Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
The OA controller will not alter the supply flow rate. The minimum flow fraction on a VAV fan only affects the fan power input calculation. EnergyPlus fans determine their flow rate based on the request from the terminal unit(s), or the fan can also be controlled using AvailabilityManager:NightVentilation (but that is intended for night cooling, not continuous ventilation). For this application, the best approach is to change the terminal unit(s) to AirTerminal:DualDuct:VAV:OutdoorAir. This terminal unit can be used in a single-duct mode (see EnergyPlus example file DOASDualDuctSchool, terminal unit Corner_Class_1_Pod_1 Dual Duct Box Component). It will set the supply flow rate for the terminal unit based on the inputs in a DesignSpecification:OutdoorAir object. Use the "Outdoor Air Flow Rate Fraction Schedule Name" field to control the day/night fractions. I don't know whether these objects can be accessed directly in the current version of OpenStudio. @aparker?
| | 2 | No.2 Revision |
The OA controller will not alter the supply flow rate. The minimum flow fraction on a VAV fan only affects the fan power input calculation. EnergyPlus fans determine their flow rate based on the request from the terminal unit(s), or the fan can also be controlled using AvailabilityManager:NightVentilation (but that is intended for night cooling, not continuous ventilation). For this application, the best approach is to change the terminal unit(s) to AirTerminal:DualDuct:VAV:OutdoorAir. This terminal unit can be used in a single-duct mode (see EnergyPlus example file DOASDualDuctSchool, terminal unit Corner_Class_1_Pod_1 "Corner_Class_1_Pod_1 Dual Duct Box Component). Component"). It will set the supply flow rate for the terminal unit based on the inputs in a DesignSpecification:OutdoorAir object. Use the "Outdoor Air Flow Rate Fraction Schedule Name" field to control the day/night fractions. I don't know whether these objects can be accessed directly in the current version of OpenStudio. @aparker?
| | 3 | No.3 Revision |
The OA controller will not alter the supply flow rate. The minimum flow fraction on a VAV fan only affects the fan power input calculation. EnergyPlus fans determine their flow rate based on the request from the terminal unit(s), or the fan can also be controlled using AvailabilityManager:NightVentilation (but that is intended for night cooling, not continuous ventilation). For this application, the best approach is to change the terminal unit(s) to AirTerminal:DualDuct:VAV:OutdoorAir. This terminal unit can be used in a single-duct mode (see EnergyPlus example file DOASDualDuctSchool, terminal unit "Corner_Class_1_Pod_1 Dual Duct Box Component"). It will set the supply flow rate for the terminal unit based on the inputs in a DesignSpecification:OutdoorAir object. Use the "Outdoor Air Flow Rate Fraction Schedule Name" field to control the day/night fractions. I don't know whether these objects can be accessed directly in the current version of OpenStudio. @aparker?
