How much solar hot water do I have ?

what you will get ..

My solar water heater installation

Solar panels transfer heat to a special fluid (red on the diagram above). An exchanger in the water tank transfer this heat to water. Hot water is flowing from the top of the tank, replaced by cold water entering at the bottom of the tank.
Late morning. Sun is up. Temperature at the bottom of the tank is already 48 °C
Stratification on the left. Heating coil on the right.

My DIY connected application

Hardware design
A DS18B20 temperature sensor. Those sensors are positioned to touch the water tank metal enclosure. I had to dig a small hole in the tank’s thermal insulation to get access to the metal. Of course I cannot get inside the water tank itself.
The two temperature sensors
The OLED screen displays various information, in particular the temperature at the top and mid point of the tank, the LIPO battery SOC (state of charge) and the Wi-Fi signal strength.
Testing on the living room table. The MicroPython application is developed with Microsoft VScode and downloaded to the ESP32 with USB (not shown)
3 days worth of data. Temperature (red and orange) raises in the morning, as the sun hits the panel. It drops a bit in the evening, as showers are taken. The blue line is battery state of charge.
The smartphone application.



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