PAW SolarBloC midi Basic 2S Installation And Operation Instruction Manual page 34

8 Function of the check valves [Expert]
Do you need to know it exactly?
The density of the solar fluid strongly decreases with increasing temperature. In systems of high
system heights and with large temperature differences, the difference in density causes gravity
circulation. This circulation can result in the storage tank cooling down.
Calculation example: Δp = Δρ * g * h
Collector temperature: 5 °C: Solar fluid density ρ = 1042 kg/m³
1
Storage tank temperature: 67 °C: Solar fluid density ρ = 1002.5 kg/m³
2
Δρ = ρ - ρ = 39.5 kg/m³
1 2
g = 9.81 m/s²
Installation height h = 10 m
Δp = 3875 Pa = 395 mm wc
The two check valves of the station (2 x 200 mm wc) are sufficient for an installation height of 10 m
and a temperature difference of up to 62 K between the collector and the tank.
34 99775810x-mub-en - V01 09/2023