Extracting heat from the ground

03 October 2011

Energy costs for heating in the farrowing house have been cut dramatically on the Co Tyrone pig farm of Gary Anderson. 

A ground source heat pump was installed in 2003 to provide water at 400C to warm the pig pads.  Gary is satisfied with the system and calculates that this has reduced the energy costs by 50%

The heat pump works by collecting low grade heat from the ground and using this to produce water at a temperature of around 40 to 450C.  A network of pipes containing refrigerant fluid is buried in the ground at about four feet depth.  At this level the temperature of the ground stays constant throughout the year at around 100C.  For each unit of electrical energy needed to run the heat pump there are around three units of heat produced.

The initial cost of installing a heat pump is high, and the payback time could be as much as ten years.  However, for new installations, this payback time could be reduced considerably if the proposed Renewable Heat Incentive(RHI) comes into operation from April next year.  This is a government support measure which pays a tariff to reward renewable heat production.  It is proposed that pumps installed from 1 September 2010 will be eligible for these payments. The consultation on the RHI closes on 3 October 2011.

Heat pumps are one of the renewable energy technologies that will be highlighted at the 'Practical On-farm Renewable Energy' event to be held on Greenmount Campus on Tuesday 1 November.  This event runs from 11.00am to 9.00pm and includes a trade exhibition, a range of seminars and tours of renewable energy installations on the farm and horticultural unit.  For further information contact David Trimble at david.trimble@dardni.gov.uk or (028) 9442 6682.