[Bldg-sim] Natural ventilation

[Karen Walkerman]

For EQ Credit 2, LEED also states that you can use a "macroscopic multi-zone
analytic model" to prove that your natural ventilation design will provide
the minimal outdoor air flow rates stipulated for mechanical ventilation
systems in ASHRAE 62.  I have used CONTAM to do this for another project.

~Karen~

On Thu, Apr 10, 2008 at 5:11 AM, July Chen <zqchen at emsi-green.com.cn> wrote:

>  Dear colleague:
>
>       I have met a serious problem during LEED a factory.
>               For this project, There equipped some HL-600G&HL-600 Gravity
> type skylight ventilator on the factory roof and some operable window at the
> surrounding walls. But the height of the ventilator is from 10.5m to 13m
> over the ground surface.
>
>             LEED/ASHRAE 62 requirment: Natural ventilation spaces shall be
> permanently open to and within 8m of operable wall or roof opening to the
> outdoors.
>
>            Assume the breathing zone is 1.6m high, So LEED accept height
> of the ventilator should be lower than 9.6(1.6+8)m. So the interior
> area(more than 8 m away from surrounding walls) does not have valid natural
> ventalition system as described by LEED/ASHRAE.
>
>
>            The designer does not agree our opinion, their reason:
>
>  1.    the design is to give comfort to the operators on the floor since
> the process equipment is very hot and the space within the 8-m high will get
> unbearably hot.  Nanjing is known for its hot summers
> 2.    the specification is for 22 air changes per hour (ACPH) and the need
> for 8-m floor to roof eave height is to aid natural draught ventilation so
> it is easier to reach 22 ACPH
> 3.    The supplier is to warrant 22 ACPH and provide ASHRAE calculations
> to reach this figure.
> 4.    It is less acceptable to fill the roof area with mechanical roof
> ventilators since it is energy dependent (an increase in the carbon
> footprint) and as such agaist the LEED concept
> 5.    The approach is within the philosophy of LEED in that the operators
> comfort and well being is at the heart of this design, the use on natural
> ventilation address sustainable design in that no energy is required to get
> 22 ACPH.
>
>     QUESTION:  1. Are the designers reason will be agreed by LEED?
>
>                 2.  If we installed some exhaust fan on the roof, makeup
> air will go in through operable windows on the surrounding walls. whether
> the ventalition system changed to mechanical ventalition system as defined
> by ASHRAE/LEED?
>
>  Any further suggestion is highly appreciated.
>
>
> Ziqiang Chen
>
> Project Engineer
>
> EMSI
>
> 86-21-54962727 TEL
>
> 86-21-64435767 FAX
>
> zqchen at emsi-green.com.cn
>
> www.emsi-green.com
>
>
>
>
>
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-- 
Karen Walkerman
Second Law Consulting
802-238-0980
kwalkerman at gmail.com
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