Solar chimney cuts energy usage
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While energy-efficient double glazing prevents heat loss through windows, it also causes temperatures to rise to unacceptable levels in conservatories and other highly glazed rooms.
However, this is a problem that Cambridge UK renewable-energy specialist theEnergyCrowd is turning into an opportunity.
By fitting a solar chimney to the side of the house, theEnergyCrowd has been able to extract warm air from the conservatory and feed it via the loft space into the rest of the house.
As it is also glazed, the solar chimney collects additional solar energy and the top of the chimney and can reach temperatures of up to 40ºC during the winter months. As the chimney is mounted upright, it has a greater angle of incidence with the winter sun than conventional roof-mounted solar panels.
The fan that circulates the air throughout the house is thermostatically controlled to ensure that the system only attempts to draw warm air into the house when the sun is shining.
Peter Kruger, the engineer who founded theEnergyCrowd.com, said: ’It has been good to see this system cutting energy use at a time when the recent “Big Freeze” in the UK was doubling household fuel consumption.’
According to theEnergyCrowd, the passive solar energy technology is a potential business opportunity for the secondary glazing industry, which has seen the sales of conservatories fall from a high of more than 230,000 units to less than 100,000 per annum.
Kruger said: ’With 39 per cent of non-transport energy in the UK currently being used for domestic space heating and the marginal cost of adding theEnergyCrowd’s technology to a conventional conservatory being low, this is an ideal way to add value to installations and for installers to gain a toehold in the green-energy market.’
Warm air from the conservatory is fed to the loft space into the rest of the house
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Readers' comments (11)
Anonymous | 19 Mar 2010 2:24 pm
This is a fine idea. The materials are readily available, the implementation simple and the complexity limited. The controls & moving parts are located in an accessible benign environment and it should be possible for a compitant DIYer to fit in a weekend.
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ceannaideach.d | 19 Mar 2010 3:26 pm
Not such a good idea in the summer perhaps? Does a fan have to run in the summer to exhaust the hot air externally?
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Mr G Whiting | 19 Mar 2010 3:58 pm
Presumably it would be very simple to fit an electrically operated damper in the ducting at the top of the chimney to prevent the undesirable solar gain in the summer months. As has been mentioned, this is a well thought out use of existing passive technology and whole house ventilation.
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brian alford | 19 Mar 2010 7:06 pm
Not such a good idea as the conservatory would produce very little usable heat during the winter months and too much in the summer.
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Neil Sherry | 19 Mar 2010 7:15 pm
In the summer the hot airflow could be just dumped to atmosphere - this would provide a cooling through ventilation for the conservatory without the security risk of having windows open. Alternatively, the heat could be stored for cooler nights, or with a suitable heat pump be used for water heating.
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Lek-Hong Kee | 19 Mar 2010 11:01 pm
Over here in Penang, Malaysia we have perpetual sunshine. So the usage of Solar Energy is excellent par, but what we actually need over here is the constant exhaust of Heat from our internal household or space. Have you anything specific to offer us ?
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Adrian Musgrove | 20 Mar 2010 0:37 am
This looks like yet another idea that sadly won`t be used for quite a long time. It seems brilliant and simple yet it is mainly a matter of education to adopt ideas such as these. Yet we continue to burn fossil fuels and cut down rain forests. Forty-one months until there is no ice at the north pole!
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T.C.Chandran | 21 Mar 2010 1:05 am
In summer months, a glazed chimney will heat the air inside it. An opening may be provided at the top of the chimney to allow the hot air to escape. When the hot air escapes, rest of the warm air in the building will be drawn towards the chimney by vacuum created by the escape of hot air. This process will draw cooler fresh air from outside into the building in summer through open windows. The opening on top of the chimney should be closed airtight to prevent infiltration of cold air during winter.
I have tried this method quite successfully in tropical countries. It might work in colder countries.
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Anonymous | 22 Mar 2010 11:36 am
Why not triple glaze them and make them even more efficient?
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James Keyes | 26 Mar 2010 2:48 am
This scheme is greatly dependent on orientation for its heat production. With proper planning (and possibly some vertical vanes for shading in summer) one can have vigorous heating winter and little heating summer.
T.C.Chandran refers to using a scheme for cooling in tropical climes.
I should think that the chimney effect (creating a draft that is used to draw cooler air into the building) might be objectionable in humid climes. It has been used quite well in desert climes for several hundred years.
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