The project St. Mary’s School was undertaken by Bath & North East Somerset (BANES) Council as part of their programme of carbon reduction.
The installation was part-funded by Good Energy, the UK’s only 100% renewable electricity supplier, which invests
in community renewable heat projects on behalf of its customers. BANES Council delivered the overall project, designing and installing the mechanical and electrical infrastructure, working with Hargassner who provided specialist design expertise on the boiler layout and a pellet fuel handling system which they subsequently installed and commissioned on site. The Hargassner service team now provide operational support and servicing for the biomass boiler.
The 110kW Hargassner biomass boiler has the simultaneous benefit of significantly reducing the carbon footprint of the school and generating an income from the Renewable Heat Incentive (RHI). The project will benefit from a payment every quarter from the RHI which will continue for 20 years, increasing with the Retail Price Index (RPI). Also as the school was using carbon intensive oil for heating, they are now saving over 65 tonnes of carbon dioxide per annum.
Originally the School had two old oil boilers and an oil tank housed in a brick building connected to the main school. The boilers and fuel tank were due for replacement, so were removed and the space created was used for the biomass heating installation. The space where the oil tank was located has been turned into a pellet store, which meant Hargassner had to use their expertise to maximise the pellet store to minimise fuel delivery frequency. The most efficient use of the confined space was a rotary extraction system, rather than a linear pellet auger. This design optimised the usable volume of the 20m3 fuel store for pellets. The fuel store is complete with pellet fill and vent pipes and a pellet deflection mat as standard.
The project also includes a 2000 litre accumulator tank, which means the biomass heating design is able to instantly respond to any rapidly fluctuating heating or hot water demands. The school also has a gas supply, so now uses gas boilers as back-up to the biomass boiler, completely removing the need to use oil at the site.