# Solar for wood boiler



## vickie

We have a hardy outside wood stove. Does any one know of a solar system that has been built to pump the water into the house and a system to run the fan? I don't understand solar enough to build it myself. If someone could build this i bet they could get great money. i know alot of people looking for this for their wood stoves. Thanks Vickie


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## TnAndy

It can be done with solar, but the reason nobody makes a "kit" is you wouldn't believe what it would cost.

If YOU are really interested, get the figures of:

How many watts ( or amps and volts ) the pump and fan take. 

Then get some kind of idea how many hours they would run per day, and how many days you would like to do this without the sun shining. ( like snowy, rainy, cloudy type of days ). 

That is the basic information needed to design a system for this purpose.

Then have a chair handy to sit in when you get the price......ahahahaaaaa


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## ||Downhome||

I think over all a two Stirling engines would be a better option.

one to pump the water and one to run the fan.

both running off the heat of the system.

the problem I see is starting and stopping them.

perhaps a small dc motor that could both be used for the initial motive force and as a brake. 

Before someone boohoos this idea, remember Robert Stirling's first engine was used to de-water a gravel pit.

Also take into account pump technology has come a long way since then.

Then I have to think the water pump engine being located outside could have a huge temp differential. If you have studied on these engines you know the larger the differential the more work the engine is capable of. 

I would assume that a well designed rotary pump along with the differential that such a system is more then plausible with a small Stirling. not the toy size type but a bit larger but also not the monster size of yesteryear that used a piston pump.

The fans not too big of a issue you can see a lot of antique ones and some of the modern ones like the freebreeze.

like I said its the matter of starting and stopping one would need to figure out.
I'm no electronics guru though, but I imagine a circuit board to control function that would tie in to a thermostat.


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## mike554

A generator to run the pump and blower would be cheaper than solar. I just got a Hardy, how do you like yours? I'm in the process of hooking it up. I will have solar (once I get time to get my panels up) to run my house.


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## vickie

It is great, We don't spit the wood. fill at 4am (that when hubby goes to work) and fills it again at 5pm and everything is warm. we run our 1800 sq. home and two, 2 bedroom apts, with it. our electric bill in the winter is about $100. in the summer about 350. we have had it for 15 years and replaced the pump twice. but it is one of the best things we did for this house. Vickie


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## mike554

Thanks Vickie, that's good to hear.


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## wendle

I believe the squirrel fan, at least the one in my old Hardy outdoor boiler uses about 45 watts. I use a 007 taco pump for the water. Not sure what that uses, but could find out if you like. Instead of a kit I would suggest building your own pv system with back up batteries. You might even consider adding a wind turbine since there will be many days of boiler use that are cloudy. One year I remember there only being about 5 days in December with sun. Generator is a good back up idea no matter where you are. If you use a heat/air exchanger to circulate the air in the house that will be another fan to think about running. Not sure what energy those take. I installed baseboard heaters and plumbing under the floors to heat. So far I'm happiest with the baseboard heaters. It's not hard to add on a solar water heating system for summer.


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## AtomicFarmer

I'm another extremely satisfied Hardy owner. Had mine going since 2007 and we're really happy with it.


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## MNSteader

We put in a Hardy H5 a couple of months ago and really like it. Once I got everything in sync so my inside boiler was not kicking on things have been great. I like going dowstairs and seeing the guage on my oil tank sitting idle.. I've also really enjoyed cutting wood and everything that goes with that.
I'm would love to have another way to feed juice to this just case case we loose power.


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## Studhauler

My thought on an outdoor wood boiler and running the system without using electricity from the grid, is to have all the pumps and fans use 12 volts. Have a battery bank the proper size. Make a sterling engine that uses the hot water from the boiler to heat the hot side of the engine. The cold side could be air cooled since it is run in the winter. The sterling would then turn an alternator to keep the batteries charged. The initial charge on the batteries could be done with wind or solar or grid power or genset.


