LONDON OLYMPICS ENERGY CENTRES
There is an agreement to achieve a
reduction in carbon emissions of 20% in 2012 as a result of the CHP services, rising to 30% in 2013. When fully operational, the scheme has the potential to save up to 12,000 tonnes of CO2 a year, compared with conventional energy supplies.
Linking up While the energy centres have been designed to operate independently, two giant heating mains link the two buildings. This enables the heating plant to be run efficiently under low-load conditions. Currently the heat loads are supplied from Kings Yard; however, as more venues are completed and heat loads ramp up as the Games approach, more capacity will be progressively brought online until each centre is operating at design capacity. Substations are strategically located
A 3D image showing, in purple, the gantry containing the biomass boiler flues which connect the existing building to the new Olympic Park energy centre. Roof- mounted cooling towers are shown in red, and the buffer tanks at the rear in brown
development. This energy centre features two 3.3 MW CHP engines; a 4 MW absorption chiller; five 7 MW ammonia chillers; and two 20 MW dual fuel gas/oil boilers. These give it a current output of 46.2 MW of heat and 39 MW of cooling and up to 3.34 MW of electrical power, depending on loads. The Stratford City energy centre also has
the capacity to add another 26.2 MW of heat with an additional boiler and two CHP engines. Some redundancy has been built into the centre’s total capacity to enable the systems to run uninterrupted even while items of plant are off-line for maintenance. Between them the two energy centres
have the potential to supply a total of 194.9 MW of heating, 64 MW cooling and 30 MW electrical power.
Design 3D modelling
The project design team used 3D packages to develop the scheme and build the energy centres virtually, before construction commenced. The design was developed
using a variety of software packages including AutoCAD 2010, AutoCAD MEP and 3D CADduct. To assemble the energy centres, the steelwork layout was imported from the fabricator. However, the existing Edwardian building, housing the biomass boiler, was modelled using 2D drawings in AutoCAD before being imported into a design package. The scheme was drawn in AutoCAD with
20 CIBSE Journal August 2011
CADduct running alongside so that the designers could access the CADduct library of pipe fittings and other services. The larger elements of plant, such as the boilers, were modelled by the CAD team and imported into the design. To render the model,
Navisworks was used. The designers used the rendered model to view the design and check for any clashes visually or run clash-detection software. The model was also used to work out delivery routes for the installation of future legacy plant. Once the designers were happy with a scheme, it was published as a model along
with dimensioned sections and plans. These are produced as PDF files and published on a Projectwise database so that the sub-contractors can access the current drawing. Along with the energy centre,
the pipework distribution network was modelled in 3D by importing ground-level data and converting this into a model of the site. The model has all 75 substations, to enable teams working on individual buildings to model the connection to the heating mains. This model has been uploaded to the Olympic Delivery Graphic Information System model of the site.
around the network to enable heating and cooling to be supplied to the venues. These skid-mounted units were prefabricated at the Milton Keynes works and comprise one or two heat exchangers, depending on whether heating and/or cooling is being provided, with controls and pipes attached. A secondary circuit transfers heat from substation to the consumer. A total of 75 substations have been installed to serve both the permanent and temporary Olympic venues and legacy schemes. The network operates as a variable-
volume, constant-temperature circuit, with the volume varied by altering the speed of the circulating pumps. The system is set up to maintain a differential pressure at the index point, which is the point in pressure terms furthest from the energy centre; in reality this means there is sufficient pressure difference between the flow and return mains to push the heating or cooling water through the heat exchanger at this point. In addition to the two McAslan-designed
buildings, the Kings Yard scheme also incorporates a Grade II listed Edwardian building, which has been renovated. This is the Olympic Park’s only retained building; it is situated adjacent to the energy centre and will house a 3.5 MW biomass boiler and woodchip store as well as provide the space for a future visitors’ centre. The boiler is due to be operational by the end of 2011, and a wood-chip supplier is currently being sought that complies with the Olympic Delivery Authority’s (ODA) sustainability criteria. There is space for a second biomass boiler to be added in the
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