**5. Conclusions**

The final parameters given in Tables 4 and 5 prove that the designed 20-row individually finned HPHE is characterized by high recuperation effectiveness (55–65%). The effectiveness and heat transfer rate is higher for winter conditions, where higher temperature differences between airstreams exist.

The designed HPHE made of an individually finned HPs bundle is a competitive solution to the continuous plate-fine HPHE. The continuous fin HEX is a more thermally efficient construction (smaller number of rows for the same heat transfer rate), although the individual finning has its advantages in HPHE:


Even though more common continuous finned HPHEs outperform individually finned constructions, taking into account the above advantages, the construction proposed by authors can be more desired, especially from the exploitation and maintenance perspective.

The heat transfer intensification by the utilization of turbulators in an individually finned tube bundle (between HPs) is an attractive research direction, as it is not a widely recognized topic in the literature. It could improve the HPHE effectiveness significantly.
