WASTE HEAT EXCHANGER OPERATING PROCESS Russian patent published in 2001 - IPC

FIELD: ventilation and air conditioning systems for recovery of exhaust air heat. SUBSTANCE: incoming and exhaust air streams are passed through respective inlet pipe connections in cross-fine channels of heat- exchange unit made for example in the form of set of aluminum plates. When air streams flow over channels heat is transferred through their walls from warmer exhaust air to cooler inlet stream. After that, these streams are brought out of heat exchanger through respective outlet pipe connections. Temperature of incoming air is reduced in the process of air passing through heat exchanger. At low ambient temperature inlet air temperature may drop to dew point causing thereby fall out of moisture droplets (condensate) on surfaces bordering heat exchanger channels. At subzero temperatures of mentioned surfaces condensate is converted to hoarfrost or ice. To prevent ice or hoarfrost formation or to remove them in the course of heat exchanger operation, measurements are made of temperature in most cold corner of heat exchanger or of pressure difference in exhaust air channel upstream and downstream of heat exchanging unit; as soon as parameter under measurement reaches predetermine maximum value heat exchanging unit is turned through 180 deg. about its central axis. EFFECT: reduced aerodynamic drag, time for preventing or removing hoarfrost while using entire heat transfer surface. 3 cl, 2 dwg