ElectraTherm has completed the first in place testing of their waste heat to electricity unit at Southern Methodist University in Dallas, Texas. The ElectraTherm unit is a waste heat recovery unit that generates electricity. The heat to electricity unit uses temperatures as low as 200 degrees Fahrenheit. The first unit was installed by Gulf Coast Green Energy. Models are available from 20 to 50 kW and larger models to 1500 kW are in planning. This is important, as process waste heat is a huge unused resource. ElectraTherm is offering that the payback is short and the operating costs after investment recovery to be under $0.01 per kW/hr. While the efficiency isn’t discussed in percentages, the price to payback is very quick and the forward operating costs way down there. This is something to be on top of if you have a heat source.

The U.S Department of Energy is saying that some seven quadrillion Btus of waste heat is available for reuse. That’s lot of coal, gas, oil, and nuclear fuel not being used. A device that can work at temperatures and pressures where the primary work is completed and reintroduce the energy back for use is an important and highly worthwhile innovation.

ElectraTherms Green Machine Installed at SMU

The device is called the “Green Machine” and uses the company’s patented twin-screw expander for the energy block without any gearboxes or costly electronics to synchronize a turbine to a generator. Instead, the twin-screw layout uses inline process lubrication that eliminates oil pumps, filters, separator tanks and the parasitic loads and maintenance issues that exterior lubrication requires. The result is a reduced maintenance and extended service life of the device. Compared to turbines the twin-screw expander costs about 10% of what a turbine would require. (Link to twin screw compressor)

Interested company representatives and policymaking people may tour the installation at SMU during the Geothermal Energy Utilization Conference this June 17th and 18th courtesy of Gulf Coast Green Energy. (Details and contact information are in the linked pdf.)

Essentially the Green Machine is a heat recovery to electrical potential generator set. Operating from the heat remaining after fuel is used for a primary purpose the direction of exhaust or latent heat to the unit will drive the expander and in turn generate electricity. As the fuel cost is spent for the primary use the fuel cost is as a practical factor none, rather some part or factor of the original fuel cost is recovered in the value of the electrical load the unit powers. Thus, the calculation would have only the operating costs and the maintenance issues after recovering the initial purchase and installation expense. ElectraTherm is saying that payback can be 2 to 3 years, which is very quick, and that the ongoing expense is at or below $0.01 per kW/hr. This is compelling.

Liquid Supplied ElectraTherm Green Machine

The device dimensions as can be seen in the photo are also diminutive. With no combustion apparatus, the input is a diversion of existing heat management equipment from using fuels. This makes the units forklift sized, easy to place and position near heat sources and occupy less than 40 square feet even at sizes of 100 kWs.

The napkin numbers seem to match the quotes by ElectraTherm. At $0.10 per kW/hr, a 2-year payback looks possible and prices suggested at about $2,000 per kW seem practical. No fuel costs can do wonders to your planning budgets. With purchase offers numbering over 2100 in hand as of the last quotation, you might want to get lined up soon.

ElectraTherm offers an evaluation form on the website. The minimums are 100 gallons of fluid at 175 degrees F or gas temperatures about 400 degrees F at 7000 CFM on the hot side and condensing to below 80 degrees for 100 gallons a minute and 90 degrees at 7000 CFM. Not huge installations by any means. Add the seasonal ambient temperatures and humidity and ElectraTherm can send you estimates that are meaningful.

But this is just round one. The opportunity for the early adopter is just hard to resist. The higher your electricity rates – the better this gets. We can expect improvements over time in efficiency and smaller and larger units and inevitably competition that will drive to even better and lower cost secondary power generation.

About 2/3rds or more of the fuel used to generate electricity is lost. In industrial and commercial business and government installations and the larger buildings, there exist great plumes of heat that can be harnessed now. This is truly getting around the corner on efficiency and if you have the minimums, this very hard to ignore.

With 3 pages of professional descriptions of 11 people, ElectraTherm looks ready to answer the market’s call in some part. On the other hand, there is an almost immeasurable amount of waste heat being expelled every moment, making it hopeful that these folks can’t possibly keep up.

The other side is efficiency, so I humbly offer a metaphor of the “iceberg” of wasted energy in heat that the developed economies pour away into the atmosphere and off into space on a continuous basis. If these innovators have only managed a 10% gain, that is chopping off the top of the iceberg. But being an iceberg, when that 10% is recovered another lump will float up into view, for another chop from the next innovator and engineering genius. With ElectraTherm offering no mention about efficiency and a justifiable focus on payback, there is likely a lot more to be harvested.

The game is on – these folks have an insightful design of their technology to recover the energy in pressure step-downs from gas – a way to get back the stored compression energy, what could be next?


1 Comment so far

  1. Brian Moon on February 1, 2009 2:04 PM

    Thank you for such a detailed article on ElectraTherm’s technology. As a dealer of the ElectraTherm technology, Roughrider Power continues to find new and inovative applications for ET products throughout the Rocky Mountain area. We look forward to implementing our emission-free generators and further the goal of US energy independence.

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