can I calculate my btu requirements this way??

[shayneyasinski]

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I have a room that I want to calculate the btu requirements for and I was wondering if I could do it like this??
I have a 100 000 btu hot water exchanger that runs of a thermostat set at 21c .
it has a consatnt flow of 180 water .
can I put a timer on the fan motor and see how many hours it runs per day and multiply that with the btu output to get the requirment of that room per day??


example. 3 hours runtime x 100 000 = 300000 btu per day

 

[wdc1160]

That sounds pretty rough.

How do you know how much heat you pulled off the exchanger. Or, how much made it to the room.


If your really after the room calc. you'll need to figure out that information.

Aren't there other rooms ducted to that exchanger anyways?

One good way is togoto heatinghelp.com get their calculator to do all the hard work. You should get a realistic range of your requirements. Check out mine
http://www.innovativesolutions.cc/boiler/images/heatloss.jpg

 

[mtfallsmikey]

Better to figure it right from the beginning...pipe/sheet metal not cheep anymore!

 

[shayneyasinski]

my house is done and my boiler is installed so there is no new construction going on.
I heat 1 big room in my house that is 1100 sq ft with 14 foot cielings and I also heat a greenhouse .
but thats not my point here .... I am trying to get a good idea of how many btu's I pump into this room to heat it and whit that info I can then size up a heat source like a pellet stove a gas stove or whatever I find that puts out heat .
I see the calculators and I have asked the plumbers around town and they can give me a round about idea but nothing exact.
now I understand that it will never be exact as a cold day that is 20c and calm will be using less heat than a day that is 20c with wind .
what I am after is that if my way of finding the BTU will give me an exact mesurement for that day and that day was the coldest day of winter and came out with a numer of 300 000 btu than I know that a pellet stove or whatever heatsource that is rated at 60 000 btu per hour will keep up with the demand of heating.
a plumber will install a 150 000 btu furnace in a small 900 sq ft house and it will work just fine as gas furnaces have no problem running for 2 minutes and going off for an hour but install a 40 000btu pellet stove in a 1800 sq ft house and it will run nonstop and then if it drops in temp outside too much it will then just not keep up and you will be cold.

 

[wdc1160]

You touched on asking informed peoples oppinion.
You have some rough estimates of your own.
Shouldn't you try one of the software solutions just to confirm your conclusions.

Also have you thought about how hard it will be to figure how much heat it exchanged then pushed into that big room.

its not as simple as 3 hrs of running at 100K exchange = 300k btu per day. You;ll need to figure how much is actually exchanged. You'd need to figure the temp drop in water, then the amount of water that flowed by the exchanger.
Thats not as easy IMO.


Bill