Heat in. Cold out. No compressor.
Adsorption cooling is a century-old thermodynamic cycle whose moment has finally arrived - because liquid-cooled AI racks now produce waste heat at exactly the temperature it needs.
Water is the refrigerant. Waste heat is the pump.
A sealed, near-vacuum vessel pairs a solid adsorbent with water. Water evaporates at low pressure - that evaporation is the cooling. The adsorbent soaks up the vapor; low-grade heat then drives the water back off, it condenses, and the cycle repeats. Two beds alternate so chilled water flows continuously. Zero-GWP refrigerant, essentially no moving parts, almost no maintenance.
Why zeolite-calcium-chloride composites.
Plain zeolite holds a lot of water but needs ~150°C to regenerate - too hot for waste heat. Silica gel regenerates cool but holds less. A salt-in-matrix composite - calcium chloride layered into a porous zeolite/silica host - does both: far more water per gram and a low regeneration temperature that matches warm-water DLC.
Composite COP and uptake figures above are drawn from peer-reviewed modeling and lab work, not yet a field-scale chiller - they are labeled modeled deliberately. Proving durability of the salt composite against leaching and corrosion under thousands of hydrothermal cycles is the core engineering we are doing.
Why now, not a decade ago: adsorption chillers need a heat source in the 50-95°C band. Air-cooled servers never delivered it. GB300-class liquid cooling does - NVIDIA warm-water DLC returns coolant around 45-65°C, and ~90% of rack heat is now captured to liquid. The waste stream and the driving requirement finally line up.
What adsorption is - and isn't - good at.
The trade-off we accept
Adsorption COP is thermal (0.2-0.6), well below a vapor-compression chiller's electrical COP of 3-6. But it runs on free waste heat, not grid electricity - so the right metric is displaced compressor kilowatts and avoided evaporative water, not raw COP.
Where it wins
Hot and water-stressed regions where dry coolers lose margin on 35°C+ days and evaporative water is the real constraint - plus trim and peak duty. That's where we deploy first, not temperate climates where dry coolers already coast.
Footprint is real
Adsorbent beds are bulky and batch-cyclic - individual units are modest capacity. We manifold rack/row modules rather than pretend a single vessel cools a hall.
A complement, not a rip-out
We sit on the DLC secondary loop beside the CDU. You keep your liquid cooling; we monetize the heat it currently throws away.
Want the deeper technical brief?
We'll walk your thermal team through the cycle, the composite data, and a site-specific model.