[Equest-users] Data Center Modelling and Ice Storage (3) Process energy reduction

[Shuichi Hendrickson]

Bruce and all,

Thanks for your input below, I will definitely take breaking out server space into additional zones per expansion phase into consideration.

Regarding process energy, my understanding is that there is a mechanism for showing process energy reduction via the exceptional calculation method per ASHRAE 90.1 ( See LEED-NC 2009 EAp2 pg 238 paragraph 2 and EAc1 p258 2nd to last paragraph of Option 1). Admittedly, I have never used an exceptional calculation to show process energy production, but it seems that it is possible. As mentioned in my second post, I came across a CIR that approved using Server Virtualization as means to show process reduction for a data center (Copied Below). We have submitted a CIR to confirm that this would be possible solution for the project, but have not received the response yet.

The CIR is for an existing data center so the baseline would have been existing equipment. In my case, I am operating under the premise that standard servers for the baseline would not adopt Virtualization. Though, to honest, I don't know if Virtualization for a new datacenter would actually save as much energy as claimed below. I think an argument could be made that Virtualization allows for higher performance machines that use more energy to being packed into the same amount of space. The energy reduction would be realized at part load when a single "Virtualized server" could support the tasks of several, allowing those units to be turned off. I don't know enough about servers to comment much beyond this at this time.

It sounds like you do a fair bit of datacenter modelling, so perhaps the above could be of value to your projects as well.

I would appreciate if anyone has any experience to share or comments on using exceptional calculations for process energy reductions.


CIR 2441
    Ruling [  ]

The applicant may use the Exceptional Calculation Method to take credit for any energy savings available from the server virtualization technology. Be sure to include as supporting documentation under EAc1 all assumptions made in the calculations, detailed data, any actual measurements taken to support the savings claims and any other pertinent information. Please note that the actual amount of credit will be determined by the review team at the time of the review.

    Inquiry [  ]


This project is a remodeling of an existing office building that will include the addition of a Data Center. The Data Center will make extensive use of server virtualization to save energy, space and money. Server virtualization is the technique of replacing multiple servers with one server running multiple "virtual servers" on one larger, high performance server. In their existing Data Center, our client runs an average of 8 virtual servers on each high-performance server. Although the high performance server uses more energy than any one of the low to medium performance servers that it replaces, this results in a net energy savings of between 60-75%. Our question is: Under EAc1, Option 1, may we use the Exceptional Calculation Method to model the energy savings accountable to server virtualization?


Thanks in advance and regards,
Shuichi


________________________________
From: Bruce Easterbrook [mailto:bruce5 at bellnet.ca]
Sent: Tuesday, June 21, 2011 1:25 AM
To: Will Mak
Cc: Shuichi Hendrickson; Patrick Keeney; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Data Center Modelling and Ice Storage (2)

Correct, you need to model them but they normally don't vary between the 2 models, just accounted for.  LEED does assess how efficiently your system deals with them for certain process loads in certain buildings.  I was describing a "industrial type" process load which a big data centre is similar to.  LEED doesn't really get into this territory or give credits for it as far as the "industrial" process load.  Now Google is very interested in it because it impacts their profitability.  LEED is more concerned with the commercial market where first cost rules and down and dirty is the norm.  Traditionally this sector did not pay much (any?) attention to operating cost.  LEED is trying to encourage longer term thinking when a building is designed and built.  Industry normally thinks long term and includes operating cost in their analysis over the life cycle of the process.  With the increase in the cost of energy plus the needs of utility companies to reduce their peak loads or reduce the rate of expansion of this peak load it makes sense for the government and all the players to be on the "team".  There is a disconnect in the commercial sector to many of the market forces which would encourage better design.  There is also a huge stock of old properties to be re-furbished.  This sector consumes a large chunk of the nations energy.
Bruce


On 20/06/2011 11:37 AM, Will Mak wrote:
Where does it say LEED does not deal with process loads? It states that you must model the process loads anticipated on the design on both proposed design and baseline models.

William Mak, LEED AP BD+C
Mechanical Design Engineer

EPSTEIN
Architecture
Interiors
Engineering
Construction
Sustainability

600 West Fulton Street
Chicago, Illinois 60661-1259

D: (312) 429-8116
F: (312) 429-8800
E: wmak at epsteinglobal.com<mailto:wmak at epsteinglobal.com>
W: www.epsteinglobal.com<http://www.epsteinglobal.com/>

? Epstein is a firm believer in sustainability. We ask that you please consider the environment before printing this e-mail.

