This section was edited by Executive Editor Harry Hutchinson.   

Geothermal Well to Wheels

A company developing geothermal power plants in the American West has more than doubled the orders it has placed for the UTC power-generation equipment it plans to use. At the same time, the company says it plans to use some of the electricity to charge a plug-in hybrid sport utility vehicle that it predicts will get 100 miles a gallon.

The developer, Raser Technologies of Provo, Utah, is currently working on eight sites where it expects to take advantage of groundwater under pressure at temperatures between 200 and 300°F.

To make use of temperatures in that range, Raser will install PureCycle power generating systems made by UTC Power in South Windsor, Conn.

Raser ordered 90 PureCycle systems in the fourth quarter last year and then followed up with orders for 110 more this spring. The 200 systems are expected to generate a total of 40 to 45 megawatts of electricity. 

This well site, where Raser Technologies plans to tap geothermal energy, is part of a tract in Beaver County, Utah. The company says it plans to develop as many as 15 sites a year for 10 to 15 years.

According to John Fox, general manager of the PureCycle program at UTC Power, the system uses heat from the water to expand a refrigerant, which drives a turbine connected to a generator. The PureCycle system is based on the design of a chiller developed by a sister company, Carrier Corp., but the cycle is run in reverse. He said parts for the PureCycle equipment are made at a Carrier factory. Both companies are owned by United Technologies Corp.

Fox said the geothermal systems have been tested at a site in Alaska, Chena Hot Springs, where they operate using water at 163°F. Part of the reason for the success using water at that temperature, he said, is the cold ambient coolant water in Alaska. The system uses the difference in temperature between the heating water and the coolant water.

Fox also pointed out that the geothermal plants, unlike photovoltaic arrays or wind farms, can generate power consistently around the clock.

Richard Putnam, Raser’s treasurer and executive in charge of investor relations, said the company “is building a pipeline of projects.” It has access to a total of 200,000 acres in six states—Washington, Oregon, Nevada, Utah, New Mexico, and California—and plans to develop 10 to 15 geo-thermal sites a year for each of the next 10 to 15 years.

He said Raser expects to bring its first site online at the end of this year and has entered 20-year power purchase agreements with the city of Anaheim, Calif. The city has agreed to buy the output of two of the geo- thermal sites, which will generate a total of 22 MW of electricity.

Putnam said that Raser has other power purchase agreements pending regulatory approvals and is in talks with prospective purchasers for more arrangements.

Raser has also developed a power system for a plug-in hybrid electric vehicle. The system, designed in cooperation with FEV Inc., a developer of engines and test systems based in Aachen, Germany, was introduced at a press conference in April. Raser calls its electric technology Symetron and says it is working with a large automobile manufacturer to build a plug-in hybrid SUV, which it expects to introduce later this year. The power system includes a 200 kW electric motor, a 100 kW generator, and an internal combustion engine that will be used only to power the generator.

Raser says the SUV, with three lithium-ion batteries, will have a range of 40 miles on electric power alone. So for local driving it probably wouldn’t use the engine at all. According to Putnam, the company has used the current standards that the federal government has established for mileage ratings, “and that is where we get the 100 mpg.”

The company claims a high level of efficiency for the motor, and has published on its Web site, Rasertech.com, results from tests conducted on an earlier model by Revolution Engineering Inc. of Livonia, Mich.

Raser said the motor, Symetron model P2, demonstrated peak torque of 567 newton-meters, or 420 foot-pounds. It was an ac induction motor 320 mm in diameter and 205 mm deep, about the same dimensions as the permanent magnet motor used in the current Toyota Prius. According to the Raser Web site, “The continuous torque was measured at 132 ft.-lbs. or 179 newton-meters, with peak efficiency of 92 percent.” The current model motor is called P-200.

Raser said it also hopes to develop high-efficiency industrial motors to help improve power plant efficiency.

According to Raser, the company plans to charge the plug-in hybrid with electricity from its geothermal sites in order to demonstrate a “well to wheels” strategy. 

Disaster Relief That Comes in a Tent
by Peter Easton

A research and development company specializing in advanced thermal control and energy conversion, Mainstream Engineering Corp., was recently awarded a contract by the U.S. Air Force to build a high-efficiency, integrated, Self Sufficient Tent system. The agreement is for $750,000 over two years.

Mainstream will integrate a multi- fuel, high-efficiency, low-noise generator, 5-ton environmental control unit, reverse-osmosis water purification system, user interface/power distribution panel, power conditioning electronics, and soft-walled shelter (tent) within a single trailer-mounted Self Sufficient Tent system. The contract calls for a demonstration of the complete system and life testing. The system will be available for production sale at the conclusion of the contract.

This tent system can be set up rapidly in remote locations, providing fast disaster relief and more mobile military deployments. According to the company, based in Rockledge, Fla., the high-reliability, high-efficiency components, ease of maintenance, and automated operation could also save thousands of man-hours per system per year in setup, maintenance, monitoring, and operation.

