budleydoright
Well-Known Member
[h=4]more:
Short Cycles[/h]Air conditioners are very inefficient when they first start
operation. It is far better for the air conditioner to run longer cycles than
shorter ones. The efficiency of the typical air conditioner increases the longer
it runs.
Figure 2 illustrates that if the on-time of
an air conditioner is only 5 minutes the efficiency (EER) is 6.2. If a properly
sized air conditioner half the size were used instead, the same amount of
cooling would take place in about 9 minutes, and the efficiency would rise to
6.9. This represents a savings of 10% for the customer.
Most of the cooling season the cooling loads are well below the capacity of
properly sized air conditioners, and for oversized units the short cycling is a
substantial problem. Because of the short cycles, Bill's high-efficiency air
conditioner is less efficient.
[h=4]Moisture Buildup[/h]The ability of the air conditioner to remove moisture
(latent capacity) is lowest at the beginning of the air conditioner cycle. The
moisture removed from the indoor air is dependent upon the indoor coil
temperature being below the dew-point temperature of the air. The moisture then
wets the indoor coil and, should the unit run long enough, will begin to flow
off the coil and be removed out of the condensate drain.
For short cycles, the coil does not have time to operate at the low
temperature and when the unit stops, the moisture on the coil evaporates back
into the indoor air. Thus, in humid climates, a properly sized air conditioner
will do a far better job of removing moisture from the air than oversized units.
Bill's oversized air conditioner could not remove enough moisture from the air,
so his house was cold and clammy.
Short Cycles[/h]Air conditioners are very inefficient when they first start
operation. It is far better for the air conditioner to run longer cycles than
shorter ones. The efficiency of the typical air conditioner increases the longer
it runs.
an air conditioner is only 5 minutes the efficiency (EER) is 6.2. If a properly
sized air conditioner half the size were used instead, the same amount of
cooling would take place in about 9 minutes, and the efficiency would rise to
6.9. This represents a savings of 10% for the customer.
Most of the cooling season the cooling loads are well below the capacity of
properly sized air conditioners, and for oversized units the short cycling is a
substantial problem. Because of the short cycles, Bill's high-efficiency air
conditioner is less efficient.
[h=4]Moisture Buildup[/h]The ability of the air conditioner to remove moisture
(latent capacity) is lowest at the beginning of the air conditioner cycle. The
moisture removed from the indoor air is dependent upon the indoor coil
temperature being below the dew-point temperature of the air. The moisture then
wets the indoor coil and, should the unit run long enough, will begin to flow
off the coil and be removed out of the condensate drain.
For short cycles, the coil does not have time to operate at the low
temperature and when the unit stops, the moisture on the coil evaporates back
into the indoor air. Thus, in humid climates, a properly sized air conditioner
will do a far better job of removing moisture from the air than oversized units.
Bill's oversized air conditioner could not remove enough moisture from the air,
so his house was cold and clammy.