Device for calculating the amount of recovered heat energy

The invention relates to a device for calculating the amount of heat energy obtained in a heat-recovery device in an air-conditioning system in which a heat exchanger is arranged in an air channel. Hitherto, it has not been possible to determine the effective power of heat recovery devices but the theoretically calculated recovered heat has had to be accepted without conclusive information on the efficiency of the heat recovery device actually being obtained. According to the invention, a process is provided which supplies precise, conclusive information on the amount of heat energy actually recovered, and the said device is characterised in that a speed meter (9) for the air speed in the air channel, a temperature measuring device for the difference in air temperature between the two sides of the heat exchanger and an input component for the cross-section of the air channel are provided, and in that electronic switching elements are provided and are connected to a display device, with which switching elements the amount of heat energy recovered can be calculated and transmitted to the display device so that the amount of heat energy actually recovered can be monitored during operation of the heat recovery device.