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Small energy fixes, BIG savings

There are ways to cut energy costs and usage that don’t involve parting with hard-earned money.


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March 26, 2010 by Canadian Plastics

Quick, simple machinery fixes can equal big energy bill savings.
Quick, simple machinery fixes can equal big energy bill savings.

There are ways to cut energy costs and usage that don’t involve parting with hard-earned money.

Remember the old adage that says you have to spend money to make money? It’s good advice, to be sure, but is it always true?

Maybe not.

Fact is, there are ways to improve your bottom line that don’t cost anything more than a few dollars and a few minutes of your time. Take energy costs. Rising energy prices are a concern for any plastics processor, especially–do we have to say it?–in today’s economic climate.

“Energy typically represents four to six per cent of a plastic processor’s total operating costs, and 12 to 15 per cent of its controllable costs,” said Graham Knowles, the consultant managing a recent Canadian Plastics Industry Association (CPIA) energy conservation outreach program. “Electricity usually accounts for 70 to 80 per cent of the total energy cost, so there’s no doubt it has a significant effect on the bottom line.”

“Controllable costs” are the key words here. Unlike, say, the price of resins, a processor has the power to determine a large part of its energy expenses. Investing in new energy-efficient processing equipment is one way to do it, of course–but implementing a replacement strategy for your old energy hogs can take time and money. There are plenty of ways, though, to save energy and trim utility bills simply by zeroing in on the equipment you already have.

START ME UP

As with so much else in life, knowledge is key in the quest to eliminate energy waste. Before anything else, understand how your company is billed for electrical cal power. The answer usually isn’t pretty. “Many commercial facilities are billed on a rate schedule typically set around the highest 15 minute power demand during a billing period,” said Mike Orto Ortolano, lano, head of renewable energy systems with consulting company Absolute Green Energy.

So far, so good, but a complete strategy goes beyond staggering your startups. What about reactive load compensation? Since the reactive load of a processing machine puts an extra load on the overhead lines, transformers, and power stations of the energy supplier’s power grid, compensation equipment is available for installation in the main distribution centre of a manufacturing facility. The goal is to ensure that the reactive power on the production floor is taken into account when planning the capacity of a company’s internal energy transfer network.

Armed with this bit of information, the smart strategy isn’t hard to figure out. “Changes with respect to startups of machines and facilities are an obvious low cost energy saving method,” Ortolano continued. “A facility’s billing charge can be reduced significantly by staggering the machine startup sequence after a shutdown instead of powering up all the machines in the same period.”

GOOD COMPENSATION

Problem is, low energy periods and performance peaks tend to alternate in a quick succession with injection molding machines, making conventional reactive load compensation systems less than ideal. Wittmann Battenfeld‘s EcoPower option for injection molding machines uses low maintenance semiconductor switches to activate a varying number of compensation levels, depending on the size of the drive unit. The compensation units are available for voltages from 230 to 480 V and frequencies of 50 or 60 Hz. Bottom line: The dimension of the power supply installation required on the shop floor can be downsized.

Fitting fixed-speed conventional AC motors with a variable-speed drive to deliver only the required energy load on auxiliary equipment is another good, inexpensive move. Motor control manufacturer Power Efficiency Corporation recently unveiled its E-Save technology, which uses a microprocessor and circuitry to sense the energy requirements of a motor. The voltage and current being fed to the motor are monitored and the motor is provided with the exact amount of energy that it needs, allowing the motor to maintain its rated speed and torque under variable loads.

According to Power Efficiency’s chairman and CEO Steve Strasser, after motor efficiency controls were installed on 25 granulators in flexible packager Berry Plastics’ Anaheim, Calif. facility, an independent audit determined the company reduced the kilowatts required by almost 45 per cent and racked up an annual saving of US$600 per granulator unit. “Power Efficiency is currently in the process of testing the E-Save technology on injection, blow molding and extrusion machines,” Strasser added.

KEEP IT HOT 

We’ve still only scratched the surface. Low cost technologies such as adding barrel insulation, insulating cooling water lines and repairing compressed air leaks can all have a quick payback and should be considered as part of any low cost energy reduction program.

“Heat escaping from a processing machine is energy the processor is paying for that’s simply being lost, but there are inexpensive ways of directing it back into the machine,” said Harry Kitz, president of Process Heaters Inc. “Ceramic band heaters, which have built-in ceramic fibre insulation, can be ordered beyond the standard one-quarter inch thick layer of insulation to provide double insulation.”

Kitz also suggested draping a simple insulating blanket over a processing unit. “Insulating blankets, like those available from Tempco Electric Heater Corporation, are ideal for water-cooled extruders and for most injection molding applications. They’re almost always a good idea for a machine startup, when heat is required very quickly.”

And while polymer processing makes up the bulk of energy costs, the lighting, heating and cooling energy required to operate a manufacturing facility are nothing to sneeze at, either. The good news? These costs are flexible, and can be trimmed with the right approach.

ASSESSING THE CPIA ASSESSMENTS

As part of the recent energy conservation outreach program undertaken by the CPIA, engineering consulting firm Hatch compiled a list of quick and inexpensive energy fixes. “Based on a series of mini-assessments carried out on 41 Ontario plastics processors, we found energy savings were reached by switching to smaller air compressors, using energy efficient lighting, fixing compressed air leaks, and turning off idling equipment and unloaded but running compressors,” said Emily Thorn Corthay, a senior energy management consultant with Hatch.

A mini-assessment of blown film extruder Tempo Plastics, of Barrie, Ont., came back with some particularly striking findings. The Hatch consultants used an ultrasonic detector to identify numerous inaudible compressed air leaks, and estimated that Tempo Plastics could save approximately $9,000 annually in this area alone. “We determined that Tempo Plastics could also save approximately $7,500 per year just by switching to smaller air compressors from Friday night to Sunday,” Thorn Corthay noted. Other recommendation
s included reducing the compressed air pressure by 10 psi for a savings of approximately $4,500 a year, using outside air as intake for the compressors in the cooler weather for a savings of $4,400 a year, and shifting loads to reduce peak demand costs.

In the end, trimming energy costs without splurging on new equipment is possible, and is definitely smart business. What’s necessary above all else, experts say, is the simple willingness to do it. “Changing the energy conservation culture in a processing plant ultimately requires commitments from senior management on down,” said Thorn Corthay. “With the right mindset, energy doesn’t have to be a fixed cost–it can be a variable that the processor can control.”