At Chillventa 2026 in Nuremberg five-year-old German company Adsorbus launched its adsorption chiller, called heatChiller, which uses water (R718) as the refrigerant for industrial and data center cooling.
Unlike competing water-based adsorption chillers, Adsorbus is the first to employ an adsorption material called MOF (metal organic framework), which is a hybrid crystal covalent structure created by reacting organic molecules with metal ions.
Encased in a shell-and-tube heat exchanger, MOF rings are used to adsorb and release water vapor, generating chilled water down to 6°C (43°F) at cooling capacities from 10kW to 3MW (2.8 to 853TR). It leverages a hot-water heat source to cause the MOF to release its water vapor.
Since it does not use compressors, the heatChiller requires up to 80% less electricity annually than a compressor-based chiller and can reduce the electrical peak load by around half, according to Adsorbus.
“Adsorption technology is not new but what we are doing is completely new because we have a new material, MOF,” said Hendrik Gillert, head of sales for Adsorbus. He spoke about the system to NaturalRefrigerants.com at the company’s booth at Chillventa 2026, where a heatChiller unit, with a capacity of 20 to 30kW (5.7 to 8.5TR), was on display.
Adsorbus plans to start delivery of the heatChiller in the first quarter of 2027, with installations at a data center and industry, said Gillert.
Adsorption technology is not new but what we are doing is completely new because we have a new material, MOF.
Hendrik Gillert, head of sales for Adsorbus
The MOF material, which remains unchanged in this process, allows Adsorbus to use a hot water source as low as 50°C (122°F) said Gillert, adding, “Normally, I would say it's 65 or 70°C (149 or 158°F) for an adsorption chiller.” In addition MOF is highly scalable, allowing the company to build larger heat exchangers for it that support higher cooling capacities.
Gillert noted that adsorption technology is effective up to 35°C (95°F) ambient temperature, at which point it could be supplemented by a conventional chiller system. Alternatively, adiabatic condensers could be employed.
Other water-based chillers on the market, from York and Yazaki Energy Systems use absorption technology with lithium bromide solutions as an absorbent.
How it works
In a schematic on its website, Adsorbus outlined how the heatChiller works. It uses two MOF-equipped adsorbers, which alternate between adsorbing and regenerating water vapor. All the water used is contained in a circulating loop.
Evaporator
Here, under vacuum, water evaporates at just a few degrees Celsius, drawing heat from water that is chilled and delivered to the end user.
Adsorber (in adsorption mode)
The dry sorption material draws in water vapor from the evaporator, thereby maintaining the vacuum there. It is cooled with water from a separate dry cooler.
Adsorber (in regenerating mode)
Hot water from an outside heat source flows through the sorption material, releasing the bound water, which flows to the condenser.
Condenser
This is where the water vapor from the regenerating adsorber condenses, cooled by the dry cooler. The condensate flows back into the evaporator.
