An air-to-air heat exchanger typically refers to a ventilation equipment that includes a full heat exchange core. Its working principle is: when the product is in operation, the indoor exhaust air and fresh air flow through the heat exchanger core in a perpendicular cross pattern. Due to the temperature difference and vapor pressure difference on both sides of the airflow separator plate, the two streams of air exhibit heat and mass transfer phenomena as they pass through the separator plate, initiating the full heat exchange process.