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HEAT PUMPS | ORKNEY COUNCIL BUILDINGS HEAT ISLANDS Orkney Islands Council has been installing heat pumps in schools and public buildings for more than 15 years in a bid to decarbonise heating and end reliance on oil. Andy Pearson looks at the lessons learnt and how a smart electric grid could soon take advantage of the relentless winds that batter the Islands Alistair Morton, energy T he Scottish government published its Heat in Buildings Strategy in October. Similar to that published in England, the document has identified the contribution heat pumps will make, as a tried and tested measure, to Scotlands fight against climate change. Scotland is ahead of the rest of UK when it comes to installing small-scale renewable schemes, with the remote Orkney Islands leading the way. According to MCS, the certification body for renewables, one in five properties on the Islands has some form of small-scale renewables. More impressively, for the past 12 years Orkney Islands Council has been pioneering the use of large-scale renewables through its commitment to heating council buildings, including offices, schools and care homes, using heat pumps. In that time, the council and its consultants have completed 16 schemes, and gained valuable experience of how best to use heat pumps on both new-build and retrofit projects. Necessity has driven the Islands to embrace electric heat pump technology. Orkney is off the gas grid, so we can heat our buildings with either electricity or oil-fired boilers, says Alistair Morton, energy and utilities officer for Orkney Islands Council, and the person responsible for implementing the councils Carbon Management Plan. Because of the councils commitment to reduce carbon emissions, weve been going down the heat pump route for all our new-build properties for over a decade, he adds. The councils first venture using ground source heat pumps (GSHPs) was on two new-build care homes: the relatively small development on the island of Westray, and Smiddybrae House in Dounby, on the Orkney mainland. Both were designed with back-up oil-fired boilers because no-one trusted the heat pumps to deliver, Morton recalls. Following on from the care homes, the council then opted to use ground source heat pumps on a series of larger, new-build schools projects: Kirkwall Grammar School (including an attached theatre and fitness centre); Stromness Primary School; and Papdale Halls of Residence. Unusually for Orkney, One thing we have learnt is the importance of thermal testing the ground to ensure we design the ground array based on actual data in addition to heat pumps the schools also incorporate liquified petroleum gas (LPG) boilers to provide high-grade heat for the hotwater coils in air handling units, and to top up the temperature of the hot-water systems. LPG was used in preference to oil because the council was aiming for a Breeam rating of Excellent. The success of the schools project subsequently resulted in GSHPs being used on The Pickaquoy Centre for sport and leisure. More recently, the council has installed a seawater heat pump to take heat from the sea at the adjacent harbour, to heat its new offices and public library in Stromness. The key lesson the council has learnt from its GSHP rollout has been the need to test the thermal response of the ground. The 28 December 2021 www.cibsejournal.com Bad files.indb 28 26/11/2021 15:16