**COP is a measurement of the energy efficiency of your air-conditioning unit's heating performance.** **EER is the ratio of a unit's cooling output relative to its input power**.

the purpose of using refrigeration cycles is **to transport heat from a low temperature place to a hot temperature place in order to keep the cold place at low temperature by applying work**. so the efficiency in this case is the heat removed from the cold place per unit of work applied (which is called COP).

Originally Answered: What is the difference between cop and efficiency? **The efficiency is calculated for the devices which are power producing, while in case of power absorbing devices cop is calculated because we want to check performance of device for a given power input**.

**Electric motor driven chillers are rated in kilowatts per ton cooling.**

- kW/ton = 12 / EER.
- kW/ton = 12 / (COP x 3.412)
- COP = EER / 3.412.
- COP = 12 / (kW/ton) / 3.412.
- EER = 12 / (kW/ton)
- EER = COP x 3.412.

COP (Coefficient of Performance)

COP is defined as **the relationship between the power (kW) that is drawn out of the heat pump as cooling or heat, and the power (kW) that is supplied to the compressor**.

Coefficient of performance (COP) — This rating **indicates a system's heating efficiency**. The higher the COP, the more efficiently the system heats. The rating is a ratio of heat produced (in Btu per hour) over electrical energy input.

Calculating the efficiency of a chiller is fairly simple. It is measured in “COP” which stands for **Coefficient Of Performance**. The Coefficient of performance is just a ratio of the refrigeration effect produced by the chiller against the amount of electrical energy that went into the machine to produce this.

You want to build a refrigerator or an air conditioner. For such a device we define the coefficient of performance COP as the ratio of the amount of heat removed at the lower temperature to the work put into the system (i.e. the engine). **COP = Q _{low}/(-W) = Q_{low}/(Q_{high} - Q_{low})**.

Simply put, COP equals **the amount of energy produced (energy out) divided by energy used (energy in)**. The energy out – the amount of heat moved by the heat pump – is measured in BTU/h, or British Thermal Units per hour.

**It is only moving the energy/heat and than can be greater than 1**. The word 'Efficiency' is generally described as 1 (100%) or less than 1. Hence the word 'COP' came into picture as it could be used for systems with more than 1 also. Otherwise there is not much difference between the two words.

Coefficient of Performance

The COP is determined by the ratio between energy usage of the compressor and the amount of useful cooling at the evaporator (for a refrigeration instalation) or useful heat extracted from the condensor (for a heat pump). A high COP value represents a high efficiency.

SEER stands for **Seasonal Energy Efficiency Ratio**. This is the ratio of the cooling output of an air conditioner over a typical cooling season, divided by the energy it uses in Watt-Hours. It may also be called a Seasonal Energy Efficiency Rating.

Energy efficiency ratio (EER) is used in the USA, and is defined as the system output in Btu/h per watt of electrical energy. Coefficient of performance (COP) is the equivalent measure using SI units, which is widely used in the UK. **A COP of 1.0 equates to an EER of 3.4**.

**The cooling capacity of 1 ton is equal to 3.517 kilowatts of power**. For 1.5 ton AC, the power consumption is the same as the cooling capacity. There was a value of 1.5* 3.517/2.954 kilowatts. The outdoor unit is called the Compressor while the indoor unit is called the Evaporator.

The coefficient of performance or COP (sometimes CP or CoP) of a heat pump, refrigerator or air conditioning system is **a ratio of useful heating or cooling provided to work (energy) required**. Higher COPs equate to higher efficiency, lower energy (power) consumption and thus lower operating costs.

The EER is **the relationship between the cooling capacity of chiller and the total power consumption of the refriger- ation unit (compressors + fans)**.

Open air refrigeration cycle

In an open refrigeration system, **the air is directly passed over the space is to be cooled, and allowed to circulate through the cooler**. The pressure of open refrigeration cycle is limited to the atmospheric pressure. A simple diagram of the open-air Refrigeration system is given below.

**COP is a measurement of the energy efficiency of your air-conditioning unit's heating performance.** **EER is the ratio of a unit's cooling output relative to its input power**.

**Divide Q (BTUs per hour) by 12,000 (the number of BTUs in one ton of cooling capacity)**. This yields the chiller capacity required to handle the process heat load in tons per hour: Example: 240,000/12,000= 20 tons/hr.

If an air conditioner has a rating of 2.5kw, giving you 2.5kw of cooling, it is only using 0.52kw to achieve that. Then the COP of that air conditioner would be **2.5 divided by 0.525 = 4.7**, essentially almost 5 times more efficient than electrical heating.

Dated : 13-Jun-2022

Category : Education