The objective of the R&D project was the development of a test method for stationary integrated refrigeration units. The test method comprises different device variants, like ceiling mounted, wall mounted or split refrigeration units. The method provides reliable performance data and thus enables a manufacturer-independent efficiency comparison.

Measurements in the 3- or 4-chamber measuring set-up were carried out using the calorimeter method with compensation of the ambient conditions. This enabled the measurements of devices with low cooling capacity (0.5 - 4 kW).

In the selected test set-up (Figure 1), the cooling capacity is measured indirectly via the electrical power of the compensation heating. To determine the total cooling capacity, the heat input into the calorimeter room and, if necessary, internal loads (sensible and latent heat) must be added together.

The test method comprises following features:

• suitable for low temperature devices (-20°C) and normal temperature cooling
• measurement in calorimeter room (3- or 4-chamber concept)
• determination of heat input via enclosing surfaces before power measurement
• establishiment of equilibrium states of the temperatures to be set (takes up to 24h)
• measurement period up to 6h at a tolerance band of 0,2K

Conclusion:

• results are implemented into the new test norm prEN 17432
• establishment of an uniform Europe-wide comparison criterion
• performance and efficiency data on a uniform basis leads to higher confidence and thus also to lower consumption costs