The purpose of estimating the efficiency
of an Air Conditioning system is to indicate the amount of relative
power required to remove an specific quantity of heat. So that, a
high-efficiency equipment will consume less power to perform the same
work.
It is similar to the case of kilometers per liter for vehicles, but
instead of km/l, Air Conditioners use the designation EER (Energy
Efficiency Ratio) which is nothing more than a simple mathematical
ratio between the Total Heat supplied stated in British thermal units
per hour (Btu/h) versus the electrical power required to reach it
(KW). Recently, the U.S. Energy Department has developed a more complicated
method to evaluate the performance of a system along a wide range
of operating conditions. The result is known as SEER (Seasonal Energy
Efficiency Ratio) which is an indicative of the operation of the Air
Conditioner during the cold season.
Since the value corresponding to SEER is considerably higher than
EER for the same equipment, it has become very popular to state efficiency
values of Air Conditioners through the use of this term (SEER) which
has already been adopted by most of the manufacturers worldwide, and
though it should have not been considered as an efficiency index for
those systems in operation in tropical places due to the inexistence
of cold times or seasons.
In any case, when you acquire an Air Conditioning system you must
know the value of its SEER or its EER and never make a comparison
between two equipment if you only know the SEER of one of them and
the EER of the other, since the one that has 10.0 SEER will consume
more energy than the one with 10.0 EER.
What matters is to make the comparison using the same parameter. An
equipment with SEER equivalent to 12,5 will consume less electrical
power than another with SEER 10,0. However, since the acquisition
cost of the first one is considerably higher and the electrical power
supply cost varies between different cities and usages, the time in
which the investment will pay itself through the saving in electrical
consumption, must be calculated and evaluated in order to make a decision.
The following formula is used to calculate the operation cost of an
equipment (CO) in Bolivars per month:
where:
T = Electrical rate in $/Kw-h
H = Hours consumed per month
C = Actual capacity of the equipment in Btu/h
