[Equest-users] Fwd: no heating loads to systems --part II

[Pasha Korber-Gonzalez]

Dear fellow eQuest-users;

With tremendous support/response from so many of you I have resolved all of
my visible issues--one due to [shameful] personal error & also with
adjusments on some schedules, heat reset control, etc.

I can't express my THANKS loud enough for you to hear my true appreciation
of your immediate help & support.  Especially since emotionally speaking I
was in a 'panic' mode b/c of my deadline and a non-working baseline model.

All is well now, I learned a lot of new things about the system controls, so
it was a good 'growing' experience too.  It's wonderful to have such a great
support group to turn too.  I'm impessed to know that there are many
professionals & simulators who are willing to extend thier experience and
assistance to help each of us become better at what we are doing.
I hope I can repay the favors to all of you.

Cheers,
Pasha
On Mon, Mar 8, 2010 at 10:01 AM, Pasha Korber-Gonzalez <
pasha.pkconsulting at gmail.com> wrote:

> Thanks Bill,
>
> I do have specified 105 supply temp, 105 hot deck max temp, 50F reheat
> delta T.  For some reason my results are very low for my ASHRAE baseline
> building & they are showing virtually 1% heating energy consumption overall
> in my building, and I have one standard effeicency boiler in the plant side.
>
> This is what I know (by gut feel) the issue is--somewhere in the airside I
> have either turned on or off some control or schedule--along with when I set
> up the model using the wizard initial inputs they were for the proposed case
> (water-to-water heat pumps-geothermal htg/clg & serving all spaces including
> thermal displacement vent, natural vent zones (for htg baseboards), FC's
> etc.  So----I am wondering if when I saved my file for the baseline model
> and then switched the plant equip (chiller/boiler) & VAV sys if there is a
> carry-over input from the HPsystems (or other) that is affecting the lack of
> heating energy with the standard systems.
>
> Not sure how to find a 'carry-over' input.  I have compared my input files
> with examdiff program and couldn't find anything specific.
>
> I've attached the non-corrupted files to this email...
>
> pk
>
>   On Mon, Mar 8, 2010 at 8:54 AM, Bishop, Bill <wbishop at pathfinder-ea.com>wrote:
>
>>  Pasha,
>>
>>
>>
>> For VAV systems you also have to specify the HEAT-SET-T (Hot Deck Max
>> Leaving Temp) to enable the main air handler heating coil. You can’t just
>> leave the field blank. For example, if your room supply air temperature
>> is 90F and you have 30F reheat, enter 60F for the hot deck temp.
>>
>>
>>
>> Regards,
>> Bill
>>
>>
>>
>> *William Bishop, EIT, LEED® AP **|** **Pathfinder Engineers & Architects
>> LLP***
>>
>> Mechanical Engineer
>>
>>
>>
>> 134 South Fitzhugh Street
>> Rochester, NY 14608
>> T: (585) 325-6004 Ext. 114
>> F: (585) 325-6005
>>
>> wbishop at pathfinder-ea.com
>>
>> www.pathfinder-ea.com
>>
>> P Please strive to live sustainably.
>>  ------------------------------
>>
>> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
>> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Pasha
>> Korber-Gonzalez
>>
>> *Sent:* Monday, March 08, 2010 10:30 AM
>> *To:* John Aulbach
>> *Cc:* eQUEST Users List
>> *Subject:* Re: [Equest-users] Fwd: no heating loads to systems --part II
>>
>>
>>
>> Thanks John/Vik- Yes. but when I do put in reheat that is the only way the
>> systems are receiving reheat, so my question is why are the heating coils
>> not doing the primary heating wherefore in my case file, all of the heating
>> is up to either reheat (specified by me) or via baseboards (also specified
>> by me.)
>>
>>
>>
>> The big question is:  why aren't the heating coils doing the job first,
>> and then the excess is to be made up via reheat and/or baseboards.
>>
>>
>>
>> I have not specified any input for humidty control (based on the help file
>> recommendations--b/c we don't have humidification control in the proposed
