Energy efficient engine turns waste hot water into electricity

It can lead to reduced energy consumption and carbon emissions for thousands of enterprises: from sea freight transport to data centers.

Exergyn company based in Dublin, Ireland, plans to launch the first industrial tests of the technology next year.

According to estimates Exergyn heat loss from hot water in industrial processes on a global scale is about 2 times the amount of energy from annual oil and gas production in Saudi Arabia.

"The world is a lot of waste of hot water", says General Director Exergyn Alan Healy. "In most cases, companies actually spend the energy to cool it."
Cargo ships, for example, are usually pumped hot water from the engine around the vessel to cool it. And in data centers for cooling servers are consuming electricity fans. The discovery of effective ways of capturing and using this energy will reduce costs and will reduce carbon dioxide emissions.

Exergyn Drive uses special properties of the Nickel alloy and tin — nitinol. You can bend a piece of nitinol, but when heated it will return to its original shape. This property of "shape memory" makes nitinol are desirable in a wide range of applications, including medical devices, shatterproof sunglasses and Rovers of NASA.

It also has another unusual quality. Unlike most materials, the nitinol expands when cooled such as water, when it turns into ice.

"In the Universe quite a bit similar materials," says Mike Langdon, Director Exergyn product management.

These two properties are the basis of the engine Exergyn. Inside the device a beam of meter-long nitinol wires attached to the piston. Hot and cold water alternately bathe the wire every 10 seconds, forcing them to quickly expand and contract by 4 inches, moving the piston up and down. The hydraulic system converts power of a linear movement into a rotary movement which, in turn, actuates a generator. The engine produces 10 kilowatts of electricity from about 200 kW of heat energy in hot water wastes.

Perhaps it is not very efficient, but it's "free" energy that would otherwise be wasted. And often it is not just wasted: cooling waste water spent new energy and money.

The company has spent three years changing the design and materials so that he could work for millions of cycles. Last year it received 2.5 million euros from the Fund for Horizon 2020 the European Commission for taking technology to market, and currently the company is planning three commercial tests in 2017 in Dublin airport and two landfills. In all three cases, technology Exergyn will use warm water from 90°C or below, from the gas engine at the airport and from biogas generators at landfills for energy production in place.

In addition, by using waste heat from industrial plants, the company hopes that the engine can expand the market for geothermal energy. At the moment the production of electricity from geothermal sources in an economically efficient way requires very hot water at high flow rates. This usually means digging very deep wells with a wide diameter, which greatly increases drilling costs. Langdon says the technology Exergyn allows you to use a wider range of geothermal sites, because it works with water at lower temperatures and flow.

John Blaus, former President of the Institution of Diesel and Gas Turbine Engineers, who know this technology, but has no stake in the company, agrees she has a wide range of applications. But he says only a small percentage of them will be viable if the company is unable to find a way to make the technology cheap. "It comes down, eventually, to commercial viability," he says.

Langdon says that a combination of the lack of fuel costs and mechanical simplicity of the machine promises that Exergyn will be able to reduce costs. He said that currently can generate electricity for 40£ per MWhr (MW) — cheaper than gas and coal. published



Source: ecotechnology


See also

New and interesting