How to Make Electricity From Wasted Energy

March 12th, 2009 by Sarah Lozanova

Energy efficiency is low hanging fruit in the clean energy movement. Low-grade waste heat may not have the allure of shiny solar panels or a row of wind turbines, but it presents an opportunity that is too good for Michael Newell, CEO of Ener-G-Rotors to pass up. The company is developing a product that generates electricity from low-grade waste heat.

“We are making electricity from a free fuel and not using a fossil fuel,” Michael Newell said this week in an interview with TriplePundit. “Every kilowatt you are generating from our system is a kilowatt you don’t need from fossil fuels.”

The generator is fed with hot water, steam, or steam condensate between 150 and 400 degrees F. There are currently other products on the market that are suitable for higher temperature applications, but the low-grade waste heat market has been largely untapped. Not surprisingly, Ener-G-Rotors received an award for the Most Promising Technology last week at the CleanTech Forum XXI in San Francisco.

The 5 kw unit is currently in the beta phase. The company hopes the product will be complete at the end of the year and then they can ramp up production next year. They also plan to scale-up to a 50 kw product for industrial use, which the company wants to deploy next year.

Eventually the products may range in size from 1 to 150 kw in capacity and be suitable for a variety of settings, from residential to industrial applications.

Large-scale Applications

Chemical manufacturing plants, combined heat and power plants, paper mills, and oil and gas companies commonly have low-grade heat as a by-product. This energy goes to waste or in the worst-case scenario the company pays to cool it.

Michael Newell estimates that 15 to 20 percent of all the energy used in the US is lost just to low-grade waste heat. This presents a wonderful opportunity that is too good to pass up.

Ener-G-Rotors expects their 50 kw product to have a payback period of less than three years for most applications. Installation is relatively simple and maintenance is minimal.

Small-scale Applications

This product is compatible with solar thermal or geothermal installations and will likely be manufactured in 1 to 5 kw sizes. The payback period for smaller applications will be much longer than in industrial-scale applications, with off-grid use as a possible exception.

The Technology

“We bring heat into a heat exchanger, where there is a working fluid, a refrigerant,” explains Michael Newell. “The heat boils that refrigerant. We take the energy from the heat source coming in and transfer it to the refrigerant and that goes to the expander. The energy causes rotary motion that drives the generator. The working fluid is cooled back to a liquid.”

Organic rankine cycle technology is not new. The first prototype was displayed by Israeli scientists in 1961. Michael Newell said that the innovation that Ener-G-Rotors brings is efficiency, durability, and more favorable economics.

Good timing is always a key component for a product coming to the market. Although the cost of energy has dipped and many companies are not eager to spend money right now, companies are still happy to save energy.









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