propane supply, 1x500gal or 2x250gal

[otter]

Recap: new home being built in Eastern Ontario and will be heated w/propane.

Buddy of mine says not to get the single submarine shaped 500gal tank and go for twin 250's instead. Says that on a really cold day, the larger tank will be prone to "locking"...propane not vapourizing.

Is he full of hot air or does his advice have merit. Inquiring minds would like to know.

[Black Adder]

If the 500 is going to "lock" what is to stop the 250's from doing the same? There appears to be no logic behind this deduction. Why fill 2 tanks instead of 1. If you need 500 then use a 500 tank.

[otter]

I figured as much, but he had a pretty convincing argument as to why he's using two. Then again, his supplier only deals in 250s.

[dna]

rate of vaporization will be the same whether you have a 100#, 420#, 500 or 1000. You probably want to PURCHASE the tank instead or renting--this generally gets you a better price for the propane. Are there going to be any other LP appliances in the home? Maybe you want to go with a 1000(above or below) and buy the product in the summer which is usually cheaper.

[watercop]

If anything, a single larger tank should be slightly LESS vulnerable to "locking" since its greater heat capacity / thermal inertia would carry the "warmth" (a relative term, I know, for January conditions in Eastern Ontario) of the day into the bitter cold of early AM.

In other words, the larger tank won't cool off as fast during the night.

In addition, a larger tank won't be as vulnerable to cooling resulting from liquid boiling off as propane is consumed. I mention this owing to a bad experience with 20 lb gas grill tanks icing, even on hot summer days, while flowing to a 100k Btuh burner for steaming crabs / boiling corn on the cob.

I do remember a mech engr prof asking in a thermodynamics class why propane is not a feasible fuel in Alaska / northern Canada

[otter]

Originally posted by watercop


I do remember a mech engr prof asking in a thermodynamics class why propane is not a feasible fuel in Alaska / northern Canada

Beacause the boiling point of propane is -42.1 deg C.


Re: better price if owning tank...the suppliers here charge rental as a separate line item once per year. 500gal tank is something like $56. I actually prefer it that way because anything to do with the tank is their problem.

Price per litre is dictated by volume used. I'll be running furnace, stove and gas fireplace and they'll be charging their lowest rate per litre for residential clients.

[firecontrol]

I'd go with the 500 gallon tank.
Another thing that might not make sense is that you should keep snow away from the tank during really cold weather. Propane as it changes from liquid to a gas cools the liquid. If snow is allowed to cover the tank it will continually get colder (snow is a great insulator) until it gets to cold to vaporize.
Had a customer with twin 1000 gallon tanks have all of his heating units quit due to lack of gas pressure. When we finally found the tanks under the snow drift they were both over half full.

[otter]

great tip, thanks.

[mayguy]

You have you looked having an underground tank?

My parents has a 1,000 gallon tank burried.. They are glad they did that!

[gasguy]

Burrying the tank is a good idea if possible. Underground temp is more consistant year round and is warmer than the air temp once below the frost line. Vaporization rate is affected by the wetted surface of the tank. (area of the tank in contact with the liquid propane) The greater the wetted area, the greater the heat transfer from outside the tank to boil the propane. You need to calculate the btu load you will have and compare it to the vaporization rate of the size of tank used at lowest expected tank temperature. This will ensure you don't run out of capacity at extreme low outdoor temps. Burrying the tank avoids the problem of outdoor temps getting below your estimated lowest temp.

[cem-bsee]

burying would also cause any blast to go upward!

do such tanks have special coating?

[mayguy]

These tanks are made to be undrground.

http://www.trinitylpg.com/products.asp?productid=Q6UJ9A0005CS&prodname=Underground+Tank

[dec]

Have never seen any burried tanks around here...... lol thats probably being their burried lol. Sounds like a good idea if it legal.

Im with dna on the 1000 gallon tank ...... buy propane in the summer when it is cheap. They rape ya in the winter.

[hearthman]

Determined by the temp. and "wetted surface". Add up all the square inches of wetted surface. While two tanks add a lot of surface, the temp. in Canada will be more deciding. Bury those tanks to keep them warmer and you'll have more gas available. Make sure you use two stage regulation with the second stage reg. as close to the appliances as possible.

Don't size tanks just for anticipated fuel consumption but vaporization rate.
HTH

[gasguy]

good point by hearthman about the 2 stage regulation. Make sure the 2nd stage reg is protected from rain/snow/ice blocking the vent opening.

[dec]

Ya I use to always have to fight with the propane outfits when they ran piping to the house. They aways wanted just the regulator at the tank and not one where it went into the house.

You could never get them to beleive that only one was going to get you in trouble when it got real cold.

Funny , with them in the business you would think they would know better.

[markwolf]

Interesting.:my cousin had a fire in his home some years back.I helped him rebuild the entire house,drywall electrical,plumbing,hvac,etc.We used a construction heater all winter during renovation.If we ran one 50lb. tank it would freeze up after six hours or so on a cold day.If we ran two twenty pound tanks manifolded together the heater ran all day & never froze.

[otter]

Well, I finally paid a visit to my preferred supplier and it went like this:

1. Huh? why in the world do you want two tanks? No, our large singles don't lock up, it doesn't get cold enough around here. Only time that you won't have fuel is if you have a bad regulator.

2. Bury it? Bwuhahahahahaha! In your dreams, pal...code doesn't allow it here.

[mayguy]

Check with another suppler and see if they offer underground tank.

[otter]

the other two suppliers only offter smaller twin tanks and don't bury either. All three say that it's against code here.

So, I guess I'll be keeping my fingers crossed the first winter I spend in the new house.

[mayguy]

I wonder why they say it's aganest code? I'd rather have ti burried and protected from getting hit or something..

Are they aware the tanks are built to be burried? They are not the standard tanks.

[otter]

who knows? But One thing is for sure, I'm having a devil of a time finding regulations for residential propane tank burial in ontario.

[mayguy]

I found this.

http://www.tssa.org/CorpLibrary/ArticleFile.asp?Instance=136&ID=836AE6B13EAD4E28A504A5D9A9220ABF

page 3, section 7.8 talks about how to bury a tank.....

i am wondering if the guys are too lazy to do the job? I know mom said the LP dealer told them they can't keep up with the buried tanks orders here.

[otter]

thanks for the link. It looks like that unless I want to undertake burying the tank myself, the suppliers aren't willing to do it.

You rent their tank and regulators (they're liable for everything), and it all stays above ground.

Bury it and you're on you're own.

[mayguy]

Otter,

Figured I link you to the link I just put up tonight.

Mom said they rent the tank.

http://hvac-talk.com/vbb/showthread.php?threadid=118650

[otter]

Mayguy,
Now I'm jealous. And I assume that this is somewhere in the US.

I have a choice of three distributors, one which has the most competetive price and none that will bury if the tank is rented.

Sucks.

[mayguy]

Yes, here in the USA, Minnesota.

Mom said one company wanted to do credit check, she told them to get lost.. So they got an local ag dealer for filling the tank.