[Bldg-sim] Diversity factors

[Cheney]

​
Well, I guess Rathna's question is the

​'​
conflict
​'​
 between ASHARE 62.1 ventilation calc
​ (100% OA systems)​
 and
​OA
 system sizing/design by designer:

for DOA or single zone ventilation calc, diversity factor shall not be
applied. However, taking school
​ building​
 as an example, HVAC system
​could be 'downs
ized
​'​
 according to the diversified occupants
​when
 designers believe the total number
​ of students and teachers​
 is fixed and they just move from one zone to the other.
​Bear in mind, ​
DCV
/CO2 control​
 is
​the key which is ​
commonly used in order to
​accommodate
 such "diversity"
​
.

​My understanding is that v
entilation calc
​ without diversity​
 in this case is actually calculating the maximum OA
​ or sum of the diffuser flows​
 for each room
​. From design point of view, two scenarios: 1. ventilation equipment can
be reduced with respect to such diversity factor provided CO2 control is in
the place. or 2. on the other hand, without CO2 control, conflict persists
and equipment sizing has to follow ASHRAE 62.1 calculation.

​Let me know your thoughts.
​


*Best Regards,*
*Cheney*
Connect with me and view my   *http://lnkd.in/bqQf52i*
<http://lnkd.in/bqQf52i>


On Aug 12, 2014 4:24 AM, "Bharath Seshadri" <s.bharath at ntu.edu.sg> wrote:

>  Hi Rathnashree,
>
>
>
> Yes, it’s not easy for a core-and-shell building. We helped design a
> core-shell building recently. Here are some points we considered:
>
> -          What *kind* of tenants do you expect to occupy the space?
> Offices/Laboratories/Workshops etc?
>
> -          If its offices, you could take the same diversity as occupancy
> i.e. assuming you are using some kind of demand based ventilation control
>
> -          If its Labs/Workshops you could refer to design guides such as
> Labs21 or local standards
>
> -          But the best option would be to study metered data of
> buildings of the same function in your region to understand what an
> acceptable diversity factor for fresh air could be
>
>
>
> Hope this helps. Do let me know if you need further references. Would be
> glad to help.
>
>
>
> Regards, Bharath
>
>
>
> [image: Description: image001]
>
> *Bharath SESHADRI *|  Research Associate | Energy Research Institute | Nanyang
> Technological University, Clean Tech One, 1 Cleantech Loop, #06-09,
> Singapore 637141 (Map) <http://maps.ntu.edu.sg/maps#q:CleanTech%20One> | Mob:
> (65) 9321-9723 Tel: (65) 6592-3284 GMT+8h | Fax: (65) 6316-3195 | Email:
> s.bharath at ntu.edu.sg <scchien at ntu.edu.sg> | Web: www.ntu.edu.sg &
> www3.ntu.edu.sg/erian/
>
>
>
>
>
>
>
>
>
> *From:* Bldg-sim [mailto:bldg-sim-bounces at lists.onebuilding.org] *On
> Behalf Of *Rathna Shree
> *Sent:* Tuesday, August 12, 2014 5:51 PM
> *To:* bldg
> *Subject:* [Bldg-sim] Diversity factors
>
>
>
> Dear All,
>
>
>
> In most of the core and shell projects, the HVAC consultant would have
> considered diversity factor on the overall cooling tonnage. While
> modelling, we will be able to comfortably take diversity on occupancy,
> equipment and lighting loads. But diversity on fresh air cannot be taken.
> Because of which the project may end up with plant unmet hours. Please
> let me know how to tackle the issue.
>
>
>
> Regards,
>
> Rathnashree
>
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