This 900kW boiler is heating six new poultry sheds (104 m x 22m / 340ft x 72ft) stocked to approximately 46,000 birds per shed and two residential houses. The biomass heating system has been fully integrated into the growers existing site management system allowing the grower to monitor output and performance. Back up and top up capacity is supplied by two industrial LPG boilers rated at 280kW per boiler. A 22,000 litre buffer tank is installed to give short term, additional peak capacity.
The Gilles Boiler
The 900kW industrial boiler uses moving grate technology to enable high moisture content chip to be burnt without loss of efficiency. The boiler has been specified to enable the grower to use both high and low quality woodchip – and has been initially configured to run on lower grade saw mill residues of up to 60% moisture content.
The boiler has a high turn down capability enabling it to maintain combustion with no detrimental effect at times of low heat demand. The boiler also has the facility to allow the grower to monitor all boiler parameters remotely using a broadband connection. Energy Innovations can remotely monitor boiler performance and change settings and parameters to maximise the efficiency of the system. In the event of any issues with the boiler, alarm emails and/or text messages can be sent out automatically.
Heat delivery is via pre insulated underground mains specified to provide long term maximum efficiencies to each shed.
Each shed has three wall mounted fan coil units. Heat meters are installed on all boilers and at the entry point to each shed enabling detailed records of energy used on each crop. The shed heat meters are fully integrated into the site management system. Load sensing pumps in combination with motorised valves in the sheds ensure that only the hot water that is required is pumped through the heating main. This minimises heat loss in the main and pumping costs.
The Fuel Store
Energy Innovations installed a ‘walking floor’ in the fuel store within an existing barn. It delivers the woodchip into a cross auger which then feeds a rising auger into the boiler. Hydraulic rams power the walking floor and sensors activate the feed mechanism only when chip is required. A walking floor can deliver large quantities of lesser quality fuels and makes optimum use of storage space available. No further mechanical intervention is required once the woodchip is tipped onto the floor. A total of 350m³ of woodchip can be stored on the walking floor – this equates to over 100 tonnes. An additional 50 tonnes can be stored in the building, enabling 10 days of fuel (150 tonnes) to be stored at the coldest times of year under maximum heat load. As well as running on wetter fuel, the walking floor enables the grower to use larger chip size and hence have a wider choice of suppliers. Fuel is delivered by a chip liner lorry in bulk loads of 90m³.
With financial backing of the Renewable Heat Incentive (RHI), this installation is receiving in the region of £75,000 per annum. Payments to RHI beneficiaries will be paid over a 20 year period and are paid quarterly and in arrears based on actual energy consumption used. The level of payment is calculated based on installed capacity and the rates are index linked to the retail price index.