Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
It's not uncommon for the solar load to lag several hours behind the peak solar. It takes time for the solar energy to pass through the construction materials. HVAC loads are typically highest 2-3 hours after the sun has reached it's peak. I suspect the solar component is causing this result. It is also common to allow the HVAC systems to operate during occupied hours. If HAVC systems do not need to run they won't. You could switch between constant fan operating mode and cycling fan if that option is available with your HVAC system.
I can think of several ways to diagnose if solar is the culprit. One is to report the inside surface temperature of the zone walls to see if that temperature is higher than the zone temperature. You could also turn off solar and run the simulation again. I am not sure what the easiest way to do this, but I do know you can edit the weather file and lower the direct solar component or add cloud coverage to minimize the impact.
| | 2 | No.2 Revision |
It's not uncommon for the solar load to lag several hours behind the peak solar. It takes time for the solar energy to pass through the construction materials. HVAC loads are typically highest 2-3 hours after the sun has reached it's peak. I suspect the solar component is causing this result. It is also common to allow the HVAC systems to operate during occupied hours. If HAVC HVAC systems do not need to run they won't. You could switch between constant fan operating mode and cycling fan if that option is available with your HVAC system.
I can think of several ways to diagnose if solar is the culprit. One is to report the inside surface temperature of the zone walls to see if that temperature is higher than the zone temperature. You could also turn off solar and run the simulation again. I am not sure what the easiest way to do this, but I do know you can edit the weather file and lower the direct solar component or add cloud coverage to minimize the impact.
| | 3 | No.3 Revision |
It's not uncommon for the solar load to lag several hours behind the peak solar. It takes time for the solar energy to pass through the construction materials. HVAC loads are typically highest 2-3 hours after the sun has reached it's peak. I suspect the solar component is causing this result. It is also common to allow the HVAC systems to operate during occupied hours. If HVAC systems do not need to run they won't. You could switch between constant fan operating mode and cycling fan if that option is available with your HVAC system.
I can think of several ways to diagnose if solar is the culprit. One is to report the inside surface temperature of the zone walls to see if that temperature is higher than the zone temperature. You could also turn off solar and run the simulation again. I am not sure what of the easiest way to do this, but I do know you can edit the weather file and lower the direct solar component or add cloud coverage to minimize the impact.
