Research & Development

Physics-based HPWH diagnostics and tuning

EnergyAE now offers heat pump water heater (HPWH) diagnostics to improve your system performance with physics-based component-level modelling and in-house expertise.

Why do some heat pumps perform well and others don’t?

Heat pumps on the market show a wide range of performance: some perform well, others less so – see the figure alongside. So, for some manufacturers, significant performance gains and customer savings are available. However, heat pump design and optimisation is tricky, with highly interdependent components, where system performance can drop due to a range of factors: under-performing compressors, undersized heat exchangers, sub-optimal charge, and control strategy.

Box plot of residential HPWH seasonal COP distribution, Sydney, medium load: 25th percentile 3.12, median 3.53, mean 3.60, 75th percentile 4.06. EnergyAE internal analysis.

“Heat pump design and optimisation is tricky, with highly interdependent components.”

Left: system schematic of an integral HPWH showing compressor, condenser, expansion valve, and evaporator with water and air flows labelled. Right: R290 refrigerant cycle plotted on a temperature-entropy diagram at A19/W60 conditions, COP 4.18, showing subcooling and superheat.
System schematic (left) and an example R290 refrigerant cycle on a temperature–entropy diagram (right), at A19/W60 conditions, COP 4.18.

EnergyAE’s physics-based modelling and system diagnostics

EnergyAE can now help you generate detailed insights and optimise your products for each market using our new suite of physics-based modelling tools and in-house expertise. Existing modelling, such as AS/NZS 4234 compliance modelling, uses system testing data (AS/NZS 5125.1) to simulate annual performance. However, performance-increasing insights are limited to control settings, sensor placement and little more – because any change to components would require physical re-testing.

New component-level modelling lets us look inside your system and understand what is driving performance. Explore the simplified vapour-compression cycle viewer below to try it out.

AS/NZS 4234 modelling vs. what component diagnostics tells you

AS/NZS 4234 modelling Component-level diagnostics
Whole-system annual performance from test data Where in the system performance is being lost
Control settings, sensor placements Compressor, evaporator, condenser, charge, and control, individually
Setpoint temperature effects Root cause behind a low or inconsistent COP
Confirms the certificate outcome Explains why the outcome is what it is, and what to change

How we work together

We take your component specifications (compressor, evaporator, condenser, tank), control regime (EEV, frequency map), and testing data to build physics-based models to represent your system. We bench-mark your system performance against ideal performance, indicating where attention is needed. We work with you, advising where extra measurements are most valuable, to understand bottlenecks and increase your performance.

What we need from you

  • System schematics
  • Component specifications (compressor, evaporator, condenser, tank)
  • Control regime (EEV logic, compressor frequency map)
  • Testing data (we advise where extra measurement points are most valuable)

We can address:

  • Are heat exchangers undersized?
  • Is the system over or under-charged?
  • Are the control systems tuned optimally? Including temperature setpoints and compressor frequency maps
  • How should the tank be sized and the inlets/outlet and heat exchangers arranged?

Apply this to your product

Tell us where you think performance is being lost. We will tell you what we need and how the diagnostic would run.

Explore our vapour-compression cycle viewer

Explore some of the tools we use with our vapour-compression cycle viewer: adjust the operating conditions and see how the cycle, and its performance, respond (best viewed on desktop).