Category: Airedale Energy Efficiency Standards Seasonal Energy
Efficiency Ratio
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Energy Efficiency Ratio
Airedale Energy Efficiency Standards
Energy efficiency is integral to all new product development at
Airedale. To enable customers to benchmark the efficiency of our
products against those of other manufacturers, we promote three key
industry standards, namely the Energy Efficiency Ratio (EER), Eurovent
EER classification and European Seasonal Energy Efficiency Ratio (ESEER).
For example see the table below relating to our new TurboChill product.


1. Energy Efficiency Ratio (EER)
The EER is the ratio of the cooling capacity to the power input of
the unit. EER is a measure of how efficiently a cooling system will
operate at application-specific conditions when the outdoor temperature
is at a particular level. The higher the EER, the more efficient is the
air conditioner.
1(a) Eurovent EER Classification
Eurovent, the European Committee of Air Handling and Refrigeration
Equipment Manufacturers, has set its own formulae to calculate EERs,
making it easier to compare the performance of chillers manufactured by
Eurovent accredited companies. Eurovent EER values are only valid at
specified ambient and water conditions. In the case of air cooled
packaged chillers, the unit EER must be given at 7/12°C water
conditions, 35°C ambient. Eurovent has also established its own
classification for full load EER. This classification follows an A to G
approach, with A as the most efficient and G the most inefficient.

Advantages: The EER enables comparable products to be benchmarked
against one another for efficiency.
Disadvantages: Currently EER figures only cover the performance of
the unit at one specific condition, at which the chiller may operate for
less than 1% of its lifetime.
Some chillers will perform better at low load and/or ambient
conditions, but this is not reflected in the traditional EER value.
2. European Seasonal Energy Efficiency Ratio (ESEER)
The ESEER is a weighted formula taking into account the variation of
EER with the load requirement and change in ambient temperature.
The ESEER calculates a unit's yearly energy efficiency based, in the
case of an air cooled packaged chiller at nominal conditions of 7/12°C
water, 35°C ambient, on a small range of ambient temperatures. The
higher the ESEER, the more efficient is the cooling system.
The calculation equation is:
ESEER = A*EER100% + B*EER75% +C*EER50%+D*EER25%
Using the following weighting coefficients:
A = 0.03 B = 0.33, C = 0.41, D = 0.23
ESEER = 0.03A + 0.33B + 0.41C + 0.23D
Advantage: Compared with EER, this method gives a more realistic
overall system efficiency on a seasonal basis, at part load conditions.
Disadvantage: The ESEER does not incorporate free-cooling to any
degree. The minimum ambient temperature of 20°C is unrealistic for most
of Europe. Water temperatures of 7/12°C are fine for comfort cooling,
but for IT/process applications, there is a wide variation. For example
a machine designed to work at 18/12°C water would be much less efficient
at 7/12°C.
3. Free-cooling Seasonal Energy Efficiency Ratio (FSEER)
Whilst the ESEER provides a good representation of a typical
chiller’s yearly energy efficiency, no advantage is given to
free-cooling chillers. Typically the ESEER of a conventional chiller
will be free-cooling or the same as an equivalent free-cooling chiller.
FSEER is an Airedale value used to represent the annual energy
efficiency ratio of a free-cooling chiller. This method is applicable to
Northern European cities and incorporates the following temperature
bands.

FSEER Calculation
The number of hours within each temperature band (Graph 1) is used in
the calculation.
FSEER = A*EER100% + B*EER75% + C*EER50% + D*EER25%

Advantage: True representation of the energy efficiency of a
free-cooling chiller.
Disadvantage: Currently only limited use by the industry.
Alternative Energy Efficiency Standards
Apart from the standards applied by Airedale, we do recognise that
there are alternative standards available, such as:
1) Integrated Part Load Value, known as IPLV, is similar to ESEER,
but applies different weighting factors, giving an apparent higher
efficiency value than ESEER - an advantage to those manufacturers using
IPLV. It has similar disadvantages to ESEER.
2) Seasonal Energy Efficiency Ratio (SEER): Developed in the USA, the
SEER uses similar calculation methods to ESEER, but with weighting
factors that are more suitable for the USA.
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