An energy-efficient system from Manchester-based CHP specialist ENER-G has been instrumental in the drive to generate low-carbon energy supplies by two local public buildings.
The system was developed for the Grade II-listed Manchester Town Hall Extension and Central Library, as part of a multi-million pound refurbishment.
Two 230kWe ENER-G tri-generation engines will produce the majority of heating, cooling and electricity required by the historical buildings. Use of two engines has enabled switching between the units in order to maximise operating hours of the system overnight, when demand is reduced.
With an 'island mode' design, the CHP system can also be switched to operate independently from the main electrical grid in the event of an electrical network failure, providing emergency power to maintain critical public services.
The 'island mode' design required a heat rejection radiator, but space constraints within the old building made retrofitting technology impossible. To combat this, the facility was linked to the existing absorption chiller radiator.
The buildings utilise all waste heat to maximise overall energy-efficiency.
Additional innovative elements include introduction of thermal stores into both the chilled and low-temperature, hotwater systems to allow for night time charging, and 24hr chilling of the ICT communications rooms.
CHP technology has not only helped the buildings secure a BREEAM Excellent rating but also reduced their carbon dioxide emissions by 710t a year, the equivalent of removing 237 cars from the road, or the carbon offset in one year by 582 acres of forest.
ENER-G Combined Power Ltd managing director Alan Barlow said: "As a local business we are pleased to help Manchester City Council deliver on its carbon reduction programme.
"The units are operating at around 90% efficiency, helping to create cleaner and affordable energy for the city. This project demonstrates the suitability of CHP for retrofit projects."
The Town Hall CHP project is the first phase of the proposed Greater Manchester Heat Network programme, which will provide a low-carbon district heating supply for the four city centre clusters of Manchester, Bury, Oldham, and Stockport.
Other partners on the project included contractor Laing O' Rourke, NG Bailey and BDP.
Image: Two listed buildings in Manchester with innovative energy-efficient systems. Photo: courtsey of ENER-G.