Woodchip heating at St Edmunds Farm
During the recent renovation of St Edmunds Farm house, the owners decided that it was the time to consider an alternative fuel heating system for the property. The rising cost of oil combined with their desire to install a ‘carbon neutral’ system were the main factors in this decision.
Having looked at all the options, they decided that wood fuel heating would be the most practical. Wood pellets were an attractive option, but as woodchip was also available locally it was decided to look at a system that could deal with both pellets and woodchip. Both products could be delivered to the property by a blower lorry, which reduced the need for additional handling facilities – a great advantage to the owners. “It’s great, we can now phone and order woodchips in just the same way we used to order oil,” commented the owner’s wife.
The Boiler
A number of boilers were looked at before the owners decided that the GILLES system would offer them the highest levels of automation. “It was always important that we had a system we could happily leave if we were too busy, or going to be away on holiday, etc.” Additionally, the farm house is to be their home in retirement and so a heating system which required a great deal of user interaction was not a viable option. They have been impressed by the level of control of their GILLES heating system. “This is press–button stuff, simple and easy to understand. You can time to a second, heat to the exact temperature you want, and run radiators where you require them.”
The GILLES HPK boilers, which are available from 10 – 145kW, will cope with woodchip up to 50mm and moistures of up to around 35%, which means that those with their own source of wood fuel could quite easily use a hired chipper to generate fuel of this specification. This can offer some very economical heating opportunities. The larger boilers, which are available up to 6,000kW, can deal with moisture levels of up to 60% and much larger fractions of material.
The GILLES cell wheel, which is a standard part of the feed system on all the woodchip boilers in the GILLES range, not only eliminates the risk of burn-back but also prevents blockage of the burner feed through cutting any oversize chips. This exclusive feature is particularly advantageous when burning your own woodchip, which can be a less consistent product.
The owners have been amazed by how little ash is generated by the system. “When the heating is running we only have to empty the ash bin about once a month, and it’s useful potash for the garden.”
The Fuel Store
The 22 cubic metre hopper system was designed to provide two to three months’ heating when used with 50mm woodchip at 25% – 30% moisture. This means that the hopper would usually be filled twice through the heating season, and once again to see the system through the summer period. The GILLES hinged arm collection system is stronger than the conventional sprung sweeper systems and ensures a consistent feed, regardless of the material being used.
Fuel Costs
With woodchip delivered at £60 per tonne and oil at 37p a litre, the system should save the property owners around 70% on their annual heating bill – amounting to around £2,350 per annum. The boilers run at up to 94.5% efficiency, so the conversion of fuel into heat output is fantastic.
Based on this saving and taking into consideration the effect of fuel price inflation, the payback on this investment is seven to eight years. The system has a useful life of at least twenty years, so the saving over the lifetime of the boiler will be well in excess of £150,000.
Energy innovations
“Energy Innovations were a great help in guiding us through the decision–making process. Their team of engineers who designed the system, and the plumbers, did a great job and the installation went wonderfully smoothly. The system has been finished to a very high standard. Since the boiler was started it has not missed a beat, which is great, as on their advice we took the decision to get rid of our old oil boiler altogether. We’ve been thrilled with how efficient and reliable the boiler has proved to be.”