AXIAL-FINNED HEAT TUBE HEAT EXCHANGER – AFHPHE STEADY-STATE AND TRANSIENT THERMAL PERFORMANCE IN THE EVAPORATOR REGION

This article presents a refined analysis of a finned tube heat exchanger (AFHPHE), which is being theoretically evaluated for use in air conditioning systems for operating rooms. The analysis provides unusual transient results for a heat exchanger with multiple thermosyphons, unlike previous studies that focused on a single thermosyphon. The objective is to provide an approximate theoretical prediction of the transient response of a heat exchanger with 49 closed two-phase thermosyphons, with 30 axial fins in each thermosiphon, in the evaporator region. The steady-state solution for the heat exchanger is already well established, with theoretical experimental comparisons performed with other similar heat pipe systems presented in the literature. The transient solution uses steady-state results of the work fluid and heat exchanger to validate the conclusions. The working fluid is the refrigerant R404a, widely used in similar systems. The transient results presented are the temporal variations in the heat exchanger rate, working fluid temperatures, the heat pipe wall temperatures, and the air outlet temperatures. Variations in the working fluid filling rates are simulated to demonstrate the consistency of the developed model. Although the theoretical model appears logically consistent, its irrefutable validation depends on future experimental results, which represents a significant challenge.