How to Select EN 14511 Test Conditions to Maximise Commercial HPWH Modelling Outcomes

For VEU Activity 44 and ESS IHEAB, EN 14511 testing forms the foundation of heat pump performance modelling.

While EN 14511 is a European standard, in the VEU and ESS schemes it is used for a specific purpose: to construct a heat pump performance map that feeds into annual AS/NZS 4234 simulation models. This map defines how the heat pump performs across combinations of air temperature and water inlet temperature.

Selection of EN 14511 test conditions is not simple. Refrigerant choice, control logic, and thermal storage configuration all influence which test points should be selected.

Regulator minimum requirements

Scheme administrators allow some flexibility in the selection of test conditions to suit different products. At minimum, the test matrix needs to include the maximum inlet water temperature expected during normal operation and at least one of the required air temperature points.

The required air temperature points are 2 C/1 C, 7 C/6 C, 12 C/11 C, or 19 C/15 C, expressed as dry bulb/wet bulb. The maximum inlet water temperature is the highest inlet water temperature expected during normal operation.

For an R-290 heat pump with a tank set point of 75 C and a temperature rise of 5 K, the maximum inlet temperature would be 70 C. For a CO2 heat pump with a 90 C outlet temperature and compressor shut-off when inlet water exceeds 50 C, the maximum inlet temperature would be 50 C.

Instead of a low temperature operation penalty, results are linearly extrapolated down to dry bulb -5 C. It is not necessary to test at -5 C.

Additional testing to improve modelling outcomes

It is strongly recommended to include additional inlet water temperatures so the performance curve is properly captured. A low inlet water temperature, often around 10 C, helps show high capacity and COP at favourable water conditions.

An intermediate inlet water temperature is also valuable. Units tend to spend more operating time at higher water temperatures, so the intermediate point should usually be biased toward the upper part of the operating range, such as 50 C where appropriate.

It is also useful to add a higher dry bulb air point, usually between 30 C and 38 C. System capacity and COP tend to be higher in hotter ambient conditions, and this additional point can materially improve certificate outcomes where it reflects realistic operation.

Baseline recommendations

For R-290 systems, a useful baseline matrix is inlet water temperatures of 10 C, 50 C, and 70 C, tested against air points of 2 C/1 C, 7 C/6 C, 19 C/15 C, and 38 C/25 C.

For CO2 systems, a useful baseline matrix is inlet water temperatures of 10 C, 30 C, and 50 C, tested against the same air points: 2 C/1 C, 7 C/6 C, 19 C/15 C, and 38 C/25 C.

These are starting points, not universal requirements. The final matrix should reflect the compressor envelope, control strategy, outlet temperature, and intended system configuration.

Summary

To maximise certificates from modelling, start with accurate performance mapping. Better test data leads to more accurate and compliant simulations, and often to stronger certificate outcomes.

How EnergyAE can help

The precise choice of test conditions depends on your specific heat pump system. EnergyAE can review your system and controls, refine the test condition selection, analyse in-house testing, arrange third-party NATA-accredited testing, and complete the final AS/NZS 4234 modelling for VEU and ESS applications.

Get in touch with EnergyAE to discuss your project.