This module impliments a waterside economizer model that consists of a heat exchanger and a shutoff valve on each medium side. This waterside economizer model can be used in two different control scenarios:
port_b2 is controlled by a built-in PID controller and a three-way valve
by setting the parameter use_controller as true.
port_b2 is NOT controlled by a built-in controller
by setting the parameter use_controller as false.
Hence, an outside controller can be used to control the temperature. For example, in the free-cooling mode,
the speed of variable-speed cooling tower fans can be adjusted to maintain the supply chilled water temperature
around the setpoint.
dpFixed_nominal at isolation valves
to avoid redundant declarations and algebraic loops.