Dr. Wayne C. Turner, Editor-in-Chief
From Energy Engineering, Vol.98, No. 6, 2001
ISSN: 0199-8595
For years, I have been preaching the merits of submetering. The values are well know but the cost and disruptive nature of installing submeters has been so significant that little progress has been made. About the best we have been able to do is "work toward submetering."
All that has changed and rather significantly. I get many phone calls and e-mails today asking about submeters, and we have done some research recently. Now, it is fairly simple for us to install our own electrical submeters with little disruption and reasonable costs. We can also tie into gas and electrical revenue meters to get "real time data" such as 15-minute interval data on power consumption. As best I can tell, there still is not an economical way to install our own gas submeters, but I would love to be educated. Anyone have good experiences on gas submetering they wish to share?
Submetering creates value. Many times those values are unexpected, such as diagnostic management by exception, but often, the values are exactly what we expect. I have attempted to outline those values below based on our research and feedback from clients:
1. Cost Allocation. Being able to tell each tenant what he or she has consumed and charging them for that power and energy consumption is a direct benefit. Typically, savings do occur as the tenant realizes that energy management savings go directly to them. I often hear numbers approaching 25 percent savings from this cost allocation; but I believe we could count on an eventual 10 percent saving.
2. Control Capability. The old adage "you can't control what you can't measure" is very true. Knowing where the energy is going and knowing the power profile over time lets us concentrate control activities where they are needed. I see no way to quantify this, but the savings do occur.
3. Diagnostic Capability. This one has surprised me. Most of the clients that talk about submetering tell me that the ability to watch the individual load profiles often tells them something bad is happening and when it is happening (see Mr. Alien's article in this issue). Thus, if a chiller or boiler COP (efficiency) is going south at a particular time, that tells us when and where to try to find the cause. Once again, there is no way to predict these, but in most cases, clients tell me this does happen.
I don't have time to list sources and make suggestions as to where and how to install submeters, but there are many vendors out there. Spend a few minutes on the Web or look around at the equipment shows. Then write an article for Energy Engineering and let us know how it went.
May the bottom of your gold pans turn yellow.
Wayne C. Turner Stillwater, OK