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Example MEPS Simulation Report

This is the deliverable you receive from a MEPS simulation: the AS/NZS 5125.1 Appendix H test method run on a validated model of your unit, reported the way a laboratory would report it. The example below is a representative ~320 L integral R290 microchannel heat pump water heater.

About this example

A representative unit, not a specific product. The figures are a genuine engine output, anonymised for publication. The proposed GEMS MEPS COP level is not yet set, so no pass or fail is shown. Simulated predictions are not a substitute for accredited laboratory testing and must not be used for compliance or marketing claims.

1. Executive summary

Across the three test conditions the simulated 24-hr COP ranges 1.95 to 3.65 and the rated 24-hr load size ranges 4 to 9 (Table H.6.1). The headline deliverables are below.

Deliverable	Hot	Average	Cold
Max delivery V50 (L)	316.4	317.7	317.9
Max delivery V_del (L)	260.3	261.2	261.2
Recharge time t_RH_adj (min)	317.7	344.0	565.3
Rated 24-hr load size	9	4	4
24-hr load L_cycle (MJ)	85.0	38.0	38.0
24-hr COP_cycle	3.646	3.032	1.952

Headline deliverables by test condition — 24-hr COP, max-delivery V50 and recharge time across the Hot, Average and Cold conditions.

2. Product inputs and provenance

The parameters below define the simulated unit. They are read from the calibrated job specification, the same data the TRNSYS deck is built from, so the result is traceable to the model inputs.

Storage tank

Storage volume	328 L
Tank diameter	0.538 m
Heat-loss UA	7.85 kJ/hr·K
Nodes (model)	20
Aux element	0.00 kW

Heat pump and control

Set temperature	60.0 °C
Dead-band	10.0 K
Aux lock-out (Taux)	-7.0 °C
Max coil temp	61.0 °C
Standby	1.0 W
Frosting threshold (Tifr)	9.0 °C
Performance map	From AS/NZS 5125.1 test data

3. Method

The report simulates the AS/NZS 5125.1:2014 Amd 1:2026 Appendix H performance test method. For each climatic condition the model runs the full sequence: system heat-up, a pre-conditioning part draw-off and re-heat, a maximum draw-off (until the outlet falls to 50°C), a re-heat, then a 24-hr tapping cycle. The 24-hr load size is found by the standard's up and down search (Table H.6.1). Draws run at 9.5 kg/min, the set temperature is 60°C, and the cold supply is 10°C. The engine is a pure-Python re-implementation of the TRNSYS 15 TYPE 104 integral microchannel model, validated TRNSYS-equivalent for the AS/NZS 4234:2021 annual simulation, run here at a 6-second draw timestep.

Test condition	Hot	Average	Cold
Dry bulb (°C)	19	9	1
Wet bulb (°C)	13.41	8.00	0.00
Dew point (°C)	9.43	7.08	-1.11

4. Results

Reported in the format of AS/NZS 5125.1:2014 Amd 1:2026 Appendix H (Tables H.8.1 to H.8.5), across the Hot, Average and Cold test conditions.

Table H.8.1 — Product clock tested time and dates

Test time and date	Hot	Average	Cold
Start of H.5	0.00 h	0.00 h	0.00 h
End of H.5	16.35 h	17.56 h	28.12 h
Start of H.6	16.35 h	17.56 h	28.12 h
End of H.6	43.90 h	45.29 h	57.93 h

Simulated elapsed clock (hours from the start of system heat-up). A simulation has no wall-clock date.

Table H.8.2 — Calculated results

Deliverable	Variable	Unit	Hot	Average	Cold
Peak thermal load deliverable	V_del	Litres	260.3	261.2	261.2
	V₅₀	Litres	316.4	317.7	317.9
	E_del	kJ	364.3	367.2	365.6
	Q_{cut_in}	kJ	27778.9	27979.0	28184.4
	Q_del	kJ	52902.3	53127.4	53148.3
Total thermal recharge of water heater	E_RH	kJ	11771.8	12589.4	20520.2
	Q_RH	kJ	51015.7	51318.5	52015.3
	t_RH	min	320.50	345.00	565.00
	ΔQ_{t_loss}	kJ	-397.3	-151.5	33.1
	Q_ratio	%	99.52	99.82	100.04
	ΔQ_{t_adj}	kJ	4686.6	5318.8	5922.8
	E_adj	kJ	1545.0	1668.9	2737.2
	P_adj	kW	0.792	0.795	0.800
	F_adj	-	3.033	3.187	2.164
	t_{RH_adj}	min	317.74	344.00	565.32
	E_{RH_adj}	kJ	11640.9	12541.8	20535.5
24 hr tapping cycle performance	L_cycle	kJ	85000.0	38000.0	38000.0
	t_cycle	min	559.20	277.40	450.70
	Q_cycle	kJ	85712.9	38584.7	38690.6
	E_cycle	kJ	22301.2	11274.2	18065.5
	ΔQ_{t_cycle}	kJ	3670.5	4631.8	3804.9
	E_{cycle_adj}	kJ	23511.2	12727.5	19823.9
	t_{cycle_adj}	min	584.65	307.88	487.32
	COP_cycle	-	3.646	3.032	1.952

