Energy auditing: The pathway to efficiency
In today’s tough economy, a main objective for many companies has become to decrease operating costs without decreasing production or compromising the quality of their product.
The next four steps, “create action plan,” “implement action plan,” “evaluate progress” and “recognize achievements,” should be conducted and revised on a continual basis. The goals remain the same over a period of time, or until they are reached, but the action plan may change after evaluating progress.
Energy culprits
Not every facility will require the same projects to achieve energy efficiency. It will depend mostly on the specific equipment used in the facility, but one thing is certain across the board: Old motors are major energy culprits. Also, motors that are too large, are improperly maintained, or run 24/7 consume significant, and unnecessary, amounts of energy.
Vande Hoef says most motors more than 10 years old are inefficient by today’s standards. Upgrading all motors in the facility may seem like an overwhelming expense, but the cost of the upgrade could quickly pay for itself. The high efficiency motors available today will deliver an immediate efficiency boost of 2% to 5%, which delivers directly to the bottom line.
“The initial purchase of a motor is only 2% of its lifetime cost,” says Vande Hoef. “The energy consumed throughout its life makes up the remaining 98%.”
Sometimes an entirely new motor isn’t the only option, however. Adding a variable-speed drive to motors that simply have an on/off control will decrease energy consumption. This allows the facility to conserve energy when the equipment isn’t running at full capacity. Michael Gurney, executive director of Concept Systems, Inc., Albany, OR, explains the benefits of a variable-speed drive.
“Many operations utilize across the line starters when instead, using a variable-speed drive system would deliver the power needed exactly when it’s needed, which not only saves energy, but also adds life to the conveying equipment,” Gurney adds. “With fans, variable-speed drives are much more energy-efficient and reduce the need for damper control by delivering the proper amount of power as needed. In general, systems which implement variable-speed control and better sequencing technology will deliver immediate benefits for these functions.”
Other common pitfalls grain handlers face is not having the right sized motors for the specific tasks.
“People think they need the biggest motor they can get so they always have enough power behind their equipment, but this wastes huge amounts of energy,” says Scholtens. “Always use the motor size specified by the equipment manufacturer to achieve maximum energy efficiency.”
Properly maintaining equipment also helps increase energy efficiency. OJ Utter, president, Utter Precision Inc., Utica, NE, recommends facilities use a predictive maintenance plan, rather than waiting to fix problems when they arise.
“Preventive maintenance can translate to energy savings because it detects issues that contribute to energy inefficiency, such as a misalignment or a fan imbalance,” says Utter. “These problems cause the motor to work harder and increase the amperage used.”
The time of day is another factor to consider when trying to reduce energy costs. Many utility companies charge more for power during peak hours, such as 7 a.m. to 5 p.m. Gurney and Scholtens both heartily recommend conducting energy audits on a regular basis to assess usage patterns and to determine if efficiencies can be captured via operating during off peak-demand hours.
“It’s better to stagger the usage of equipment throughout the day,” says Scholtens. “It’s going to be dependent on the mill and the utility companies, but sometimes it’s most efficient to run loads overnight.”
Jon Wheeler, support services department manager, Interstates, says that while common sense may tell you to turn off equipment if it’s not being used, it is not always the best idea. Because of the sheer power it takes to start things up, large pieces of equipment should not be turned on and off several times throughout the day.
“There’s a fair amount of debate over whether or not to leave equipment running so you don’t get that high initial power intake,” says Wheeler. “My recommendation is that if you stop a load for only 10 or 20 minutes during the day, you should leave it on. However, if you’re going to be running something for only eight hours in a 24-hour period, leave it on while in use and then turn it off the rest of the day.