>> building...
>>
>>
>>
>> The DOE2 help file indicates:
>> *REHEAT-DELTA-T*
>>
>> Maximum increase in temperature for supply air passing through the zone
>> (or subzone) reheat coils. The value specified here applies to all zones in
>> the system. This keyword is required in order to simulate heating the air
>> as it passes through the terminal reheat coil. Note that when very little
>> air is passed (see MIN-FLOW-RATIO) there may be insufficient reheating.
>>
>> The highlighted statement is noted, but it still doesn't indicate that
>> this input is required *in order to simulate any heating requirement.*
>> It only states it is required to simulate reheat heating requirements.  Why
>> don't the heating coils work in my model is my "black & white" question....
>> all in all my space heating energy (with reheat & baseboards) is only 1% of
>> the total building energy for a climate in Vancouver, BC...  why is it so
>> low?
>>
>>
>>
>> ...if I am just really missing something---please don't hesitate to tell
>> me so. ---- I have also specified the hot deck temp coming off the htg coils
>> which then gave me some capacity in my heating coils, but unfortunately by
>> adding this input  all of my numbers have dropped instead of increased.
>>
>>
>>
>> I also looked back into the archives to find an answer to this issue--I
>> found two others who were having the same problems I have, but they have
>> responded that they never figured out the problem either...
>>
>>
>>
>> Pasha
>>
>>
>>
>>
>>
>> On Sat, Mar 6, 2010 at 10:34 PM, John Aulbach <jra_sac at yahoo.com> wrote:
>>
>> Pasha:
>>
>>
>>
>> I believe the short answer to this is that not all VAV zones have reheat.
>> Therefore, you need to put reheat in the zones that have it. otherwise, all
>> systems would get reheat.
>>
>>
>>
>> John Aulbach
>>
>>
>>  ------------------------------
>>
>> *From:* Pasha Korber-Gonzalez <pasha.pkconsulting at gmail.com>
>> *To:* eQUEST Users List <equest-users at lists.onebuilding.org>; Vikram Sami
>> <vsami at lasarchitect.com>
>> *Sent:* Sat, March 6, 2010 9:30:09 PM
>> *Subject:* [Equest-users] Fwd: no heating loads to systems --part II
>>
>>
>>
>> Thank you both for looking at this.  I'm a bit dumbfounded that it can't
>> be as easy as the fact that I need to specify reheat, since I have indicated
>> that it is a VAV with reheat system, but if that is the case then I will
>> re-instate the reheat delta t so that I can generate heating energy.   (when
>> I had input a reheat delta t of 30 degrees F, I was able to successfully fun
>> a simulation, but the heating energy numbers where so high (i.e. 30 kWH/sq
>> ft or more) that it just didn't seem like this was the correct input for my
>> model.
>>
>>
>>
>> I just think that it is a bit weird even for the programming that the only
>> way I can get heat out of the heating coil is that I have to enlist reheat
>> or baseboards in order for the system to assume that there is a heating
>> load.
>>
>>
>>
>> I understand the logic of why this works, but I don't understand why it is
>> a requirement in DOE to have some or ll of the heating capacity specified
>> for it to "autosize" or react to the fact that heating loads need to be
>> passed to the systems module only if reheat or baseboards are specified.
>>
>>
>>
>> If it is possible for any of the eQuest programmers to comment on this
>> input requirement I would like to hear thier feedback.  In the meantime,
>> what I am understanding is that it is a requirement to specify supplementary
>> heating (i.e reheat or baseboards)  in DOE2 for a VAV reaheat system before
>> DOE2 will allow a basic heating coil to assume a heating load...somebody
>> please tell me I'm wrong-because this doesn't make sense.
>>
>>
>>
>> Pasha
>>
>> ---------- Forwarded message ----------
>> From: *Seun Odukomaiya* <sodukomaiya at laceindy.com>
>> Date: Sat, Mar 6, 2010 at 4:59 PM
>> Subject: RE: [Equest-users] no heating loads to systems --part II
>> To: Pasha Korber-Gonzalez <pasha.pkconsulting at gmail.com>
