| Boiler: | Gilles HPKI-K 900kW |
| Output: | 900kW |
| Fuel: | G50, W50 woodchip, locally sourced from Estate woodland |
| Fuel Storage capacity: | 100 tones |
| Annual Heat Load: | 1,575MWh |
| Annual Fuel Requirement: | 450 tonnes (G50, W50 woodchip) |
| CO2 Saving: | 417 tonnes per year |
| Features: | Automatic ignition, pneumatic heat exchanger cleaning, ash removal, district heating featuring weather compensation, self optimising terminations, variable flow pumping. |
| Dating back to the late 18th Century, Heveningham Hall is a beautiful country house set in its own parkland and estate. Now privately owned, the house is undergoing an extensive programme of restoration. The hall was once heated by electric boilers which the current owners changed for a large log boiler. This very much reduced running costs but required almost full time stoking during the winter. With the service life of the log boiler coming to an end, the owners began to investigate replacements, ideally still utilising wood fuel from the estate but not involving the same levels of user interaction. Making this heat available to many of the other estate properties was also seen as an important factor. |
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Energy Innovations took on this design concept and proposed a central automated woodchip boiler together with district heating to supply the Hall and other properties. This allows timber harvested from managed woodland on the estate to be processed at one location, minimising fuel transport and keeping all fuel operations away from the domestic properties.
The system is currently linked into some 26 commercial and residential buildings. A programme of expansion of the district heating system is planned for the future. The boiler house, fuel store and pipe work have been designed with these considerations in mind. SUITABILITY OF A GILLES SYSTEMThe Gilles HPKI-K boilers are recognized as market leading in terms of reliability and performance. The boilers are fired by an underfeed stoker, improving efficiency by following the natural combustion process of wood-fuel. An industrial cell wheel forms a proven barrier to burn-back and contains cutting edges which chop oversize chips before they reach the boiler. A ceramic lined combustion chamber with replaceable fire bricks, primary and secondary combustion airflow measurement and regulation, pneumatic heat exchanger cleaning, multi-cyclone flying ash removal, Lambda controlled combustion and frequency controlled flue gas fan for boiler under-pressure regulation are all standard items. These features all reduce the level of maintenance required and keep the boiler running efficiently at all times. Modulation from 100% to 30% of rated output with flame preservation below 30% allows the boiler to match its output to the district heating system’s demand throughout the year. FUEL STORAGEThe majority of fuel is sourced from estate woodland. This timber is stored on hard standings where it is seasoned for up to 12 months. Wood chippers capable of chipping material up to 32” in diameter are available for hire in the region, allowing a broad spectrum of timber to be chipped. The estate currently makes use of a co-operatively owned wood chipper, which, it is projected, will visit the site around 5 to 7 days per year to produce the annual requirement. The fuel store, which contains a six metre industrial sweep collector for automatic transfer of woodchip to the boiler, has been converted from a disused grain store. This store holds around 100 tonnes of woodchip. |
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DISTRICT HEATING SYSTEMIn order to distribute the heat to the Hall and estate properties, an extensive district heating system has been installed. The high efficiency, variable flow system incorporates weather compensation and self optimising terminations, requiring minimal commissioning. Pre-insulated district heating pipe has been used, with larger sections carried out in steel to allow higher operating temperatures and greater carrying capacity. Buffer tanks and thermostatic, proportional control valves are used to minimise heat and pumping losses from the district mains. A plate heat exchanger is used at each termination to allow both new and existing heating systems to be operated independently from the district mains. The heat exchangers protect older heating systems from the higher operating pressures of the district heating system. A heat meter has been installed at each property to allow heat usage to be monitored and re-charged to end users. Income from heat sales will cover fuel production costs and allow the capital investment to be re-paid.
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CARBON SAVINGSAssuming the alternative fuel used for heating and hot water was oil, the woodchip system should offset some 400 tonnes of CO2 per year. The installation was supported by a grant under the Defra Bio-Energy Capital Grant Scheme. |
| "The owners of Heveningham Hall Estate were keen to further exploit the forestry activities on the Estate and the installation of a biomass boiler fuelled by woodchip from the Estate had been a long term goal. The biomass boiler linked to a district heating system has allowed the provision of heat and hot water to 26 buildings initially with further capacity to add buildings as they are refurbished. After discussing the Estate’s requirements with a number of different suppliers, Energy Innovations were appointed to design and build the installation. We were pleased with the enthusiasm and level of expertise from the outset and these were maintained throughout the project. A huge benefit of Energy Innovations’ management of the project was that the designer of the network also managed the installation process. This led to a well run project that was completed to high standards. We would have no hesitation in approaching Energy Innovations for our future projects." | |
