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Partial Table of Contents
Beta MAIN DTE Smart Meter Energy Book TED MTU Data Format

A Book on
Electrical Energy Measurement, Conservation, and Methods
Reduce Your Electric Bill


This book is available for $ 23 plus shipping, and handling from:

                Yogaware, Ann Arbor, Michigan
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Information is provided on making electrical energy measurements that can help you reduce your electric bill.

Both a general and a more detailed technical discussion are provided on:
      electrical power (watts and kilowatts), and
      electrical energy (watt-hours and kilowatt-hours).

Whether you are technically inclined or not there is useful information in these notes for the typical homeowner interested in measuring energy use in their home.

The subjects discussed are:

1. The general aspects of power, energy, and energy conservation.
2. Your power company meter, and two low cost instruments that can help
      you make quantitative measurements.

      These instruments are the Kill-A-Watt EZ, 4460 manufactured by
      P3International, and the TED 1000 whole house system manufactured
      by The Energy Detective, and limited discussion on the TED 5000 system.

      Some of the information is applicable to other competitive instruments.

3. Data and a number of graphs are provided.
4. There are suggested experiments for power and energy measurement
      of various electrical loads.
5. The sales pitch for residential power factor correction at the main panel
      is shown to produce NO power or energy saving.

6. Four of the plots included in the book are shown below to illustrate how power
      consumption may vary thru the day, the large variation from one day to another,
      and how this smooths out when averaged over many days.

      The plots are first shown with captions explaining each plot, and then
      duplicated without the captions for easier comparison of the plots.

The following plots are with captions.


PE1 --- Plot 110812_B.

This is a plot of whole house power and voltage for one day from midnight (0 time) to the next midnight (24 time) with a resolution of 1 second where needed. The particular day was 12 August 2011. The blue curve is power in kilowatts, and the black curve is voltage in volts.

The total energy used for this day was 37.6 kWh, about $ 4.90. Peak power was about 4.2 kW. Average power was 1.57 kW. Min to max voltage variation was 122 to 125 volts. The many, short in time, but large in power, spikes are motor startup and are less than 1 second. These very short spikes have little influence on your total electric bill.

My base power load thru the night is much higher than for the typical consumer. This results from a considerable amount of equipment that runs 24 hours per day.

Generally I do not like to present graphs with a displaced 0. But, for voltage there is seldom much change from a moderately narrow range so the scale is expanded and zero is moved way below the graph.

All the plots shown here have exactly the same scale factors on the Y-axis for easy comparison.


PE2 --- Plot 110814HR-B2--8-12-11.

This plot is identical to PE1, except, the average power for the preceeding hour is calculated from the 1 second average power values of that hour, and plotted as a dot at the end time of the one hour period.

Because the averaging time for each dot is 1 hour this means that the numerical value for that dot is equal to the kWh of energy used in that last hour.

The voltage is also averaged over the preceeding hour, but plotted as connected dots.

You should be able to mentally overlay this average power plot with the PE1 power plot, and see the relationship.

Power is blue, and voltage is red.


PE3 --- Plot 11-8-15--9-14--COMP-B1.

This plot is like PE2, but it is many days, one month, overlaid on top of each other. The calendar range is from 8-15-11 thru 9-14-11. You can see the wide swing in power use at a given time of day from one day to another. But, also note, you can see a common general trend of use thru the day.

Power is blue, and voltage is red.


PE4 --- Plot 11--8-15--9-14--AVE-All-B.

This plot is derived from PE3, but it is like PE2.

Here is displayed the average of of all the values of PE3 at each hour. Note, how much more uniform the use is during the day when many days are averaged together as compared to the single day in PE2.

Because of daily variations in your power usage it is very difficult to make energy comparisons form one day to the next to evaluate the effect of changes you may make. But, also note, month to month variations are going to include seasonal variations.

To a large extent you need to measure individual loads to evaluate what a change in the load might do to energy consumption. Then use whole house monitoring over some reasonable time frame to see how much change in total energy consumption results from making many changes in small loads.

Power is blue, and voltage is red.

The following plots are the same as above but without captions.





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This web page prints reasonably with Internet Explorer. Some browsers may split the graphs over more than one page.

You are encouraged to print a copy of this web page to make easy comparisons of the graphs. The four plots are duplicated at the end without captions to make adajacent comparison easier.

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