Cladding

When the Co-operative Insurance Company was faced with a crumbling service tower at its Manchester headquarters, it turned a problem into an opportunity. The windowless tower was originally clad in mosaic tiles, which were intended to shimmer in the sun.

Forty-three years later, pollution had turned the building a dull grey and the tiles were falling off. “It had to be refurbished,” says Dave Smith, a spokesperson for CIS. “We looked around for the best way to reclad it and found solar panels were the ideal solution.”

When the building is completed at the end of this year, the UK’s tallest building outside London will become Europe’s largest vertical array of solar panels. The 122 m building will be clad on three sides with PV panels which will generate 180,000 kW/h of electricity a year, enough to power 1000 PCs. PV panel installations are said to be so expensive that they have an infinite payback period – but not according to Smith. “It wasn’t very different when you compare it to traditional cladding when you factor in the electricity you gain and the fact we had to clad the building anyway,” he says. The whole project will cost £5.5m, but a grant of £175,000 from the DTI and another grant of £885,000 from the Northwest Regional Development Agency will ease the pain.

Work started on the project last November. The first stage was to repair areas of damaged concrete then fix a wire mesh to the face of building to stop any more tiles falling off. The PV panels will form a ventilated rainscreen, although a few apertures will be left at the base of the building so people can see some of the original mosaic tiles. Once the mesh was in place, vertical rails were fixed to the building ready to receive the PV cladding.

A total of 7224 PV panels are being used. These are incorporated into cladding cassettes that each hold seven PV panels. These are then attached to the vertical rail in horizontal bands. Each band is plugged into a wire running around the building. The PV panels produce direct current, which is turned into alternating current by an inverter. This is then fed into main electrical supply via electrical meters that record how much power is produced. Although the panels won’t be able to provide enough electricity for all the building’s needs, it should make a dent in the electricity bill – as well as providing Manchester with a fine landmark.