Difference of COP, EER, APF, SEER, IPLV, NPLV of Air Conditioning Heat Pump Chiller


1. COP (COP=cooling capacity/compressor electric power)

The COP value (cooling efficiency) is actually the ratio of the cooling capacity (heating capacity) that the heat pump system can achieve to the input power.

Under the same working conditions,

The larger the ratio, the higher the efficiency of the heat pump system, the more energy-saving. The COP of GESON’s chiller can reach up to 7.1.


2. EER (EER=cooling capacity/total electric power of air conditioning system)

In summer cooling, the ratio of cooling capacity (W or Btu/h) to input power (W) is defined as the energy efficiency ratio (EER) of the heat pump (energy efficiency ratio, W/W or Btu/W.h)

In order not to cause ambiguity, we use the COP (energy efficiency ratio) to express the coefficient of performance of the heat pump cycle in winter and the energy efficiency ratio of the heat pump in summer.

The higher the EER value, the more heat absorbed by evaporation in the air conditioner or the less electricity consumed by the compressor


3. The annual energy consumption rate of APF is in the cooling season and heating season,

The ratio of the sum of the heat removed from the room and the heat sent into the room during the cooling (heating) operation of the air conditioner to the sum of the electricity consumed in the same period is also called the annual comprehensive energy efficiency ratio.

APF evaluates the performance of air conditioners more comprehensively,

And it is more suitable for evaluating multi-connected units.


4. Seasonal Energy Efficiency Ratio SEER is the ratio of the total cooling capacity of an air conditioner in a specific area to the total power consumption during the normal cooling period.

Considering the steady-state efficiency, as well as the changing environment and switching loss factors, it is a more reasonable evaluation index.




IPLV Integrated Part Load Performance Factor.

It is a single number to express the partial load efficiency index of the chiller for air conditioning,

It is based on the value of the coefficient of performance of the unit at part load,

According to the weighting factor of the operating time of the unit under various loads,

The value obtained by the IPLV formula.

IPLV(C) is the comprehensive performance coefficient of refrigeration,

It is used to measure the part-load efficiency of multi-connected air conditioners in the cooling season.

Since most of the family life uses some air conditioners,

Therefore, IPLV(C) can better reflect the energy-saving type of household central air-conditioning in real-time operation.

IPLV(C) can be divided into 5 levels

Level 1 has the highest energy efficiency rate, level 5 is the limit value of energy efficiency, and level 2 means reaching the level of energy saving


The formula of IPLV is as follows: IPLV=2.3%×A+41.5%×B+46.1%×C+10.1%×D


A=The efficiency of the unit at 100% load (COP, kW/kW, the same below)

B=Efficiency of the unit at 75% load

C = Efficiency of the unit at 50% load

D = Efficiency of the unit at 25% load


6. NPLV refers to the partial load value under non-ARI standard working conditions.

To scientifically evaluate the operating cost of a unit, it is necessary to consider not only the efficiency of full load, but also the efficiency of part load.

In fact, the unit operates at full load less than 2% of the time and at part load 98% of the time.

The American Refrigeration and Air Conditioning Institute (ARI) has put forward a widely accepted scientific evaluation method after a lot of research.

That is, the comprehensive part load performance index (NPLV) of the unit is used to comprehensively evaluate the overall efficiency of a unit.


NPLV comprehensively considers the performance of the unit at different load points of 100%, 75%, 50% and 25%,

And determine the weight of different points according to the actual operation to comprehensively evaluate the efficiency level of the unit.

China’s latest public building energy efficiency design standards also include this comprehensive part-load efficiency index.

Calculating operating costs in this way is more scientific and closer to the actual situation.

NPLV stands for Integrated Part Load Performance.

According to the ARI550/590 standard of the American Refrigeration and Air Conditioning Institute, it is calculated by weighting the four part load performance points of 100%, 75%, 50% and 25%.

The calculation formula of NPLV is as follows: NPLV=0.01*A+0.42*B+0.45*C+0.12*D

Among them, A, B, C, and D represent the COP values of the unit at 100%, 75%, 50% and 25% respectively.



That is, the comprehensive partial load value under the ARI standard working condition.

The three working conditions are different, as follows:

Name Chilled Water Outlet Temperature Cooling Water Inlet Temperature
IPLV 100% Load 7℃ 30.0℃
0% Load 15.5℃
0% Load 15.0℃
NPLV 100% Load Operating Temperature Operating Temperature
0% Load 15.5℃


1. The cooling water inlet temperature has a linear relationship with the load percentage.

2. For general calculation, the values under four loads of 100%, 75%, 50%, and 25% are used for calculation.

3. Cooling water inlet temperature of different loads under IPLV=0.145×(load percentage)+15.5

Name Chilled Water Outlet Temperature Cooling Water Inlet Temperature
IPLV 100% Load 7℃ 30.0℃
75% Load 26.4℃
50% Load 22.8℃
25% Load 15.5℃
75% Load 25.8℃
50% Load 22.2℃
25% Load 15.0℃
NPLV 100% Load Operating Temperature Operating TemperatureA ℃
75% Load (A-15.5)/75 ℃
50% Load (A-15.5)/50 ℃
25% Load 15.5℃

According to ARI550-98, ARI560-98, and ARI590-98, the calculation formula of IPLV is stipulated.

Performance coefficient IPLV calculation:


Calculation of energy consumption coefficient NPLV:


A——coefficient of performance COP at 100% cooling capacity

B——coefficient of performance COP at 75% cooling capacity

C——coefficient of performance COP at 50% cooling capacity

D——coefficient of performance COP at 25% cooling capacity

Annual power consumption = (energy consumption coefficient IPLV) × (full load cooling capacity) × (annual operating time)

The annual running time is counted on the basis of 12 hours a day for the four months from June to September, and the annual running time is 1200 hours.

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