Hi Tommy, you have probably moved on from this question but for those who still have unmet hour issues and are looking for some tips, here is what I have been trying.
Unmet hours can be a result of several things, from systems with too many zones where a few will drive the system and starve the others to under-sized equipment (coil capacity or airflow capacity) or very slim setpoints (for instance, a high supply air temperature of 70F to a room at 75F). Lets assume that the zoning is correct and there are still unmet hours. I recommend finding which zones are out of hour ranges (look in SS-F?) and increasing that thermal zone's local design cooling/heating or airflow design criteria or increasing the whole systems design criteria.
For thermal zones, often, equipment (coils and fans) are not explicitly defined by an energy modeler and eQuest autosizes them. Use the SV-A report you can see what eQuest has autosized each system and each child-thermal-zone to for cooling, heating and airflow. One way to reach unmet hours is to specify the cooling capacity required at that zone (if unmet cooling for instance) above what the SV-A report is currently sizing it for. Effectively, increasing the coil size.
For designs where you know the specific cooling capacity of each system and the design is further developed, re-sizing fans and coils may not be possible. In these instances, I would study the hourly outputs first and check to ensure that the thermostate is acting as you anticipate, the right amount of air is moving through the space, and the conditioning system is actually engaging. The other day, I found that my PVVT system when set to Heat Pump for heating never actually turned on, despite very cold conditions in the space. Still not sure why this happened, but, the hourly reports are key.
Hi Tommy, you have probably moved on from this question but for those who still have unmet hour issues and are looking for some tips, here is what I have been trying.
Unmet hours can be a result of several things, from systems with too many zones where a few will drive the system and starve the others to under-sized equipment (coil capacity or airflow capacity) or very slim setpoints (for instance, a high supply air temperature of 70F to a room at 75F). Lets assume that the zoning is correct and there are still unmet hours. I recommend finding which zones are out of hour ranges (look in SS-F?) and increasing that thermal zone's local design cooling/heating or airflow design criteria or increasing the whole systems design criteria.
For thermal zones, often, equipment (coils and fans) are not explicitly defined by an energy modeler and eQuest autosizes them. Use the SV-A report you can see what eQuest has autosized each system and each child-thermal-zone to for cooling, heating and airflow. One way to reach unmet hours is to specify the cooling capacity required at that zone (if unmet cooling for instance) above what the SV-A report is currently sizing it for. Effectively, increasing the coil size.
For designs where you know the specific cooling capacity of each system and the design is further developed, re-sizing fans and coils may not be possible. In these instances, I would study the hourly outputs first and check to ensure that the thermostate is acting as you anticipate, the right amount of air is moving through the space, and the conditioning system is actually engaging. The other day, I found that my PVVT system when set to Heat Pump for heating never actually turned on, despite very cold conditions in the space. Still not sure why this happened, but, the hourly reports are key.