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srouth@gci.net 12-07-2008 02:10 AM

Choosing furnace for remote lodge in alaska
 
i'm building a lodge in remote Alaska (an area about 40 minutes by small airplane from Anchorage). i'm trying to size a furnace to fly out. we've settled on getting a boiler type of furnace, and using baseboard heat. the lodge will get cold between October and March, and be warm from March through September. for redundancy we are also installing two woodstoves (one BlazeKing King, and one BlazeKing Princess), and probably a small Toyo wall unit as well. the boiler and Toyo will be run off diesel/furnace oil, which has to be flown in.

we have super-insualted the lodge by putting batts in the 6" walls, and then 2 inches of foam board to the inside on all walls and top cieling. it has become very tight. i've used an online estimator that tells me that for a 4500 ft building in area code 99516 i need 194,000 btu output. my questions are:

1. does the boiler size change if we are using glycol in the baseboards, and not water, due to the lodge getting cold in the winter? i know glycol is less efficient than water. would it make more sense to use water, but try to design everything so we can fully drain before freezeup?
2. does the boiler size change because we are super-insulated?
3. what boiler make/model should we shop for? our suppliers are high on the weil-mclain gold high-efficiency series. i need something that is very reliable, since flying out technicians will be costly.

thanks!

beenthere 12-07-2008 04:41 AM

Do you have prints, and specs on the construction.
I recomend you get a proffesional load calc done, and not use one of those rule of thumb internet calculators. They just aren't very accurate.
Most just use a average multiplier.
And do not account for insulation or infitration rates.

Glycol will lower the heat output of your emmiters. You will have to increase their length.
Depending how much glycol you mix with the water, you may have to add 10% or 50% more baseboard then with just water.

Since you have to have your fuel flown up.
Don't guess on boiler size. Have a REAL load calculation done.
Also, don't use 100% glycol.

A truely well insulated, and tight building doesn't take a lot of heat.
Unless your outdoor temps drop below -30F.
Thats when bat insulation loses its value.

Marvin Gardens 12-07-2008 11:35 AM

Quote:

Originally Posted by beenthere (Post 195009)
Since you have to have your fuel flown up.
Don't guess on boiler size. Have a REAL load calculation done.
Also, don't use 100% glycol.

A truely well insulated, and tight building doesn't take a lot of heat.
Unless your outdoor temps drop below -30F.
Thats when bat insulation loses its value.

He will have to use 100% glycol. Temperatures can get to -40 or -50 for short periods and even a 70% mixture will freeze at those temperatures. Even the diesel will get real thick at those temperatures and make it hard to get the boiler fired up.

He could use light oil but even that gets rather sluggish in really cold temperatures as well but way less chance of freezing and is much better at heat transfer.

As for the heat source you can probably adjust the size downward since it is super insulated and only going to be used during the mild months.

Keep in mind that they are calculated to heat year round and take ambient temperatures into consideration. Since there is no activity in the winter then a smaller unit would work. Calculate on the months that the facility will be used only and ignore the winter calcs.

I lived in Alaska for years and can tell you that it is not a good idea to ask those in the lower 48 for this kind of advice. You need to ask an experienced sourdough who knows about this stuff. People down here don't understand dealing with things like permafrost and temperatures in the -50 range. It's a whole different world even in Anchorage. Going remote is even worse.

When I lived up there I remember having to burn through 6 feet of permafrost to put in a sewer line. Or putting in water returns in the basement. No one down here knows how that is done or what I am talking about.

If you have the option of wind power you could put up a tower and use the electricity to power heat tape and that would help out a lot in the winter. Even a few hours a day will go a long ways to keeping pipes relatively warm. Obviously solar will not work since there is no sun in the winter.

beenthere 12-07-2008 11:55 AM

Check out the antifreeze solutions they have today.
65% will protect to below -60F.
Over the years, they have made some advancements in antifreeze.
Which allows for better heat transfer.

10 years or so ago, it would have to be 100%.

srouth@gci.net 12-07-2008 09:52 PM

any thoughts on brand/model of furnace to look for? needs to be really realiable and efficient.

Marvin Gardens 12-07-2008 10:56 PM

Quote:

Originally Posted by srouth@gci.net (Post 195335)
any thoughts on brand/model of furnace to look for? needs to be really realiable and efficient.

Get one with onsite service for 10 years.

I can see some repair guy renting a tail dragger flying out in the wilderness and landing on the tundra in the middle of the winter.

It would be a good commercial for the furnace.

Any of the top brands would work. I have installed different models and had few problems with any of them.

beenthere 12-08-2008 02:59 AM

Find out what brands are the most popular for the area, that you'll will be calling for service.

You don't want a brand that uses any part that is not commonly stocked by who ever you use for service.

EG:
A boiler with a Reillo burner, could be a bad choice, if no one has parts for a Reillo burner in stock.

pcampbell 12-08-2008 01:06 PM

Have you considered just running multiple Toyo stoves?


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