On-Site Magazine

Generating efficiency

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December 1, 2012 by Corinne Lynds

For most of us, discussing the finer details of generator advancements does not make for the most titillating of conversations. There are, however, a few key points that all contractors need to stay abreast of. 

The biggest difference you’ll notice the next time you’re out shopping for a generator is cost! The price tag on these jobsite staples could go up by as much as 35 to 45 per cent next year. That massive increase is the result of Tier 4 standards that came into effect on January 16, 2012 and apply to engines manufactured on and after that date. As in the U.S., these new engine emissions requirements have necessitated dramatic changes in the overall design of generators.

As such, manufacturers are hard at work updating older models. This is no small challenge. Not only do the engines need to change, but so does piping for the intake and the exhaust. The engine  dimensions change too, a DPF (diesel particulate filter) needs to be added, and both affect the outer frame.

“Everything gets affected,” says Mike Marion, product and business development manager at Atlas Copco. “If I had 10 engineers in our department working on generators, I bet you six or seven of them are working on engine emissions.”

John Garcia, generator development manager at Doosan Portable Power agrees, emission reductions have significantly impacted overall design. “Mobile generator compartments or boxes have to be able to handle the high heat rejection from new engines, as well as provide room for new diesel oxy catalyst and diesel particulate filters used for final cleaning of the new engines.”

Additionally, manufacturers are trying to ensure those new designs include maximum fuel capacity and quiet operation, as well as ease of operator control.

Fluid containment
It’s no surprise that emissions reduction is the primary focus for generator manufacturers, but according to Marion, operators are also concerned about another environmental aspect. “Customers are starting to ask us: ‘Do your machines have 110 per cent fluid containment?’”

It’s a good question. It’s not at all unusual to have environmentalists poking around jobsites these days, and construction equipment dripping engine fluids is the express route to bad press.

To address concerns of punctured fuel tanks or fluid leaks in the engine, manufacturers are building fluid containment into the frame. It is essentially a fluid tub, so anything that is inside the frame—engine fluents, coolant, engine oil—would actually come down and land in that containment tub.

Marion explains there are plugs in the tub to drain out fluids, and the system is designed to manage oil changes as well. “What we do is remote mount. Basically, at the bottom of the oil pan we run a tube to a drain point, then if it’s coolant or engine fluid, bring all of that to a central fluid point, so you just have to unscrew the pipe plug and then open a valve on the engine plug to drain the oil out. It’s the same if there’s a fuel failure for some reason and it drains into the tub.”

Dual-wall tanks are another strategy for fuel containment that has been around for years. Doosan Portable Power offers rugged units with this feature. Essentially it’s two layers of steel, so if the outer wall is punctured, the inner wall still safely contains the fluids. This same strategy is used for massive liquid storage containers.

In control
Beyond environmental considerations, contractors want generators with efficient and simple controls. Ease of use is especially important in the rental industry, where contractors are not specifically trained on the equipment.

“They just want to walk up to it, push a button and know that they have power at the plug,” says Marion. “That’s all they care about, they don’t care if the DPF is going into regeneration mode.”

For most average construction jobs, plug and go is perfect, but for some of the larger projects by big companies such as Aecon or PCL, more complex controls may be required.

On a big jobsite, generators are often used for a multitude of applications large and small. Sometimes the output power capacity of standard generator units available in the market may greatly exceed your minimum requirement, or at the other end of the scale, fall short of your maximum requirement. It is in these situations where paralleling generators might be the ideal solution.

The easiest way to setup a parallel system is to use generators that are exactly alike, or at least have the same output rating and alternator pitch. Another flexible approach to backing up your power requirements is to have two or more generators of variable output. In either scenario, these can be connected in parallel with paralleling switchgear to achieve maximum output during peak requirement or the desired minimal output during other times.

Until recently, many contractors both large and small have refrained from parallel operation of generator sets because it was perceived as too dangerous and complicated. With the introduction of sophisticated integrated digital control technologies, it has now become much easier to operate systems in parallel and benefit from the additional advantages they provide.

Before you buy
There are several key questions that a contractor should ask before forking over the cash for a new generator—big or small. However, before asking any questions of the dealer or manufacturer, it’s a good idea to start by clearly defining what your requirements are. What applications are you going to use the generator for? In what climate? Under what conditions? How much power do you need? Would paralleling make sense for your applications?

Once you have nailed down these basic details, Garcia recommends asking the dealer or manufacturer: “Does the unit have an AC alternator (the part that makes electricity) that can provide SKVA (or motor starting capability) and still maintain high overload capabilities to protect the generator and whatever load it’s running?”

Work out the numbers and specs, but also keep the environment in mind. Make sure the machine you buy meets emissions regulations in the countries that you plan to operate it in. This is especially important for contractors that work on projects north and south of the border. Marion warns: “Make sure whichever manufacturer you go with has a good parts distribution network and serviceability in the area where you will be using the machine.”

Whether you buy or lease this equipment, being aware of changing technology and industry regulations will enable you to choose the most cost effective and safe equipment for your future jobs.

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