As we talk with energy managers, most agree that a good monitoring system would help them do a better job but most are at a loss as to how to start. Some have even tried to install meters but soon learn that aggregating those meters into a useful, working system can be really hard.
Having installed many working systems, Summa can help with this. We have developed a fool-proof process that virtually guarantees a positive outcome.
A 7-Step Process.
- Decide What You Want to Meter
- System Design and Engineering
- Acquiring the Required Hardware
- Hardware Installation
- Hardware Programming and Commissioning
- Software Installation and Configuring
- Ongoing Maintenance
If you leave out any of these steps, you will likely end up with a system that at best doesn’t meet your needs and which might not ever work at all. This post is the first of a multi-post blog covering the 7 steps and why they are so important.
Step 1: Decide What To Meter.
This might sound trivial but it is actually a very important and sometimes difficult step. In an ideal world, we would meter every load. Then we could see, down to the mini-fridge under the counter, how much power each device is using. On the other end of the scale, you might have just one meter for the entire building. With that, we can know a lot about the building’s consumption but perhaps not much about individual loads.
Building Level Monitoring
If you’re only trying to measure and verify that energy conservation measures are having a positive impact on your consumption, one meter for each utility per building might be enough. With that, you can easily see if the latest lighting upgrade has reduced your overall consumption – as long as you didn’t make any other changes at the same time.
Mission Critical Load Monitoring
A more sophisticated application might extend into equipment monitoring for maintenance purposes. For this, it is useful to identify your mission critical loads and how metering might make those loads more reliable.
For example, if the under-counter fridge in your break room fails, a few lunches might spoil, but if the main drive motor on your plastic extrusion machine fails, your production line is down until you can get it repaired. If the failure occurs during a production run (and it always does), you will have employees standing around and waiting or busy removing melted plastic from the machine so it will be ready to be started back up when the motor has been replaced. Neither of those activities is making you any money.
If metering can help you predict when that motor is about to fail, it can be serviced or replaced before it causes an active production line failure, which could save you thousands of dollars.
Weighing Costs Against Benefits
Unfortunately, there is a cost to everything and you must do a cost/benefit analysis to determine where you get the most value for the dollars spent.
There is a good variety of power meters to choose from, but as a rule of thumb, you can assume that good, revenue quality meters will cost you roughly $1,000/each. Add installation and data connection costs and you could be as high as $1,500/meter. Data monitoring fees and software will further add to this cost but that portion of the cost typically goes down on a per-unit basis as the number of meters goes up. A revenue quality meter follows either the ANSI or the IEC electric metering standard. The most important core requirement in the ANSI and IEC revenue meter standards is the accuracy of the meter. Both ANSI C12.20 and IEC 62053-22 have similar accuracy requirements that depend on the “class.” Class 0.2 instruments allow for a deviation of +/- 0.2% at a Power Factor of 1.0. Class 0.5 allows for a deviation of +/- 0.5% at a Power Factor of 1.0.
Weighing those costs against potential savings makes it a little easier to decide where you really need to have meters. Keep in mind that additional meters can easily be added at any time and that existing meters can be moved to new locations, so it might make sense to start out with a conservative number..
In conclusion, conservatively determine those locations that need to be metered to provide the information you need. Given that starting point, we can move on to the subsequent steps.
Coming up: In the next post I’ll explain why engineering and design are essential to a successful monitoring system.