Table H.8.4 — Maximum draw-off flow rate, outlet water temperatures and time

Deliverable	Unit	Hot	Average	Cold
Time-averaged cold water supply flow rate	kg/s	0.1583	0.1583	0.1583
Cumulative time of maximum draw-off at which flow > 0 kg/s	s	1644	1650	1650
Time-averaged water outlet temperature of the water heater at which flow > 0 kg/s	°C	58.62	58.65	58.67
Maximum delivery temperature	°C	60.00	60.00	60.02

Table H.8.5 — Cumulative time of heater operation in 24 hr tapping cycle

Deliverable	Unit	Hot	Average	Cold
Minimum delivery temperature	°C	55.52	54.08	51.17
Average dry bulb temperature	°C	19.00	9.00	1.00
Average wet bulb temperature	°C	13.41	8.00	0.00
Time-averaged cold water supply flow rate	kg/s	0.1583	0.1583	0.1583

Test data by condition

For each condition: the recorded tank stratification at the end of each test stage (Table H.8.3), then the two continuous graphs over the full test sequence.

Click any chart to enlarge.

Hot condition (19 °C)

Table H.8.3 — Recorded stratified-tank temperatures at the end of each test stage

Deliverable	Test stage	T1	T2	T3	T4	T5	T6	Avg	Dur (min)
Maximum thermal delivery	Temperature of tank at the start of system heat-up	10.0	10.0	10.0	10.0	10.0	10.0	10.0	–
	System heat-up	60.0	60.0	60.0	60.0	60.0	60.0	60.0	420.5
	Pre-conditioning part draw-off	59.8	58.7	49.7	32.8	16.4	10.7	38.0	15.6
	Pre-conditioning re-heat	60.0	60.0	60.0	60.0	59.5	59.1	59.8	197.0
	Maximum draw-off	46.5	34.0	19.8	15.0	13.1	11.0	23.2	27.4
	Re-heat after maximum draw-off	60.0	60.0	60.0	60.0	60.0	60.0	60.0	320.5
24 hr tapping cycle performance	Temperature of tank at the start of system heat-up (if applicable)	–	–	–	–	–	–	–	–
	System heat-up (if applicable)	–	–	–	–	–	–	–	–
	Pre-conditioning part draw-off	59.8	58.7	49.8	32.8	16.4	10.7	38.0	15.6
	Pre-conditioning re-heat	60.0	60.0	60.0	60.0	59.5	59.1	59.8	197.0
	24 hr tapping cycle	57.6	57.6	57.6	57.5	57.0	55.4	57.1	1440.5

Hot condition (19 °C): system variables. Test-chamber conditions (dry and wet bulb), average tank temperature, cold-water inlet, heated water outlet, water flow and electrical power over the full test sequence; test stages marked.

Hot condition (19 °C): tank stratification. Water temperatures at the centroids of six equally-spaced tank segments, T1 (top) to T6 (bottom), with the delivered outlet Tout, over the full test sequence; test stages marked.

Average condition (9 °C)

Table H.8.3 — Recorded stratified-tank temperatures at the end of each test stage

Deliverable	Test stage	T1	T2	T3	T4	T5	T6	Avg	Dur (min)
Maximum thermal delivery	Temperature of tank at the start of system heat-up	10.0	10.0	10.0	10.0	10.0	10.0	10.0	–
	System heat-up	60.0	60.0	60.0	60.0	60.0	60.0	60.0	457.5
	Pre-conditioning part draw-off	59.8	58.7	49.7	32.8	16.3	10.7	38.0	15.6
	Pre-conditioning re-heat	60.0	60.0	60.0	60.0	59.8	59.6	59.9	208.0
	Maximum draw-off	46.4	33.6	19.5	14.7	12.9	10.9	23.0	27.5
	Re-heat after maximum draw-off	60.0	60.0	60.0	60.0	60.0	60.0	60.0	345.0
24 hr tapping cycle performance	Temperature of tank at the start of system heat-up (if applicable)	–	–	–	–	–	–	–	–
	System heat-up (if applicable)	–	–	–	–	–	–	–	–
	Pre-conditioning part draw-off	59.8	58.7	49.7	32.7	16.3	10.7	38.0	15.6
	Pre-conditioning re-heat	60.0	60.0	60.0	60.0	59.8	59.6	59.9	208.0
	24 hr tapping cycle	56.9	56.9	56.9	56.9	56.6	55.1	56.5	1440.3

