Controlling valve position in EnergyPlus

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I have a chilled water loop in which primary and secondary loops are decoupled with a fluid-to-fluid heat exchanger. The outlet of the chiller in my model is in series with an ice storage tank. I want to control the system performance by using chiller evaporator output temperature ( chiller setpoint ) and the three-way valve position at the outlet of the tank ( which directs fraction of flow from the bypass pipe in parallel with the tank ).

I think that only has one setpoint available to manipulate in each loop. I can manipulate tank outlet temperature but that would not be practical in my case. I need the above-mentioned combination of control variables to set.

Is there an EMS solution for this problem?