One month load curve

The charts below show the average power use in 5 minutes intervals, along one whole month of electricity use.
The first one shows the curves separated for weekdays and weekends, the second one is just an average for the whole month.





The most surprising effect of this "averaging" process for me is the fact that the highest power peak present on the average chart is below 1100W, while the highest power sample on the source data was 6794W, during a short period on a Weekend day, at 20:48h, in the evening. The reason why this happens is because I averaged the values of power for each 5 minutes of each day of the month and while on some days this value was high, on others it was very low. I guess I'll need a lot more days of analysis to be able to draw more accurate conclusions.

It is however interesting to see the difference between week days and weekends, although in our particular case that difference is surely smaller than with normal families, because we homeschool the kids, so there is always people in the house, even at week days.

The other interesting conclusion is about where are the energy "mountains". There are two smaller ones, one in the morning and one other at lunch time, and then there are two bigger ones which correspond to dinner time and to "cloth washing time". We have double tariff, so we tend to turn the washing and drying machines late in the evening, that is the second high energy peak of the day.

Let's see in the future, with more data gathered, if these curves will change significantly.

Bimby cooking a meal

As I promised before, here it is a chart of the electricity used by Bimby while cooking a soup and boiling vegetables afterwards (with Varoma).



There is, however, something that is not exactly right in the chart: the system takes more power samples when there is frequent change than when the power level is steady. The power samples could be 12, 24, 36, 48 or 60 seconds apart between each other, but Excel does not draw them differently, it'll have to be me to create the missing samples to make them all 12 seconds apart. This means that the chart is not exact in terms of time axis, but it shows what happens to power during the meal cooking period. I assumed in my calculations that the 200W you see as a base load did not belong to the Bimby itself.
That said, I calculated the energy needed for the two moments, the soup and the vegetables. That took exactly 49 minutes and 48 seconds and the energy used was 0.336kWh. This means about 5 Euro cents of electricity to cook a meal.

Now, what is the amount of energy you need to supply to 1 L of water to make it raise from 15ºC to 100ºC? It is the difference of temperatures (85ºC) times 1 Cal per gram, which means 85,000Cal or about 0.1kWh. To make the soup, it took about 25 minutes and the cooking needed only a little more than 0.1kWh. This demonstrates (roughly, I know) that the Bimby is indeed a very efficient device. Perhaps one of these days I will make the experience of boiling 2 L of water with a thermometer inside the Bimby to check exactly how much energy do you loose with the losses and the energy transference from electricity to heat. I would say the overall efficiency is above 90%.

How much does my oven spend?

Recently I bought an electricity monitoring device, connected to Internet, with which I can analyze what is spending what at the house.
The system I bought is the Owl Intuition lc.


Today I bring you the energy use profile of the oven. The chart shows the oven and about 200W more that were present besides the oven itself. It is noticeable the thermostat working. This is not yet a thorough analysis, because the oven is not isolated from the rest of the grid, but I thought it would be interesting to watch how it turns on and off the resistance.
After all, the energy used was less than one kWh, it was about 0.75kWh in about 50 minutes.



I'll bring some other analysis done with the device in the next posts.