Scientific Study from the year 2024 in the subject Physics - Thermodynamics, language: English, abstract: The objective of this report is to make up for the following deficiencies at least on a general level - while still using first principles. Air-cooled condensers are widely used at the cold end of thermal power cycles. With this equipment cooling water required in wet cooled power plants may be saved on a large scale. To operate fans which convey dry cooling air to the condenser modules electric power is required which reduces overall power plant effectiveness. Consequently, pumping power consumption should be as small as possible. During operation it is therefore common to reduce fan power consumption by switching down or off fans of individual modules or, in some case complete ACC streets if ambient conditions and operation parameters are promising. Performance guarantees are normally specified with all equipment in full action. Only primary variable variations such as ambient temperature, ambient air pressure or total steam flow rate for a reduced range at fan full speed are part of the performance guarantee. Therefore, effects of fan switch or high cross-wind levels remain open issues.