A New Type of Compact Heat Exchanger with a High Thermal Efficiency

Abstract

Advances in cryogenic technology have increased the need for helium liquefaction and refrigeration in the lower temperature range. Low temperatures can be achieved with the aid of the well-known cryogenic processes» which incorporate the use of counterflow heat exchangers, The need in liquefaction processes for heat exchangers with a very high thermal efficiency is generally not essential because of the unbalanced mass-flows in the heat exchanger, In recent years, however, the need for refrigerators at liquid helium temperature has gradually been increasing. In a refrigeration cycle, the mass-flow rates in both directions are equal, and in this case the attainment of an acceptable overall efficiency of the cycle depends on the thermal performance of the heat exchanger.