Are BTUs international? i.e in Bulgaria, we have colder winters

kpc_49

you need to look at are inside temp and outside design temp. Here in New Hamshire I design for a 70F temp @ -20 F outside design.

Ali

Are BTUs international? i.e in Bulgaria, we have colder winters

I have calculated that I need 24 kilowatt boiler to heat my house with water-circulating radiators and the hot water. But I made this calculation with British Thermal Units based on a target temperature of 19 degrees Centigrade, using the rough equation 1 kilowatt = 3000 BTUs.
In Bulgaria, however, we have winters that are on average 10 degrees Centigrade colder than Britain. Does this matter? By how much should I increase my calculation?

Mark Hunt_6

BTU's are stictly imperial units

A BTU is the amount of heat required to raise the temperature of one pound of water, one degree Fahrenheit.

The metric equivalent as far as definition is concerned, the unit is the calorie, a kilogram raised or lowered one degree centigrade.

For heating (and cooling) units, the usual unit is the kilowatt, 3,413 BTU's as the equivalent.

Mark H

Brad White_191

Uh,

No. It is strictly in Imperial Units (pounds, Fahrenheit). The metric equivalent as far as definition is concerned, the unit is the calorie, a (EDIT:gram not kilogram) raised or lowered one degree centigrade (Celsius).

For heating (and cooling) units, the usual unit is the kilowatt, 3,413 BTU's as the equivalent.

Mark Hunt_6

Uh


Isn't that what I just said?

Mark H

Tim Weaver

I think you are both wrong

A calorie is the energy to change a gram of water one degree centigrade. A gram of water is also one cubic centimeter. A kilogram is a thousand grams. Et-cetera.

Uni R_2

Yup... they are thinking Kilocalories

1 Kilocalorie will raise the temperature of 1 KG of water by 1°C.

Unknown

Its easy to confuse

because when we look at food labels they are in kilocalories, indicated by a capitol C.

Brad White_191

Yes

gram, not kilogram, of course! I am glad those suckers are so small, so I can eat more of them...

Thanks

Brad White_191

LOL , Mark!

Glad you found the go-back-and-edit feature

scrook_2

You're close at 3000 kW = 1000 BTU. about 14% low. Use (as others have stated) 3413 kW = 1000 BTU

steve_197

I see two issues

One is the matter of metric vs Imperial units that others have clarified . The other issue is what is the effect of lower outdoor temperature on heat loss.

From the wording of your question I assume that you did your heat loss calculation (and found that a 24 kw boiler is needed) based on an interior target temperature of 19 deg C and an outdoor temperature (not specified) that would be appropriate for Britain.

Since, as you say, the outdoor temperature in Bulgaria is about 10 deg C lower than in Britain, your heat loss will be higher. You will need to recompute the heat loss with the actual expected temperature conditions.Here is a link to climate data for Sofia, Bulgaria http://www.esru.strath.ac.uk/Courseware/Case-study/blagoevgrad_swu/swu.htm In Sofia, the winter design temperature is -16 deg C . Depending on where you are in the country you may be facing even lower winter temperatures.

Baltimore/Maine Doug_4

You are all wet

BTU or British Thermal Underware is a unit that was created when the British Army first encountered the wicked cold winters in what became America. It was a measure of how many layers of Fruit-of-the-Loom or BVD's one had to wear depending how far north one was stationed.

Since there were no standards at the time, many butts were freezing as a result of inadequate insulation and poor quality of clothes and the difficulty in how to convey just how cold it was. So in a time of need the army set a standard using a pair of underware made from the very fabric that was used to make the first pair of jeans.

Thus the British Thermal Underware unit was created which tells you how well you have to cover your parts to retain heat.

Steamhead (in transit)

ROFLMAO!!!!!!!

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gerry gill

If you just adopt our system

then the BTU would also be a Bulgarian Thermal Unit, and life would be easier for all us yanks who refuse to conform

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Ali

GREAT!

Thankyou very much Steve! At last a clear and exact answer to my question. Maybe I didn't word it clearly? Yes, the climate where I am building my house is similar to Sofia's so I will base my calculation on minus 16 degrees. Yippee!

And I am still amazed by the power of the Internet!!! It is putting heating engineers who expect $400 for a heating plan, out of a job!!!

DanHolohan

Ali,

would you like to tell us about the heating systems in Bulgaria? I would love to learn more. Thanks.