BTU Requirements Uggghhh!!! How to Figure??

shayneyasinski · Post by **shayneyasinski** » Thu. Mar. 15, 2007 11:21 pm

I have a outdoor boiler and it must go!!
so in my search of a new system I am looking at a multi fuel unit that can burn coal wood and waste oil all of wich I can get for almost free or in the case of coal for about $40 a ton.
as you know most boiler units ask for a BTU requirement when selecting a unit and this has me stumped.
what I do know is that my greenhouse has a 20x22 exchanger with a furnace fan behind it and at night it will run almost all night straight .
my house has the same exchanger mounted in the furnace and it will run for about 15 minutes every hour on average.
my shop has another 20 x20 and it will run for 15 minutes every hour also .
they are all 100 000 BTU exchangers so if I had all 3 running at the same time for 1 hour would that then mean I need 300 000 btus an hour??
sorry if this is posted on the wrong forum

shayne

Post by **coaledsweat** » Fri. Mar. 16, 2007 7:22 am

Google the waste oil thing, there are a LOT of good ones out there but you would have to put it in the greenhouse or detatched building. They are no-nos in a residence.
The coal side, get a commercial boiler because of the size. Rare, but you do see used now and then.

I think when you size something for solid fuel the BTUs are determined by your heat loss, not size or area.

Complete Heat · Post by **Complete Heat** » Fri. Mar. 16, 2007 9:13 am

In the northeast, it is 50 btus per sq. ft. in a well insulated house. There are calculators online that you can use to figure out for your application. If it is a green house, it will be a lot higher than the 50 btu/sq. ft..

Mike

Post by **coaledsweat** » Fri. Mar. 16, 2007 9:19 am

This may help.
**Broken Link(s) Removed**

Yanche · Post by **Yanche** » Fri. Mar. 16, 2007 12:38 pm

shayneyasinski wrote:as you know most boiler units ask for a BTU requirement when selecting a unit and this has me stumped.shayne

What you want is a heat loss calculation on the building you are trying to heat. It will take into account the building size, construction, windows, doors, geographic location and orientation, etc. Depending on the level of detail it will give you heat requirements in BTU per hour for each room and/or the entire building. The most accurate analysis uses a "Manual J" calculation. This is one of many manuals used in the heating and air conditioning (HVAC) trade to design systems. There is an abridged version that's a less complicated and easier to understand. It uses an Excel spreadsheet to make the calculations. Even the abridged version has an above average learning curve but it will give accurate results for both heating and air conditioning.

Do you want to do this analysis yourself? If your home is a typical residence you could get some price quotes for a new heating system and use their numbers. Installation contractors frequently use "rule of thumb" analysis that work for typical jobs based on their installation experience. If there is anything atypical get a complete analysis. Expect to pay for a Manual J calculation done by a professional.

Yanche

coal nut · Post by **coal nut** » Fri. Mar. 16, 2007 1:56 pm

Just curious. Why must the outdoor boiler go?

shayneyasinski · Post by **shayneyasinski** » Sun. Mar. 18, 2007 6:18 pm

coal nut wrote:Just curious. Why must the outdoor boiler go?

I could not afford glycol so I had to keep it hot if I used it or not.
I was ill for a 2 weeks and having to load wood every 6 to 12 hours was too much .
I like it and burning wood is great but I also would like to be away from home for longer than 12 hours max.
I also use it to heat my wifes greenhouse and right now it is minus 8c at night and it will eat a full load of wood in 6 hours .
I also can get waste oil and wood for free and coal is available so thats why I am looking at a multi fuel unit.

MINO · Post by **MINO** » Mon. Mar. 19, 2007 10:11 am

40 dollars a ton, it must not be anthracite? the only problem with dual fuels some of them are in-efficient. I have an efm 520 dual fuel coal/oil it mainly is a coil boiler but designed with an oil gun. I only use the oil in the summer for hot water, and when I go on vacation,when im not home for an extended period of time. I would never try to heat with the oil because it would never shut off!!!!! 1.5 gallons an hour when its running (do the math)
I know the efm 520 has a gross BTU output of 214,000 bth/h with coal. I know where you could get an efm 700 (its in the local paper where I live) its a bigger boiler,but offhand I don't know the btu/h. if u want pm me I can give u the number.

LsFarm · Post by **LsFarm** » Mon. Mar. 19, 2007 11:23 am

An EFM burner will not burn Bituminous, I tried. Anthracite only. Bituminous cokes, clinkers and jams, then the fire goes out.

Greg L.