For all of us who work in the process and manufacturing industries, focus has always been on production. Utilities almost always get a back seat. We consider a utility to be something where you open a tap and it flows! Nevertheless, this mentality is changing and several sites now follow the cost center approach for energy accounting. While energy accounting is important and should be done by everyone, I continue to do energy assessments at sites where utilities are considered a “cost of doing business” and these costs are not properly determined.
The most common utility streams are compressed air, steam, chilled water (and/or glycol), hot water, thermal fluid, plant water and nitrogen. A plant produces (or procures) these utilities and distributes them individually through a complex network of piping throughout the site. Generally, flowmeters located on the headers at transfer points provide proper accounting for these utility streams. It’s extremely important to install flowmeters and calibrate them periodically. These devices are our counters and determine utility consumption by different cost centers. Understanding the usage of different utility streams can significantly enhance an engineer’s ability to optimize operations and understand operating costs and, thus, often can identify substantial energy-saving opportunities.