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## Ross

Just how big a stirling motor can you get these days?? I've seen the little wood stove jobbies and they're great for what they are but no where near a furnace fan for capacity. Or are there better bigger ones available?


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## Studhauler

I was thinking of building a sterling out of an old motorcycle engine. But I got WAY to may other projects to do first.


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## Studhauler

http://www.stirlingengine.com/wp-co...built_a_5_hp_stirling_engine_book_product.jpg

Here is a link to how someone built a 5 hp stirling. I like the 55 gallon drum as part of the engine.


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## AtomicFarmer

I'm not all that familliar with Stirling engines but since they seem to be based on a temperature differential there may be a problem with them on relatively warm days. When it's much abofe 50 degrees my Hardy H5 will only turn on a couple times a day. It has 2 seperate temp control systems. When the thermostat in the house calls for heat, it kicks on the water circulation pumps. (I have baseboard hot water heat but they can also be used with forced air systems). This pulls hot water from the furnace, through the house, and back again.

When the water in the firebox drops below around 160 degrees, it turns on a squirrel cage fan on the furnace and literally fans the flames to rekindle the fire, which has just been smoldering. My father in law put some cardboard in the furnace one morning, which I hate but I wan't home when he did it. Hours later it hadn't burned yet, because the fan hadn't kicked on.

Point is, if the house stays warm because it's relatively warm outside, the furnace will just idle all day. In fact, I really have to watch the water level in times like this because the water evaporates pretty quickly.

Will a Stirling work on something like this?


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## Studhauler

I got no idea if it will work with a stirling engine. However if you run all 12 volt fans and pumps you can provide power with any 12 volt source.


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## Bob Huntress

Vickie, solar in my opinion is about the least productive of the 3 main natural power supplies. Personally, I am a big fan of wind power (I realize the mild pun with "fan" & "wind"). I realize that others my disagree with me, and I respect their views. I just feel that between wind, solar and hydro power, wind is more readily available with the main surface area of the turbine blades above 100 feet. It is better to produce DC electricity to a battery bank and to a DC motor. Here again, I respect those who feel that they would prefer to invert the power and use AC motors. The fan would be easier and I believe that two 60v motors within the ducting should maintain good air pressure thru an 1800 sqft home. 

As a teenage boy I got into trouble at the far rightwing Christian boarding school I was attending and was "sentenced" to a smaller school along the same idea, but much smaller scale. My first duties included maintaining the fires for the furnaces. The school/church/admin building had a wood fired furnace. The boys dorm (a remodeled doublewide trailer had one, though unlike the others it was in a block structure behind the trailer. The rest of the buildings had varies wood stoves. I wasn't responsible to maintain a fire in the cafeteria cook stove. The people who did the cooking were responsible to light that as needed, and it was only hot while actually cooking. The two main furnaces, were "locally fabricated". Each consisted of a main burning area with a lower box for collecting ashes. It appeared as if they were made from air compressor tanks various pieces of steel and lots of 6011. All in all, whoever did the work really did a good job, however. Around from one side of the door to the fire box to the same point on the other side of the door and wrapping around the back was a thinner grade steel where the air would heat. There was a squirral cage fan that blew into the jacketed area and near the top of the air jacket was the single duct outlet that would then branch throughout the building, or mobile home as applicable. If I forgot to shut the door to the fire box under the school/church/admin building the rooms would be filled with smoke when next I went on my rounds. At any rate, I have always known that wood heat is inherently drier, yet since the only poor design feature that went into the school/church/admin building heating furnace was that unless I left the fire box door open, 100% of the air entering the heating jacket was drawn from the return air, while the newer system designed by an even smarter fellow drew air from near the bottom of the room where a vent to the outside was, and the return air from the boys dorm trailer discharged into the space where it mixed with both the room air and the outside air. There was a constant need to dust our dorm, but the air wasn't nearly as dry.


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## defenestrate

I've seen these in the area - they seem purpose-built for your application. Looks like they need some electricity but might be reasonably adapted to solar. I just mention it because they look cool - don't see solar conversion info here.


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