Performance Test of the Hera 3 × 6500 w Helium Refrigeration Plant

The HERA-superconducting proton ring magnet system, part of a 820 GeV proton/30 GeV electron colliding beam facility at DESY, Germany, will be cooled by a helium liquefier/refrigerator as described previously. The refrigerator has been specified by DESY, detailed design, fabrication and assembly have been executed by industry. All assembly work was finished by April 1987. A short description of the final design of the plant is given. Some first results of performance tests as values for refrigeration power at 4.4 K and between 40 K and 80 K as well as liquefaction rates at 4.4 K with one coldbox system out of three will be presented. Preliminary values for efficiencies of cold-boxes and compressor groups are calculated.