HEAT PUMPS | ORKNEY COUNCIL BUILDINGS In addition to promoting corrosion, the wind also draws heat from the buildings. Orkneys temperate maritime climate means that temperatures average 5C in winter and 15C in summer as a result of the warm Gulf Stream. The Islands relatively consistent temperatures are accompanied by almost continuous wind, which averages 7m.s-1 (13.5 knots) over a year. The wind strips the heat out of the buildings, so we have to design them with minimal envelope penetrations, says Morton. Extract fans can really cause problems, so, in new builds, we put in centralised MVHR units with one intake and exhaust. The relentless wind is the reason Orkney is dotted with wind farms, which result in it annually exporting more electricity than it consumes. Interconnectors transfer the wind-generated power to the mainland grid. Bizarrely, this is then sold back to the Islanders with a surcharge of 2p per unit. We end up paying 2p per unit more for electricity than the rest of the country, Morton explains. He admits that, if Orkney did have access to the gas grid, he probably wouldnt be using heat pumps for most schemes, because the cost of electricity would make them uneconomic. Most of the time, we propose heat pumps on the basis of lower carbon emissions, but the bottom line is that, currently, electricity is at least three times more expensive than oil, he says. Another frustration for Islanders is that insufficient grid capacity means that, when the wind is blowing hard, wind turbines have to be shut down to limit electricity generation. It is a situation that is set to change under the ReFlex project, which will develop an electricity smart grid. Under the scheme, electric vehicle chargers will be switched on, and heat pumps will top up heating systems in public buildings and homes with cheap electricity when the grid starts to become overloaded. This will enable the turbines to keep running. Meanwhile, the project currently occupying Morton is the refurbishment of the heat pump system at Smiddybrae House, the councils first heat pump scheme. This involves the installation of a new borehole array and replacement of the heat pumps. And, 12 years after the heat pumps were first installed in the care home, the council has removed the oil-fired boiler backup. Were now confident we can meet 100% of the heat load using heat pumps, says Morton. CJ The Scottish Net Zero Public Sector Buildings Standard is a voluntary standard to support public bodies in meeting their net zero commitments for their new-build and major refurbished infrastructure projects. The Islands relatively consistent temperatures are accompanied by almost continuous wind Heat pump council projects Site New build/ Tech Capacity RHI kW Installed 2020 New build 1 New build 2 Yes Notes Smiddybrae House Care home GSHP 230 Kalisgarth Care home GSHP 36 2006 Stromness Pool Swimming pool GSHP 32 2007 Glaitness Primary School School GSHP 72 2007 The Pickaquoy Centre Campsite amenity block ASHP 32 2008 Stromness Community Centre Community centre ASHP 80 2009 Braeburn Court Care home GSHP 12 2010 New build Warehouse Building Library/ Community space SSHP 40 2012 New build 4 Stromness Primary School School GSHP 154 Yes 2012 New build 5 Childrens House Residential care GSHP 35 Yes 2013 New build Sanday Junior High School School/pool GSHP 120 Yes 2013 Kirkwall Grammar School School GSHP 756 Yes 2013 New build 6 The Pickaquoy Centre Swimming pool GSHP 380 Yes 2013 New build 7 Papdale Halls of Residence Student accommodation GSHP 253 Yes 2013 New build 8 3 New build Evie Primary School School GSHP 113 Yes 2016 New build Hamnavoe House Care home GSHP 302 Yes 2019 New build Kirkwall Care Home Care home GSHP 390 2022 New build St Andrews Primary School GSHP 330 2022 OIC housing stock 94 installations ASHP Various OIC housing stock 171 installations EAHP Various OIC housing stock 41 installations GSHP Various 9 10 New build Notes 1 Replacement of original HP/oil boiler system installed 2006 2 Oil boiler backup 3 HP does pool water to allow boiler to be switched off out of hours 4 Sea source heat pump 5 LPG boiler backup 6 LPG boiler backup 7 Oil boiler backup 8 LPG boiler backup 9 Water-to-water heat pump for DHW (start on site Q1 2022) 10 Water-to-water heat pump for DHW (on site) 30 December 2021 www.cibsejournal.com Bad files.indb 30 26/11/2021 15:16