Heat exchanger operation

Operation of the heat exchanger, for air-to-air heat transfer


The operation of heat exchangers occurs by transfer of energy in the form of heat from one medium (air, another gas, or a liquid) to another. The operation of heat exchangers in which there is complete separation between the two media and where no intermediate storage of heat occurs is known as "recuperator heat recovery". Recair develops and manufactures recuperator units for air-to-air heat transfer.


Operation of the heat exchanger with the maximum possible efficiency

In order to maximize the heat transfer in the operation of a heat exchanger, the shape of the intermediate wall in the heat exchanger is designed such that the distance which the heat flow must pass through is minimized. In this connection it is necessary to take into account the permissible pressure drop in the heat exchanger.
The two air streams move countercurrently but parallel to each other along the intermediate wall, which wall is in principle infinitely large (in practice maximally large). The cold air stream can be heated to the temperature of the exiting hot air stream, and vice versa (the hot air stream can be cooled to the temperature of the exiting cold air stream).

In order to achieve uniform distribution of the air streams over the width of the heat exchanger, triangular channels are formed in the intermediate wall; these channels are of low diameter, and of like resistance. In this way, the air flows in all of the channels are identical. Each triangular channel is surrounded by three similar channels, in which the counter-flow takes place. In this way, one can reach the extremely high efficiency of 93% in the heat exchanger. Because of the fact that the heat exchanger results in only a very small temperature difference between the in-flowing external air and the out-flowing internal air, the result is a very comfortable living and working climate.


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