# Custom Control of AHU using EMS in Energy Plus

I want to design a customized control logic for a CAV AHU in E+ that controls the Fan operation and the Cooling Coil's valve position based on a certain Temperature value.

The logic goes as follows:

Condition 1: if T_d <= 20 then AHU_supply_Fan is OFF, AHU_Cooling_Coil is OFF

Condition 2: else if T_d > 20 and T_d <= 22 then AHU_supply_Fan is ON, AHU_Cooling_Coil is 10% Open

Condition 3: else if T_d > 22 and T_d <= 24 then AHU_supply_Fan is ON , AHU_Cooling_Coil is modulating

Condition 4: else if T_d > 24 then AHU_supply_Fan is ON , AHU_Cooling_Coil is 100% Open

I have the following queries:

1- Can I control the Availability Schedule of the Constant:Volume:Fan without the need to modifying the AirLoop's Availability Schedule or will the latter always override the former? Is there a way to have the two Availability Schedules independent from each other?

2- How to implement the AHU's Cooling Coil position for Conditions 1 and 4? As per the RDD and EDD files, I do not have a dedicated actuator for that. The available actuators for the cooling coil outlet water flow are as follows:

EnergyManagementSystem:Actuator Available,AIR LOOP AHU COOLING COIL WATER OUTLET NODE,System Node Setpoint,Mass Flow Rate Setpoint,[kg/s]

EnergyManagementSystem:Actuator Available,AIR LOOP AHU COOLING COIL WATER OUTLET NODE,System Node         Setpoint,Mass Flow Rate Maximum Available Setpoint,[kg/s]

EnergyManagementSystem:Actuator Available,AIR LOOP AHU COOLING COIL WATER OUTLET NODE,System Node Setpoint,Mass Flow Rate Minimum Available Setpoint,[kg/s]


Will the following be correct? -> Setting the Mass Flow Rate Setpoint actuator based on the 1) rated/design CC water flow rate, and 2) Valve position - Water flow rate relation.

3- For Condition 3, I need to link the the valve position modulation strategy to the particular Temperature value T_d that is actually calculated not directly sensed. How can that be achieved?

Thank you.

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