need suggestions for alternative heat source

[xiphias]

Hi all. Some-time unregistered lurker, first-time poster.

I live in a place where it is necessary to have an alternate heat source during prolonged winter outages, for which I currently use a catalytic wood stove (an older Federal Airtight) that vents through an unused fireplace chimney flue. Works great. House has a reasonably open floorplan and the whole place heats adequately with the wood stove when necessary.

I have also spent the past decade ascending the energy-efficiency pyramid (insulation, air sealing, conservation, efficiency, etc.). Added a solar domestic hot water system a couple years ago. Now ready to cover the rest of the roof with PV. But... there is a large brick chimney that shades some prime roof space for much of the year.

Bottom line is that the chimney needs to have the upper 10 ft taken off to allow more productive PV. Would prefer to keep burning wood as the alternate heat source, as I do it sustainably and the system works well.

But I'm guessing some kind of sealed, outside combustion air, direct vent system is needed to vent out the reduced chimney, a sidewall, or out the back of the chimney at fireplace level. My preliminary research suggests pellet stove or gas insert.

What are the options? Would strongly prefer wood as opposed to pellets but not sure wood is still an option with a non-code (and obviously unsafely low) reduced chimney height. Gas is a distant third option to wood and pellets, but could do that if necessary. Whatever choice, it also needs to work when the electricity is out (and under these conditions, the PV would typically be covered with snow....).

Max output would need to be in the 20-25k BTU/hr range. Fireplace is 36"w 30"h 18"d.

Any suggestions would be most appreciated.

TIA!

 

[stoveguy2esw]

if there is a "direct vent" or "power vented" log burner on the market im not privy to it, and obviously a substandard chimney is out of the question. question is in which do you realize the greater gain? with a full chimney and a woodstove (especially a more modern one which uses less wood per btu of output) pellet, which needs electricity but not a chimney, or what you will gain in the PV without a flue in the way.

 

[xiphias]

Thanks for the feedback.

Unfortunately, building another chimney is not an option for a variety of reasons.

The impact of the existing chimney on PV production is substantial (did all the homework with a solar Pathfinder and modeling shadows through the year, etc.) and year-round.

The wood stove is really a backup and only occasionally used for ambiance. Total firing days/season is probably <10. In the big picture, it's probably not truly essential as freeze-proofing the house is pretty quick and easy. Just uncomfortable.

So where does this leave me? SOL?

 

[madrone]

Removing a masonry chimney? Would a stainless chimney really block too much PV? Is it possible to install or uninstall 10 ft of metal chimney as needed?

 

[woodsmaster]

Ventless propane wall heater ?

 

[begreen]

Greetings and congratulations for the work you have done on the house. What is the primary heat source for the house? If that fuel cost twice as much, how much more likely would burning wood come into play?

I would relocate the stove with a new stainless flue on the north side of the PV panels if the heating with wood was more extensive. But in this circumstance, putting in a nice looking gas unit like a Valor sounds reasonable, especially if it is for <10 days a year.

 

[vvvv]

Removing a masonry chimney? Would a stainless chimney really block too much PV? Is it possible to install or uninstall 10 ft of metal chimney as needed?

ya seems a transition from current chiney to shiny class a wouldnt impede the solar as much. minimize the height to suit the 10/2/3 rule & remember you'll have to clean it=my similar setup involves a homemade hinging system at the transition which aint legal but worx great

 

[xiphias]

Thanks all for the ideas and suggestions.

Moving stove location not an option due to house layout.

10 ft of stainless chimney would still shade a fair bit (think fat sundial shadow from 9a-3p with the PV panels as the face of the sundial...). That much chimney height would also need to be stayed, which would create aesthetic issue. It's also windy here. (If microwind was viable, there'd be a turbine in the backyard....)

Primary heat source is high-eff hydronic gas boiler. Works great. Fuel price doubling would probably not increase wood-burning, as we'd pass the sustainable wood consumption threshold and have to buy. NG could go through the roof and still beat what wood costs around here.

Have been looking at various gas inserts, which would fit the bill. Will check out the Valor and start combing through the forums for other possibilities. [EDIT: turns out there's a Valor dealer in the next town over. Cool.]

Thanks again for the thoughtful suggestions and advice. Nice place you have here.