No. AOTS-T-2023-02
Date: June 23, 2023
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Subject: Understanding EER, COP, IPLV and IEER.
Issued by: AOTS <aots_group@dit.daikin.co.jp>
Introduction
Government and agency has their own different energy efficiency measurement methods. You may
need to know how to calculate each energy efficiency ratings of air conditioners to support the markets in
each country to meet their local requirements.
Get to know about EER, COP, IPLV, IEER and calculations
The four calculation methods presented in this newsletter are the most common and widely used -
EER, COP, IPLV and IEER, which will be detailed as below.
EER (Energy Efficiency Ratio)
EER or Energy Efficiency Ratio is a calculation method of energy efficiency by dividing the cooling
capacity of A/C (BTU/hr) by the power consumption that supply to A/C (W).
EER =
Cooling capacity of A/C (BTU/hr)
Power consumption (W)
Example
Calculations : EER = Cooling capacity of A/C(BTU/hr)
Power consumption (W)
EER =
Answer :
Figure 1, Specification table
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9,000 (BTU/hr)
810 W
EER = 11.11
COP (Coefficient Of Performance)
COP or Coefficient Of Performance is a calculation method of energy efficiency by using capacity
of A/C in (W) units to compared with power consumption in (W) units. This calculation method is similar
to EER but the difference is in the Power Output units of measurement used.
COP =
Capacity of A/C (kW)
Power consumption (kW)
Example
Calculations :
COP =
COP =
Figure 2, Specification table
Answer :
Capacity of A/C (kW)
Power consumption (kW)
16 kW
3.38 kW
COP = 4.73
IPLV (Integrated Part Load Value)
*Vietnam EER has similar formula.
IPLV or Integrated Part Load Value is a calculation method of energy efficiency by using the EER
values at the different capacity loads. This method is different from the previous two methods.
IPLV is developed by AHRI (Air-Conditioning, Heating and Refrigeration Institute). IPLV will have same
outdoor temperature at 35˚C for all capacity loads.
IPLV = 0.01A+0.42B+0.45C+0.12D
*Constant values can be change depending on ANSI/AHRI standard.
Figure 3, Breakdown of frequency of loading %
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Example
Figure 4, Cooling capacity and Power Input at different loading
Formula : IPLV = 0.01A+0.42B+0.45C+0.12D
A = EER@ 100% Load, Outdoor temperature 35˚C.
B = EER@ 75% Load, Outdoor temperature 35˚C.
C = EER@ 50% Load, Outdoor temperature 35˚C.
D = EER@ 25% Load, Outdoor temperature 35˚C.
According to details as above.
Use the data in Figure 4 to calculate the EER.
Then input the EER value into IPLV formula.
Calculations : IPLV = 0.01A+0.42B+0.45C+0.12D
IPLV = (0.01x16.15)+(0.42x20.00)+(0.45x25.00)+(0.12x9.30)
Answer :
IPLV = 20.92
IEER (Integrated Energy Efficiency Ratio)
IEER or Integrated Energy Efficiency Ratio is a calculation method of energy efficiency where it
considers the loads at different outdoor temperature conditions. IEER will have different outdoor
temperature for each capacity loads.
IEER = 0.020A+0.617B+0.238C+0.125D
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*Constant values can be change depending on AHRI standard.
Figure 5, Breakdown of frequency of loading % and temperature
Example
Figure 6, Cooling capacity and Power Input at different loading and temperatures
Formula : IEER = 0.020A+0.617B+0.238C+0.125D
A = EER@ 100% Load, Outdoor temperature 35˚C.
B = EER@ 75% Load, Outdoor temperature 27.5˚C.
C = EER@ 50% Load, Outdoor temperature 20.0˚C.
D = EER@ 75% Load, Outdoor temperature 18.3˚C.
According to details as above, Use the data in Figure 6 to calculate the EER.
Then input the EER value into IEER formula.
Calculations : IEER = 0.020A+0.617B+0.238C+0.125D
IEER = (0.020x16.00)+(0.617x20.60)+(0.238x23.83)+(0.125x16.30)
Answer : IEER = 20.73
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Summary
The energy efficiency ratings mentioned above are the most commonly used in the market.
There are different consideration for the use of the different energy efficiency rating. There is no
correct rating to use for any conditions. It is left to the system designer to make their own judgment on
which efficiency rating is suitable for their design.
Figure 7, Summary table
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