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Energy indices ESEER and IPLV
Nowadays European Market, US market and elsewhere are very interesting to reduce the power consumption of all industry device.
So the possibility to valuate the real consumption of current by the machine like chillers become necessary in all markets. It is difficult estimate the total consumption during the full life of a chiller so it has been created several indexes that reflect the average values about the partial load condition the unit usual works in its life. The valuation index adopted in the United States is called IPLV (Integrated Part Load Value) and is defined (American Refrigeration Institute):
Where EER% is the partial load efficiency of chiller at 100%,75%, 50%, 25%, in according with the table below:
| Water leaving temperature (°C) |
6.7 (constant) |
| Delta T full load (°C) |
5 |
| Load (%) |
100 |
75 |
50 |
25 |
| Water Cooled Chiller |
| Condenser water temperature (°C) |
29.4 |
23.9 |
18.3 |
18.3 |
| Air Cooled Chiller |
| Condenser air temperature (°C) |
35 |
26.7 |
18.3 |
12 |
| Weight in IPLV (%) |
1 |
42 |
45 |
12 |
In European market the index adopted is called ESEER and it is in accord with EECCAC proposal (Energy Effieciency and Certification of Central Air Conditioner)
Where EER% is the partial load efficiency of chiller at 100%,75%, 50%, 25%, in according with the table below:
| Water leaving temperature (°C) |
6.7 (constant) |
| Delta T full load (°C) |
5 |
| Load (%) |
100 |
75 |
50 |
25 |
| Water Cooled Chiller |
| Condenser water temperature (°C) |
30 |
26 |
22 |
18 |
| Air Cooled Chiller |
| Condenser air temperature (°C) |
35 |
30 |
25 |
20 |
| Weight in IPLV (%) |
3 |
33 |
41 |
23 |
Using the energy indices
The real absorbed power can be calcolate with the following formula based on discussion above:
Average power abosorbed = Max Cooling capacity / Index of efficiency
For example:
Max cooling capacity required in US for a water cooled chiller: 500 kW;
Hitema simulation software can provide the EER at each percentage of load:
EER100% = 4.66
EER75% = 5.72
EER50% = 6.31
EER25% = 5.99
IPLV = 0.01*4.66+0.42*5.72+0.45*6.31+0.12*5.99 = 6.01
Average power adsorb (kW) = 500 / 6.01 = 83.19 kW
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