Maybe you’ve been noticing with alarm the increase in your company’s electric utility bills over the past months, and perhaps you’re also becoming more carbon footprint conscious. Maybe you’re even the plant facilities engineer and have been told that you simply must do something to reduce utility costs. So what does a smart, responsible person do?
SMaybe you read some articles on the subject and even look at some related industry standards and guidelines such as the ASHRAE Guideline 14-2002, the Department of Energy’s M & V Guidelines: Measurement and Verification for Performance-Based Contracts, Version 4.0, or the Efficiency Valuation Organization’s International Performance Measurement and Verification Protocol (IPMVP).
After this initial investigation, the first issue that probably jumps out at you is: How can I quantify our energy and dollar savings? As everything you’ve read makes abundantly clear, the only way to get a handle on savings is to first determine your facility’s “baseline” energy consumption (kWh) and demand (peak kW). But everything you’ve read about how to accomplish this may have also left you feeling very concerned if not downright confused.
Not only are there a variety of approaches suggested, depending on your facility’s particular circumstances, but they all utilize at least one year’s worth of data collection and analysis – and many approaches suggest two years.
Speeding the Baseline Process
Reliable and accurate baselining is indeed necessary to establish a way to quantitatively measure savings that works for your facility, in your climate and for all seasons of the year. While very rigorous guidelines are promulgated by government agencies and industry standards, this creates a serious conundrum for users like you, who would like to start saving energy next week, or next month at the latest – not one or two years from now.
This problem falls equally hard on energy management system (EMS) providers like Encycle and others in the field, who must provide their clients with reasonable and timely estimates as to what they expect, and what they can ultimately deliver, in the way of savings from their energy management programs. Obviously, some compromise must be made between accuracy and timeliness.
At Encycle we have put a lot thought and effort into continuously improving and refining our baselining procedures, generally using a “bootstrap” kind of approach. More particularly, after installing our system, we collect and analyze sub-meter data for each HVAC unit (including energy consumption, peak power and outside temperature) every five minutes continuously for a period of up to three weeks.
After this “baseline” period, we then apply Swarm Logic® HVAC controls and compare these results, corrected for temperature, with the baseline information. While a comprehensive discussion of the analysis methodology would not be suitable here in a short blog post, suffice it to say that it includes establishing, by statistical analysis, baseline curves of energy consumption (kWh) and peak demand (kW) versus outside temperature (mean, and peak, respectively) and versus “cooling degree days” (the number of days in a billing cycle that are above a threshold temperature multiplied by the temperature difference for those days).
These baselining procedures are repeated at least two additional times during the first year, once for each season (summer months, winter months and spring/fall or “threshold” months). Baselining may also be carried out periodically in subsequent years, whenever changing circumstances such as facility configuration or usage patterns dictate.
This is an approach that has proven both effective and timely in creating a starting point for setting energy efficiency improvement goals and providing a comparison point for evaluating the effectiveness of consumption reduction initiatives and overall HVAC performance. If you'd like to learn more about Swarm Logic, we invite you to download our brochure.