We've had more than a few folks ask about our wood fired boiler system, so I figured I'd take a shot at explaining how it works. There's also the fact that I am extremely intrigued by the whole setup and won't pass up a chance to talk about it. :)
I'll start with the wood boiler itself.
In the simplest terms, an outdoor wood boiler consists of a fire box, a water jacket surrounding the fire box, and a pump to circulate the heated water into the house...where it is used for heat and then returned to the boiler water jacket. The heated water can be used in a forced air system by being pumped through a plenum or, as in our case, a baseboard heating system. The boiler's fire box is loaded with fire wood and heats the water in the water jacket to between 175 and 185 degrees.
The temperature is regulated by a thermostat which controls a damper on the door. When the temperature of the water in the water jacket drops below 175 the damper opens to allow air into the fire box. This stokes the flames to increase the temperature of the water. Once the water temperature reaches 185 the damper closes. The fire is then held to a slow burn until the water temperature drops again to 174. This minimizes the amount of wood needed. We're finding that we have to fill the fire box with wood only twice per day, in the morning and again before bed.
The pump that is mounted in the boiler runs to continuously circulate the heated water to the house, through the heat exchange system, and back to the boiler. You can also see in the picture how well insulated this boiler is. The entire unit is fully insulated, as are the lines that run underground to the house.
The heated water that is circulated by the wood boiler pump is run through two heat exchangers in the house. One is mounted to our LP fired boiler, and one is mounted to our hot water heater. The LP boiler and water heater are separate and closed systems from the wood boiler, meaning that the water from the wood boiler is not actually shared. What is shared is the heat, via the heat exhcangers. The heated water is run through the exchangers, thereby heating them to approximately 170 degrees. This heat is transferred in the heat exchanger to the water in the LP boiler and the hot water heater. Because the water is heated via the heat exchangers the LP boiler and water heater are both turned off. Yes...off...as in free heat and hot water. :)
Our system is a four zone baseboard heat system. The system is controlled by four thermostats which control the heat for the bedrooms, bathroom, basement, and living room & kitchen. The existing LP boiler supplies heated water on demand, as dictated by the thermostat for a particular zone. When the temperature in a particular zone drops below the set temperature a gate valve is opened in the boiler system. When it is fully opened the pump on the LP boiler starts, which circulates the heated water through that zone. Below are the four gate valve motors controlled by the four thermostats.
Here is a shot of the complete LP boiler system.
As far as maintenance on the wood fire boiler, it's fairly minimal. There's the twice daily stoking of the fire, of course. Then there is the need to occasionally clear the fire box of ash. Tools were provided with the boiler for doing this. The ash will be hot when removed from the boiler, so a metal container is needed. I have a 30 gallon metal drum with a hinged lid that we use. The drum should be large enough to hold the ash from an entire heating system, and we'll be spreading the ash on our garden. There is also a test that needs to be performed, basically the same as that of testing the water in a pool. This ensures that the water is properly balanced to prevent any rusting of the water jacket. There is some additional care and maintenance to be done at the end of a heating season...cleaning and lubrication...but nothing too involved.
That's about all I can think of. If you have any other questions post them and I'll respond as best I can. :)
Well Dave has asked me to add an update on how things are going from my perspective, so here goes.
It's been CRAZY!!
Dave touched on all that we've done in the past year but what he failed to mention is that the majority of it happened in the last six months. But, we are settling into a routine.
I've been trying to make the place feel like home and it's finally beginning to. We have curtains on the windows instead of sheets, nice rugs down even though the flooring needs to be replaced, a new bed and bedding in our room. These little changes made a huge difference. I've also been cooking and baking again, which makes any place feel more like home.
Life is about to get crazy again with the holidays, Kyle home from school and a LOT of travel in January. All that aside, I'm really looking forward to renovating things around here and making it ours. We have big plans and hopefully we can pull it off.
We've been moved in at Shangri La for three months now, and things are finally beginning to normalize. This past year has been like nothing we've ever experienced. The highlights include a high school graduation, two graduation parties, a new job, splitting the family between two houses, temporary blindness, moving son into college, gall bladder attacks, pancreatitis, selling a home, moving to Michigan, bronchitis, and celebrating a 25th wedding anniversary. Having survived all of that, we're now beginning to settle into a routine...a routine which I hope will include far more frequent updates here.
We have been able to get a few things accomplished...not as much as we'd like, but a few things. One very huge thing off the to-do list is the installation of the wood fired boiler, which also includes the installation of a new hot water heater. The boiler is now fully installed, and its care and feeding are quickly becoming a part of our daily routine. It is proving to be every bit as effective as we had hoped, and our expectation for a 3-4 year return on our investment is looking to be very realistic.
The barns are now fully cleared out and organized, and we've made a serious dent in clearing out the basement in preparation for finishing. The basement project is going to be our first major renovation.
One project which will most definitely be in the works is the installation of new windows throughout the entire house. The house itself is very well insulated, but the windows are a serious weak point. For this winter we put plastic on all of the windows, and we hung curtains. The two together made a HUGE difference, and the curtains certainly dressed up the place.
Aside from the above, and I'm sure that I'm forgetting some things, we've been unpacking and organizing. Fitting everything into a home of half the size is a serious challenge. :)
So, that's it for this update for me. Shelly will be providing an update as well, and I'm sure she'll do a good job of filling in any blanks I've left. I hope to be back here very soon, talking about all of the stuff we're getting done.