This Engine Generates Electricity Using Waste Hot Water

A new engine converts waste hot water from industrial equipment into electricity.

Exergyn, a startup based in Dublin, Ireland, is planning to run the first industrial trials of the new energy-efficient engine by next year, New Scientist reports. The engine generates electricity from heated water that is left over from other equipment. According to co-founder and chief executive Alan Healy, waste hot water (low-grade waste heat or LGWH) from industrial processes amounts to about twice the energy in Saudi Arabia's oil and gas output per year.

"There's just so much waste hot water in the world," Healy told New Scientist. "In most cases [companies] are actually spending energy to cool it."

Cargo ships, for instance, pump LGWH from the engine around the vessel to cool it. Data centers use expensive cooling systems to disperse the heat coming from the servers. This inspired Exergyn to find a way to capture and make use of the wasted energy to reduce cost and at the same time cut global carbon emissions by 2 percent.

The engine, called Exergyn Drive, works by feeding off any steam of heated waste water already being produced by another device or equipment. The drive uses the properties of an alloy of nickel and titanium called nitinol. Inside, a bundle of meter-long nitinol wires is attached to a piston. Hot and cold water are flushed alternately over the wires every 10 seconds, which makes them expand and contract, causing the piston to move up and down. A hydraulic system turns the linear motion into turning motion that drives the generator.

The drive is capable of producing 10 kilowatts of electricity from around 200 kilowatts of thermal energy in the LGWH. While this might be small, the device still produces "free" energy that would have been wasted, the makers said.

"Our device can be retrofitted and plugged into these engines to produce extra power and electricity from the hot water pumping through the traditional engines," Healy said in a report by The Journal. He also added that the application could revolutionize the geothermal power industry and allow energy providers to produce electricity more efficiently.

Exergyn has recently been granted funding by the European Commission's Horizon 2020 Fund and is now planning three industrial tests in 2017 at the Dublin Airport and two landfill sites.