An integrated approach for designing Joule-Thomson refrigerators operating with mixtures

Abstract

• An integrated design approach of JT refrigerators operating with mixtures. • Optimal circulating mixture composition in JT refrigerator steady-state operation. • Low-temperature refrigerator for thermostatting medical objects at −150 °C. Throttle low-temperature closed-cycle Joule-Thomson refrigerators with low performance (compressor volumetric flow rate less than 25 m 3 /h) are one of the promising directions of development of refrigeration equipment. These refrigerators operate with mixtures of refrigerants and are capable of thermostatting different samples at the temperature below −160 °C. Such refrigerators have several special features so that it would take an integrated approach to design new types of refrigeration equipment based on Joule-Thomson refrigerators. This paper proposes such a method for mixtures with more than three components. The method comprises a design calculation stage and an experimental stage; the stages are interlinked. As a part of considering these design stages, we describe an original method for calculating the multi-component mixed refrigerant charge and the original algorithm of solving the problem of ensuring the “estimated circulated composition” in the steady-state operation mode in 3–5 iterations. Also, we present the results of experimental verification of the integrated approach to the design for the case of a low-temperature medical refrigerator created based on the original patented layout.