What Is Heat Exchanger Effectiveness ?

A heat exchanger’s effectiveness can be measured by calculating its performance. Heat exchanger effectiveness is defined as the ratio of actual heat transfer to attainable heat transfer in an infinitely long counterflow exchanger. As a result, we select an infinitely long exchanger since it will allow for the maximum amount of heat transfer (i.e. Eventually, enough heat will be transferred so that the driving force will disappear – both streams will reach the same temperature). 

To understand the rationale behind the choice of a counterflow exchanger (in this definition), it is instructive to look at both cases: an infinitely long parallel exchanger and one an infinitely long counterflow exchanger

Plate heat exchangers are efficient heat recovery units used in a variety of commercial, industrial and residential settings. By extracting sensible energy from exhaust air and using it to cool or heat incoming air, a plate heat exchanger can significantly reduce a building’s energy costs and environmental impact.

Simple engineering principles are used to build them. Aluminium or polymer plates are placed in the heat exchange core with gaps between them, allowing air to circulate freely. The exhaust air is funnelled between layers. In the meantime, incoming air is funnelled in the other direction between the layers. 

The exhaust air heats or cools the plates, depending on the climate. Sensible energy is then transferred to the incoming air. Plate heat exchangers can recover the vast majority of sensible energy, so their impact is significant.