Hi, the CI project I am working on uses only the base building system supply for meeting rooms with between 2 and 8 people. These rooms are all located internally and only use a temperature sensor to modulate the 100% OA VAV base building system. As the system is 100% OA there is ample ventilation being provided to the space. Also the VAV damper is connected to a temperature sensor that will modulate with the occupant density.
I would like to confirm that our system meets the intent of the credit and that CO2 sensors are obsolete in this senario.
Any meeting rooms with more than 8 people are provided with a supplementary system with temeprature and CO2 sensors.
Roger Chang
Principal, Energy and Engineering LeaderDLR Group | Westlake Reed Leskosky
LEEDuser Expert
398 thumbs up
January 5, 2016 - 12:31 pm
There is no exception for a case like this, because there is still the potential that a VAV box could fully close or not open sufficiently, resulting in an indoor environmental issue. An issue could also develop at the air-handling unit itself where having carbon dioxide sensing would provide another layer of feedback. I do agree with the direction you're headed in conceptually, as this type of system has a greater chance of providing sufficient ventilation under all conditions versus a VAV system with a lower system level ventilation fraction.
Christie Rimes
January 10, 2016 - 5:08 pm
Any system has the potential to not work resulting in an indoor environmental issue. The credit asks that a damper is connected to a CO2 sensor in the room. This has the same potential to not work as a VAV box.
If there is a problem at the air-handling unit itself this would be picked up due to the temperature sensors as the rooms wouldn't be conditioned correctly.