This paper addresses the design and thermal–hydraulic analysis of a heat exchanger designed for cooling sampled process air from a fermenter prior to its transport to a mass spectrometric analyzer. Due to the high humidity of the sampled air, effective cooling is required to prevent unwanted condensation during transport over a distance of 200 m. A tube-in-tube counter-current heat exchanger was selected and analyzed with respect to heat transfer, condensate formation, cooling water demand, and pressure losses. The results show that the proposed design achieves the required outlet air temperature with a minimal heat transfer area and acceptable hydraulic losses. Although the amount of condensate is low, periodic purging of the air-side tube is recommended to prevent a reduction in heat transfer efficiency. The proposed solution provides a reliable and efficient method for conditioning humid process air in fermenter monitoring applications.
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