Solutions
CO₂ heat pumps & domestic hot water circulation
Stable, efficient domestic hot water — cut compressor cycling and avoid electric or gas backup.
CO₂ heat pumps are highly efficient for domestic hot water — typically achieving a COP around 4 in large commercial buildings. But in real installations, low-consumption periods force frequent start–stop cycles and inefficient operation, and direct electric or gas backup often kicks in to avoid this — significantly reducing overall efficiency. The Thermal Box buffers the circulation loop with stable, ready-to-use heat: compressor run-time drops, mechanical wear falls, and a typical installation saves around 19 000 kWh of electricity per year per installed module.
Typical impact
CO₂ heat pumps & domestic hot water circulation- ~19 000 kWh/yr
- electricity saved
- COP ≈ 4
- from the CO₂ HP
- Stable
- DHW supply
The challenge
CO₂ heat pumps are highly efficient for DHW but suffer from frequent start-stop cycling in low-consumption periods, often triggering electric or gas backup that erodes overall efficiency.
The Cartesian outcome
The Thermal Box provides consistent, ready-to-use thermal energy for the circulation loop — cuts compressor cycling, removes the need for backup, and saves around 19 000 kWh / yr per installed module.
Best fit when…
- Commercial buildings with CO₂ HPs
- Hotels and apartment buildings with high DHW demand
- Sites with electric or gas backup
How it works
From signal to saving — every cycle.
- 01
Audit the DHW system
We profile DHW demand, circulation losses and current backup energy consumption.
- 02
Pick the PCM temperature
Typically PCM at 65 °C — covers DHW set-points with margin.
- 03
Integrate with the HP
The HP charges the Thermal Box at COP ≈ 4; the box covers circulation losses and low-load periods.
- 04
Verify the saving
Energy meter and dashboard track kWh saved vs. baseline with direct electric or gas backup.
FAQ
Common questions about co₂ heat pumps & domestic hot water circulation
Does it work with non-CO₂ heat pumps?
Yes — any heat pump that benefits from steadier load and fewer cycles will see improvements.
How much electricity do we really save?
Typical installations save ~19 000 kWh / yr per Thermal Box. Exact figures depend on baseline backup usage.
Does this work for apartment buildings?
Yes — anywhere with central DHW production, a circulation loop and a CO₂ heat pump.
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