Abstract: A model based optimization method for determining optimized operating conditions to minimize overall power consumption of a chiller plant includes identifying each of the plurality of chiller plant subsystems in the chiller plant, generating a chiller performance model and a chiller stalling model, generating a cooling tower performance model, generating a chilled water pump performance model, generating a condenser water pump model, formulating a chiller plant optimization model, receiving chiller plant input data from the chiller plant, solving the chiller plant optimization model using the chiller plant input data, generating optimized chiller plant subsystems outputs, comparing the optimized chiller plant subsystems outputs to current operating chiller plant subsystems, generating projected energy savings of the optimized chiller plant subsystems, comparing the projected energy savings to an energy saving threshold value, when the projected energy savings exceeds the energy saving threshold value, sending