Sunday, July 03, 2016
more TOU and dishwasher continued
The actual electricity the dishwasher is using is about 300 watts less than this since there are other "always on" things that use electricity in my house right now. The fridge and freezer are the biggest parts of the background. There are a few lights on and the computer I am typing on, a few charges, some CO2 and smoke detectors, the garage door openers a few radios that even though they are off still draw some "keep awake" power as well the network and the Blueline Innovations whole hose energy monitor itself. The background varies constantly from about 150watts to 300watts. I almost started the toaster oven but stopped since it is a big energy user. I am running this test of the dishwasher and want it to be uncomplicated by other heavy use appliances. The dishwasher is almost done.
The dial on the right in the screen shot shows my total usage for the month. Since it is the beginning of July, that dial has just reset. Briefly it was near zero but now marches forward through the billing month. It does not show peak/off-peak but I can see that elsewhere in the software.
The bottom part of the display shows me the outside temperature and the date and time? That part is not correct. I don't know yet what the 333kWh "estimate" is yet. I guess I'll have to read the manual? I don't know what the buttons do. Clearly I haven't explored the functionality of the remote.
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Now as far as Time of Use relates to the dishwasher, it is very clear to me that I should be running the dishwasher during off-peak. I am not sure I am going to change my behavior as a result of having this power monitor?
In an earlier run, I found that the water heater started shortly after the dishwasher. This time, I had resolved to turn off the water heater so that it would not start after the dishwasher. I turned off the water heater at the bereaker panel shortly before 6am. Then I started the dishwasher at shortly after 6am. When I got back the the software, I saw that the water heater had already started and had been running for about 10 minutes before I turned it off.
As I pointed out before, the water heater starts if its internal temperature sensor detects that the water is below the set point. The dishwasher draws hot water and the water heater replaces that with cold water from the water supply. The new water is much cooler than the tank and causes the internal temperature to fall triggering the sensor to call for heat.
It is just a coincidence that my water heater, without any hot water having been drawn from it, chose to come on at about 5:20. Funny thing about a water heater is that unless you have one of these whole house meters, you cannot tell that it is running!
Note that the peaks from the water heater are simple ON-OFF shapes while the dishwasher has a rather more complicated signature. I don't know what the small addition square on top of the second water heater peak is? That might be the fridge or the freezer, which are normally buried in the background, becoming visible on top of the water heater.
I am having the read the data off a screen capture. I am amazed that the software does not do this for me. It does not even know that this is the dishwasher. Well perhaps Plotwatt will one day figure it out but not yet, so I am calculating the hard way. I will use the millimeter measure of 21.24mm = 1 hour to find the width of each block by comparison using the CorelDraw dimension feature.
Here is the calculations for the blocks:
(there is a little space
Total = 1.454 kWh
This does not include the energy used to heat the water in the water heater, the water that was used during this run. That energy is included in the water heater draw, at least for this run.
So 1.454kWh would cost me during the peak-period (1.454kWh x C$0.54/kWh) = $0.78. During non-peak, my cost would be (1.454 x C$0.11) = $0.16!
A lot of calculation and thinking to show me that the dishwasher does not cost much if run off peak. I don't use it very often, although I did run it three times in three days to get a relatively clean signature. I hope I will be able to use my figure to compare to new dishwashers? I don't think they give the cost per run but per year.
Thanks for your interest,
Lion's Head, Ontario, Canada