Redevelopment of the Regional Performance Centre for Sport at Caird Park, Dundee includes an innovative Low Carbon District Energy Hub that utilises surrounding greenspace to provide energy for the buildings on-site with potential for off-site supply in the future.

Caird Park is a 111 ha park to the north of Dundee city centre. It is well used for active recreation offering facilities such as a golf course, a velodrome and athletic tracks. Dundee City Council and sportscotland are creating a new Regional Performance Centre for Sport which will also include a Low Carbon District Energy Hub (LCDEH) utilising Low or Zero Carbon Technologies.

The energy hub is part of a bigger redevelopment of the site, where previous buildings have been demolished to be replaced by new, more energy efficient buildings with an estimated completion date in Spring 2020. The driver for this was the 1st October 2015 change to the Scottish Building Standards which require an improvement in energy conservation/efficiency for new buildings by reducing carbon emissions by approximately 43% compared to the previous 2010 standards (60% compared to the 2007 standards). Such a significant reduction in carbon emissions necessitates the utilisation of Low or Zero Carbon Technologies.

The LCDEH in Caird Park will combine multiple green energy technologies. A 600kW Ground Source Heat Pump (GSHP) solution will be installed based on 116 vertical boreholes, mostly 200m deep and 12m apart, arranged in a square grid pattern. This will extract ’low grade’ heat (circa 8°C to 10°C) from below ground and convert this into a higher grade heat (70°C), which then becomes useful in providing the heat demands of the various buildings. This is achieved using a device known as a 'heat pump'. The heat pump runs on electricity, and for every 1kW of electrical energy consumed, it will produce 3.6kW of heat energy, due also to the heat obtained from below the ground.

Thermal conductivity testing was undertaken at three locations before finalising the borehole design. It was expected that all boreholes would be drilled to 200m depth but in a small number of cases the vertical drilling hit fractured rock limiting the drilling depth. For these, their depth was reduced to 100m and, to offset this, additional 12 boreholes were added.
Due to the differential costs of gas (3p/kWh) verses electricity (11.3p/kWh), the plan is to use a Combined Heat and Power (CHP) unit to generate the electricity that is required to run the heat pumps. This enables the project to benefit from the significantly cheaper cost of gas, whilst using electrically powered heat pump units. The CHP unit will also contribute valuable heat to the system.

    

Lastly, solar thermal panels, mounted on the Energy Centre’s roof, and solar PV panels, mounted on the Performance Hub’s roofs, will boost hot water and electricity generation for use in the buildings. On-site gas boilers will be available for back-up heat generation if needed at peak periods.

     

The new buildings, including an energy centre, will be clustered and surrounded by significant areas of green space for sports like cycling and athletics. The campus style design is key to making the district heat network cost effective. As a result of the design, there is additional capacity within the district heating system to provide heat to neighbouring social housing which, in a future phase of works, will allow us to help alleviate fuel poverty in these areas.

Technical system parameters of the Energy Hub in Caird Park:

• Ground Source Heat Pump Loop consists of: 116 boreholes, mostly at 200m depth
• Ground Source Heat Pumps deliver: 600 kW heat output
• Designed GSHP Coefficient of Performance: 3.61
• Low Grade Heat Thermal Store Capacity: 3,000 litres
• Solar Thermal Panels consist of: 33 No. flat collector panels
• Solar Thermal Panel dimensions: 1,056mm x 2,380mm
• Solar Thermal System delivers: 50 kW heat output
• Combined Heat and Power (CHP) delivers: 150 kW electricity and 236 kW heat output
• CHP Unit Input: 478 kW
• High Grade Heat Thermal Store Capacity: 31,070 litres
• Gas-Fired Boiler Plant delivers: 2,367 kW heat output
• Gas-Fired Boiler Plant efficiency: 108% condensing
• Integrated Low Temperature: Flow temperature, 70°C
• Hot Water (LTHW) Circuit Return temperature: 40°C
• Integrated LTHW Circuit Flow Rate: 32.08 l/s

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