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'the very efficent heating company'

Very efficent heating company

 

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Installing an energy efficient heating system in to 4 adjacent buildings, with solid granite walls over two feet thick was always going to be a challenge. Old stone houses i can only guess were never really that warm, additionally it takes a significant time to really make an impression warming them up.

For our co-op, with a strong environmental policy it only seemed right to try and find and environmental solution to our heating problem. When we first moved in 1995 we were shocked to discover the whole place was heated by electric heaters only, probably mainly as it had been developed as a B+B type place, not really developed with winter in mind. Not only was it heated by electric, the least efficient way of all to heat a home, but by those 1960's/ 50's style heaters that look really dangerous and use loads of energy.

Step one was to remove all these heaters and replace them with wood burners, we also replaced al the electric cookers with gas ones, for efficiency reasons. Although this represented an improvement of sorts it did mean we were burning 6 or 7 stoves at the same time and generally failing to heat the place throughout at the same time. There are several downsides to having burners in your home as we discovered, and when it came to have a new system we learned a whole lot more about these issues. I will reference some articles which are well worth reading if you want to burn wood efficiently. But here are a few shortfalls: Fires create drafts. Really big drafts, as loads of air is simply sucked up the chimney. Usually nice warm air from your living room as well, that is why you get the sensation when you sit in front of a fire of being warm in front but feeling a cold draft on your neck.

Get this: a badly burning fire can actually have a net COOLING effect on your room, as more warm air goes up the chimney than actually makes it into the room. The other really big downside after the dirt and ash, is the simple fact of carting all that wood into the home, its really messy, you usually need your boots on as well, so you trample in loads of dirt, as well as all the things living in the wood pile, like wood lice, spiders etc. Next big issue is that to burn wood really efficiently, you need to burn it as hot and as fast as possible, yet to heat a stone house, you need a low level fairly constant heat.

NEW SYSTEM

excavating heatmain

So after years of struggling with it we decided finally to look into getting central heating. And after two years of looking into it, we found oursleves no where near a decision, what would be the cheapest, easiest to install, most efficient, most eco friendly, convenient and not vulnerable to a huge fuel price rise in the near future.

Along came Chris, of the Really Efficient Heating Company, conveniently an old friend of a Chickenshack member, who persuaded what we needed was something we couldn't nearly afford. A mixed Solar and Biomass system - we would be amongst the first in the whole country to have it, and it would be probably the most energy efficient heating system in Wales at the time of instalation.

As it is wood fired it is a sustainable local fuel, and one which we can grow ourselves and contribute to from our own wood. The total system would cost £15,000, and the Co-op had a budget of £7,000. Enough for a conventional gas system for the house and cottage I guess. Luckily we managed to get a 50% grant from the DTI via the clear skies scheme, which is there to encourage use of renewable fuel sources. We raised the final £1,000 by plundering our rennovations fund.

heatmain
The Heat main. This insulated Insupex pipe cost £1,000 and it carries hot water from the new system under the yard to the house - its the main artery of the system.

baxi solo innova wood fuel burner

This is a 30 kw Baxi Wood burner from Denmark.
They do a similar one that burns straw or pellets as well

Research shows what was an astounding fact for me: a wood burner, like an old fashioned Jotl burns its fuel at about 400c - if however you burn the fuel at >1000c then the same wood yields up to 5 times as much energy. And more than that, it produces no smoke at all. Smoke being essentially un-burnt fuel, so not only wasted energy, but unnecessary pollution. In fact poorly combusted wood is a major source of really toxic pollutants, and in the words of our heating engineer, 'you may as well burn old tires as burn wet wood in a an open fire' in terms of pollution..

New generation wood burners.
Luckily technology has moved on a lot since then and he new generation burners operate in a different way to the old ones. They are located outside the house, in an outhouse, and burn at incredibly hot temperatures in a fan assisted kiln, in a super insulated burner. This gets you that 5x efficiency boost on the burn, and removes the draft problem entirely. There is also a gain by having one effecieint fire than 6 or so small smoky ones - like we used to.

But of course if all the heat is generated at once, what happens to it? This is the second way the new burners are so different, they have an accumulator tank, which stands close by, which is essentially a huge water tank in a sealed insulated jacket. This can store enough heat for a whole day, and if not needed will keep it hot for up to three days. This tank then feeds heat to a conventional heat distribution network (except the radiators are bigger than normal), in the form of radiators and pumps throughout the property. We have now been running the system for a year, and it is working well. It has several additional efficiency features - which I shan't describe here, but the principle is what is important, if you do nothing, then it goes off, this default off principle is very important in energy efficiency, most other systems can be left on so easily, and if you get a bit hot, then some bright spark opens a window!

expansion vessel & heatstore
The red thing is an expansion vesel, as it is a pressurised closed system. The tank on the right is the Heat sorage or Laager tank, (or Puffenspicher) and it contains 750l of hot water.

The rest really is a an extensive network of large radiators throughout the House, Cottage and Studio, and a set of mixers, timers and pumps. The system takes areading of inside and outside temperatures and adjusts the heat it sends to the radiators accordingly. To fully complete it we meeed to install one more storage tank and finsih putting radiators through to the bungalow. It will take 2 - 3 years before we even attempt that though.

More Heating pics

Chickenshack Woodfuel Heating Resources

Solar Water Resources