Hi, we are designing a project that has a DOAS unit serving code min outside air through underfloor plenum to the space with ceiling radiant panels handling heating and cooling load. The DOAS system will have underfloor diffusers that can be adjusted by the user. we have the following questions in regards to EAc5 requirement:
1). does the underfloor diffusers in this case (supplying only min outside air) qualify for the thermal controls for this credit?
2). if not, what do we need to do to make the underfloor diffuser qualified for the thermal control for this credit? For example, if we increase the airflow supplied by the diffuser, how much cfm increase is acceptable (or how much % of the load handled by the diffusers)?
Per a CIR dated 3/22/2007, providing individual occupants control over one of the primary thermal comfort factors (i.e., air temperature, radiant temperature, air speed, and humidity) does satisfy the credit requirements.
Thanks.
Dylan Connelly
Mechanical EngineerIntegral Group
LEEDuser Expert
472 thumbs up
December 4, 2017 - 11:40 am
Yuna - you probably qualify in LEED's eyes even though you are only supplying minimum ventilation air. However, IMO to qualify I would say the underfloor air system would need to be contributing to the comfort of the space. So it would be dependent on the supply air temperatures and air flow profile of the system and the diffuser. Like you said - the diffusers would need to be contributing to the one of the following: air temperature, radiant temperature, air speed, and humidity. So does the UFAD change the air temperature or air speed in the space and can you rotate the diffuser to change the air volume - if so you qualify.