The Danfoss heat pump is linked to a display panel in the school’s reception area which gives a continuous digital readout of its performance, including the amount of renewable energy it is generating.
The pump was installed at Bowland High School in Grindleton near Clitheroe as part of a newly built music block. It provides space heating for the block, which includes a classroom, storeroom and toilet facilities.
The project was commissioned by Lancashire County Council, which has also specified ground source pumps from Danfoss Heat Pumps UK in two of its other schools and has been impressed with their high system efficiency.
Readings taken over a 12-month period, including the harsh winter of 2010/2011, show that the pump is achieving an average Coefficient of Performance (COP) of 3.39. This is above the system’s initial target of 3.08, based on calculations at the time of installation and is enhanced by the high level of insulation within the building.
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A calculation of the building’s heating energy needs showed that it was expected to require 29,000kWh per annum, and the heat pump has consumed just 9431 kWh, representing an annual energy saving of 19,569 kWh.
The pump is a DHP-L 10kw 3-phase unit with a 100 litre buffer tank which heats the 187m2 single storey building via radiators. It is fed by two 250m ground loops laid in a field adjacent to the building at a minimum 1m depth.
To further enhance the energy efficiency of the building and performance of the heat pump, the music room’s block cavity walls included 100mm of insulation, which achieves a U-value of 0.2 W/m2K. The profiled metal deck roof is also highly insulated.
The system was specified by Andrew Kells, a Mechanical Design Engineer for Lancashire County Council, he explained: “The school’s management was very keen to have renewables fitted in the new building and we were also successful in obtaining a grant from the Low Carbon Buildings Programme, which helped with the cost of the heat pump system. Another issue was the school’s remote position, set 100m back from the road. A new gas connection would have been necessary to supply the new building which would have been very expensive to install. A heat pump was the best solution in terms of long term performance and it is very satisfying to be able to heat the new building through a more natural, sustainable energy source.”
Chris Dale, Director of Danfoss Heat Pumps UK, said: “Lancashire County Council is one of several local authorities which has cut their carbon emissions and energy costs by specifying heat pumps. With the amount of land available, ground source heat pumps were perfect for this project and it is satisfying to hear that the system is delivering a high level of efficiency, whilst teaching students about the importance of green energy.”
Heat pumps are effective both in summer and winter, day and night because the ground temperature remains constant at only a few feet below the surface. Non-domestic installations of ground source heat pumps in the UK can be eligible for payments under the Renewable Heat Incentive (RHI).
(GK/KMcA)
