AS/NZS 5125.1 Report Review | Knowledge Base

The AS/NZS 5125.1 performance test report is the primary input for TRNSYS modelling. Many errors are subtle and only surface when regression outputs are used in the model — catching them at this stage avoids costly remodelling and regulator queries.

Work through the checks below before accepting a report.

1. Identity and Component Checks

Confirm that the names and descriptions in the 5125.1 report match the technical data sheet (TDS):

Tank model name
Volume
Tank standing heat loss (the AS/NZS 4692 result)
Evaporator area / flow rate
Compressor details (make, model, refrigerant)

2. Sensor Configuration

Sensor errors are common and silently invalidate all downstream calculations.

Sensor positions must be verified against the tank schematic before submission. Mismatches between the position drawing and the schematic (e.g. minus-plus vs plus-plus configuration) invalidate the Tw calculation and all downstream correlations.
T1 sensor height must be physically possible given the total tank height. A stated sensor height exceeding the total tank height is an immediate flag that the schematic and sensor data have not been cross-checked.
If T6 is consistently the hottest sensor across all test conditions, the sensors have almost certainly been mislabelled. A bottom sensor reading higher than all others across every test condition is not a product quirk — it means the lab has mapped the wrong channel to T6. Tw and all correlations must be recalculated once corrected.
Sensor ordering is not always simply highest-to-lowest temperature — it depends on the product’s coil position and tank geometry. The lab must physically verify which sensor maps to which data channel rather than assuming a fixed order.

3. Test Conditions

Check the temperature ranges in the 1-minute data for each condition.

TC5 — Low temperature test:

Air temperature < 10°C
Relative humidity 80–90%
Initial water temperature < 10°C, heated up to the maximum heat pump operating temperature (highest required set point, > 60°C)

TC2 — Performance test:

Air temperature 18–20°C
Relative humidity 60–70%
Initial water temperature < 15°C, heated up to the maximum heat pump operating temperature (highest required set point, > 60°C)

4. Raw Data Processing

When a test crosses midnight, the processing code must detect the date change and add 24 hours to subsequent timestamps. Failing to do this produces a negative time duration and therefore a negative calculated power — an obvious error that should be caught before submission.
Date jumps within a single test (e.g. rolling back to the prior year, or jumping forward by weeks) are data entry errors that propagate through all power and energy calculations. Each test condition file should be checked for timestamp continuity before any calculations are run.
The average power shown in the summary tables must be consistent with what is visible in the minute-by-minute graphs. A table showing ~210 W when the graph shows power immediately exceeding 400 W means something is wrong with either the TPP boundaries or the energy meter reading used.

5. Test Point Periods (TPPs)

The test start temperature, TPP1 start temperature, and TPP1 average temperature are three distinct values. Conflating them makes it impossible for an auditor to verify whether the Cl 4.2 distribution requirements have been met. All three must be clearly reported.
The final TPP must achieve the full 5.0–5.5 K temperature rise required by the standard. A short final TPP is not a minor formatting issue — it means the test did not comply.
Presenting overlapping TPPs in the low temperature data table makes it impossible to independently verify the declared start and end conditions. The table needs to show the actual initial and final tank temperatures and energy meter readings, not just the first and last TPP boundaries.
TPP exclusion requires two conditions to both be met: the point must be outside 3 standard deviations, and there must be a physical explanation such as a start-up transient. If excluding a point would break the Cl 4.2 distribution requirements, the correct approach is to keep it and document the investigation — not to delete it and leave the distribution non-compliant.

6. Thermal Capacity Calculation

Tank heat loss must be added in the thermal capacity equation, not subtracted. This is a sign error in the implementation — Q increases when the tank is losing heat to a cooler room, so the loss term adds to the apparent capacity. Verify the sign in the code directly.
Water density and specific heat must be recalculated as temperature-dependent values for each individual TPP using that period’s average tank temperature. Using fixed constants (ρ = 1000, Cp = 4.18) for the entire test is non-compliant with Appendix C and introduces a systematic error that grows at higher and lower temperatures.
The MwCpw term must update with each TPP — computing it once at a fixed reference temperature and reusing it throughout the test is incorrect.

7. COP and Regression Coefficients

Note which regression function is used — (Twi − Ta) or (Tw − Ta):
- Integral systems normally use Tw
- Stand-alone systems normally use Twi
Check that start-up and shut-down transients have not distorted average power calculations for the first and final TPPs. These periods should be excluded from the regression if the heat pump was visibly cycling rather than running continuously.
A high TC1 start temperature is acceptable under the standard but has a modelling consequence: it widens the temperature range over which the frosting penalty is applied in annual performance calculations. Flag this so it is not treated as a free choice.
Confirm the low temperature test reports: electric energy used / heat added to tank (MJ), and the lowest air temperature used for performance testing (Tifr).

8. Report Contents Checklist

The submitted report should contain all of the following:

Test period data for all test conditions
Maximum water temperatures obtained, corresponding to the maximum set point temperature required for daily or weekly heating
Regression coefficients for COP and Power
Stand-by electrical power measured for TC2 (expected range: approx 1–6 W)