The purpose of the hot water tank is to store energy for days with poor solar radiation. Its volume should be about 1.5 to 2 - times more than the daily consumption of hot-water, which means 80 to 100 litres per person.
Enamelled steel tanks are typically used, from the conventional heating technology known as they. You need a magnesium or an external current anode for corrosion protection. Stainless steel tanks have a longer life expectancy, but more expensive.
Good solar tank have a slim, cylindrical form, to develop a layering of the temperature in the tank. This allows optimal use of heated water in the upper memory area, without that the entire content of the tank must not be heats at the desired temperature. Unwanted mixing of the fuel capacity by incoming cold water is prevented by a special tube construction or an impact plate. The arrangement of the solar circuit heat exchanger in the lower, colder storage space causes to work the solar panel up to a lower efficiency due to low water temperatures.
Hot water tank with two heat exchangers
So that is the heater to heat up not a unnecessarily large volume, the heat exchanger in the upper part of the container is arranged.
The entire surface of the container tightly with a radial insulation at least 10 inches thick without any gaps to fit. To further lower heat loss, the connections in the run cold lower level only by a range.