[Bldg-sim] DOAU in Baseline vs. Proposed Model

[Chris Jones]

Its an interesting problem because if the DAOU is 
a system has over 5000 cfm and over 70% OA the 
baseline system requires heat recovery 
(G3.1.2.10).  I know because I asked the question 
of ASHRAE as an Interpretation Request.  Even 
though the individual systems served by the DAOU 
have less than 70% OA, the baseline systems still 
require heat recovery of at least 50% effectiveness.

At 11:53 AM 4/22/2010, Carol Gardner wrote:
>In my opinion, it should not be modeled in the 
>baseline building and outdoor air should be added to the systems.
>Carol
>
>On Thu, Apr 22, 2010 at 8:11 AM, Seth P. 
>Spangler <<mailto:sspangle at rmf.com>sspangle at rmf.com> wrote:
>
>Hello All,
>
>
>
>For the majority of the LEED projects I work on 
>I decouple the space load from the ventilation 
>load by using a dedicated outdoor air unit 
>(DAOU). Before GBCI took over the review process 
>the proposed and baseline models contained the 
>same number of systems meaning if we used a DOAU 
>in the proposed model  - we modeled the same 
>unit in the baseline. I recently received a 
>comment to remove the DOAU from the baseline and 
>add the ventilation air to the space load 
>systems. For that particular model it didn’t 
>have a very big impact so I didn’t think twice about it.
>
>
>
>The question – should a DOAU be modeled in the 
>baseline case or should the outdoor air load be 
>added to the mechanical systems that take care of the space load?
>
>
>
>Thanks
>
>
>
>Seth Spangler, LEED® AP
>
>Project Engineer
>
>
>
>RMF Engineering, Inc
>
>Ph: (843) 971-9639 ext:1497
>
>Fax: (843) 971-9641
>
><mailto:sspangle at rmf.com>sspangle at rmf.com
>
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Chris Jones
14 Oneida Avenue
Toronto, ON M5J 2E3.
Tel.  416-203-7465
Fax. 416-946-1005

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