Method for operating a heat exchanger, arrangement with a heat exchanger, and system with a corresponding arrangement

An arrangement having a heat exchanger which heat exchanger has a warm end and a cold end, wherein the arrangement comprises:

• means to carry out a first operating mode in first time periods and to carry out a second operating mode in second time periods, wherein the second periods alternate with the first time periods,
• in the first operating mode, means to feed a first fluid flow into the heat exchanger in a first region at a first temperature level, and means to cool the first fluid flow partially or completely in the heat exchanger,
• in the first operating mode, means to feed a second fluid into the heat exchanger in a second region at a second temperature level, and means to heat the second fluid flow partially or completely in the heat exchanger, and
• in the second operating mode, means to partially or completely halt the feeding of the first fluid flow and of the second fluid flow into the heat exchanger,
• wherein passages are provided in or on the heat exchanger in the second region, but not in the first region, which comprises the terminal 30% at the warm end of the heat exchanger, and
• means configured to cool the second region in the second time period using cooling fluid conducted through the passages in or on the heat exchanger in the second region, but not in the first region.