Convert multiple LPG Furnaces to Hydronic Coal

You can store millions of BTU's in tens of thousands of gallons of mega-super unbelievably well insulated tanks, but that still doesn't mean you can squeeze meaningful quantities of said BTU's through a single 1.5" ID pipe over long distances and deliver it where it is needed when the emitters need is for 500,000 BTUH. It changes nothing.

But true redundancy would require the backup piping to carry the full 500k btu...
So which is more expensive 6 runs of pex or 2 runs of 2.5 inch steel pipe?...

Better not lose a single degree F. to the underground run while traversing 400 feet at 33-1/3 cumulative GPM through multiple pipes. The cost of this loss calculates to roughly 1.82 lbs. of coal per hour, or an extra 43.7 lbs. of coal burned per day. And heaven forbid that you lose 2 degrees (or more)....

BTUH = GPM x Delta-T x 8.34 Lbs/Gal x 60 min/Hr
BTUH = 33.333 x 1 x 8.34 x 60
BTUH = 16,680 BTU's lost per hour

16,680/0.75 (for a boiler at 75% efficiency) = 22,240 BTU's of extra coal to be burned each hour

22,240 BTU's/12250 BTU's/Lb. = 1.82 lbs extra coal burned per hour

1.82 Lbs/Hr. x 24 hours = 43.7 extra lbs. of coal burned per day.

More to think about....

NJ, The EFM 520's are tough, easy to dial-in, and reasonably priced. If the numbers ad up to more BTU's than a single 520 can manage maybe two could be hooked up to carry the load.

It sounds crazy at first, but a large, hard to run at idle boiler could be a struggle for you during the shoulder months of the year.

Tandem boilers are not hard to do. And its a ''one time effort'' .

JMHO , Dave

lsayre wrote: ↑

Sat. Jul. 06, 2019 11:12 am

You can store millions of BTU's in tens of thousands of gallons of mega-super unbelievably well insulated tanks, but that still doesn't mean you can squeeze meaningful quantities of said BTU's through a single 1.5" ID pipe over long distances and deliver it where it is needed when the emitters need is for 500,000 BTUH. It changes nothing.

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I do not disagree with you at all Larry. The home he is examining must be huge in total square area and living space.
All we are doing is sitting and waiting to hear more if he wants to discuss it further.
We have no idea what the heating system looks like, what the burner sizes are, what the fan ratings are for the 3 furnaces are, whether the furnace ducting is insulated or bare sheet metal, or how many registers in total this place has that have to be supplied with scorched air. If he wants to add central air conditioning or has central air conditioning and that is or may be another variable in the math problem.
I hated the forced air system that were in the houses I grew up with as they created a huge amount of dust and did not heat well compared to the heat made by a tiny one pipe steam boiler that heated the apartment we lived in over my parents business. That is why I mentioned running refrigerant grade soft copper pipe in the ducts or in lieu of the ducts to feed dry steam to radiators placed over the openings that would be sealed that had the original registers as they are most likely under the windows in the home as most of them are.

Oops! I had no idea I got more responses to this thread. We're going to close on the house at the end of the month.

It's a little over 4100 square feet with mostly solid stone walls (according to the seller). The house was built in the 50s and the second floor was an attic conversion in the 80s. I haven't been able to confirm much about the construction because I'm still deployed, and I haven't actually seen the house first hand.

The seller has been a snowbird for the past decade or so, but he estimates the LPG heating cost at $4000-5000 a winter (1050-1300 gallons?). In my current house I spend around $900 a winter to heat with coal at $100 a ton (I scavenge from basements). Thankfully we'll have renters in the house until our current house sells.

I don't see an underground PEX run going more than 100 feet. I would love to find a way to heat the pool and a future workshop/garage with coal. I'm going to need open ducts in the house for AC.

I'm going to take some time to dissect what's been written. I really appreciate all the thought that has gone into it.

Large furnaces are available. Is there something I'm missing as to why you would not install one?

https://leisurelinestove.com/product-category/furnaces/

Listen to the BIG dog. I use an AK 180 with great success and all the other ideas are too expensive and inefficient.

It would seem very impractical with 3 separate existing (LP) forced air heating systems and all being physcically scattered and independent of each other to ever distribute from a central forced air source. Coal and ash handling over 3 scattered independent locations is not likey desired or even possible.
From any central location there comes a great benefit of ash and coal handling. Smaller pipes diameters and reasonable sized circulators may be used and routed from a central location with much more ease than any required large central ducts and blowers could be.
Much can be gained or expense saved by using the majority of the 3 separate, existing in place LP forced air heating distribution componets which are likely located in scattered mechanical hall closets.

Optimistically, the LPG supply pipe could possibly be used in the hydronics loop now and would then allow for only a single new pipe to be required added and there by saving even more labor and material expense.

Three furnaces. One of them is in a carpeted upstairs hallway.

I like the idea of using the LP line for hot water.

Beware dealing with snowbirds; bad houses abound in that scenario since they are not lived in the year round.

Have a heat study done and the house inspected before you buy the place as it may not be so pleasant to look at after you get the heat study and snow birds will not hesitate to hide water damage and bad roofs with lots of paint(they did in my case). You will be up Shhitts Creek otherwise and you also need to have a plumber come up and look at the heating system before you even think about buying the place as the problems will not start appearing until the following year; YES the following year.

If you own your LP tank, you can currently source propane for under $1.40/gal 65-200gallons. I believe there is another price break at 250gallons.

To much overthinking going on. Work out how much you save in three years and that is the ROI and that is how much you spend. I have posted on this before so over and out.

coalnewbie wrote: ↑

Thu. Oct. 10, 2019 11:10 am

To much overthinking going on. Work out how much you save in three years and that is the ROI and that is how much you spend. I have posted on this before so over and out.

Agreed. I was illustrating that 1000gallons can be sourced for less than $4000-5000/yr. Like you said, the math is simple.