[Equest-users] HVAC System Lockout

Cory Duggin crduggin at gmail.com
Fri Feb 4 13:43:37 PST 2011


Based on what you have said, I think I just need a new heating and cooling
schedule.  I found them in my component tree, but I am not sure how to do
what I want because the annual schedule only specifies an ending month and
day.  How do I know when that schedule starts?

On Thu, Feb 3, 2011 at 9:24 PM, Nick Caton <ncaton at smithboucher.com> wrote:

>  Whoah buddy =)!
>
>
>
> First, let me give the preface that I’ll be passing the 70hr mark for this
> workweek tonight, so I’m kind of in zombie-mode right now XD!
>
>
>
> Okay, I reckon you’re hunting rabbits with a  bazooka by resorting to an
> absorption chiller/boiler setup to approximate your gas furnace!  I’d go
> ahead and save your work in a separate file for reference, then I’d step
> back to the wizards to try a packaged single-zone furnace with DX cooling
> for your 2-story zone, and a single-zone heatpump (DX/DX) for your garage.
> Make the systems “on” 24hrs with intermittent fan operation, and be sure
> you’re not specifying “system per zone.”  Use the shell wizard to be sure
> the zones are assigned to the right system.
>
>
>
> If you wish, you can restrict heating and cooling availability for each
> system, the way a residential thermostat has “heating” and “cooling” modes,
> with a COOLING-SCHEDULE and HEATING-SCHEDULE.  By default, heating and
> cooling are generally available whenever they’re called for, but you can
> edit that without going to a chiller/boiler system ;).
>
>
>
> If you are finding your building is flip-flopping between heating and
> cooling hour-to-hour in the dead of summer, it might be a sign other items
> are off… check your envelope constructions/layers, and note that
> oversimplifying geometries/spaces (i.e. – one per floor) may result in a lot
> of thermal mass from partitions being excluded that would otherwise be a
> stabilizing presence.
>
>
>
> I’m copying the eQuest list, because I will be of little use to you others
> in the next 24 hours…  Our strength is in numbers, so do keep everyone in
> the loop as you work through this and you’ll get the best chance of quality
> assistance - best of luck =)!
>
>
>
> Back to the grindstone…
>
> ~Nick
>
>
>
> [image: cid:489575314 at 22072009-0ABB]**
>
> * *
>
> *NICK CATON, E.I.T.***
>
> PROJECT ENGINEER
>
> Smith & Boucher Engineers
>
> 25501 west valley parkway
>
> olathe ks 66061
>
> direct 913 344.0036
>
> fax 913 345.0617
>
> www.smithboucher.com* *
>
>
>
> *From:* Cory Duggin [mailto:crduggin at gmail.com]
> *Sent:* Thursday, February 03, 2011 1:23 PM
> *To:* Nick Caton
> *Subject:* Re: [Equest-users] HVAC System Lockout
>
>
>
> I am modeling a two story house with a one story garage that has been
> converted into a conditioned space.  It is setup so there are 3 zones.  One
> in each floor of the two story part and then the garage.  The real system in
> the house is one unit for the two story part that has gas heat, and the
> garage has its own small heat pump unit.  Since most people don't flip their
> thermostat back and forth between heat and cool, I don't want my systems
> suddenly switching to heat for an hour in the middle of summer because one
> of the zones got below set point.  I have now changed the system to a
> chilled water loop and a hot water loop.  Where the hot water is provided by
> a natural draft boiler and the chilled water is provided by a single effect
> absorption chiller.  I am trying to create a loads file that will have the
> load on the chiller rather than the load on each coil for each zone and also
> the heating load for all the zones, but I don't want it to be able to change
> from cooling to heating in the cooling season or vice versa.  Does that
> makes sense?  Thanks
>
> On Thu, Feb 3, 2011 at 11:19 AM, Nick Caton <ncaton at smithboucher.com>
> wrote:
>
> Cory, your query needs more description to include what you’re trying to
> model and what you’ve input, but if you’ve got simultaneous calls for
> heating and cooling being handled, it sounds like you have either a
> multi-zone system or multiple systems specified where you want only (1)
> single-zone system.
>
>
>
> If I were trying to model the behavior of the HVAC in my apartment
> accurately (a simple CV electric furnace with DX cooling controlled by a
> single remote thermostat), I’d group all conditioned spaces and their zones
> under a single system, taking care to assign the thermostat zone where the
> thermostat actually resides – it’s the zone highlighted red in the graphic
> under the airside HVAC tab.
>
>
>
> I’d suggest revisiting the quantity and type of system you’ve specified
> first, and modify/reassign your systems/zones as necessary to see if that’s
> where the problem resides.  If you’re still having troubles, you’ll need to
> provide a better description of what sort of system you’re trying to model
> (layman’s terms are fine in this forum) and what you’ve tried to specify on
> the model side.  Attaching your project’s .inp/.pd2 files may encourage
> others to help troubleshoot also ;).
>
>
>
> Best of luck!
>
>
>
> ~Nick
>
>
>
> [image: cid:489575314 at 22072009-0ABB]
>
> * *
>
> *NICK CATON, E.I.T.*
>
> PROJECT ENGINEER
>
> Smith & Boucher Engineers
>
> 25501 west valley parkway
>
> olathe ks 66061
>
> direct 913 344.0036
>
> fax 913 345.0617
>
> www.smithboucher.com* *
>
>
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Cory Duggin
> *Sent:* Wednesday, February 02, 2011 4:07 PM
> *To:* equest-users at lists.onebuilding.org
> *Subject:* [Equest-users] HVAC System Lockout
>
>
>
> Is there a way I can create a schedule to lockout either the heating or
> cooling system based on the time of year?  I am modeling a residential
> system, so I don't want it to try and satisfy heating a cooling loads
> simultaneously in different zones.  Thanks
>
> --
> Cory Duggin, EI
> Tennessee Tech University
> Graduate Research Assistant
> Mechanical Engineering
>
>
>
>
> --
> Cory Duggin, EI
> Tennessee Tech University
> Graduate Research Assistant
> Mechanical Engineering
>



-- 
Cory Duggin, EI
Tennessee Tech University
Graduate Research Assistant
Mechanical Engineering
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