[Bldg-sim] Heat Recovery Chillers and Lab Outdoor Air

[dlombard at earthlink.net]

Hi Sam,

You can contact Vanderweil Engineers in NJ as they did the energy modeling for the Yale Uninversity's Chemistry Research Lab Building when I was the sustainable design consultant for RETEC (working with Mark Loeffler - now at Atelier Ten). 

Lee Schofer was the engineer at Vanderweil and hopefully they will give you full details on how they modeled the 100% outside air lab building per the USGBC's response to our LEED-NC v2.1 CIR. note the building received LEED-NC v2.1 Silver certification.

Regards,
Debra Lombard, LEED AP, EIT
Sustainability research & consulting
dlombard at earthlink.net


-----Original Message-----
>From: Sam Mason <sam.mason at atelierten.com>
>Sent: Oct 15, 2009 12:12 PM
>To: Paul Erickson <perickson at aeieng.com>, "Matutinovic, Luka" <LMatutinovic at halsall.com>
>Cc: bldg-sim at lists.onebuilding.org
>Subject: Re: [Bldg-sim] Heat Recovery Chillers and Lab Outdoor Air
>
>Paul,
>The item in 90.1 you pointed out is exactly the problem we are having
>(and that 90.1-2004 does not address lab buildings). We just submitted a
>lab/hospital building to the GBCI and included a separate narrative
>which reads very similar to your email below, pointing out real life
>construction and operation for 100% OA buildings (no recirculation air)
>versus ASHRAE (with recirculation air). It sounds like the response we
>will get from GBCI is to follow ASHRAE exactly, but we can hope.
>
>Thanks for your input.
>
>Sam
>--
>Sam Mason
>Atelier Ten
>
>
>-----Original Message-----
>From: Paul Erickson [mailto:perickson at aeieng.com] 
>Sent: Thursday, October 15, 2009 9:43 AM
>To: Matutinovic, Luka; Sam Mason; bldg-sim at lists.onebuilding.org
>Subject: RE: [Bldg-sim] Heat Recovery Chillers and Lab Outdoor Air
>
>Luka/Sam,
>
>I agree with Luka's response most of the time.  However, in laboratory
>facilities, the air change rates aren't typically dictated by code or
>ASHRAE, and usually the Client/standards/best practice drive them to be
>100% OA.  With regards to modeling and Appendix G, one way to interpret
>modeling approach is to see the Baseline system (i.e. System 7) as also
>being a 100% OA system.  Thus, any ventilation or load driven spaces
>needing more than minimum ventilation are still being supplied with 100%
>OA.  With Appendix G, one reading of the ventilation requirement is that
>the Baseline AHU should only be modeled with the minimum required OA
>cfm, with the remaining supply air needed to be from return air.  This
>is what one recent reviewer stipulated.  The issue with this that many
>modelers that understand labs will struggle with the fact that such a
>system would NOT be installed in a project because return air lab
>systems are practically non-existent.  What we did see lately on a GBCI
>project review was the requirement to limit the Baseline OA to the
>minimum required no more than the Proposed OA, forcing us to have a
>return air lab AHU for the Baseline building.  ASHRAE 90.1 and USGBC
>interpretations have often not been concerned with what is typical or
>"real" in the case of the Baseline building, it's really about energy.
>So, if other reviewers consistently rule this way, as we recently
>experienced, the message is that the energy target of 90.1 holds steady
>even for labs and outweighs the safety concerns of real design when
>considering the Baseline building.  Thus, Proposed designs looking at
>chilled beams, fan coils, or other zone level systems used to decouple
>ventilation will be compared against a return air lab system.  This will
>clearly reduce the potential to show savings between the two models.
>
>Paul
>
>Paul Erickson
>Sustainable Practice Leader
>
>AEI | Affiliated Engineers
>5802 Research Park Blvd. | Madison, WI 53719
>P: 608.236.1112 | F: 608.238.2614
>perickson at aeieng.com  |  www.aeieng.com   
>
>-----Original Message-----
>From: bldg-sim-bounces at lists.onebuilding.org
>[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of
>Matutinovic, Luka
>Sent: Tuesday, October 13, 2009 11:43 AM
>To: Sam Mason; bldg-sim at lists.onebuilding.org
>Subject: Re: [Bldg-sim] Heat Recovery Chillers and Lab Outdoor Air
>
>Sam,
>
>Regarding point 2, I think the fundamental question is: what are the
