August 2006 Mechanical Engineering Departments: Tech Focus, Pt. 2

This section was edited by Executive Editor Harry Hutchinson.

Fluid Handling and Fluid Power

Blow-Out Sale
by Jeffrey Winters

Looking for an efficiency edge, American Electric Power of Columbus, Ohio, has agreed to lease a system that will remove deposits from boiler heat transfer surfaces while the boiler is in operation.

The SHOCKSystem application has been developed by Pratt & Whitney, a company of Hartford-based United Technologies Corp. It uses a pulse detonation technology that was originally created for advanced aerospace propulsion. Combustion-driven detonation waves introduced during normal operation travel at supersonic speeds to scour surfaces of ash and other hard-to-remove material.

AEP will operate the system in one of its two 1,300 MW boilers at a coal-fired generating station in Rockport, Ind. In four days of operation, the utility reported that the system removed some 140 tons of ash. Boiler efficiency has also improved by more than 0.3 percent.

The boilers at the Rockport plant are among the largest in the world.

Financial terms of the agreement were not released. The SHOCKSystem was introduced by Pratt & Whitney in December 2005.

Power and Air
by Harry Hutchinson

A manufacturer of battery-free uninterruptible power supplies has come up with a system that uses compressed air to store energy. The company, Active Power Inc. in Austin, Texas, calls the product CoolAir DC, because it can not only provide backup power, but also vents cool air, which can be used to keep electronics from overheating during a power interruption.

Georgia State University in Atlanta has signed up for a CoolAir UPS system to protect a bank of critical servers in its Network Operations Center.

Active Power also makes systems that rely on flywheels for energy storage. According to the company's president, Jim Clishem, the company's UPS systems provide backup power to data centers and to semiconductor and pharmaceutical manufacturing operations. A UPS system can be used to bridge the time it takes for a backup generator set to kick in, or it can be used without a genset to power a graceful shutdown of equipment after a power failure. The system at Georgia State will be able to provide 80 kW for as long as 15 minutes.

Double duty: A compressed-air battery replacement system cools as it provides backup power.

The CoolAir system stores its energy as compressed air at 4,500 psi and as heat in an electrically heated thermal storage unit. During a power disruption, the air is released from the tank and passes through the thermal storage unit to acquire heat energy. The air drives a small expansion turbine to generate electric power. Because the air cools as it expands, the exhaust, which leaves the system at about 59¡F, can be used to keep electronics, such as data servers, from overheating when the conventional air conditioning system loses power.

The temperature of the exhaust stream is adjustable. The thermal and compressed air storage technology can replace the battery of any three-phase uninterruptible power supply, the company says. By itself the storage system costs $29,000, plus an annual maintenance fee starting at $1,800. Active Power says the system can be expected to last for 20 years, far longer than a bank of batteries. The company also makes the system available under various usage arrangements. A five-year plan, for instance, starts at $7,500 a year, according to Ashish Moondra, the product manager.

The manager of Georgia State's Network Operations Center, Jerry Allen, said the university is using the CoolAir system under an annual usage agreement. The school currently has 54 servers that store records ranging from registration and financial information to student grades. That system has a flywheel-based backup power supply.

The CoolAir system will be used to protect a new bank of servers that will eventually replace the current ones. At the conclusion of the contract year, the school can decide whether to send the CoolAir UPS back to Active Power or to use it with other servers at the center that are operating currently without backup power supplies.

Active Power also said it had received an order for CoolAir DC from a European maker of photovoltaic modules as a means of storing solar electric energy.

Steam Heat
by Peter Easton

The Babcock & Wilcox Co. will supply eight identical supercritical coal-fired boilers and selective catalytic reduction systems to TXU Corp.'s solid-fuel power generation program in Texas.

Expected revenue from the deal for Babcock & Wilcox exceeds $1 billion.

The eight boilers, each with a capacity of 858 MW, will be B&W supercritical Spiral Wound Universal Pressure units, the largest of this kind under construction in the United States to date, according to the company. The units will burn Powder River Basin coal.

The selective catalytic reduction systems will be installed to reduce nitrogen oxide emissions to below the levels required by federal and state environmental standards.

Design of the new boilers is currently under way at B&W's headquarters in Barberton, Ohio. B&W supplied its first supercritical boiler in 1957.

TXU Corp. is based in Dallas.

Smarter Tires
by Peter Easton

Van Hool NV has selected SmarTire Systems Inc. of Richmond, British Columbia, to supply its tire pressure and temperature monitoring systems on its buses and coaches.

Van Hool, based in Belgium, is one of Europe's largest independent bus manufacturers. The company exports 85 percent of its buses and coaches, 60 percent of them to Europe, and an average of 600 coaches a year to the United States.

The SmartWave tire pressure and temperature monitoring system provides drivers real-time information while their vehicles are in motion. At the push of a button, the SmarTire system displays each tire's temperature and pressure deviation. If the system detects a loss of air pressure or abnormally high tire temperature, a bright warning light automatically alerts the driver to the condition.

Van Hool NV produces 1,700 buses and coaches and 4,000 commercial vehicles per year.

SmarTire develops and markets proprietary advanced wireless sensing and control systems worldwide under the SmartWave trademark.

Inter- national Accent
by Peter Easton

How's this for some international manufacturing cooperation? A Michigan-based company, Visteon Corp., has begun to manufacture automotive climate control components and systems in Turkey. The new facility is operated by Visteon's Korean affiliate, Halla Climate Control Corp. Visteon owns 70 percent of the equity shares of Halla.

The plant, located in Gebze, manufactures and assembles heating, ventilation, and air-conditioning units and cooling modules for the subcompact Hyundai Accent. The Accent is produced by Hyundai's Turkish manufacturing operations in Izmit.

The new Visteon/Halla Climate Control plant currently employs about 150 people. It is expected to run at full production capacity by October 2006. Visteon plans to increase the production capacity in Turkey and is currently evaluating additional business opportunities.

Green Gas
by Michael Abrams

The military depends on FDECUs, or field deployable environmental control units, to keep portable shelters at a comfortable temperature as well as to make air breathable in chemically or biologically contaminated areas.

The current crop of FDECUs uses a refrigerant (called FHC 134A) that's safe for the ozone layer but has the potential to add to global warming—and it is banned in Europe. The Air Force hired Mainstream Engineering, in Rockledge, Fla., to find a more environmentally friendly coolant. The surprising result was propane.

The seeming drawback of using propane is that it is, of course, highly flammable. But the military is less concerned with flammability than it is with explosiveness. Propane, it turns out, is not explosive. Mainstream decided to make sure. "We filled up a heat exchanger and fired bullets into it," said Greg Cole, Mainstream's engineering director. "We fired 30-caliber, 180 grain bullets into a charged condenser coil."

As the experiment produced no explosion—or fire—propane was given the OK. "The Air Force told us they don't think it's a problem." Cole said. "They have things a lot more flammable than propane in the field."

Compared to 134A, which has a global warming potential of 1,725, propane's global warming potential is a mere 11. "What a lot of environmentalists fail to realize is that even though it might sound like you're replacing something with a greener refrigerant, if the efficiency is worse, it doesn't help you any because you still have to power these units," Cole said. "But propane is higher in efficiency as well."