January 8, 2010

Construction Corner | Korky Koroluk

Hybrids make push into heavy equipment sector

It took a decade of research and development, but the first diesel-electric bulldozer has been delivered to a customer — and he loves it. It will, he says, save his company money.

A press handout marking the occasion called the tractor, manufactured by Caterpillar, the first bulldozer in the world to employ hybrid diesel-electric technology. Others are sure to follow. The tractor, designated the D7E, is now in full production, and Cat’s competitors are ramping up as well. In the United States, John Deere is close to having a hybrid ready for market. Others, including Komatsu, Volvo and New Holland, are experimenting with hybrid technologies in other heavy equipment. Whether they apply their technology to dozers remains to be seen.

There is a good deal of uncharted territory surrounding hybrid technology. Caterpillar has about 100 new patents on bits and pieces of its new tractor, for example. This was not a case of simply making a better diesel engine; it was a case of inventing a whole new power system.

The heart of the new machine is an improved diesel engine, but it doesn’t drive the tractor. Instead it drives a powerful electrical generator that produces the electrical power to operate the machine.

During its testing, prototypes typically showed 25- to 30-per-cent improvements in fuel efficiency, while improving productivity by moving more dirt per hour than the conventionally powered D7.

At about US$600,000, the D7E isn’t cheap, but the manufacturer believes the machine will pay for itself in about 2 years.

“It goes right to the bottom line,” said Dan Klingberg, of T. J. Lambrecht Construction, the firm that took delivery of the first machine. “It was one of the easiest decisions we ever made. This machine is going to save us money.”

At a time when more and more emphasis is placed on productivity in a tight economy, the arrival of new things like the D7E is good news — and if you look around a little bit, there is far more good news out there than you might think from reading the large papers or watching television.

For example, Weidlinger Associates, a structural engineering firm based in New York City, is developing durable hybrid solar roofing panels with integrated photovoltaic (PV) cells and thermoelectric materials that harvest the sun’s energy to produce both electricity and hot water for buildings.

They’re still in the prototype stage, but they are already making people sit up and take notice.

They have a clear protective cover over a layer of PV cells that converts the sun’s electromagnetic radiation into electricity. Then comes a layer of thermoelectric material that converts the sun’s heat into electricity.

Beneath that is a layer with a system of tubes to circulate water to cool the other layers, then carry heated water away. The bottom layer is simply reinforcing plastic.

The tubes are a crucial part of the design because PVs lose efficiency as they heat up. That has led many scientists to experiment with water cooling, but the idea of putting the heated water to good use is a nice added touch.

Physicists have understood the principle of thermoelectricity for a century, but the evolution of nanoengineering has enabled the creation of highly specialized materials like those used in Weidlinger’s panels.

The hoped-for result is hybrid roofing panels that deliver heat and hot water, while replacing much of the environmentally unfriendly roofing materials presently in use. Because, says a statement from the U.S. environment department, the panels “will be part of the building’s skin.”

Nanomaterials have already meant good news for the construction industry, but, as the Weidlinger project illustrates, there is more — much more — good news to come.

Korky Koroluk is an Ottawa-based freelance writer. Send comments to editor@dailycommercialnews.com

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