From: Bruce Easterbrook [mailto:bruce5 at bellnet.ca]
Sent: Monday, June 20, 2011 10:22 AM
To: Shuichi Hendrickson
Cc: Will Mak; Patrick Keeney; equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: Re: [Equest-users] Data Center Modelling and Ice Storage (2)

LEED doesn't deal with process loads.  Typically it is not something you can have much effect on.  The process defines how much heat you have to deal with and normally it is not negotiable.  Economically your main technique is to load shift.  Time of use electrical billing (TOU) if in effect will further reinforce this technique.  If you have cheap natural gas available and a large enough load absorption chillers become an option as well.  Economizer use and free cooling can be very effective.  As far as your project goes and myself knowing very little about the actual project you seem to be on the right track.  You are using a legitimate technique to load shift.  There aren't really any "rules" except to design an energy efficient system which is inexpensive to run.  As far as your set up of your model I would use zones to correspond to the planned expansions.  Your first zone would represent Day 1 conditions without any techniques used to reduce server loads.  Your last will correspond to the full design.  You will need to get some idea of how they plan to expand and enhance the server performance but just start with a plain baseline for them.  Looking at your unit combinations I would go with more zones myself, break down Day one conditions into 2 or 3 zones.  It is easier to combine zones later than try to add more.  You will probably be able to provide input on their proposed expansion plan and the timing as well once you have a model running.  You want to keep your model flexible so it is easy to adjust as you learn more about the system without having to start over.  Because there are discrete equipment sizes both for HVAC systems and servers you could assist in planning the expansions by optimizing the size of each addition and by having a certain amount of over capacity to handle smaller additions to the servers without adding to the HVAC system.  You would also optimize the size of the extra capacity to minimize inefficiencies in the part load running.  You would be able to add their strategies for reducing the process load to the model.  Make sure you keep a copy of the model before you start to run different ideas.  Some things suggested may require you to back up to the base model.  With copies along your process you just jump back to where you need to restart your model creation without going right back to the beginning.  Servers are a little different from people.  You have to remove all the heat all the time.  They have to be operational 24/7 no if ands or buts, 100% up time.
Bruce Easterbrook P.Eng.
Abode Engineering

On 20/06/2011 01:24 AM, Shuichi Hendrickson wrote:

Patrick, Will, John and all







Thank you all for the quick responses to my original post.





Based on your comments, I have a couple more questions that I hope someone may have insight into.



It seems that due to the large process equipment energy usage for datacenters, others have experienced that showing significant energy reduction through HVAC alone is difficult. Following from this, for the purposes of LEED it appears that is would be best to find some strategy to minimize process loads in the model or somehow show a process load reduction.



1)  For the project I am working on, we are starting off with 3 X 600RT CWH chillers + 2 X 600RT dual mode (CHW and Ice) chillers on Day 1, but with an additional 1 x 600RT CHW + 2 X 600RT dual mode units are planned for full future design cooling capacity. Correspondingly, the Server (process equipment) will be installed in stages as well.



Does anyone know what if there are any rules as to what point in project development the model should be based on? My original plan was to model at full design capacity, but I am thinking now that it would be better to model Day 1 conditions if permissible to lower the denominator in the energy reduction calculation.



2) The client is considering using Server Virtualization technology for the IT equipment. I understand that this is a much more efficient means of operating server equipment and I am considering using this as a basis for showing process energy reduction based on a CIR I have come across (CIR 2441). The CIR was originally submitted for a remodelling project, so the process reduction would have been shown versus the originally installed equipment.



Does anyone have any thought or experience any with showing this type of process reduction for a LEED-NC project? I am imagining the baseline will be based on servers without virtualization. I don't really know enough about "Virtualization" at this stage to really quantify what energy reduction, if any, could be expected. Some long conversations with the IT designer are warranted, but would appreciate if any one has any thoughts to share.



Again, any thoughts will be greatly appreciated.



Thanks in advance,

Shuichi


Shuichi Hendrickson
Environmental Engineer, LEED AP

ERM Japan
The Landmark Tower
Yokohama 19F
2-2-1-1, Minatomirai, Nishi-ku
Yokohama, 220-8119, Japan

T:+81(0)45-640-3780<tel:%2B81%280%2945-640-3780>
F:+81(0)45-640-3781<tel:%2B81%280%2945-640-3781>
shuichi.hendrickson at erm.com<mailto:shuichi.hendrickson at erm.com>
www.erm.com<http://www.erm.com/>
Ranked No1 All-Environmental Firm: ENR Magazine (2004, 2005, 2006, 2007)
Environmental Adviser of the Year: Acquisitions Monthly (2005, 2006, 2008)
P Please consider the environment before printing this email


________________________________
From: Will Mak [mailto:wmak at epsteinglobal.com]
Sent: Friday, June 17, 2011 11:15 PM
To: Patrick Keeney; Shuichi Hendrickson
Cc: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: RE: [Equest-users] Data Center Modelling and Ice Storage

Side note that you may want to keep in mind that's been brought up here is how you model the data center process loads. If the loads are too large, you may have a difficult time meeting the prerequisite.

