When we use the S-by-S method we have problems with some rooms being over-lighted. On average, we are pretty good. ASHRAE 90.1 table 9.5.1 gives various building types for doing the whole-building method. Data centers are not listed. Has anyone been successful in picking one of the listed building types to represent a DC? Thanks.
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Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5906 thumbs up
May 28, 2019 - 12:10 pm
i don't see a good fit so I would use space by space method.
David Edenburn
ESD ConsultantRetired
17 thumbs up
May 28, 2019 - 9:54 pm
Thanks for your reply. I didn't see a good fit either. Problem is the data halls (very large rooms). The Owner wants 500 lux for when the technicians are working in there. That's too many Watts for ASHRAE. We can shut off half the lights for normal operations and have a manual over-ride for when work is going on (seldom). Can we count the half-lights as normal for the LPD and ignore when all the lights are on? Does that sound like something they would accept?
David Edenburn
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5906 thumbs up
May 29, 2019 - 11:04 am
You can always exceed the LPD as it is not mandatory. You just pay a penalty for doing so. The total LPD is the LPD and both models must follow the same lighting schedule. So no you can't count half the lights. Which space by space category are you planning to use. Typically this should be active storage which is no longer differentiated from regular storage in 2010. ASHRAE 90.1-2010 Addendum cn adds an allowance for computer rooms equal to 1.71 Watts per square foot. Note that a large portion of the lighting should be modeled off for most of the time due to the
mandatory control requirements; therefore the impact on the predicted lighting energy consumption would be very limited.