Development of a Cryocooler-based Remote Cooling System at Low Temperature

Remote cooling systems are a promising technology that could close the existing gap in cooling power between the powerful cryoplants and the compact, low-power, cryocoolers. Such systems could be accomplished by adding a carefully designed convection loop to a cryocooler. This upgrade has several advantages, notably decoupling mechanically and spacially the cooling interface from the cryocooler, enabling applications that could otherwise be harmful for the latter or that are sensitive to vibrations, as well as increasing the total cooling power capabilities. A critical component of the remote cooling systems under development is a counter-flow heat exchanger (CFHEX). Very high CFHEX effectiveness values (above 95%) are required to achieve high system cooling powers. With that in mind, the focus of this thesis is twofold. On the one hand, an analysis of different remote cooling system architectures was performed to determine their best fitness for a range of applications. The prototype systems were found to reach ~3.5 W of cooling power with only 2 W available at the cryocooler alone, both at 4.5 K. On the other hand, several measurement campaigns and its data post-processing were carried out on the novel CFHEX design. Effectiveness values of up to 98% were reached, exceeding the initial 95% goal.