Average condition (9 °C): system variables. Test-chamber conditions (dry and wet bulb), average tank temperature, cold-water inlet, heated water outlet, water flow and electrical power over the full test sequence; test stages marked.

Average condition (9 °C): tank stratification. Water temperatures at the centroids of six equally-spaced tank segments, T1 (top) to T6 (bottom), with the delivered outlet Tout, over the full test sequence; test stages marked.

Cold condition (1 °C)

Table H.8.3 — Recorded stratified-tank temperatures at the end of each test stage

Deliverable	Test stage	T1	T2	T3	T4	T5	T6	Avg	Dur (min)
Maximum thermal delivery	Temperature of tank at the start of system heat-up	10.0	10.0	10.0	10.0	10.0	10.0	10.0	–
	System heat-up	60.0	60.0	60.0	60.0	60.0	60.0	60.0	746.0
	Pre-conditioning part draw-off	59.8	58.6	49.6	32.7	16.2	10.6	37.9	15.6
	Pre-conditioning re-heat	60.0	60.0	60.0	60.0	60.0	60.0	60.0	333.0
	Maximum draw-off	46.2	33.1	18.7	14.0	12.3	10.7	22.5	27.5
	Re-heat after maximum draw-off	60.0	60.0	60.0	60.0	60.0	60.0	60.0	565.0
24 hr tapping cycle performance	Temperature of tank at the start of system heat-up (if applicable)	–	–	–	–	–	–	–	–
	System heat-up (if applicable)	–	–	–	–	–	–	–	–
	Pre-conditioning part draw-off	59.8	58.6	49.6	32.6	16.2	10.6	37.9	15.6
	Pre-conditioning re-heat	60.0	60.0	60.0	60.0	60.0	60.0	60.0	333.0
	24 hr tapping cycle	57.2	57.2	57.3	57.3	57.3	57.3	57.3	1440.1

Cold condition (1 °C): system variables. Test-chamber conditions (dry and wet bulb), average tank temperature, cold-water inlet, heated water outlet, water flow and electrical power over the full test sequence; test stages marked.

Cold condition (1 °C): tank stratification. Water temperatures at the centroids of six equally-spaced tank segments, T1 (top) to T6 (bottom), with the delivered outlet Tout, over the full test sequence; test stages marked.

5. Discussion

The simulated 24-hr COP ranges 1.95 to 3.65 across the test conditions. COP decreases from the hot to the cold condition, as expected: lower air temperature reduces heat-pump efficiency and brings in the frosting penalty. The cold condition (1 °C) COP is 46% below the hot condition.

Recharge time after the maximum draw-off rises from 318 min (hot) to 565 min (cold), driven by the lower heat-pump capacity at low air temperature. The rated 24-hr load size falls from 9 at the warmer condition to 4 at the cold condition: at 1 °C the reduced capacity limits the daily load the unit can deliver while keeping every draw above 50 °C.

Delivery temperature is the most sensitive quantity in the test. The model runs a fine 6-second draw timestep to capture it. These are simulated predictions of the Appendix H test, not lab measurements.

6. Conclusion

The simulated unit achieves a rated 24-hr load of size 4 to 9 (Table H.6.1) with a 24-hr COP of 1.95 to 3.65 across the conditions tested. These figures predict Appendix H performance from the model inputs and should be confirmed by accredited laboratory testing before use in any compliance or marketing claim.

7. Appendix

Sanity checks

All physics sanity checks passed: V_del ≤ V50 ≤ 2·Vt; recharge adjustment small; COP plausible and ordered Hot ≥ Average ≥ Cold.

References

AS/NZS 5125.1:2014 Amd 1:2026 Appendix H (test method, Clauses H.4 to H.8).
Engine: EnergyAE python-based HPWH simulation. Calculations per Clause H.7.
Simulated prediction of the AS/NZS 5125.1 Appendix H test method. Not a substitute for accredited laboratory testing.

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