Centre for Green Technologies, Cambridgeshire

Image kindly provided by Clegg Construction

As part of a £13.5 million investment in a new, highly sustainable green skills college, the developer of this facility had an ambition to utilise the latest technologies to reduce its environmental impact. Alongside electric vehicle charging infrastructure and solar panels, the developer also wanted to demonstrate a commitment to water efficiency by incorporating rainwater harvesting.

The 2,400 sq ft development is home to EV workshops, renewable energy laboratories and a sustainable construction zone, supporting training on electric vehicles, solar panels, air source heat pumps and other sustainable construction practices. By incorporating a rainwater harvesting system, the developer was able to achieve a BREEAM rating of Very Good while significantly reducing on-site mains water consumption.

Stormsaver worked closely with the building engineers to safely and reliably capture rainfall from the college’s 1,000 m² roof area, providing an alternative water supply for toilet flushing throughout the building.

Due to the reliability requirements of the rainwater harvesting system, our team recommended a non-pressurised solution to minimise the risk of supply interruptions caused by component failure. Throughout the project, we worked closely with the engineering team to ensure the system would deliver long-term water savings and remain easy to maintain once commissioned.

The system filters rainwater through a pre-tank filter before storing it within a 22,000-litre below-ground storage tank. The tank was sized in accordance with BS EN 16941-1 and provides sufficient capacity to support the needs of the building’s 400 occupants.

Overall, the rainwater harvesting system is expected to save 537 m³ of water annually and meet 68% of the college’s non-potable water demand using harvested rainwater. In addition to the water efficiency benefits, the system is expected to utilise 97% of the rainfall that lands on the roof, helping to reduce stormwater discharge from the site.