>code ventilation requirements for your facility? The proposed building
>may require less total supply air due to efficiency improvements such as
>less glazing, but there shouldn't be a difference in the amount of
>outdoor air you have to provide.  In fact, in hospital and lab
>facilities, the total supply air is often also mandated.  In Canada for
>example, patient rooms must provide 2 ACH OA and 6 ACH total supply air.
>
>
>That's why I think it's important to understand the code requirements.
>If there is a code that governs how much outdoor air and total air must
>be provided, then the same rates must be used in both proposed and
>baseline buildings. Most, if not all, efficiency improvements will
>reduce the amount of energy required to condition and move that air, but
>the actually amount of outdoor air (and sometimes total air) should be
>the same in both buildings, provided that you're not exceeding the
>minimum ventilation requirements.  
>
>If a 100% OA system is a designer's/client's choice, but the same
>building could be built to the governing code with say 33% OA, the
>baseline building will use the minimum code rates, but the proposed
>design should get penalized for over-ventilating. What I've found on
>previous projects is that the code ventilation rates typically govern
>the sizing of air-handling systems, meaning that the heating and cooling
>loads can usually be met by the total ACH required by code for infection
>control or required as make-up air when the fume hoods are operating. 
>
>I don't know if this has any bearing on ventilation rates and so it may
>not help your situation, but I recall seeing a CIR requesting that the
>Labs21 modelling requirements be used in lieu of Appendix G since the
>latter penalizes lab systems. I think the response from the USGBC was
>that the 2007 version of 90.1 addressed particular issues that made it
>difficult for labs to get significant savings and therefore Labs21
>should not be used.
>
>I hope I haven't muddied the issue further with my comments.
>
>Cheers,
>
>Luka Matutinovic, B.A.Sc., LEED(r) AP
>Green Building Consultant / Energy Specialist
> 
>T. 416.644.0649
>F. 416.487.9766
>Toll Free 1.888.425.7255
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>
>
>-----Original Message-----
>From: bldg-sim-bounces at lists.onebuilding.org
>[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Sam Mason
>Sent: Monday, October 12, 2009 3:00 PM
>To: bldg-sim at lists.onebuilding.org
>Subject: [Bldg-sim] Heat Recovery Chillers and Lab Outdoor Air
>
>Thanks in advance for any help.
>
>1. I am trying to model a York heat recovery chiller for a lab facility
>and one of the options on the table is adding a second injection rig to
>boost the heat recovery capacity of the chiller. When I set the controls
>and temperatures for a single rig, it operates closely to what my hand
>calcs show for three months of operation in heat recovery mode. However,
>I don't know how to boost the heating capacity in heating mode to
>simulate the second rig. The heating capacity seems to be limited by the
>cooling capacity. Do I need to do hand calcs and provide an exceptional
>calculation which accounts for the derated chiller performance and
>recovered heat? Any thoughts?
>
>2. For the same lab, the baseline and proposed systems are 100% OA VAV
>reheat. After all efficiency measures are included, the total system CFM
>for the proposed model is 50,000 CFM less than the proposed, and because
>it is a 100% OA system, the baseline system is providing an additional
>50,000 CFM of outdoor air. Per ASHRAE G.3.1.2.5, the minimum ventilation
>rates shall be the same, but changing the baseline model fundamentally
>changes the way a 100% OA lab system is designed to work. If 100% OA is
>not provided, then some amount of recirculation is assumed, and for labs
>handling sensitive testing and materials, recirculation is not allowed
>under any circumstance. Is there a CIR or addenda regarding this issue
>in lab modeling? Any thoughts or experience are greatly appreciated.
>
>Sam
>
>--
>Sam Mason
>Environmental Designer
>
>Atelier Ten
>Consulting Environmental Designers
>45 East 20th Street, 4th Floor
>New York, NY  10003
>T +1 (212) 254-4500 x221
>F +1 (212) 254-1259
>sam.mason at atelierten.com
>www.atelierten.com 
>
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