Four drilling rigs are in the county to drill boreholes for the ground source heating system at each of the new schools being built as part of Orkney Islands Council’s Schools Investment Programme (SIP).
The geothermal system will supply heating for the new Kirkwall Grammar School (KGS), Stromness Primary School, the new Papdale Halls of Residence and the new pool and squash courts at the Picky Centre.
The work is being carried out by Geothermal International, working for Morrison Construction as contractor on the SIP programme, and is well underway at KGS, Stromness Primary and the Picky Centre.
At KGS, an ‘array’ of 96 boreholes will be drilled – each 150m deep and 150mm in diameter – which will then feed the ground source heating system to provide underfloor heating throughout the new school.
Morrison Construction expects the bore works at KGS to take around 12 weeks in total.
Initially three rigs were on site at KGS with each managing a hole a day on average.
This was recently reduced to two rigs, with further drilling at Stromness Primary and Picky now also underway.
It’s expected the rigs will finish with drilling work at the new Papdale Halls of Residence in Spring.
Ground source heat pumps (GSHP) use the ground as a heat source. A pipe is put in the borehole and filled with water and antifreeze. When the liquid passes through the heat pump, it exchanges naturally occurring heat from the ground – like a refrigeration system in reverse. The heat from the liquid is transferred into the heating medium - in the case of KGS, an underfloor heating grid.
Underfloor heating works on a thermal store principle, or a constant low temperature source of heat.
Heat pumps are an efficient way of providing heat for underfloor systems – for every 1Kw of energy put into the system it’s possible to get between 3 and 4 Kw of heat out.
It’s expected the ground source heating will cut carbon emissions by 30% when compared with conventional oil-fired heating systems for a similar sized school.
GSHP systems will be used in the new schools to provide approx. 75% of the heating and domestic hot water supply. LPG gas boilers will be used to top up the system and provide smoothing during peak loads.
Between the various projects in the Schools Investment Programme, 196 boreholes of up to 150m in depth will be installed to provide approximately 1MW (megawatt or 1000 kilowatts) of thermal energy. At KGS alone the GSHP system will provide approximately 600kW of thermal energy.
This forms part of the greener sustainable energy systems being providing for these modern 21st century facilities. In addition to the GSHP systems, approximately 600m2 (square metres) of solar PV panels will be installed across the Schools Investment Programme.
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Notes to editors
Morrison Construction have contracted the installation of GSHP systems to Geothermal International Ltd. Geothermal’s scope of supply includes drilling of boreholes, installation of the ground source loops themselves, the interconnecting pipework and the supply and installation of the heat pumps and control systems.
Orkney Islands Council’s Schools Investment Programme is supported by the Scottish Government, SportsScotland and the European Regional Development Fund (ERDF).
Orkney Islands Council’s £57m Schools Investment Programme will deliver:
- A new ‘Orkney Arts Theatre’, a 350-seat multi-purpose theatre for music, drama and dance at Kirkwall Grammar School. The project will be funded by OIC capital investment and £1.104m from the ERDF. Construction of the new facility forms part of the Council’s Schools Investment Programme.
- A new Kirkwall Grammar School on the existing site
- A new Stromness Primary School at the head of the Hamnavoe
- A new ‘halls of residence’ next to Kirkwall Grammar School
- A new six-lane swimming pool at the Picky Centre with moveable floor and teaching/training pool, toddler pool, beach area, health suite and squash courts - funded by a mix of OIC capital investment, SportsScotland (£1.2m) and a portion of the Scottish Government’s Schools Investment funding.