Coefficient of Performance (CoP) Definition

The Coefficient of Performance (COP) is the efficiency of a heat pump expressed as a percentage. The heat output from the condenser, called Q, is compared to the power supplied to the compressor, also known as W, when calculating the COP for a heat pump.

The equation

COP = |Q|


The COP is measured in terms of the amount of power (kW) drawn out of the heat pump as cooling or heat, and the amount of power (kW) supplied to the compressor.

Related: Cop Vs Efficiency

How To Calculate COP?

A COP of 2 indicates that for each kW of power consumed by the heat pump’s compressor, 2 kW of cooling capacity is obtained.

The COP figure is expressed as a decimal. As a result, during COP calculation, the produced heat and the supplied electricity use the same units.

COSP (Co-efficient of System Performance) is a measure of the total (electric) energy consumed by a heat pump in relation to the total work done (cooling or heating) by the pump, whereas COP is a metric that measures electrical energy.

For example, the electrical energy consumed to produce one kilowatt of cooling may be expressed as COSP.

COP of a Heat Pump

Here’s how to calculate the theoretically maximum COP of a heat pump:

COPheat pump = Thot/(Thot-Tcold)

Thot is the warm temperature we want to enjoy during the winter months. (let’s say 95F; that’s 308 in Kelvins).

The TCOLD will be the cold temperature at which the heat pump is activated. (57F or 287K).

Theoretical maximum COP is calculated like this:

COPheat pump = 308K/(308K-287K) = 14,67

A heat pump, in theory, may have a COP higher than 10. In reality, the actual COP of a heat pump is far lower.

Seasonal COP Or SCOP

The Seasonal Coefficient of Performance (SCOP) is a number that measures the average COP throughout a heating season.

The SCOP value may include different sections of the heating system than just the heat pump, depending on how it’s defined.

For cooling and air conditioning purposes, SEER, or Seasonal Energy Efficiency Ratio, is most often utilized.

EER (Energy Efficiency Ratio)

The Energy Efficiency Ratio (EER) is a measurement of how efficiently a cooling system can operate when the outside temperature is at a specific level.

The ratio is calculated by dividing the cooling output by the power input. The higher the EER, the more efficient the system.

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