Energy Monitor - Power Factor?

[jk96]

I've set up an energy monitor for our house and I'm currently monitoring the following

Whole house
Hot Water Heater North
Hot Water Heater South
Geothermal HVAC North
Geothermal HVAC South

I've found that my usage since install on my monitor has been higher than my usage on my electric bill. After doing some research I'm guessing the reason is that I have the power factor adjustment set to 1. I'm assuming my hot water heaters would be close to 1 but not sure how to figure or get a an idea of the power factor for my geo units? Anyone have any insight on this?

 

[chim]

Been a while since I studied that sort of thing, but I'll get the conversation started. It's oversimplified and there are things to consider that I'm missing.

If your system has inputs for each of the WH's and HVAC systems and then lumps them plus everything not mentioned as a total load or whole house, it will lack some accuracy. There must be other loads in the house and some that aren't quite at a unity power factor, and to what extent they can be ignored depends on how much accuracy matters to you and how much effort you want to put forth.

Sounds like you already know the power company only bills you for KW and not KVA.

I'd suggest you subtract the power company's KW from your whole house KVA and assume the difference is due to the motors used for HVAC. You list two HVAC systems so you can track them individually. You can calculate percentage of power (KW) each uses. Then take those KW values and subtract them from the KVA you have recorded.

Just to throw numbers at it, if you show 150 KVA and the calcs from your bill indicate 125 KW, the PF is 125/150 or 0.833. I'd guess it's higher than that, but this translates into the power company needing to generate about 1.2 times the current necessary to run your unit. Power companies haven't been hard on residential consumers with regard to PF, but it's a different story with industry.

 

[dadster4]

I operate a co-gen powerplant and our customer is a VA hospital. All the power, both utility and our generated power, run through our switchgear and is monitored by us. The normal range for the power factor is between 89 and 94 with most loads operating at 92 most of the time...see if that number works for you.

 

[jk96]

I operate a co-gen powerplant and our customer is a VA hospital. All the power, both utility and our generated power, run through our switchgear and is monitored by us. The normal range for the power factor is between 89 and 94 with most loads operating at 92 most of the time...see if that number works for you.

Thanks guys. I've adjusted the monitors on my HVAC to .88. For the two that monitor our whole house usage as a group I've adjusted them to .97 based on the difference in past usage between my monitor and outside meter. I'll watch over the next few days and see if that gets me closer to what I'm actually showing on the utility meter.

 

[buckeyefarmer]

an energy monitor should be showing you your power factor. For resistive loads, like electric water heater, it's 1. Motor loads will be less. What kind of energy monitor?

 

[Industrial Toys]

When SMART meters came under scrutiny, it was revealed how inaccurate they could be. Maybe, it's not your equipment. I use an Effergy system and am quite pleased with it, but use it mainly for generator loading and am not sure how accurate it is..

 

[buckeyefarmer]

Would like to know more about inaccuracy of smart meters.

 

[buickanddeere]

Resistance loads will be 1.0. The hvac equipmemt will be somebwere between 0.7 and 0.8 lagging PF.

 

[jk96]

an energy monitor should be showing you your power factor. For resistive loads, like electric water heater, it's 1. Motor loads will be less. What kind of energy monitor?

I've been using eyedro.com for my monitor since last April and really like it so far. It does not automatically show power factor but lets you specify your power factor manually for each sensor. No monthly fees which is nice as well.

 

[Redneck in training]

Some monitors assume voltage and measure only current. Those can't tell the direction of the current and power factor. The better one measure both current and voltage and the phase difference between them. Those can tell current direction and calculate power factor.
TED Pro Can calculate and display PF.
eGauge | Overview Also calculates and display Apparent and Real power and PF.