>>
>>  Pasha,
>>
>> I took a look at your model. When employing a VAV-Reheat System as you
>> have in your model, you must also specify the reheat Delta-T for the zone
>> heating coils attached to the units (see attached screenshot). If this is
>> not done, the program assumes that the zones have no reheat, and thus will
>> never put a load on your hot water loop. This, in turn, causes the error
>> that you've seen. The DOE-2 documentation describes it as follows:
>>
>>
>>
>> Maximum increase in temperature for supply air passing through the zone
>> (or subzone) reheat coils. The value specified here applies to all zones in
>> the system. This keyword is required in order to simulate heating the air as
>> it passes through the terminal reheat coil. Note that when very little air
>> is passed (see MIN-FLOW-RATIO) there may be insufficient reheating.
>>
>>
>>
>> According to your model, the maximum zone entering supply air temperature
>> is 105 degrees. I also noticed that your zone minimum entering supply
>> temperature is 55 degrees. As such, you need to specify your reheat delta-T
>> as 50 degrees (as in the screenshot). This ensures that your zone coils are
>> able to raise the 55-degree air from the AHU up to the 105 degrees that you
>> have specified. Try that, and your model should run just fine.
>>
>>
>>
>> *Seun Odukomaiya, LEED AP  -  **Mechanical Engineer*
>>
>> L'Acquis Consulting Engineers
>>
>> 9229 Delegates Row, Suite 550
>>
>> Indianapolis, Indiana 46240
>>
>> voice:  (317) 706-2075, ext. 255
>>
>> fax:     (317) 706-2076
>>
>> email:  sodukomaiya at laceindy.com
>>
>> web: www.laceindy.com
>>
>> P* **Please consider the environment before printing this e-mail.*
>>
>>
>>  ------------------------------
>>
>> *From:* equest-users-bounces at lists.onebuilding.org [
>> equest-users-bounces at lists.onebuilding.org] On Behalf Of Pasha
>> Korber-Gonzalez [pasha.pkconsulting at gmail.com]
>> *Sent:* Saturday, March 06, 2010 4:26 PM
>>
>>
>> *To:* eQUEST Users List
>> *Subject:* [Equest-users] no heating loads to systems --part II
>>
>>
>>
>> Hi all,
>>
>>
>>
>> okay-I'm back to where I was last time I posted this question:  why are
>> there no heating loads being passed to my systems?
>>
>>
>>
>> Here's the story: (160,000 sf high school building)
>>
>>
>>
>> The attached file is my baseline 90.1 model using System 7 (VAV w/reheat)
>>
>> As the file is now-I have removed the reheat delt-T (30 deg), and removed
>> any baseboard heating in all /systems/zones and removed any input of heating
>> capacity of the coils.  With this, my file receives the following error:
>>
>>
>> ***ERROR***********************************************************************
>>
>> Loop: Hot Water Loop has zero design flow.
>>
>> Check input for consistency, or specify design loads.
>>
>> Right now I am trying to have DOE2 'autosize' anything it can so that I
>> can get a good run and go back and adjust equipment capacities....but I
>> don't know where else I can look further for why the systems aren't
>> receiving the design loads.---thus creating the above error.  Something is
>> stopping DOE from passing the loads to the systems.  When I open my sim
>> file, the only reports being produced are the L-reports.
>>
>>
>>
>> If anyone has any hints or can take a look to find what it is I'm
>> missing--I know it's a simple thing, but can't seem to find why it is doing
>> this.  (I've been staring at these files tooo long...)
>>
>>
>>
>> ---on a side note--after all the help I received with this issue earlier
>> this week I have input all of the temp schedules that are required, and all
>> that I know needs to be input to get the systems to run.  any help would be
>> greatly appreciated so I don't have to go back and rebuild this model from
>> the beginning....I'm too close to the end to go back and rebuild
>> another file.
>>
>>
>>
>> Thanks in advance!
>>
>> Pasha
>>
>>
>>
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