Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
@Dustini, I am going to assume in my response that all the lighting will be installed in the future as a TI because I am unsure whether it is just the administrative area, or the process/break area too.
I am not sure what version of CBECC-Com you are using, but CBECC-Com v3a and v3b have a compliance type "New Envelope". You can access this in CBECC-Com by double clicking on the 'Project' object and there is a drop down selection for the compliance type. If you do this, you will notice that the default lighting status at the space level is "future" rather than "new". The future status sets the LPD based on the space type selected making the baseline and proposed LPD the same, as well as enforcing the same daylighting controls. Simulating the lighting as if it were installed simulates zones with more accurate loads allowing for the HVAC systems to be simulated more accurately. For the HVAC systems, you need to make a dummy system that is the same as the baseline system and these details can be found in the non residential ACM linked in the next paragraph.
The answer regarding ASHRAE guidelines is not an acceptable method for Title 24 compliance as Title 24 does not follow the ASHRAE guidelines. Title 24 has it's own set of guidelines you should follow in the Title 24 non-residential alternative calculation method (ACM) manual that can be downloaded from here. If this manual does not describe your issue specifically then you should get in touch with the California Energy Commission (CEC) hotline if it is a questions regarding the energy code or if it is a question regarding CBECC-Com and how to model specific scenarios then you should submit an issue here.
Regarding unoccupied zones I would double check that both the zone and the space are set to unconditioned. If you could copy and paste the exact error (shown in full in the .log file) then it would be easier for us to advise. Alternatively, you can get in touch via the CBECC-Com specific link above and ask them directly for guidance.
| | 2 | No.2 Revision |
@Dustini, @Dustinl, I am going to assume in my response that all the lighting will be installed in the future as a TI because I am unsure whether it is just the administrative area, or the process/break area too.
I am not sure what version of CBECC-Com you are using, but CBECC-Com v3a and v3b have a compliance type "New Envelope". You can access this in CBECC-Com by double clicking on the 'Project' object and there is a drop down selection for the compliance type. If you do this, you will notice that the default lighting status at the space level is "future" rather than "new". The future status sets the LPD based on the space type selected making the baseline and proposed LPD the same, as well as enforcing the same daylighting controls. Simulating the lighting as if it were installed simulates zones with more accurate loads allowing for the HVAC systems to be simulated more accurately. For the HVAC systems, you need to make a dummy system that is the same as the baseline system and these details can be found in the non residential ACM linked in the next paragraph.
The answer regarding ASHRAE guidelines is not an acceptable method for Title 24 compliance as Title 24 does not follow the ASHRAE guidelines. Title 24 has it's own set of guidelines you should follow in the Title 24 non-residential alternative calculation method (ACM) manual that can be downloaded from here. If this manual does not describe your issue specifically then you should get in touch with the California Energy Commission (CEC) hotline if it is a questions regarding the energy code or if it is a question regarding CBECC-Com and how to model specific scenarios then you should submit an issue here.
Regarding unoccupied zones I would double check that both the zone and the space are set to unconditioned. If you could copy and paste the exact error (shown in full in the .log file) then it would be easier for us to advise. Alternatively, you can get in touch via the CBECC-Com specific link above and ask them directly for guidance.
