Building Energy Assessments, Solutions, and Technologies BEAST
DX VAV System
The DX VAV system consists DX coil through an air-sourced heat pump to provide heating or cooling as needed. The system serves three zones with VAV boxes with hot water reheat.
DX AHU
Air Side Economizer
The system contains three dampers: outside , return , and exhaust dampers to control the amount of ventilation introduced to the system. if the outside air is suitable, the control activates the economizer so an appropriate amount of fresh will be introduced to produce free cooling. The control provides several control strategies to active the economizer. A new strategy can be added to the control.
VAV System Control Strategy
The system has the following major control loops: space control loops, supply air temperature SAT control loop, and duct static pressure control loop, and ventilation control loop. The SAT control is to maintain the SAT at its setpoint by modulating the cooling or heating DX coil capacity or outside/retune/discharge dampers. The duct static pressure control is to maintain the duct static pressure at its set point by modulating the fan speed. The zone air temperature is controlled by two cascaded control loops; the error between the space temperature and its setpoint determines the airflow rate setpoint in the first control loop, and the VAV box damper is modulated to maintain the airflow rate at its setpoint in the second loop.
Return Duct and Fan
The system is equipped with return air duct and fan to bring the air back form the zones to central chilled water AHU. The fan is controlled to maintain a slightly positive pressure in the zone.
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The control set points can be reset through multiple build-in control strategy options but any future strategies can be added for testing.