Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
Caution! Wild assumptions below.
Would it not be possible in OpenStudio to set up an Empty Air Loop without any coils such as an ERV (DOAS) system serving each VRF indoor unit? Obviously, the ERV would not be added to describe the system above. The fan and the AirLoopHVC Outdoor Air System are are the key objects you need. It should not matter, but is the indoor unit supply fan variable speed as well, or is it constant?
There is an attempt to model an ERV (DOAS) in OpenStuio in this forum question: https://unmethours.com/question/8359/how-do-i-model-erv-doas-with-vrf-in-openstudio/.
That post is discussing an ERV (DOAS) providing tempered or even conditioned outdoor air to each VRF indoor unit, which is common practice in my experience. There were errors, according to the original poster, when the loop was modeled without a setpoint manager. I am not sure how you could work around that issue if you are providing raw unconditioned air directly to the indoor unit, unless you ignore the many warnings/ errors associated with a loop setpoint manager without anything to manage.
| | 2 | No.2 Revision |
Caution! Wild assumptions below.
Would it not be possible in OpenStudio to set up an Empty Air Loop without any coils such as an ERV (DOAS) system serving each VRF indoor unit? Obviously, the ERV would not be added to describe the system above. The fan and the AirLoopHVC Outdoor Air System are are the key objects you need. It should not matter, but is the indoor unit supply fan variable speed as well, or is it constant?
There is an attempt to model an ERV (DOAS) in OpenStuio in this forum question: https://unmethours.com/question/8359/how-do-i-model-erv-doas-with-vrf-in-openstudio/.
That post is discussing an ERV (DOAS) providing tempered or even conditioned outdoor air to each VRF indoor unit, which is common practice in my experience. There were errors, according to the original poster, when the loop was modeled without a setpoint manager. I am not sure how you could work around that issue if you are providing raw unconditioned air directly to the indoor unit, unless you ignore the many warnings/ errors associated with a loop setpoint manager without anything to manage.
UPDATE: There is a MassFlowRate setting under Setpoint Manager Scheduled - Scheduled Deck Temp for the Control Variable. I am not sure if this fixes the fatal errors that are likely without the manager, but a good place to start.
| | 3 | No.3 Revision |
Caution! Wild assumptions below.
Would it not be possible in OpenStudio to set up an Empty Air Loop without any coils such as an ERV (DOAS) system serving each VRF indoor unit? Obviously, the ERV would not be added to describe the system above. The fan and the AirLoopHVC Outdoor Air System are are the key objects you need. It should not matter, but is the indoor unit supply fan variable speed as well, or is it constant?
There is an attempt to model an ERV (DOAS) in OpenStuio in this forum question: https://unmethours.com/question/8359/how-do-i-model-erv-doas-with-vrf-in-openstudio/.
That post is discussing an ERV (DOAS) providing tempered or even conditioned outdoor air to each VRF indoor unit, which is common practice in my experience. There were errors, according to the original poster, when the loop was modeled without a setpoint manager. I am not sure how you could work around that issue if you are providing raw unconditioned air directly to the indoor unit, unless you ignore the many warnings/ errors associated with a loop setpoint manager without anything to manage.manage. You could always schedule "OFF" the coils you place in order to get the simulation to run, but the warnings will likely be monstrous.
UPDATE: There is a MassFlowRate setting under Setpoint Manager Scheduled - Scheduled Deck Temp for the Control Variable. I am not sure if this fixes the fatal errors that are likely without the manager, but a good place to start.
