Cryogenic test chamber - LE/LK - F. Zaugg

In order to guarantee the quality and resistance of materials, tests under extreme conditions are necessary. To maintain a room temperature of -60°C in this cryogenic test chamber, the system builder, F. Zaugg AG Kälte und Klima, used a special two-stage Roller direct evaporator coil for cascade operation. The test chamber is first cooled to -20°C with R449a via the first circuit. When this temperature has been reached, the second circuit with the cryogenic refrigerant R23 is switched on and the first circuit now cools the cascade condenser for the cryogenic circuit. In order to reliably generate the evaporation temperature of -66°C in the second circuit, the requirements regarding the nature of the evaporator coil as well as the thermodynamic requirements are very specific. In close cooperation with the customer, an optimally suitable solution was also found for this project.