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

kpc_49
kpc_49 Member Posts: 12
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.

Comments

  • Ali
    Ali Member Posts: 2
    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
    Mark Hunt_6 Member Posts: 147
    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
    Brad White_191 Member Posts: 252
    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
    Mark Hunt_6 Member Posts: 147
    Uh


    Isn't that what I just said?

    Mark H
  • Tim Weaver
    Tim Weaver Member Posts: 49
    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
    Uni R_2 Member Posts: 589
    Yup... they are thinking Kilocalories

    1 Kilocalorie will raise the temperature of 1 KG of water by 1°C.
  • Its easy to confuse

    because when we look at food labels they are in kilocalories, indicated by a capitol C.
  • Brad White_191
    Brad White_191 Member Posts: 252
    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
    Brad White_191 Member Posts: 252
    LOL , Mark!

    Glad you found the go-back-and-edit feature :)
  • scrook_2
    scrook_2 Member Posts: 610


    You're close at 3000 kW = 1000 BTU. about 14% low. Use (as others have stated) 3413 kW = 1000 BTU
  • steve_197
    steve_197 Member Posts: 1
    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.
  • 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.
  • gerry gill
    gerry gill Member Posts: 3,078
    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 ;)

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
    gwgillplumbingandheating.com
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • Ali
    Ali Member Posts: 2
    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
    DanHolohan Member, Moderator, Administrator Posts: 16,600
    Ali,

    would you like to tell us about the heating systems in Bulgaria? I would love to learn more. Thanks.
    Retired and loving it.
This discussion has been closed.