Revision history [back]

LEED System 4 is a package single zone heat pump with CAV Fan. I have implemented this in OpenStudio as a regular AirLoopHVAC with Constant Volume Fan. I noticed in DView, looking at mixed air flow, that this fan truly runs constantly 24/7, i.e. does not cycle at night. Yet, I believe the LEED (well ASHRAE 90.1-2016 Appendix G) baseline allows this system to be on constantly during the day, but needs it to cycle at night - G3.1.2.4 Fan System Operation? If so, do I need to replace the Constant Volume Fan with an OnOff Fan, or maybe even implement System 4 as a Unitary System? If OnOff Fan, that does not seem to be available in OpenStudio?

LEED System 4 is a package single zone heat pump with CAV Fan. I have implemented this in OpenStudio as a regular AirLoopHVAC with Constant Volume Fan. I noticed in DView, looking at mixed air flow, that this fan truly runs constantly 24/7, i.e. does not cycle at night. Yet, I believe the LEED (well ASHRAE 90.1-2016 Appendix G) baseline allows this system to be on constantly during the day, but needs it to cycle at night - G3.1.2.4 Fan System Operation? If so, do I need to replace the Constant Volume Fan with an OnOff Fan, or maybe even implement System 4 as a Unitary System? If OnOff Fan, that does not seem to be available in OpenStudio?