best [486]
05-07-2006, 05:57 AM
Alot of people are asking for conversions so put 'em here.
:google: is your friend :)
http://www.convert-me.com/ energy conversions
watts x 0.00133 = HP
1 horsepower = 745.699872 watts (power, energy/time)
1 watt = 3.41214163 BTUs per hour (heat transfer)
1 ton of ice = 12,000 BTUs per hour (heat transfer)
1 ton of ice = 3517 watts (heat transfer)
For converting BTUs to Tonns:
(1 / 12,000) * Zbtu/h = T%
Where Z = Your BTU rating
T% = Tonnage in a percent
There is a problem here, alot of people dont understand that a 1hp compressor for example, doesnt mean it is rated at 1hp (2545btu/h) with respect to heat moved.
Watts, HP, btu/h all measure the same thing, power, which is energy over time. However there are two different systems to consider. There is the power of the compressor motor, thats one thing. Then there is power with respect to heat moved, thats another thing. The first one does not equal the second.
So dont assume your 1/2hp compressor is rated at 1272.5Btu/h, because its not. The rating for motor power and power with respect to heat moved by the system are very different things.
Further more yes the power with respect to heat moved by the system is a function of the compressor motor power but thats not the only variable, there are many others that impact the result.
So be carefull what you convert.
Right, one question I see sometimes, and it's about the lower 'BTU' ratings, that I thought would be good to answer in here.
For instance, you have a 850BTU low temp compressor.
That's not much is it? Or is it?
Generally compressors are rated to what they do. So having one that's rated to Ashrae or Cocemaf whatever will read a lot lower than one rated to higher temps.
So, if you have 850BTU at -25 (Cecomaf) for instance as your rating, then you have around 250w of heat removal at -25.
That would put it at the approximately 1/3HP range for a compressor.
So it's a good idea to look at the spec sheet of the compressor you're looking at, and check what the heat removal is at the temperature that you'd actually be using it at.
Then the HP rating and all that starts to make more sense, because the rating of a compressor and what it actually translates into for YOU can look a lot different when you look deeper into the real spec of the compressors.
:google: is your friend :)
http://www.convert-me.com/ energy conversions
watts x 0.00133 = HP
1 horsepower = 745.699872 watts (power, energy/time)
1 watt = 3.41214163 BTUs per hour (heat transfer)
1 ton of ice = 12,000 BTUs per hour (heat transfer)
1 ton of ice = 3517 watts (heat transfer)
For converting BTUs to Tonns:
(1 / 12,000) * Zbtu/h = T%
Where Z = Your BTU rating
T% = Tonnage in a percent
There is a problem here, alot of people dont understand that a 1hp compressor for example, doesnt mean it is rated at 1hp (2545btu/h) with respect to heat moved.
Watts, HP, btu/h all measure the same thing, power, which is energy over time. However there are two different systems to consider. There is the power of the compressor motor, thats one thing. Then there is power with respect to heat moved, thats another thing. The first one does not equal the second.
So dont assume your 1/2hp compressor is rated at 1272.5Btu/h, because its not. The rating for motor power and power with respect to heat moved by the system are very different things.
Further more yes the power with respect to heat moved by the system is a function of the compressor motor power but thats not the only variable, there are many others that impact the result.
So be carefull what you convert.
Right, one question I see sometimes, and it's about the lower 'BTU' ratings, that I thought would be good to answer in here.
For instance, you have a 850BTU low temp compressor.
That's not much is it? Or is it?
Generally compressors are rated to what they do. So having one that's rated to Ashrae or Cocemaf whatever will read a lot lower than one rated to higher temps.
So, if you have 850BTU at -25 (Cecomaf) for instance as your rating, then you have around 250w of heat removal at -25.
That would put it at the approximately 1/3HP range for a compressor.
So it's a good idea to look at the spec sheet of the compressor you're looking at, and check what the heat removal is at the temperature that you'd actually be using it at.
Then the HP rating and all that starts to make more sense, because the rating of a compressor and what it actually translates into for YOU can look a lot different when you look deeper into the real spec of the compressors.