For installers
A retrofit you can calculate and quote
The pressure exchanger replaces the expansion valve in your client's existing installation. The compressor, heat exchangers, refrigerant and charge stay as they are. The calculator gives you the payback time to put in front of your client.
Already done once
Retrofit pilot on an office heat pump at The Green Village
Seven months on a real installation. Installer Warmtebouw, who installed the existing heat pump, carried out the retrofit; heat pump specialist IBK supported the system engineering. The device integrated into a heat pump that was never designed for it, and ran.
Calculator for installers
How soon does it pay back for your client?
For industrial heat pumps and refrigeration plants from 100 kW. Check whether the installation fits, describe it, and enter the investment. The calculator gives the payback time, the saving per year and over the remaining life, and a report you can hand to your client.
Example results
The interactive calculator needs JavaScript. These example installations show the annual saving the model gives; the payback needs the price of the pressure exchanger, which we quote per installation.
| Refrigerant | Evaporating / condensing | Duty | COP without → with | Cost saving |
|---|---|---|---|---|
| Ammonia (R717) | -33 / 7 °C | 500 kW × 8,000 h/yr | 3.06 → 3.15 | €6,962 €/yr |
| CO₂ (R744, subcritical) | -35 / 10 °C | 300 kW × 8,000 h/yr | 2.28 → 2.55 | €20,375 €/yr |
| Butane (R600) | 30 / 80 °C | 1,000 kW × 7,000 h/yr | 3.04 → 3.41 | €44,524 €/yr |
Results
Send us the schematic, we will run the numbers
This calculator models a single-stage subcritical cycle with a natural refrigerant. For two-stage and cascade systems, transcritical CO₂ and other refrigerants we assess the potential case by case. Send us the system schematic and operating point and we will calculate it for your client's installation.
Send us the schematicThis combination is outside the modelled single-stage range for this refrigerant. Lower the condensing temperature or raise the evaporating temperature.
Payback time
– years
Saving per year
- – Cost saving €/yr
- – Electricity saved MWh/yr
Over the remaining life
- –
- – Net present value
- – Internal rate of return
Cumulative cash flow
- – Freed grid capacity kW
- – CO₂ reduction t CO₂/yr
Less electrical power for the same duty, which helps where the grid connection is full.
Sensitivity
| Running hours | |||
|---|---|---|---|
| Electricity price | |||
Sends us this scenario. We reply with a quote, or tell you plainly if it does not pay off for this installation.
How is this calculated?
For each refrigerant we simulate a full subcritical vapour-compression cycle with CoolProp, once with an expansion valve and once with the Expantec® pressure exchanger, on a 2 K grid of evaporating and condensing temperature; the calculator interpolates between grid points. The heating COP is exactly the cooling COP plus one. The compressor runs at 61% and the pressure exchanger at 80% isentropic efficiency. Each refrigerant's data ends where its single-stage cycle drops below a cooling COP of 1, or reaches the critical point. Electricity per year is duty × running hours ÷ COP; the saving is the difference with and without.
Net investment: pressure exchanger + installation hours × hourly rate + downtime − subsidy (a percentage applies to the pressure exchanger and installation). Simple payback: net investment ÷ first-year saving. With a price rise, the saving grows by that percentage a year; with a discount rate, each year is discounted; the adjusted payback is when the cumulative cash flow turns positive. Net present value: the discounted cumulative cash flow at the end of the remaining life. Internal rate of return: the discount rate at which that value is zero. Sensitivity: simple payback with electricity price and running hours each 20% lower or higher. Freed grid capacity: duty ÷ COP without − duty ÷ COP with.
Indicative only, based on modelled assumptions and the figures entered. Actual results depend on the installation. No guarantee is given or implied.
The test rig behind the model
The proof-of-concept was built and successfully tested in Delft between October 2024 and March 2025. See the technology.