Hi John,
Since none of the replies I've seen so far fully answer the question, I'll
throw in what I could figure out from an intensive web-surfing session:
>From web surfing, I see that in France air conditioners are sold by:
Cooling power (in Watts) and
Air flow (in cubic meters per hour, or m3/h)
In America, they are sold by "tons" or by BTU/h.
1000 BTU/h = 293 Watts
1 ton = 12000 BTU/h
1 ton = 3500 Watts
For air flow, American units use cubic feet per minute:
1 ft3/min = 1.7 m3/h
It's important to keep in mind that cooling power is watts of heat removed
from the air you are cooling. It is NOT the amount of electricity the air
conditioner uses.
Unfortunately, the U.S. has decided to use a hideous unit for energy
efficiency:
Seasonal energy efficiency ratio (SEER) = BTU / (watt hour)
where BTU is the total amount of heat removed over an entire season and watt
hours is the energy it took to remove it. Higher is better. The reason they
average over a season is that it efficiency depends on the outside
temperature.
The French sites I found don't give efficiency numbers. I propose the
following as a good start:
Efficiency = (total heat removed over a season) / (total electricity used)
Since you are dividing energy over energy, this definition is unitless. We
find that:
1 SEER = 0.293
Thus, since an efficient modern air conditioner may have a SEER of about 14,
Efficiency = 4
This means that for every 1 Watt of electricity you use, you will get 4 Watts
of cooling power, on average.
Hope this is helpful,
John
On Tuesday 23 September 2003 11:00, john mercer wrote:
> Could someone please tell me what the S I unit is for measureing the output
> of airconditioners? In imperial it's B T U. What is the conversion factor
> to convert B T U's to S I? Thanks for all your help.
