How does a crossflow heat exchanger work?

In a crossflow heat exchanger, the cold and the warm air flow perpendicular to each other.Two neighboring aluminum plates create channels for the air to pass through. The supply airpasses on one side of the plate and the exhaust air on the other. The heat in the exhaust airis transferred through the plate from the warmer air to the colder air.

A very important parameter for the performance of a plate heat exchanger is the spacingbetween the plates. A narrow channel leads to high-pressure drop but also to higheficiency. The latter means that more heat is transferred to the cold side. A higher platedistance is better if a lower pressure drop is required. The trade-off is lower efficiency.

Usually, the exhaust air is contaminated with humidity and pollutants, but with a plate heatexchanger, airflows never mix, leaving the supply air fresh and clean.