### Abstract

A counterflow heat exchanger (CFHX) is an essential element for recuperative cooling cycles. The performance of the CFHX strongly influences the overall performance of the cryocooler. In the design of a heat exchanger, different loss mechanisms like pressure drop and parasitic heat flows are often treated separately. Acceptable values for the pressure drop and total heat leakage are estimated and thus a CFHX geometry is more or less arbitrarily chosen. This article applies another, less familiar design strategy where these losses are all treated as a production of entropy. It is thus possible to compare and sum them. In this way, a CFHX configuration can be found that is optimal for a certain application, producing a minimum of entropy and thus has minimum losses. As an example, the design steps of a CFHX for the micro cooling project at the University of Twente are given. Also a generalization of micro CFHX dimensions for cooling powers between 10 and 120 mW is presented.

Original language | Undefined |
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Pages (from-to) | 659-669 |

Number of pages | 11 |

Journal | Cryogenics |

Volume | 45 |

Issue number | 10-11 |

DOIs | |

Publication status | Published - 2005 |

### Keywords

- METIS-227184
- IR-76636
- Optimization
- Counterflow heat exchangers (E)
- Micro cryocooler
- Entropy minimization
- Joule-Thomson coolers (E)

## Cite this

Lerou, P. P. M., Veenstra, T. T., Burger, J. F., ter Brake, H. J. M., & Rogalla, H. (2005). Optimization of counterflow heat exchanger geometry through minimization of entropy generation.

*Cryogenics*,*45*(10-11), 659-669. https://doi.org/10.1016/j.cryogenics.2005.08.002