Thermodynamic optimization analysis of a tube-in-tube helically coiled heat exchanger for Joule-Thomson refrigerators

In the present study, a novel optimization model is developed based on the available work loss minimization for tube-in-tube helically coiled heat exchangers. The present numerical model takes into account available work losses, i.e. irreversibilities, due to heat transfer and frictional pressure drops of heat exchangers. By employing the expression of Carnot cycle efficiency, the formula for calculating the available work loss resulting from the irreversible heat transfer process is obtained and then utilized in the computation of the total available work loss. In the case under study, the effects of main design parameters of the heat exchanger on the available work loss are discussed in detail and the optimal design parameters of the heat exchanger are also obtained under the specified condition. The model and results presented here for the optimization of tube-in-tube helically coiled heat exchangers may provide a helpful guidance for applying such heat exchangers in Joule-Thomson refrigerators.