Waste heat to power refrigeration

Absorption chillers are thermal machines that allows to obtain cold from heat.
This special kind of chillers are usually machines of a high power capacity, employed in conditioning plants or industrial plants with significant thermal duties, and most of all constantly present. That’s because these machines employ a delicate thermal cycle. The application are mostly in the HVAC sector, both for residential and industrial conditioning.

But there are also machines with lower power capacities on the market, allowing to operate both in conditioning and production processes applications, being able to reach temperatures of -10° C.

Those are machines produced by Robur, and Italian company that acquired many years ago the patent of this technology from an American company. These are in fact small size absorption refrigerators. The standard range of these machines employs a direct fired burner which provides the heat required to trigger the thermal cycle for cold production.

A very interesting and smart idea that fascinated me is to leverage waste heat coming from industrial production to start that same thermal cycle. The company has in fact modified its machines to integrate a sort of heat exchanger, which allows to work using waste heat coming from industrial processes, waste steam or diathermic oil at the end of a process.

The interesting thing is the extension of an energy recovery approach for the production of cold, leveraging energy that otherwise should be lost and dissipated.
The only limit I see here is that this application requires waste heat at very high temperature levels, between 190° C and 220° C. And it’s not easy to find waste heat at this temperature, but in case it is available the solution becomes surely extremely interesting and intriguing.

I’m thinking about applications where there is a continuous generation of waste heat, allowing the continuous production of cold. A kind of solution that could then be very interesting in a wide variety of applications, such as on waste fumes from cogeneration plants, or fumes coming from steel industries of metallurgy plants, where high amounts of high quality energy is available, meaning high temperature waste heat.

Subscribe here to our Tempco Newsletter – Solid Temperature.