[Equest-users] Two HVAC system definition problems

[Dakota Kelley]

Lars,

 

For 1) , I assume you’re trying to recover heat from the hot gas side of a DX cooling coil.  This is considered waste heat, so I would research WASTE-HEAT-USE  = SPACE-HEAT.  The screen shot below shows where to get started, and you’ll need to determine what percent of your condenser capacity is available for reheat.  Note that it only works for packaged multizone systems, so you probably need to treat your single zone system as a multizone with only one zone.  

 

   

 

For 2), you accomplish it two ways.  At the system level, you could define the following:

 

   MIN-OUTSIDE-AIR  = 0.1029

   OA-CONTROL       = FIXED

 

You’re using MIN-OA-METHOD, but that’s more for specifying whether you’re using an economizer or demand-controlled ventilation.  You’ll want to use OA-CONTROL to specify that the defined percent is constant (rather than a minimum).  In the interface, this is selected under economizer control (FIXED meaning there is no economizer). 

 

The other way to specify an exact flow is at the zone level:

 

   OUTSIDE-AIR-FLOW = 216

 

If you specify it at the zone level, you could leave the MIN-OUTSIDE-AIR undefined at the system level.  Zone OA settings/requirements trump whatever is specified at the system level.  When zone & system settings are in conflict, it often results in a warning in the SIM file.

 

Thanks,

                                

                         DAKOTA KELLEY                                                              

                                Project Designer

 

                                Office:      214-744-6199

                                Cell:         214-280-3825

                                Fax:         214-744-0770 

                

http://www.teliospc.com <http://www.teliospc.com/>           3535 Travis St. Suite 115 

dakotak at teliospc.com <mailto:dakotak at teliospc.com>              Dallas, TX 75204 

 

| MEP ENGINEERING · ENERGY MODELING · LEED CONSULTATION · COMMISSIONING |                         

 

 

CONFIDENTIALITY NOTICE: This email is intended only for the use of the individual or entity to which it is addressed, 

And may contain information that is privileged, confidential and exempt from disclosure under applicable law. If you 

are not the intended recipient, please email the sender immediately, and delete this email from all computers.  Any 

distribution or other use is strictly prohibited.  Copyright © 2009 Telios Corporation.

 

 

 

 

From: Lars Fetzek [mailto:lfetzek at phoenixeng.us] 
Sent: Friday, September 18, 2009 9:28 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Two HVAC system definition problems

 

eQuesters and DOE2-2ers,

 

    I have two problems concerning the code below, from my .inp file as processed by eQuest into a BDL file:

 

1.    Per my e-mail yesterday, I am trying to figure out how to make line 3275 do hot-gas reheat.  Any ideas?  Apparently, the only gas that DOE2-2 recognizes is combustible natural gas - not what I intend here.

 

2.    What is the problem with line 3278?  According to text page 361 (PDF page 368) of the DOE22Vol2-Dictionary.pdf, this line is permissible and meaningful.  What I am trying to do is simply tell eQuest that HVAC has a constant 216 CFM of OA.  Since DOE2-2 won't allow such a simple thing, I'm trying to define it instead as 10.29% of the 2100 CFM that this PSZ delivers to the single zone that it serves.  Any ideas?

 

    I'm tired of reverse-engineering the whole world just to tell eQuest simple little things.  However, if I do things in eQuest proper instead of in the .inp file, then I have no idea what variables trump other variables, or even how to conjure all of the mysterious data that eQuest shows/asks for.

 

    Thanks, everyone, for accepting my daily quiz.

 

Lars Fetzek, EI

Phoenix Engineering Group

Tampa, Florida

 

 

    *3272 * "HVAC3 System" = SYSTEM
     *3273 *    TYPE             = PSZ
     *3274 *    HEAT-SOURCE      = ELECTRIC                  $verify
     *3275 *    ZONE-HEAT-SOURCE = NONE                      $How do I make this hot-gas reheat?
     *3276 *    BASEBOARD-SOURCE = NONE
     *3277 *    MIN-SUPPLY-T     = 51.36
     *3278 *    MIN-OA-METHOD    = FRACTION-OF-DESIGN
*ERROR**************************** ================== ****************************************ILLEGAL CODEWORD
     *3279 *    FAN-SCHEDULE     = "HVAC3 Fan Sch"
     *3280 *    FAN-PLACEMENT    = DRAW-THROUGH
     *3281 *    FAN-CONTROL      = CYCLING
     *3282 *    SUPPLY-KW/FLOW   = .000749
     *3283 *    SUPPLY-DELTA-T   = 0 $Net capacity value used
     *3284 *    COOLING-CAPACITY = 88170
     *3285 *    COOLING-EIR      = .316
     *3286 *    CRANKCASE-HEAT   = 0
     *3287 *    CONTROL-ZONE     = "Zone Space 3B"
     *3288 *    ..

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20090918/044ccf4e/attachment-0002.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/png
Size: 3170 bytes
Desc: image004.png
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20090918/044ccf4e/attachment-0002.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 28580 bytes
Desc: image001.jpg
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20090918/044ccf4e/attachment-0004.jpeg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 2327 bytes
Desc: image006.jpg
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20090918/044ccf4e/attachment-0005.jpeg>