Values evaluated

Easy to calculate and use for the comparison are:

• Volumetric refrigeration capacity q_ov in J/m³
• coefficient of performance COP
• isentropic discharge temperature t_{V2 is} in °C

See also: Thermodynamics.

Somehow more complex and only approximately calculated is

• Seasonal energy performance ratio SEPR

The main point is the energy efficiency comparison. Thus, the most important values are COP and SEPR. The discharge temperature is a limiting factor. The volumetric refrigeration capacity states how much refrigeration capacity is generated in W, when 1 m³/s at suction conditions is pumped. From this value, it can be estimated which size of systems, pipes and compressors are needed with different refrigerants. With higher volumetric capacity, the pipes for a given refrigeration capacity are smaller.

The seasonal efficiency SEPR according to EN13215 allows to compare the efficiency on the basis of a weighted average for a year. By this, the evaluation is not only for one operating condition, but also takes strongly into account lower ambient and thus lower condensing temperatures. But also here some simplifications were neccessary for the refrigeration system and for the weighting to be able to put this into a spread sheet. This has some influence on accuracy of the comparison.