859 conveyor technology enables around 60% round trip efficiency and that improved low-rolling-resistance belts and low-friction idlers can raise performance toward 70% (Jennings, 2020). Sensitivity analysis was implemented across representative ranges of system main parameters. The used ranges included vertical drop ranging from 100–300m, belt speed from 2–4 m/s, material load from 230–660 kg/m, motor–generator efficiency from 0.90–0.95, material-handling loss factor from 0.03–0.07 and mechanical efficiency from 0.60–0.91. As indicated in Figure 2, the analysis confirms that vertical drop/conveyor inclination is the dominant driver of efficiency, because increasing inclination directly increases the gravity term relative to resistive losses. This aligns with conceptual CB-GES investigations in decommissioned pits, where geometry and slope are repeatedly identified as the governing constraints controlling both feasibility and energy recovery (Galetakis, 2023). Figure 2-Diagram for the sensitivity analysis for the CB-GES energy storage efficiency. The second most influential contributors to round trip efficiency are the mechanical efficiency (representing cumulative resistances in belt, idlers, pulleys, and material interaction) and the materialhandling losses associated with loading/unloading, pile interaction, and transfer inefficiencies. This outcome is substantially intuitive since when frictional losses rise, a larger portion of gravitational potential is dissipated as heat, reducing both discharge output and round-trip performance. Conversely, technological improvements that reduce rolling resistance through belt material selection, optimized idlers, and improved bearing design can substantially improve storage performance, as supported by experimental and analytical work on conveyor energy consumption (Bajda & Hardygóra 2021; Kulinowski et al., 2021). Power output sensitivity shows a different order as indicated in Figure 3. While higher vertical drop increases the available gravitational power, the strongest scaling occurs with mass throughput, which is governed by the product of belt speed and material load m,qv. Increasing either v or q therefore raises both charging demand and regenerative output, enabling higher power ratings from a single conveyor line. However, regenerative operation requires that the downslope component of weight exceeds conveyor resistances thus, a minimum slope is needed to remain in generating mode. This condition is consistent with experience from downhill regenerative conveyors, where the transition between motoring and generating depends on inclination and resistance state. 100 0.6 0.9 0.07 230 1000 2 300 0.91 0.95 0.03 660 4 0.34 0.38 0.42 0.46 0.50 0.54 0.58 0.62 Vertical drop per 1000m of length Mechanical efficiency Motor/generator efficiency (90-95%) Loss factor due to material handling Material Load (kg/m) Conveyor Length (m) Belt Speed (m/s) Storage efficiency (round trip)
RkJQdWJsaXNoZXIy MTM0Mzk2