Coefficient of Performance (COP)

The coefficient of performance is used to measure the unit’s efficiency while in the heating mode and is applied to heat pumps, of any nominal cooling capacity, that operates on three phase current. To evaluate a heat pump’s efficiency while in cooling mode, EER or SEER must be used. The COP is a dimensionless value defined as the energy produced by the heat pump (in watts) divided by the energy consumed by the heat pump (in watts). In an air to air heat pump, the evaporating refrigerant moves heat from the outside air (when in heating mode) and this heat plus the heat equivalent of the work of compression is rejected to the recirculated air flowing over the condenser coil and to the space to be heated. There is always heat energy in the outside air, however, at lower temperatures, it becomes more difficult to extract. 


Therefore the COP decreases at lower ambient and the ARI COP rating is calculated at two different ambient temperatures (47℉ and 17℉). The formula for calculating COP is shown below in EQ–9. 

Thus, a heat pump with a COP = 2.5 would produce two and a half times as much heat than the heat equivalent of the watts input. If electrical resistance heat is used to condition the space, it is by definition, 100% efficient. In this case only 1 watt of heat would be obtained for every watt input, and the resulting COP would be equal to 1. 


COP represents the efficiency of a heat pump while in the heating mode. A higher value of COP reflects a higher heating efficiency. 

Coefficient of Performance - COP

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The COP value of water-cooled chillers (WCCL) are 3.3~5.6 which amount to 20W

The COP value of air cooled air conditioners are 2.2~2.8
The conventional florescence T8 tube is 48W
The LED T8 Tube is 18W
The energy saving is 48W-18W=30W for one tube.

If there are 10 tubes inside a room, the total saving is 300W
The saving in cooling is 300W/2.2=136W

The total energy saving is 436W