Energy costs and potential energy shortages are increasingly driving commercial building and industrial facility owners to find ways to use less energy for the same level of activity. According to the Petroleum Conservation Research Association (PCRA) in New Delhi, energy audits can help identify all energy streams, quantify energy usage per building or process system, and help enable energy cost optimization, pollution control, safety and improved maintenance practices.


“An energy audit profiles the energy consumption of an active facility, by day, week, and sometimes by month, with the objective of discovering those activities that are consuming more energy than they should,” said Leah Friberg, education and public affairs manager for Fluke Corp., Everett, Wash.


Since each facility—especially an industrial one—contains a unique set of activities, a tricky aspect of energy audits is defining the kind of energy consumption that is wasteful.


“For that reason, the auditor needs to do more than analyze the utility bills, which certainly provide information about the mass energy consumption for the entire building but offer no insight into which systems are consuming how much and when,” Friberg said.


To determine that level of energy consumption, an energy auditor needs to identify the biggest loads, ascertain when they occur, and then log consumption at those loads.


“Once the auditor can see the real, not assumed, energy consumption of the load, he or she can determine whether the machine or building system is running efficiently and whether it’s operating at the most affordable time of day according to the rate schedule,” she said. 


The auditor can take other actions, such as inspecting equipment health, examining the overall building envelope for leaks, exploring the benefits of performing lighting retrofits, and so forth, but often the biggest energy savers come from changing operational behaviors or schedules rather than changing large equipment or the structure.


Energy audits can be divided into two categories: preliminary and detailed. Preliminary audits essentially are a data gathering and analysis effort completed within a few days; these focus on the identification of obvious sources of energy waste. The detailed audit goes beyond quantitative estimates of costs and savings and includes engineering recommendations for well-defined, projects efficiency.


Both levels of audits require the use of instruments that can monitor voltage, current, power factors, active power, apparent power (demand), reactive power, energy consumption, frequency, harmonics, etc. Parameters of importance—other than electrical—include temperature and heat flow, radiation, air and gas flow, liquid flow, air velocity, noise and vibration, dust concentration, moisture content, relative humidity, flue gas analysis, combustion efficiency, and so forth.


One of the primary instruments used in an energy audit is the three-phase energy logger. This portable tool is meant to be connected to a load or panel and left behind for a full operational cycle to collect data. It measures voltage, current, kilowatt-hours and other parameters, such as harmonics.


“It’s essential to log this data in three phases simultaneously and in actual kilowatt-hours, not just current, since the point is to compare consumption against the utility,” Friberg said. 


Upon cycle completion, the data is exported to a computer where waste areas are identified and graphed.


Energy loggers used to be tricky to install, and the setups difficult to check. In recent years, they have become much more foolproof and now presort the multiple cables to prevent confusion.


“They will now digitally autocorrect any connection mistakes and have screens that enable the electrician to ensure that the instrument is working correctly,” Friberg said.


In addition, the software today is much more intuitive and includes automatic energy-cost calculations and visual displays for diagramming and reporting energy consumption.


Thermal imaging cameras are another ideal tool for energy audits and are used to identify heat or cold issues that occur outside of normal operating ranges in electrical and mechanical applications.


“Managing the temperature range of equipment optimizes their lives, and thermal cameras offer a safe, noncontact solution for finding problem before they actually arise,” said Paul Alger, strategic account manager at Flir Systems Inc., Nashua, N.H.


Just a few years ago, the average cost of one thermal imaging camera exceeded $30,000. Today, contractors can outfit multiple employees at similar to lower costs.


“Now, for less than $500, contractors and industrial facilities can quickly define energy issues with noncontact applications testing,” Alger said (see Cool Tools, page 110, for some examples).


Electrical contractors that can leverage their client relationships and use their electrical system knowledge to sell the return of an energy audit can build new revenue streams. And, with the variety of energy audit instruments available, helping to manage their customers’ energy consumption is now more cost-effective than ever.