Expansion vessel sizing for solar collectors loop

The sizing has the following assumptions: Collector loop is closed and when collectors are overheated the water/glycol mixture is vaporized in the whole volume of collectors. No automatic air separator shoud be instaled. Only security valve. Additionally the solar medium is expanded by ten percent. No static pressure is assumed. I suggest expansion vessel near collectors and security valve on top of the collectors for manual discharge.

Operating parameters

Vessel operating pressure: bar
Max pressure in vessel: bar

Glycol/watter volume

Collector serpentine length: m
Collector serpentine internal diameter mm
Number of solar collectors:

Supply pipe length: m
Supply pipe internal diameter: mm

Hot water tank exchanger volume: litres


You should choose at least one liter bigger vessel than minimum!
Leon Kos
Last modified: Mon Jul 23 15:18:52 CEST 2005