Among Mainstream’s areas of expertise are thermal control, energy conversion, turbomachinery, chemistry, and nanotechnology.

Pipeline Seals Mimic Blood Platelets
by Alan S. Brown

What do blood cells have to do with fixing holes in undersea oil pipelines? Everything, according to Brinker Technology Ltd. of Aberdeen, Scotland. The result is a technology that detects, seals, and signals the location of leaks in a single step.

The technology takes its cue from the body’s platelet-shaped blood cells. They find cuts and wounds by the simplest of methods: They are drawn to wounds where blood leaves the body the way hair or soaked toys move toward the drain in a bathtub. The disc-shaped blood cells eventually cover the gap and begin releasing chemicals that cause blood to clot.

Brinker’s platelets behave the same way. Engineers do not even need to know the exact location of the leak. Instead, they introduce them into a pipe upstream of the leak. The plastic platelets flow through the pipe until the current of fluid moving through the leak captures some of them. This pulls the platelets down to the leak. After the platelets cover the breach, the positive pressure differential of fluids moving through the pipeline locks them into place.

This sounds simple and elegant, but Brinker has put a lot of engineering into its platelets. According to sales engineer Klaire Evans: “Oil from different oil fields has different densities, so we formulate the platelets so they match the density of the oil in the pipeline. That way, they float in the liquid instead of sinking to the bottom or rising to the top.”

To make sure it makes the best possible match, Brinker uses computational fluid dynamics to model pipeline geometry, pressure, flow, viscosity, and density. This provides information on platelet dispersion and entrainment. Finite element analysis enables Brinker engineers to model the behavior of entrained platelets near a leak, and to determine whether they are strong enough to provide a good seal.

The company has also developed techniques to tag platelets using either radio frequency identification or radioactive isotopes. These enable remotely operated submersibles to pinpoint the location of the leak.

Brinker has tested its platelets with companies like Shell and BP on holes of 0.3 to 50 millimeters in diameter. It says the platelets will stay in position for 12 months or longer. This lets oil producers seal leaks within days and make permanent repairs at their leisure. 

Magnetic Cleanup

Filings and chips of ferrous metals have a way of turning up in hydraulic lines, HVAC systems, and other places where they can do harm. One way to remove them is to make use of their magnetic attraction to pull them out. The Electrodyne Co. in Cincinnati sells high-strength magnets under the name Plastalloy, which it recommends for the purpose.

According to the company, the magnets capture metal filings, chips, and other ferrous materials floating through drivetrains, hydraulic lines, HVAC systems, and metalworking equipment. Adding magnets to the system can extend the service life of the equipment and enhance the performance of filter elements, Electrodyne says. 

Attractive little things: Plastalloy can be fashioned into drain plugs or other forms to draw ferrous contaminants from process systems. 

Plastalloy products are rubber bonded strontium ferrite flexible magnets. Electrodyne says they can be bent, twisted, and flexed without loss of their high magnetic energy. The magnets can be produced as sheets, strips, or die-cut shapes.

The Plastalloy magnets are available in various configurations and can be custom designed. Electrodyne says the magnets work in temperatures up to 150°C. They are oil resistant, and are suitable for the extremes of automotive applications, as well as for off-road vehicles, hydraulic lines, metalworking applications, and fluid recirculation systems.

Face to Face With Heat

A better understanding of the dynamics of heat transfer between different materials, and a means to make heat cross barriers either faster or slower, can make a difference in a number of systems, including the composite materials and electronics used by the U.S. Air Force.

A group plans to study the behavior of thermal vibrations on the atomic level and hopes to develop technology that can enhance heat-transfer properties at interfaces. Mechanisms that block heat transfer would be useful to apply to thermal barrier coatings and thermoelectric energy conversion materials, while mechanisms that make for more efficient transfer of heat would be desirable for heat sinks.

The team, led by a University of Michigan mechanical engineer, has received a five-year, $6.8 million grant to take a detailed look at how thermal vibrations move from atoms of one material to those of another. The grant comes from the Air Force Office of Scientific Research under the Defense Department’s Multidisciplinary University Research Initiative.

The research group includes nine scientists and engineers from three universities—Michigan, Brown University, and the University of California, Santa Cruz. Kevin Pipe, an assistant professor in the University of Michigan’s Department of Mechanical Engineering, is the lead on the project.

A key tool in the group’s research will combine an ultrafast laser and X-rays. The laser will provide a heat pulse, and then X-ray diffraction will be used to image the movement of the heat pulse through a material. By tracking the X-ray diffraction pattern, researchers will be able to observe the behavior of atoms as heat vibrations cross the interface with a second material.

