When and why should you add a CIMM Intermediate Solar Tank to a CIMM Solar expansion vessel?

In solar energy systems, it is useful to provide a CIMM Intermediate Solar Tank – which is an additional tank without membrane – in order to protect the Solar expansion vessel from overheating in case of stagnant water. According to the VDI 6002 Directive, the use of an additional tank, such as CIMM Intermediate Solar Tank, is recommended when the fluid of the pipes placed between the solar collector battery and the expansion vessel is less than 50% of the correctly measured reception capacity of the expansion vessel.