i try to figure out how Energyplus divides demand to each primary equipment (chillers, boilers, etc..) with step by step. After getting the loop demand values and available supply loop components available values ( pump flows, boller/chiller capacities and flows), how ManagePlantLoopOperation, mentioned in EP doc, choose optimal PLR and required load for each primary equipment ? Optimal PLR makes me confusing most. How i need to understand about that optimalPLR in this case ?