According to Pipe, the ability of electronic devices to shed heat is affected by the materials that are used to make them. Heat flowing between a silicon device and a diamond heat sink, for example, would have to bridge an “acoustic mismatch” caused by the different frequencies at which thermal vibrations occur in the two materials, Pipe said. Tuning interface physical or chemical structures may be needed to help heat to transfer more efficiently between materials that have such a thermal mismatch.

The researchers plan to use techniques of nanotechnology to re-engineer the surfaces of materials to control the flow of heat.

In addition to Pipe, the UM team includes materials science and engineering professors Rachel Goldman and John Kieffer, and assistant professor Max Shtein, as well as physics professor Roberto Merlin and associate professor David Reis. Other members of the team include physics professor Humphrey Maris and engineering professor Arto Nurmikko of Brown University and electrical engineering associate professor Ali Shakouri of UC Santa Cruz. 

$77.6 Billion Worth of Industrial Valves

A Cleveland-based market research firm predicts that global demand for industrial valves will increase 4.4 percent annually through 2011 to $77.6 billion.

According to the research firm, the Freedonia Group Inc., valve demand in the energy production sector will benefit from a pickup in primary energy consumption in mature markets like North America, as well as in developing valve markets such as Latin America. Growth in valve demand in the U.S., Japan, and Western Europe will trail the world average through 2011.

Growth will be much stronger in rapidly developing nations, such as China, Indonesia, Thailand, Malaysia, and India, according to Freedonia’s report, World Industrial Valves. More information about the study is available on the firm’s Web site, www. freedonia.com. 

Ozone Gets Good Word as Water Disinfectant
by Peter Easton

A Cambridge, Mass., engineering consulting firm, CDM, has partnered with Denver Water to determine that ozone is an effective and environmentally friendly alternative to the traditional chlorine-based method of disinfecting water mains. Water main disinfection is necessary to prevent waterborne disease outbreaks in the public water supply.

The three-year research study by CDM and Denver Water to evaluate ozone as a water main disinfectant was recognized by the American Academy of Environmental Engineers with an honor award in the research category.

The complex research project involved three stages: laboratory, pipe-loop testing, and full-scale field trials. The study proved that ozone is very efficient when combined with an innovative high-pressure spray wash pre-cleaning system, which targets the bacteria attached to pipe walls. Ozone is completely safe for the environment, converting into oxygen within one hour. It requires 50 percent of the labor needed for the equivalent chlorine method, resulting in reduced operating costs for pipeline disinfection. Ozone disinfection also saves time, taking 20 to 30 minutes, while chlorine-based disinfection is a 24-hour process and requires dechlorination, which can take an additional 24 hours.

Based on the research results, Denver Water has incorporated a trailer-mounted high-pressure pre-wash and ozone disinfection system into its standard distribution system disinfection processes. Several other utilities are now looking to implement these green technologies.

CDM is working with the American Water Works Association and the U.S. Environmental Protection Agency to establish ozone disinfection of water mains as a best practice. 

Study Assesses the Future of Desal-ination
by Alan S. Brown

Technology advances are making desalination a realistic option for increasing U.S. water supplies, but first researchers must further lower costs and energy use and minimize the process’s environmental impact, according to a new report from the National Research Council.

The study comes at a time when policy makers might be willing to listen. During the prolonged drought in the southeastern United States, communities restricted water use and some utilities had to reduce output at generating plants.

More than 97 percent of the Earth’s water is either seawater or brackish groundwater that is too salty for drinking or agriculture. Desalination could provide more than enough drinking water for heavily populated coastal areas, especially if power plants and manufacturers recycle more process and heating water.

The process supplies less than 0.4 percent of the potable water in the U.S. Yet desalination capacity grew about 40 percent between 2000 and 2005.

Most desalination plants use reverse osmosis, which forces water through a membrane to separate out most salts. Until recently, reverse osmosis was prohibitively expensive, but recent advances have lowered costs and energy use. Desalination uses about 10 times more energy than traditional surface water treatment.

The study believes that better water pretreatment to remove sediments and the development of permeable membranes could lower costs still further. Yet these improvements are unlikely to reduce energy costs by more than 15 percent. A most energy-efficient technology might be thermal desalination using low-grade industrial waste heat.

“Uncertainties about desalination’s environmental impacts are currently a significant barrier to its wider use, and research on these effects—and ways to lessen them—should be the top priority,” said Amy K. Zander, chair of the committee that wrote the report and a professor at Clarkson University in Potsdam, N.Y.

The report called for research to prevent saltwater intake systems from trapping fish and other animals, and to improve disposal of salty wastes after desalination.

The report recommends that the federal government continue to fund desalination at its current level of $25 million per year. It also proposes coordinating research through the White House Office of Science and Technology Policy. This would give programs greater strategic direction rather than running them through a variety of agencies.

The study also notes that even if engineers manage to lower desalination costs, water conservation will remain a less expensive option in most cases.

The study, Desalination: A National Perspective, was sponsored by the U.S. Bureau of Reclamation and U.S. Environmental Protection Agency. It is available at www.nap.edu.