Renewable energy technology is developing quickly to mitigate global climate change. We don’t have any time to lose if wood and pellet heating technology is going to compete amongst the renewable energy solutions.
Pellet stoves and then automated pellet boilers were a huge technological step forward. We believe a next step may be affordable, automated wood stoves to maximize the potential of the stove and minimize its inefficiencies.
The Collaborative Stove Design Workshop will be held at Brookhaven National Lab from Nov. 4 – 7. Building off the very successful Wood Stove Decathlon, Aprovecho will assist in testing, assessing and helping to improve up to six automated stoves, who will be competing for a modest prize. Instead of a large event open to the public, this will be an intensive four days for thirty stove professionals to push the envelope of stove innovation.
Please spread the word for this excellent event!
Heating Air in Modern Houses
There are three types of heat exchangers generally used to capture the heat produced in a combustion chamber.
The hot flue gases can:
A.) Heat mass, like heavy stone or masonry
B.) Heat water which then warms the house or
C.) The easiest and least expensive route: utilizing hot stove gases to efficiently heat the air inside the room.
A lot of people still live in drafty houses with multiple air exchanges per hour. An air-to-mass stove evolved to heat just such a house. It is less necessary to use a massive heat exchanger in tighter, better insulated houses. Today many houses are not so drafty. Modern houses can have one-half an air exchange per hour. Heating air becomes an acceptable option. The hot air has time to warm occupants and interiors. Sealing the cracks that allow air into the house is the most important first step to holding heat in a house. Insulating the house is the second most effective step in using less wood to keep warm. Heat exchangers increase heat transfer to the room by making sure that the hot flue gases leaving through the chimney are as cool as possible. Even a smoldering fire turns at least 70% of the wood used into heat. Heat transfer efficiency (heat delivered to the room) can be less than 20% in poorly designed systems. When analyzing a system, try to improve the least efficient part first. This has the greatest beneficial effect on overall system efficiency!
Aprovecho Research Center
PO Box 1175
Cottage Grove, OR 97424, USA