The National Trust has hundreds of oil range cooker / central heating systems (Aga, Rayburn, Stanley) across its 20 or so thousand buildings. We are looking for a more environmentally friendly but economic equivalent cookers. As we saw before Christmas there is such volatility in the price of oil and the CO2 emissions, conflicts, environmental damage that oil causes should be raising alarms with us all. The NT have an aim of ‘getting off oil’ But its not simple since we are all including organisations in our way addicted to the stuff, its what our entire economy is built around – enough with the preaching…
Ty Mawr Wybrnant deep in a valley near Betws y Coed in Snowdonia is an important icon in Welsh culture being the Birth place of the Bishop William Morgan. He was the translator of the Bible to Welsh recognized as one of the key aspects in saving the Welsh Lanuage. Next to the house is the house of the custodian which had until recently a very ancient oil heating system together with and even more ancient oil tank . npower agreed to fund a trial of a wood pellet and log range cooker to heat water and central heating and this would be an excellent pilot for the whole organisation.
Scandinavian / Austrian/German houses retain their heat much better than granite Welsh cottages do and so we suddenly found that the few wood pellet range cookers we could find were large in size but small in heat out put . so we called on the expertise of an engineer to look at the problem in a bit of detail and no mater what we did we could not get the house ‘heat load’ lower than around 19kw and the best range we found (and bought) was 7kw which was ideal for the Austrian farm house it was designed for. We contacted the company and asked if they could increase the output to 20kw which they would if we placed an order for 500. So we compromised with the pilot (not the order of 500!) – we added a Clearview 650 wood stove with a back boiler and 5kw of Worcester solar thermal, insulated the house with wool and hoped for the best – on paper the sums added up!
Ah – 7kw of Austrian heat output on logs was based on high quality sub10% moisture Austrian timber, the availability of logs with tis moisture content is not thick on the ground in the uk and a bit expensive to buy. With pellet the system was a form of batch boil which was not ideal. (on then off) The custodian and his wife having struggled through 6 months of pilot had to call it a day and the stove was replaced with an Esse Ironheart which will burn just about anything but not as automated and would not be such a like for like replacement.
I feel a British wood pellet range cooker is not far away and it was worth trailing the best available at the time. But the main lesson was that we should not have used such a low output range to provide the base load of heat without either having a decent back up or insulating the house a lot more – but technology and understanding is moving very quickly in this field.