Solutions
Thermal storage, six ways to pay for itself.
Every building has a thermal load. Cartesian helps you decouple production from consumption — so you can charge cheap, discharge smart, and free up grid capacity.
Solutions
One thermal battery, six ways to increase your thermal capacity.
Increase cooling capacity
Add chilling capacity to existing installations without upsizing chillers or compressors.
- +25% installed capacity
- No chiller upsize
- Quieter daytime operation
Increase heating capacity
Cover peak heating demand by storing thermal energy off-peak — keep your heat pump small.
- Avoid heat pump upsize
- Stable peak supply
- Lower OPEX
Reduce grid peak demand
Shift load away from peak hours and tariff windows to cut demand charges and grid stress.
- Lower kW demand charges
- Decouple from grid peaks
- Avoid grid upgrade fees
Unlock computing power for data centres
Free up cooling capacity for additional racks — without any expensive grid or chiller upgrade.
- Backup cooling support
- Better use of on-site PV
- Potential revenue from grid flexibility
Compact thermal storage for urban projects
A practical alternative when energy wells, noise limits or rooftop space rule out conventional storage.
- 5× less volume than water
- Silent operation
- Indoor or outdoor
CO₂ heat pumps & domestic hot water circulation
Stable, efficient domestic hot water — cut compressor cycling and avoid electric or gas backup.
- ~19 000 kWh saved / yr
- No electric backup
- Charging with COP ~4
- Improved seasonal performance
Common questions
Got questions about thermal storage?
From PCM chemistry and lifetime to indoor vs outdoor installs and typical payback — the answers are in the full FAQ.
Read all questionsWhat is thermal energy storage?
The term is used when storing energy as heat or cold, which can be released at a later stage. The heat or cold is usually stored when energy is cheap and then released when the heating or cooling demand is at a peak or the cost of energy is high.
What is PCM?
PCM means Phase Change Material and refers to any material that changes state, for example from solid to liquid, when reaching a certain temperature. This phase change enables large amounts of energy to be absorbed or released. Water is one PCM, storing cold at zero degrees Celsius by changing phase to ice. Cartesian uses a wide variety of other materials, such as bio-based waxes, to store heat or cold at different temperatures.
Is the Thermal Box and the PCM flammable?
For applications with HVAC systems, Cartesian's Thermal Box is not considered flammable. While some PCM might be flammable when they reach temperatures above 100 °C or more, the Thermal Box is designed to eliminate any risks of reaching flammability conditions in operations.
Are PCMs safe?
Cartesian offers only safe PCMs and primarily uses bio-based PCMs in the Thermal Box. The PCM will stay in the Thermal Box for its whole lifetime and is not consumed during operation. The Thermal Box is also designed to avoid any risk of PCM leakage.
Let's build the smarter grid