William Mak, LEED AP BD+C
Mechanical Design Engineer

EPSTEIN
Architecture
Interiors
Engineering
Construction
Sustainability

600 West Fulton Street
Chicago, Illinois 60661-1259

D: (312) 429-8116
F: (312) 429-8800
E: wmak at epsteinglobal.com<mailto:wmak at epsteinglobal.com>
W: www.epsteinglobal.com<http://www.epsteinglobal.com/>

? Epstein is a firm believer in sustainability. We ask that you please consider the environment before printing this e-mail.

From: equest-users-bounces at lists.onebuilding.org<mailto:equest-users-bounces at lists.onebuilding.org> [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Patrick Keeney
Sent: Friday, June 17, 2011 9:06 AM
To: Shuichi Hendrickson
Cc: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: Re: [Equest-users] Data Center Modelling and Ice Storage

Hi Shuichi,

Below is a link to an additional source from a previous post that helps explain how to model UFAD and/or displacement ventilation.  Their method is very similar to yours, in that you split the equipment loads between the plenum and the space.  In particular, there is a section which explains pretty clearly how to model UFAD in eQUEST.  This may be repeat info to you, but it may be able to help.

http://www.archenergy.com/ieq-k12/Public/Proj2_Deliverables/D2.9c_FinalDVDesignGuide_2006-0630.pdf


Best, Patrick



On Fri, Jun 17, 2011 at 3:07 AM, Shuichi Hendrickson <Shuichi.Hendrickson at erm.com<mailto:Shuichi.Hendrickson at erm.com>> wrote:
Hello all,


I am attempting to model a data center in eQuest for LEED. This will be a first attempt at modelling a data center for me and I am in hopes someone could provide some sage advice on the subject.


My understanding is that the data center will be a standard hot/cold aisle configuration with underfloor cooling (UFAD). The CRACs are on CHW and the CHW plant consists of multiple chillers, as well as, dedicated chillers for ice storage.

Recognizing that eQuest doesn't consider fluid air dynamics or temperature stratification resultant from UFAD, I am considering using the UFAD modelling guidance in the EDR Design Guidelines: HVAC Simulation Guidance (http://www.energydesignresources.com/resources/publications/design-guidelines/design-guidelines-hvac-simulation-guidelines.aspx)

This document addresses UFAD, but not specific to data center or hot/cold aisle. What Ive gotten out of the guidance is that for comfort UFAD applications, the upper portion of a room (non occupied ) space is defined as plenum and the internal loadings for the room are apportioned between the occupied zone and plenum. It seems to me that this method could be appropriate for hot/cold aisle scenarios as well, with the hot aisle as the plenum and cold as space. From the guidance equipments loads are suggested to be apportioned 67% space 33% plenum for comfort applications.

My understanding of hot/cold aisle configurations is that cold air is supplied on the front side of the server racks, pulled through the racks by the server internal cooling fans, and exhausted in to the hot aisle. Following from this logic it seems to me that the equip load should apportioned mostly to the plenum (hot aisle).

Does anyone have a better suggestion for load proportioning for a datacenter?  Am I over complicating this?

My next challenge is modelling the Ice storage. I have 6 chillers of which 2 are dual mode CHW and Ice making. My guess is that I will have to model the dual mode units as 4 chillers (2 for CHW and 2 for ice) because of the different efficiencies and supply temps, while somehow using to the equip controls to make sure the chillers are not operating simultaneously.

This will be another first attempt for me. If anyone knows of any useful modelling guidance docs or has any advice on this it would be highly appreciated.


Thank you in advance and regards,



Shuichi Hendrickson
Environmental Engineer, LEED AP

ERM Japan
The Landmark Tower
Yokohama 19F
2-2-1-1, Minatomirai, Nishi-ku
Yokohama, 220-8119, Japan

T:+81(0)45-640-3780<tel:%2B81%280%2945-640-3780>
F:+81(0)45-640-3781<tel:%2B81%280%2945-640-3781>
shuichi.hendrickson at erm.com<mailto:shuichi.hendrickson at erm.com>
www.erm.com<http://www.erm.com/>
Ranked No1 All-Environmental Firm: ENR Magazine (2004, 2005, 2006, 2007)
Environmental Adviser of the Year: Acquisitions Monthly (2005, 2006, 2008)
P Please consider the environment before printing this email


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