Data Center Modeling

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Dear All,

I need to learn about data center modeling for LEED v2009 certification.
In particular, I will have to inform the client about how to build a
baseline model and what strategies can earn us points. Is there any
guideline or note regarding data center modeling for LEED v2009 to which
you can direct me to?

Best regards,

?mer Moltay, LEED AP BD+C, ASHRAE BEMP, ASHRAE CPMP, BREEAM Assessor

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Omer,

ASHRAE Addendum bu might be a good starting point.
http://www.ashrae.org/standards-research--technology/standards-addenda/Addenda-to-Standard-90-1-2007-IP-SI-Versions

Regarding LEED for data centers, have heard that LEED 2012 will have some compliance categories/paths.

While working on a recent data center project (non-LEED), I had come across this website that you could browse through for ideas on strategies:
http://www.datacenterknowledge.com/leed-platinum-data-centers/

Best of luck,
Umesh

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Omer,

Be careful with how you handle process energy in the LEED energy modeling for a data center. LEED requires that the process energy be modeled realistically and it has to be the same in the baseline and proposed models, unless you are making a case that you're doing something extraordinary to reduce process load. The server energy is typically a very large percentage of the total building energy usage in a data center, and it's considered process energy. So, it is difficult to save enough energy with envelope, HVAC, and lighting strategies to overcome that process energy to meet the minimum energy performance prerequisite. I think there may be some LEED CIRs related to data centers and process energy, so you might read up on those.

In my experience, the LEED reviewers will not allow you to model the process energy in a data center as just 25% because that's much lower than what is realistic. I know there are a number of LEED certified data centers (I've been involved in a couple of them myself), so it's possible to get certification, but I would manage expectations carefully with your client.

Maybe others have had different experiences. It seems like we've been waiting a long time for the "LEED for Data Centers" standard. I think there was a draft of it created before v2009 came out.

Stormy Shanks, PE

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Dear Stormy,

Thanks for the info. Is it the case that only the IT equipment power is
considered process energy? About 40% of the energy in a typical data
center is cooling energy. If the cooling energy is also considered
process energy, than you are absolutely right. However, if this is
regulated energy and the baseline model is built from Appendix G
requirements for cooling equipment, than I believe that there will be
some potential for energy savings. What do you think?

Omer.

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Dear All,

In addition, what is the baseline HVAC system for a data center? Is it
again defined through Table G3.1.1A?

Thanks,

?mer Moltay

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Omer,

I believe that the cooling is considered regulated energy usage, not process energy. I'm not certain how the Appendix G baseline would be modeled, though. There may be CIRs that provide direction on this. Addendum bu to 90.1-2007 that Umesh linked below takes away the economizer exception for data centers that's been used as a "loophole" in the past to model the baseline system with no economizer. But, you may be able to disregard that because you are not forced to use addenda for LEED models, right? There may be a CIR that addresses economizer, too. Have you reviewed the CIRs for information related to data centers and the baseline model?

Stormy Shanks, PE

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Classification: UNCLASSIFIED
Caveats: NONE

Something I have ran into over and over with data centers is that often the IT people will say "We require 10 tons of cooling for this room." But is that the actual load? How much is the safety factor or for future? Is that 10 tons 24hr 365 days a year?

Often at the time I am building the energy model, the building/data center is over a year away from being up and running. It is difficult to get an IT person to give you product cut sheets for computer equipment which won't be purchased for a year.

I have done a bit of research on server rooms and found that an older server which puts out 200 watts of heat when it is using 100% of its processing power will often give off 170 watts when it is using 10% of its processing power. Server manufactures are finding that servers are a major energy user and are starting to make greener servers. One of these servers was basically an old server split into 4 parts. 1 part would always be on and the others would only power up if they are needed, this allowed a 200 watt server go to 50 watts when the traffic is low.

In about every eco-design meeting I tell anyone who will listen that the server room is the elephant in the corner. I modeled a building where the server room + server room cooling was 50% of the total annual energy use.

John Eurek PE, LEED AP

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Omer,
Exactly, there is only SOME potential for energy savings. On the brighter side, one LEED datacenter is equivalent to saving energy in 10 office buildings.

If you can get 40% energy in HVAC in a datacenter, you would be lucky. Measured & modeled data put this at less than 30%; that if the datacenter is occupied to 90% of its capacity. LBNL has great research on this.
Challenges in datacenter energy efficiency are:
1. To provide technology for reduction in the server load (and hence getting into the realm of cloud computing and other 'exceptional' measures), while designing with uncertainty on tenant requirement.
2. Designing for flexible/expandable cooling with modular units.

Without overcoming the above two, its difficult to get more than a few LEED EA1 points, unless your datacenter is in Antarctica and there is some snow left around :)

Kapil Upadhyaya, LEED AP

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