The VSG vessel provides a method of heat dissipation above the expansion vessel, protecting the membrane from excessive temperatures. The correctly sized additional tank also allows a decrease in the temperature of the solar liquid in the expansion system. Zilmet has also developed a series of innovative and special expansion tanks for solar energy systems. The SOLAR gamma of tanks was developed according to the DIN 4757 and satisfies the requests of the most important manufacturers of solar energy systems. There are: SOLAR-PLUS tanks VSG the additional intermediate tanks.