I need to report on the most interesting issue i have come across in a long long time.
The last week we were installing for a client that has to deal with an electrical bill of between 8k and 10k per month. Normal modern house and the consumption did not make sense. This was an remote quotation and we had no recordings to work from and the size of the system was based on the available budget. We did the best we could to install the most panels and batteries to try and offset his account.
While installing we did a five day recording to get the proper data to know what we are working with and were surprised to see an average of 100kwh per day with 60kwh being at night time. looked at what was on at night and the sum did not make sense. Stated investigating and ended up at the two geysers. Guess what we found?
1 x 150l with a flat plate collector and a circulation pump.
1 x 200l also with a flat plate and a collector.
And then all that were wrong, no insolation on the pipes, no anti syphon loop to prevent heat creep and the two pumps were plugged into a wall outlet without any control unit, directly connected to power running 24/7.
As an explanation, the controller will measure the temp at the Flatplate as well as the geyser and when the temp at the flatplate is 7deg higher than the temp in the geyser, the pump will start to circulate the warmer water to the geyser till there is a 3deg difference and stop to wait for more water to be heated again to 7deg above.
In this case the pump was running 24/7 circulating the water even on cold days and during the night, this will cool down the water over the area of the flat plate as well as this un-insulted pipes (At 137wh per meter of copper pipe) all the time while the element would try to heat the water again. this resuslted in night time loads of up to 10kwh during most of the night.
As a test we just unplugged the pumps and installed timers to prevent the elements from switching on during the night as we still have heat creep and losses through the pipes. Within the first day of testing, we reduced the daily consumption to 45kwh with a usage of less then 10kwh from the grid.
All of this because the flat plate collectors were installed incorrectly. We have ordered controllers and insulation from Gauteng and will install them next week.