Saturday, February 16, 2019

measurement 2

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My electricity - Where does it all go??

Ideally, I would have an individual energy meter monitoring each electrical appliance. But that is not practical because of cost and complexity.

I now measure about a third of my kWh use by appliance directly.

Some appliances I don't measure since they are hard wired (like the furnace or the dish washer) so I cannot attach a plug in meter. Or, the appliance uses high voltage 240 VAC (like the water heater or the clothes dryer) and plug in meters are not readily available or easy to hook up. Some appliances are used infrequently (kitchen mixer) or they are moved around the house (vacuum cleaner) or they use so little energy (CO2 alarm) that they aren't worth a dedicated meter.

Nevertheless, using plug in meters I have been monitoring about 10 of my appliances at their plugs. Monthly, I record kWh from the meters. The newer meters are wireless and can control ON/OFF as well as accumulate energy use. It has cost me between $20-75 to monitor and control each outlet as I have tried various meters. I want to explain my usage with my own measurements while learning things about my energy use. I can also verify that I am indeed using less when I make changes. It is difficult to see the change of one appliance in the total house utility bill (avg 300 kWh per month).

This is one of my TS-1500 workhorse plug in meters monitoring both my toaster and microwave. [click any pic to enlarge]

Compared with the grand total for the house, neither of these would qualify for a meter of their own but I dedicated a meter for the two of them. You can see the cube splitter to allow both appliances to be measured. The meter will show the total use of the two appliances which last month (Jan) was only 2.14 kWh.

It helps that I've taught myself never to use the toaster and the microwave at the same time or I would overload the TS-1500 which is rated at max 1800W/15A (and the circuit breaker!).

TS-1500 is a generic meter that shows up in web searches, made in China. I have the US version plug but it is available in other configurations.

This TS-1500 is in the top outlet. It might look as if the lower outlet could be used to plug in something else but in most cases, the TS-1500 blocks the use of the other outlet.

The top line of the meter is showing that the microwave is drawing a standby current of 0.010 Amps, just to run the clock. I can push a button and cycle the top line to see that this is 1W, or that the voltage is 117 Volts, the frequency is 60Hz and other measurements. I leave it at current (Amps) since this is also the only setting at which the meter will reset.

The second line also has multiple displays. I leave it at kWh used. This second line will accumulate until manually reset. If the power fails, the TS-1500 has a built in battery.

On the second line I see that between the two appliances, 0.84 kWh has been used so far this month.

On the first day of the month (sometimes the second day) I go around the meters and record the second line as the usage for the month. I then push the left most button (hold it down actually, for a few seconds) until it chirps and the memory is reset to zero.

The bottom part of the display which looks like a bar graph does nothing for me. I have never seen any of the bars "lit". Maybe I am not using enough through the meter? In any case, these give me a monthly total, are easily reset and are "inexpensive".

TS-1500 is available on Ebay and from Amazon. I see them now for about C$18-20 and higher.

The TS-1500 has worked for me. If you are not ready to wade into WiFi energy meters or you just want to measure an outlet or two on a trail basis as a test, perhaps the TS-1500 is worth trying.

The TS-1500 liquid crystal display is very low contrast. I use a flashlight to make it easier to read.

Two years ago, I wrote about some net-workable WiFi energy meter/switches. The early models I tried had a physical deficiency in that they blocked the unused outlet of a pair, like the TS-1500 does. They were also very expensive, upwards of C$75 per meter.

Models now available cover only one outlet position. I am using the Itead Sonoff S31 to control and measure three appliances, my refrigerator, a small chest freezer and a dehumidifier.

The S31, as well as accurately measuring and accumulating usage also functions as a switch/timer all accessible through WiFi, supposedly "compatible with everything" if you want to use home automation. I don't at this moment, I just want measurements and timers.

S31 also allows you to download the usage history and display plots of monthly usage through the free eWeLink app from Itead.

This is the graph showing when I changed freezers, from an S31 via eWeLink. I added the yellow.

All new measured outlets I make from now on will use the S31.

Cost is about C$20 each.

If you are wondering, these plug in energy meters use between 1 to 2 watts each themselves. I measured.

I should point out that these devices I am talking about are imported directly from China and are not yet CSA or UL approved.

I've used what I learned to make reductions in my electricity usage and cost. For me, measurement is a key tool.

When I replaced my refrigerator I was able to show a 50% actual reduction, and for the chest freezer also replaced this year (graph above).

I compare my measurements with the total on my bill. Ideally, all my measurements would add to the billed kWh but I can't yet measure all of them. I want to measure all of my appliances but so far about a third.

My spreadsheet shows individual meter/appliance readings that I make and the total house usage from my utility invoice.

The total of my billed usage that I can currently explain with actual measurements is about 25-33% of the total bill.

I don't have a way to meter my lighting usage yet. All lighting here is now LED but I have no idea what my usage is for "lighting".

Thanks for your interest

George Plhak
Lions Head, Ontario, Canada

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Tuesday, February 05, 2019

home electric progress 4

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I have changed the slope of my electricity demand and it is quite easy to see with a simple tool.

This chart [click any pic to enlarge] shows my actual kWh/month graphed against how cold it got in the area for the last six years.

The three lines at the top are ancient history, my first three years here, before my changes described in this blog. They cluster well. As the outside temp falls I use more electricity (for various reasons but mostly the furnace motors).

The blue line is the 2016-2017 heating season. Parallel but noticeably lower.

2017-2018 (last year, purple) is lower still.

I've just plotted this year (black line) to date even though winter isn't finished. This year is different!

This year 2018-2019 I have a new furnace and six new windows. This line is not parallel to the others, it rises less (less electricity used) with increased degree days.

This means my house is less susceptible to cold from an electricity use point of view.

You can track your data to see the electrical effect of changes you make to your home in a very clear way. You only need one number from each electricity bill and the degree days closest to you.

Here's how I do it: I use a simple spreadsheet because that's the way I am most comfortable making a graph. I make a list of three columns to organize my data: the date, the kWh and the degree days.

The total kWh used each month is clearly shown on your bill. Here are mine, listed by month.

Next you add your weather data, the degree days near you. I get mine here.

Then I graph the points and add a regression line. You can do that with a ruler and some graph paper. I won't give you step by step since there are many ways and much software to do that - your choice. You compare the "best fit" lines of individual heating seasons, or cooling seasons using cooling degree days if you are cooling rather than heating (or both?!).

Then I show the regression lines but not the data. It's a whole lot easier to see what is going on without the data points in view especially when plotting multiple years.

Another view of my usage, December last six year kWh totals. I am using less electricity.

Update Feb 12: My usage of On-Peak has gone down! This chart shows my average On-Peak kWh per day for the months Nov-Feb for the past six years. I adjusted the figures for heating degree days to make all the winters equivalent.

Electricity used during the Peak periods often contributes to the need for my utility to run peaker gas generators producing more CO2. So they make it more expensive for me to buy.

This is my current pricing and TOU periods with HydroOne. On-Peak is twice the price (+103%) of the base rate. We also have a Mid-Peak rate which is 45% higher than the base rate.

My On-Peak is largely the "stuff I can't turn off", like the furnace in winter.

My On-Peak usage is an indication of the absolute minimum kWh I would need to produce in order to be electricity self sufficient.

I had hoped with the furnace and window upgrade that the latest reduction would be more significant.

However the chart suggests that my gains are harder to get from here on.

Thanks for your interest.

George Plhak
Lions Head, Ontario, Canada

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