building – high temperature units for hot water, reversible units to provide heat recovery to the hot water when in cooling mode and a complete package of compatible cylinders.

An open loop borehole will extract groundwater directly from the aquifer beneath the site and circulate it around the site on a ring main via a 1MW heat exchanger. Distribution systems specified vary according to the use of the area; a combination of Tarmac Termodeck, underfloor heating and air handling units will be used.

Luton Sixth Form College achieved the Learning & Skills Beacon status in 2004 and was awarded Outstanding by Ofsted in its last inspection. The new college will accommodate 2,300 students, in line with projected demand, and will actually offer around 20% more space than the current site, although on a smaller footprint. The old buildings are still operational while the new building takes shape on the current playing fields. The new complex is scheduled to be opened to students in September 2010, after which the old buildings will be demolished and that space used to accommodate new sports facilities and car parking.

The new college site will incorporate a wide variety of environmentally-friendly features, including a containment area under external recreation space to minimise the risk of flooding in the event of exceptionally heavy rain, a brise soleil mounted on south sides of the buildings to limit solar gain and glare in summer, rainwater harvesting for reuse in the toilets and for irrigation and maximum use of natural light and ventilation.

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