This major sustainable energy heating system was one of the first of its kind to be installed in a stately home in Scotland and has delivered significant savings in carbon emissions. Replacing the oil-fi red heating system, which consumed approximately 100,000 litres of oil a year, the woodfuel boiler has resulted in a saving of 500,000kg of CO2 per year, the equivalent of heating 10,000 houses for a day.
The boiler uses approximately 500 tonnes of woodchips from low grade timber from the Roxburghe Estates. The wood is stacked in the forest after cutting and then allowed to dry naturally for 6-9 months before being chipped and transported to the woodchip store next to the boiler. The optimum moisture content for the chips is 35 – 45%. Woodchips are loaded into a 5 tonne hopper and an automated auger then feeds the chips into the boiler on demand. In the main burner, the woodchips are roasted with limited oxygen supply to form wood gas which is then burned with a regulated supply of air to produce an exhaust gas of around 800oc. The exhaust gas transfers heat to the water supply through a heat exchanger before the hot water is stored in two large accumulator tanks. Underground insulated circulating pipes supply hot water to Floors Castle and to the greenhouses and other buildings at Floors Gardens.
2013 saw the completion of the second phase of the biomass boiler programme which included the installation of heating systems to 16 cottages at Floors Home Farm and the Estate Office.