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<DIV dir=ltr>Hi, Neeraj and Vikram: <BR> <BR>Thanks for your promote advice. I'm reading DOE22Vol3-Topics.these days and found that IU's one application is just ceiling radiator .<BR> <BR>Now, I have changed my system type to IU system with no separate MAU systems, but I still have two puzzles :</DIV>
<DIV dir=ltr>1) The fan control is gray which means you can't choose variable, so is it says that the fan is running the full power all the time?</DIV>
<DIV dir=ltr>2) How to define the induction ratio and make it reasonable? I'm not sure whether the recirculating air volume will affect the fan power. it seems not. </DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr>And another question is about water economizer? Can we simulate water economizer now?</DIV>
<DIV dir=ltr>For eQUEST 3.64, there are two methods, one is the water economizer in airside system, but the weakness of this water economizer is it will add the AHU fan power.</DIV>
<DIV dir=ltr>The other one is the water economizer chiller in waterside system, but it seems the function is not matural, I tried , but the hourly report shows the chillers still running in the winter for very low cooling load. </DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr>Thanks in advance. </DIV>
<DIV dir=ltr>Eleanor Shen</DIV>
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<DIV dir=ltr><BR>Date: Sat, 13 Aug 2011 02:11:07 -0700<BR>From: near_ej@yahoo.com<BR>Subject: Re: [Bldg-sim] DOAS and chilled beam/radiator<BR>To: shenjie820730@hotmail.com<BR>CC: Vikram.Sami@perkinswill.com; bldg-sim@lists.onebuilding.org<BR><BR>
<META content="Microsoft SafeHTML" name=Generator><BIG><FONT size=-1><BIG><FONT face=Arial>Hello Eleanor,<BR>Adding to Vikram's advice -- You may then also apply the heat recovery to the individual IU units instead of the DOAS.<BR><BR>But, an important question for experts who may be experienced with working real-life Chilled Beam systems is --<BR><BR>Whether </FONT></BIG></FONT></BIG>or not the OA moved through the active chilled beams is completely (100%) Outside Air only <U>OR</U> Whether some of the supply air is still recirculated?<BR>I presume it'll depend on latent loads but I understand that for most occupied zones some air is actually recirculated back to the AHU's to control the RH and balance the system!?<BR>Please correct me if that is any different from anyone's real-life experience and what Vikram is referring to is the experience you all share? Vikram, your veiws?<BR>We are modeling a couple of chilled beam and slab systems but with little live examples and experiences to corroborate on this aspect.<BR><BR>Your inputs would be valuable . . . .<BR>Thanks,<BR>Neeraj<BR><BR><SMALL>Neeraj Kapoor<BR>t: +91.99581.70018<BR>Kalpakrit Sustainable Environments Pvt. Ltd.<BR>New Delhi, India</SMALL><BR><BR><BR>On 12-08-2011 17:13, Sami, Vikram wrote: <BR></DIV>
<DIV dir=ltr>
<BLOCKQUOTE cite=mid:5CFB01489F62D143B61289AF32DC98B104287BA70D@chi01exmb.perkinswill.net><PRE>If you are using an active chilled beam, then you don't need to model the doas - just use 100% OA for your ahu.
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From: Éò½à [<A class=ecxmoz-txt-link-freetext href="mailto:shenjie820730@hotmail.com">mailto:shenjie820730@hotmail.com</A>]
Sent: Friday, August 12, 2011 04:25 AM Central Standard Time
To: <A class=ecxmoz-txt-link-abbreviated href="mailto:bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</A>
Subject: [Bldg-sim] DOAS and chilled beam/radiator
Hi, all£»
I¡¯m simulating a project with chilled beam/radiator plus dedicated fresh air system, I search from archive, it seems most of you using DOAS (a dummy zone) and IU/FCU to simulate, DOAS provide the fresh air and IU/FCU use the ¡°Outdoor air from¡± DOAS, the radiator use baseboard instead with zero fan energy power.
But the DOAS in my project is 1) variable speed to reduce the fresh air energy base on occupancy schedule; 2) wheel heat recovery with exhaust air; 3) during the transition period, the DOAS will bypass the wheel to provide maximum fresh air to offset all the heating and cooling demand and chilled beam and radiator will shut off.
Now, my method is :
1) using VAV system to represent DOAS , enter the ¡° Design supply/return ¡° flow to show the DOAS fresh air and exhaust air volume;
2) Define the wheel heat recovery with fresh air and exhaust air, and operation control is ¡°OA exhaust DT¡±
3) Define the dummy with the same maximum fresh air volume, and also control the cool and heat temperature (otherwise the heat recovery will not work at all).
It seems works very well. But when I reading hourly report, I found the fresh air volume keeps the maximum all the time, so the fan running at the rated power the whole year, which results in the large fan energy consumpation.
How can I make the DOAS¡¯s fresh air volume variable and fan variable according to the acutal IU/FC¡¯s fresh air volume ??
Any comments and suggestions will be appreciated.
Eleanor Shen (Éò½à£©
Consultant
Environmental Resources Management
Tel: +8621-5385 3050, ext:158
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