A Lancashire secondary school set in the rural area of Grindleton, Clitheroe, is benefiting from a ground source heat pump which is exceeding expectations in terms of energy efficiency and helping young people to understand more about how renewable energy works.
The pump was installed at Bowland High School as part of a newly built music block, providing space heating for a classroom, storeroom and toilet facilities.
A calculation of the building’s previous heating energy needs showed that it was expected to require 29,000kWh per annum.
But the heat pump has consumed just 9,431kWh, representing an annual energy saving of 19,569kWh. This equates to a reduction in CO2 emissions of 10.7 tons, based on the UK Carbon Trust published figures of 0.54522kg CO2 per 1kWh grid electricity energy source.
The project was commissioned by Lancashire County Council who also specified Danfoss’ ground source pumps in two of its other schools having been very impressed with their high system efficiency.
One of the things that also made the county council chose a heat pump from Danfoss was the secondary 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," says Andrew Kells, a Mechanical Design Engineer for Lancashire County Council.
10% better efficiency than estimated
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.
Readings taken over a 12-month period, including the harsh winter of 2010/2011, show that the pump is achieving a coefficient of performance (COP) as high as 3.73.
This means that for every 1 kW electricity input, 3.73 kW heating output is generated. This compares to, for example, a 1 kilowatt electric heater which would use 1 kW of energy input to only generate 1 kW of heating output.
An actual performance of 3.39 kW heating output generated from 1kW of electrical input by the heat pump is also above the system’s initial target of 3.08 kW, which was based on calculations at the time of installation and has been enhanced by the high level of insulation within the building.
The difference means that the efficiency has been 10% higher.
In terms of energy savings this could help the school make further reductions in its energy bills of around 6-8%.
Pictured right: Danfoss’ ground source heat pump utilizes nature’s own heating principles and, in popular terms, the sun simply lends a helping hand by transferring free-of-charge solar energy from the ground to the Bowland High School. 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.