CLIMBING THE THERMODYNAMIC EFFECTIVENESS SUMMITS OF MECHANICAL VAPOR COMPRESSION COOLING THROUGH DISCHARGE GAS HEAT CONVERSION: A THEORETICAL APPROACH

摘要

This work presents results of the mechanical vapor compression refrigeration cycles provided with power (TWRCR) and cooling (TTRCR) recovery of their discharge gas, respectively. The TWRCR thermodynamical limit is established by the isothermal compression operation The work analyses the Trilateral Flash Cycle (TFC) as possible recovery cycle candidate. Compared to TFC, the Rankine Recovery Cycle is prefered in the TWRCR operation. The single- and two-stage TWRCR NH_3 cycles are modeled for the RRC and a particular recovery generator structure based on shell-and-tube heat exchangers. The single-stage, but especially the two-stage cycles results show the TWRCR NH_3 cycles are potentially feasible. The cycles effectiveness and the recovery generator heat exchange area should result according to a technical-economical optimization calculus. Concernig the TTRCR, its thermodynamic limit, established by a theorem proved here, is given by the Carnot cooling effectiveness of the mechanical vapour compression cycle. Two TTRCR study cases results show the TTRCR is less matched with the discharge gas source so far, therefore less efficient as compared to the TWRCR, but its feasibility is higher, comparatively.