I am ordering a GARN . . .

[Jim K in PA]

. . . and mortgaging my house. This stuff aint cheap, but it will pay for itself in a few years. I am looking at over $20k installed (by me) when all is said and done.

I confirmed my calcs with my oil supplier - I used 1274 gallons of oil last year. Ouch!

I thank the dedicated members of this group for getting me to this point. A couple of months ago I was shopping for, and almost ordered, aCB6048.

We are going with a WHS 2000. My dealer, This Warm House in Mansfield, PA, has been outstanding so far. I have spent almost two hours on the phone with them, including a conference call with them and Jim atGARN (an application engineer). I have some things to iron out, but here are the basics:

Garn 2000 installed in my attached shed behind my detached two story 24x36 garage/wood shop (2nd floor).

I am running pre-insulated 1.25" PEX between the garage and the house (~60') -probably Uponor. The balance of the run (another ~60') will be inside the garage (traditional PEX with insulation).

I will be heating (ultimately) the house, garage, wood shop and a yet to be built greenhouse. Heat loss calcs for all the buildings totals ~135k Btu/hr max.

I will be incorporating multiple home made passive solar collectors to be placed on the roof of the garage/shop and integrated via a plateHX in the garage. Solar side will be a mix of water/glycol to -10F. This is mainly for summer heating of the GARN for D and whatever near-shoulder season heat we might need.

I also intend to eliminate the oil furnace altogether, and use a 150K Btu/hr propane fired pool heater to supplement the GARN if/when I can't re-fire the GARN. The GARN engineer persuaded me to go this route rather than keeping the oil burner. The Propane unit will be outside, and incorporated into the system via the same plateHX that I am using for the solar collectors. The propane unit will also be filled with water/glycol to -10F . Although not adequate to keep up 100% in the worst conditions, it will certainly do well enough to keep the tank and the building from getting dangerously cold.

If anyone is still interested and reading this, please feel free to suggest some options for the following:

D - we currently use the coil in the furnace w/o storage. I suppose the best option would be to get an electric HW tank, and build a sidearm exchanger and heat it with the line from the GARN. Other options?

Plate HX - I expect they (the dealer/GARN) will size it to match the output of the propane unit. Will this be a problem when circulating the fluid from the solar collectors?

Am I being foolish by eliminating the oil furnace and going with the propane unit? For the first year it wont be a problem, but if I wind up with 3+ year old oil in the tank, the reliability of my oil furnace becomes more and more tenuous.

Wish me luck!

 

[Nofossil]

Sounds good to me, though I'd need to see a plumbing diagram before I can say that I understand three devices sharing one plate HX.

Home heating oil is diesel fuel - the leftover oil in your tank sounds like justification for buying a diesel tractor -;-)

 

[sinnian]

I would make sure to ask your insurance company what they think. If the Hx goes they all go don't they? (It sounded as if everything was coming off of that) The insurance company is going to want assurances that the pipes in the house won't freeze should the GARN or Hx go down.

 

[sparke]

Why cant you fire the Garn in shoulder seasons and summer? With that size storage tank I would think you could get by with one or two fires a week.

 

[Jim K in PA]

Sounds good to me, though I'd need to see a plumbing diagram before I can say that I understand three devices sharing one plate HX.

Home heating oil is diesel fuel - the leftover oil in your tank sounds like justification for buying a diesel tractor -;-)

I already have a diesel JD 955 with a loader and BH. But it would probably take me 10 years to use 100 gallons of fuel oil! That little workhorse just sips the stuff.

As to the HX, the GARN obviously would connect on the return side, and then I would have two circ pumps, one for the solar and one for the propane unit. I would manifold the other side of the HX and run a 1" circuit to/from the collectors, and a 1.5" circuit to/from the pool heater. I think I would need a check valve on the solar circuit at least, and perhaps also on the return line to the PH.

I am not sure how to go about uploading a diagram to the forum. I'll check the FAQ section.

 

[Jim K in PA]

I would make sure to ask your insurance company what they think. If the Hx goes they all go don't they? (It sounded as if everything was coming off of that) The insurance company is going to want assurances that the pipes in the house won't freeze should the GARN or Hx go down.

Interesting point Sinnian, but I wonder why it would matter. If I run out of oil, or propane, it would be the same result. Honestly, I was not even considering my insurance company, but I guess I should, eh?

Lots of learning going on here . . . thanks.

 

[Jim K in PA]

Why cant you fire the Garn in shoulder seasons and summer? With that size storage tank I would think you could get by with one or two fires a week.

Oh, I certainly CAN fire the GARN during those seasons, but if I have the available "free" Btu's from the solar panels, it will certainly reduce the number of times I do have to burn, and delay/extend the burn-free periods.

 

[sparke]

Cool, I misunderstood. I thought you meant you were going to use the propane exclusively in the shoulder/summer period. My bad.