# Energy Audit Suggestions

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I'm trying to do a DIY energy audit of a large church, where I work as a maintenance tech. (mostly in controls). I've been trying to conduct an energy audit, so I can pie chart how much energy is being used by the various circuits/equipment/appliances. I was going to try shutting down all but one circuit on a holiday or at night and take readings off the power meter, but it doesn't seem to display actual current usage, and working off the accumulated usage is impractical. So...

Plan B is to amp/clamp the circuits at the switches and breakers. I started playing with that yesterday, starting with the equipment that I most need data on, one of our large chillers. The switch has three 3-phase (480v, I assume) cables/circuits passing through it, the legs of which circuit bundled and connected together to the three switch terminals.

So I amp clamp the only wire that I can get the clamp around and read almost 30 amps. Assuming that I'm able to get an amperage reading from the other wires, what formula can I use to calculate watts? Do I just use the 30A in a standard power equation (V*A=W), do first I sum the amps of the 3 legs, do I apply a formula to the 3 amp values to get some "effective equivalent" to plug into the power formula?

If it's not that easy, is there a way to do it without hiring a consultant?

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Power (Watts) is V x A x power factor. Unless you have a fairly sophisticated meter, you are going to find it difficult to measure power factor. But if you want, you can estimate it at 0.8. That's probably good enough for what you are doing.

There are easier ways though. There are very inexpensive watt meters out there which you can install on any specific load to give you the exact power usage. One very popular one is called a "Kill-A-Watt", but it is only for 120V plug-in loads. They are about \$24.00

If you want to be able to read the whole facility or isolate a specific area or a larger 240V load such as a chiller, you could use this one. The installation is a bit trickier. These are about \$150.00

"He's not dead, he's just pinin' for the fjords!"
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...snip...

If you want to be able to read the whole facility or isolate a specific area or a larger 240V load such as a chiller, you could use this one. The installation is a bit trickier. These are about \$150.00

Actually, that last one only seems to do single and dual phase, and only up to 220V. It would be useful for data logging the smaller circuits, but not the ones we need to do first.

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From a little research, I'm wondering if I can use this formula for our three phases circuits:

"Three phase watts = volts * amps * 1.73

The amps in this case is measured on any one ungrounded (hot) wire."

Would I still need to do the .8 power factor adjustment?

I'm guessing the 1.73 is for phase adjustment only...?

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