Hello,
I'm currently working on a project of a huge office building with a small area for retail and a restaurant. The restaurant has a commercial kitchen which, per LEED interpretation 10279, needs to comply with ASHRAE 55 - 2004 for thermal comfort design (to achive the IEQc7.1 point). As per section 5.2.1.2 of ASHRAE 55 - 2004 (Computer Model Method for General Indoor Application), I'm using the berkeley.edu comfort tool.
However and unlike other spaces, I understand that the air temperature and mean radiant temperature are far from being similar one to another for this specific case.
1_ What input data for air temperature and for mean radiant temperature should I use for a typical commercial kitchen?
2_ Can anyone advise me on a reliable source for this values?
Thnaks in advance!
Christopher Schaffner
CEO & FounderThe Green Engineer
LEEDuser Expert
963 thumbs up
September 21, 2016 - 10:29 am
We've struggled with this situation as well. The credit language says you're supposed to consider radiant temperature asymmetry which usually gets ignored. The actual cooking surface temperatures introduce radiant asymmetry to the occupants which leads us to believe that the only way to document air temperature and MRT is with a CFD analysis.
There's actually an ASHRAE research project which suggests that ASHRAE 55 is not appropriate for commercial kitchens. ( http://www.tandfonline.com/doi/abs/10.1080/10789669.2013.840494 )
In any case, we've been successful with an alternative compliance approach for the kitchen area. Following LI #10279, we had the engineers provided a narrative describing how the Kitchen systems have been designed to maintain acceptable comfort conditions to meet the credit intent.
Sample Language:
"The design of the HVAC system for the kitchen in the XXX Dining Hall used a different approach than the rest of the building because it operates separately from the other spaces. A 100% outdoor air makeup unit provides effective ventilation and includes a hot water heating coil that will maintain space temperature heating set points as needed.
During design, the team and the building owner determined that a cooling system would not be required for the dining hall kitchen. Due to the negative pressurization of the kitchen from the hoods and dishwasher exhaust, air will be drawn in from adjacent spaces on the open cooking line and the dish room to provide cooling. At full operating conditions, expected heat gains in the space from people and lighting will be offset by the amount of air being drawn in. It is estimated that the temperature of the kitchen will be slightly higher than the temperature of surrounding spaces in the summer months when usage is low. "
Jens Apel
134 thumbs up
November 9, 2016 - 4:23 am
Dear Christopher,
I've got a project with the same issues. I am not sure if I get you right. I would think as well that the cooking equipment's surface temperature needs to be included, which would require CFD.
In you alternative compliance path, did you include a CFD or just the sample language above? What was the temperature of the adjacent spaces? Was that language above accepted by reviewers or did you submit more complex calculations as well?
Thanks, Jens
Christopher Schaffner
CEO & FounderThe Green Engineer
LEEDuser Expert
963 thumbs up
December 22, 2016 - 4:22 pm
Just the sample language (with actual project details of course). It was accepted.