High performance and energy efficiency in construction might also be the motto for users of a new sports facility in Birmingham, writes Austin Williams.
The Birmingham High Performance Centre (BHPC), currently featured on a rather naff advert singing the praises of the Lottery, includes a 132m sprint straight, two long jump areas, a pole vault run-up and landing bed, a practice area for throws and a high jump, all to Olympic standard. In addition, the 4,000m2 facility has a physiotherapy suite and a strength and conditioning suite operated by the English Institute of Sport.
Situated at Alexander Stadium in the centre of Birmingham, the BHPC also claims a bigger array of roof-mounted photovoltaics than any other building in Europe.
The BHPC has been designed to minimise its total energy consumption, contributing towards its own running costs, as well as making significant savings in greenhouse gas emissions. By exceeding current best practice, the architects expect this building to act as a catalyst for similar projects in the UK.
As one of 18 successful projects to receive Department of Trade and Industry funding for the development of solar technology, the BHPC demonstrates how solar photovoltaics can be integrated sympathetically on a large-scale building, by using them alongside energy saving features, such as lighting management, halide lighting and zoned heating systems.
The 1,500m 2of thin-film photovoltaics will generate more than 80MWh of electricity per annum - an energy equivalent of some £6,292 a year and a saving of 61,100kg of carbon dioxide annually.
Gas-fired radiant heaters have been used and are arranged in zones for maximum efficiency and low emissions. Low-pressure hot water heating to ancillary areas is zoned. The main sports hall is naturally ventilated, with the vents forming part of the external design of the building.
Kalwall's insulated translucent panels, in an aluminium framing system, have been included to the gable ends and at high level on the side walls, affording large amounts of natural lighting without glare to minimise the lighting load.
The largest electrical consumption for the building is the lighting loads, so highfrequency control gear and low-energy halide lamps have been used throughout the main hall. The overall lighting requirement is 60 250W units, a total of 15kW. The expected year-round energy consumption of 55MWh, which includes predicted small power loads, is less than the annual production of photovoltaic electricity.
Direct solar radiation onto the roof heats the structure and can adversely affect the quality of the internal environment. The reduction of summer heat gains due to the presence of the solar array facilitated the decision to avoid installing costly and energy expensive summer cooling systems. Stackeffect ventilation to the main hall is via low and high-level louvres.
Kaneka thin-film, solar modules require significantly less silicon and energy to produce than crystalline solar modules, hence energy payback periods are lower, cost per Wp and kWh are lower, while the technology lends itself to mass production and cost-perunit volume production savings more readily than crystalline versions.
A novel purpose-designed bracket resulted in a quick and efficient form of installation of the photovoltaics.
In summer, the dark modules (with an anti-reflective coating) absorb a significant amount of solar energy and heat up as a result (in largely still air, the modules may reach over 70infinityC).
However, because these modules are mounted at least 100mm above the roof, both the front and rear sides of the modules are exposed to the cooler air stream, increasing the heat-shedding characteristics of the roof. The designers are currently attempting to quantify the benefits of this cooling effect.
Low-angle solar gain is controlled by overhanging roof sheeting to shade the Kalwall glazing.
Rainwater from the roof is discarded into grass-covered swales, where it is able to permeate naturally back into the subsoil and provide new wildlife habitats.