Green is good

Environmental awareness has become part of the fabric of our society. And while we still have a very long way to go, there's more of an effort than ever to make the products we use and consume more environmentally friendly. Compressors and generators supply much of the power on today's jobsites, so manufacturers' efforts to design and build greener machines go a long way toward ensuring cleaner and greener jobsites.

"Manufacturers are putting a great deal of effort into making equipment more environmentally friendly - and with compressors, that focus is primarily on noise reduction and fuel efficiency," says Chance Chartters, direct accounts manager, Mobilair, Kaeser Compressors.

As most are aware, EPA regulations for diesel engines have gotten much more strict over the past decade and are due to get tighter still in 2008 as Tier III/Tier IV interim regulations go into effect. According to Todd Howe, product marketing manager for generators at Ingersoll Rand, this presents a formidable challenge to manufacturers who aim to build energy-efficient, quiet and compact compressors and generators.

For example, Howe says, new EPA-compliant engines are not usually "drop-in" replacements for their predecessors. Often, the new engines mount differently and require different plumbing and wiring. As a result, the entire product can require a redesign to incorporate the new engine.

With each [EPA] Tier change, the engines run hotter, so the cooling systems in the machines get bigger, the machines themselves get louder and so on. Balancing all the various design objectives keeps engineers very busy, Howe says.

What's more, he says, is that the electronic controls in the new engines have increased in complexity, making it more difficult to interface them with the machine's electronic controls which the customer uses.

Marc James, product marketing manager for compressors at Ingersoll Rand, notes that the complexity of engine controls is a challenge but comes with some positive side effects too. Since engines have become more electronic, it allows manufacturers to develop the potential for better diagnostic and troubleshooting features.

Fuel for thought
Unfortunately, cleaner-burning engines are not necessarily more fuel efficient. In fact, OEMs say that between Tier I and Tier II, fuel efficiency actually went down rather significantly. Engine designers have worked hard to maintain fuel efficiency while reducing emissions, but haven't been able to improve it.

"For manufacturers, cleaner-burning engines have reduced NOx and particulates, but they run hotter and use more fuel," says Marc Leupi, product manager, utility equipment at Wacker Corp. "Then the challenge becomes how to quiet the unit but keep enough cooling air, because now we have to cool a hotter-running engine in the same tight enclosure. The effect is it increases the manufacturing cost. There's a lot more complexity to the equipment, but it's the same product."

Structurally speaking
The way compressor and generator enclosures are designed and built has a large effect on the machines' environmental friendliness.

"Noise is the most important customer attribute with regard to generators," says Howe at Ingersoll Rand. "We keep the noise level down with design techniques that improve air flow through the packages without increasing the noise."

Both compressors and generators are generally kept quiet with the use of additional foam insulation and thicker sheet metal, but there is always room for improvement.

"Noise pollution can be significantly reduced by offering a fully enclosed package with a solid floor," explains Chartters. "Our [compressor] enclosure includes not only a solid-steel floor, but 2.5 inches of sound-dampening foam for maximum sound attenuation."

He continues, "Having precision-machined airends also contributes to lower noise levels. Tighter tolerances and heavy-duty bearings designed for longevity provide smooth operation and lower vibrations in any compressor."

While noise levels on compressors and generators are not legislated at this time, quieter units do have a competitive advantage, Leupi says. "The quieter, the better," he says. "Quieter units can be more flexible and used for parties and in urban environments."

Chartters adds, "Especially in high-growth areas, we're seeing tighter quarters in construction zones. Developers and builders seeking to be good neighbors will want to minimize noise for the health and safety of their workers on site and for citizens in close proximity."

Another structural issue that isn't legislated yet in the United States but most likely will be is the use of fluid containment systems. This consists of sealing the bottom of the generator or compressor package so that in the event of fuel or oil leaks, the fluids will not contaminate the ground. This is vital on some jobsites which have to meet strict environmental standards, and it promises to be an issue on more and more sites as environmental restrictions increase. Right now, Howe says this feature is standard across Ingersoll Rand's mobile generator range.

Wacker also offers a spill containment option on its mobile generators, a choice Leupi says is becoming more and more popular, even for jobs that don't require such features.

"The spill containment option helps businesses mitigate risks," Leupi says. "Often, generators are rented to power pumps that maintain the ground water level at a jobsite, for example. If there was a fuel spill and the fluid got into the ground water, the [rental] company could face substantial cleanup costs. Spill containment systems are an insurance policy for prudent rental companies."

Worth the investment?
Few would argue with the need to be environmentally conscious when manufacturing generators and compressors, but will the added cost associated with the necessary technology sell?

"The challenge is educating rental companies about the benefits of quality and environmentally responsible [equipment]," says Chartters. "Investing in a durable unit that has been designed to reduce noise and provide oustanding fuel efficiency will pay for itself over time."

Portable power gets greener too
It's not just large mobile power sources that are affected by environmental regulations. Marc Leupi at Wacker Corp. says that California Air Resources Board (CARB) regulations for gas engines are creating challenges for small, portable generator manufacturers as well. In the case of smaller gas engines, the focus is mostly on

evaporative emissions which come from the gas cap, fuel tank and fuel line.

To meet 2008 CARB regulations on evaporative emissions, Wacker has designed its portable generators so that gasoline vapors from the vent cap are filtered through a carbon cannister. During engine operation, any captured vapors are recirculated back to the engine and burned, resulting in fewer emissions.

In addition, fuel tanks are being constructed of new plastics which are less permeable and allow fewer fumes to escape.