Increasing utility rates and ever-increasing energy demands eat into the operations budget and the increased greenhouse-gas emissions spells disaster for the environment. Institutional and commercial organizations cannot assume that they can operate as they always had or that the environment will be able to sustain the ongoing facilities operations. Energy use will continue to increase, hence maintenance and engineering managers need to monitor and control energy use in facilities.
The key to this effort is to understand the energy consumption trend in any given facility. Power sub-metering plays a huge role in achieving this goal by helping managers better understand facilities’ overall energy use and take essential corrective actions.
As a front-line data-gathering tool for energy-using systems, sub-meters can improve a company’s overall bottom line dramatically by bringing tremendous visibility to the overall energy footprint. By introducing energy profiling at the source, such as a lighting panel or power panel, down to the individual piece of equipment, a manager can truly begin to understand a facility’s energy profile and design energy conservation
One area in which sub-metering technology excels is measurement and verification. Since we can install a sub-meter almost anywhere in the electrical-distribution or branch-circuiting system, managers can specify meters for use in energy intensive equipment / system clusters. To understand a building / factory overall energy profile, these meters can help by monitoring individual pieces of equipment, such as chillers, pumps, air handlers, air compressors, large blowers, conveyors etc.
We can identify operational inefficiencies through analysis of the collected data. This step can reveal interesting trends, such as two or more large motor loads starting at the same time, which causes system spikes. By alternating or staggering these loads, we can eliminate spikes and also improve efficiency.
Sub-meters can also be used as a condition based maintenance tool. Monitoring the current drawn by a piece of equipment generates a profile. Once that piece of equipment starts to draw more than the recorded profile current, we can program an alert to let us know about potential problems. The technology allows us to take preventive measures before catastrophic failures occur. The resulting savings in downtime and maintenance costs can more than pay for installation of the sub-meters.
Adapted from an article by David Rosenberger in PE April 2010