Paper Title
A Comparative Study of Energy Management Techniques in Asubcritical Organic Rankine Cycle for Waste Energy Recovery Technology

The organic Rankine cycle (ORC) technology occupies great attention due to its flexibility and wide energy applications at various grades of source temperatures. In the present research, many cycle arrangements were examined for the energy management and improvement of the(ORC) thermal performance. Two temperature levels were tested in an (ORC) system operated at (160) °C saturation temperature with superheat degrees of (10-80) °C in the high-temperature grade and (130) °C saturation temperature with (50) °Csuperheat degree in the low-temperature mini-cycles. Bleeding from the expanders and open feed heaters utilization were examined for both of the high and low-temperature sources. R-123 was circulated in the high-temperature mini-cycle whereas either R-123 or R-600 was utilized in the low-temperature side of the system. At fixed superheat degreeassessment basis, the R-123/R-123 fluid pair in the compound (CORC) system exhibited higher waste energy consumption, net power output, and thermal efficiency by (3-4) %, (4-4.5) %, and within (1) % than those of the compound bleeding (CBORC) system. The corresponding values of the R-123/R-600 system were (3-4) %, (5-6) % and (2-3) % respectively. R-123/R-123 compound bleeding (CBORC) system produced higher thermal system efficiency and net power output than those of the R-123/R-600 (CBORC) system by the range of (4-5) % and (2-3) % respectively, it required about (2) % lower heat load than that of R-123/R-600.The predicted system net thermal efficiency of the compound-bleeding (CBORC) R-123/R-123 and R-123/R-600 systems fell in the range of (14-15.5) % and (13.7-15) % respectively for the examined envelope of the superheat degree. The consumed heat load, net power output, and the net thermal efficiency showed an augmentation with a superheat degree increase and they were higher for the R-123/R-123 fluid pair than that of R-123/R600 ones.The independent (IORC) and (IBORC) systems have consumed a higher heat load than that of the compound ones by (2) % to attain equal superheat degrees or produce anequal net power output. At fixed extracted heat load, the (CBORC) has enhanced the thermal efficiency by (3-9) % when compared to that of the (IORC) one.Several outcomes of the present work were deduced and a new concept for the previously implemented energy management methods was outlined. Keywords - Compound Cycle, Energy Management, Expander Bleeding, Multi-Temperature Grades, Waste Energy Recovery