[Equest-users] Adding DOAS workaround to simple (SD wizard generated) building causing hard crash
Brian Fountain
bfountain at greensim.com
Mon Mar 26 05:46:57 PDT 2012
It crashed for me too. I made 3 changes to the file -- one of which
fixed it:
- in the dummy zone the OA was forced to 0 -- I reset this to default
(OA must pass through the dummy zone -- sort of.)
- the DOAS type was PVVT -- I set the fan minimum flow rate to 1.
but the one that fixed it:
- the DOAS fan does not have a flow rate -- give it an initial value,
even something low like 5000cfm and it will increase it up to the OA
required (~69,000 cfm). -- check the SV-A report. Once it runs once you
can set the actual OA value in the fan volume.
On 3/26/2012 4:45 AM, Jason Quinn wrote:
> I'm running a baseline case to compare to my more complicated model.
> This model is completely generated in the SD wizard - now I've added a
> DOAS supply per the "standard" workaround: add a dummy space, dummy
> zone and system for that dummy zone Pak Var vol Var temp. Edit the inp
> to put the DOAS first and then change the 4pipe FC to use the DOAS to
> supply OA. This baseline case runs just fine through the loads and
> then locks up my windows 7 machine - have to power-cycle it. I've
> added it twice and the problem is repeatable. When I implement this
> same work around in a much more complicated model it doesn't crash so
> I think I've done it correctly but I'm not sure what to do at this
> point. .pd2 and .inp attached - Any suggestions would be welcome.
>
> Thank you,
> Jason
>
> Warnings at the end of the .sim file are:
>
> **WARNING**********************************************************************
> ZONE dummy zone
> might have insufficient heating capability.
> Check that the SYSTEM or ZONE HEATING-CAPACITY plus this
> ZONEs BASEBOARD-RATING is adequate to maintain the ZONE
> specified DESIGN-HEAT-T for the calculated peak ZONE load
> (see LS-A or LS-B for the ZONE peak load.)
>
> SYSTEM DOAS
> which supplies the above listed ZONE, has a design heating
> coil exit temperature, HEAT-SET-T,(plus any zone reheat)
> below its MAX-SUPPLY-T or the ZONE DESIGN-HEAT-T, which
> might account for the insufficient heating capability.
>
> ZONE dummy zone has a THERMOSTAT-TYPE
> of REVERSE-ACTION, which, when added to the issues listed
> in the messages above, will cause excessive underheating.
>
> **WARNING**********************************************************************
> DOAS defined as an OA-FROM-SYSTEM
> has OA flow requirement of 69286. CFM
> But its calculated/specified SUPPLY-FLOW is only 10. CFM
> Its SUPPLY-CFM has been reset to meet requirement, however it is
> strongly recommended you re-run with this SUPPLY-FLOW specified.
>
> **WARNING**********************************************************************
> DOAS defined as an OA-FROM-SYSTEM
> has OA flow requirement of 69286. CFM
> But its calculated/specified minimum SUPPLY-FLOW is only
> 10. CFM
> Its MIN-FLOW-RATIO has been reset to meet requirement, however it
> is strongly recommended you re-run with this
> MIN-FLOW-RATIO specified.
>
> **WARNING**********************************************************************
> In the Southern hemisphere, the daylight savings start date
> should be later than the end date. If the latitude is taken
> from the weather file, you must manually specify the
> daylight savings interval in the SITE-PARAMETERS component.
>
> **CAUTION**********************************************************************
> In curve: DX-Bypass-Factor-fAirFlow the dependent value
> is exceeding the limits.
> Value/Min/Max/First time: 1735581.875 -1000000.000
> 1000000.000 1/ 1/ 1
>
> **WARNING**********************************************************************
> Energy-recovery ventilator: DOAS has
> frost on the exhaust outlet. First occurrence: 1 1 4
> OA T&W: 52.0 0.0051 Return T&W: ***** 0.0000
>
> **WARNING**********************************************************************
> Energy-recovery ventilator: DOAS has
> frost on the OA outlet. First occurrence: 1 1 4
> OA T&W: 52.0 0.0051 Return T&W: ***** 0.0000
>
>
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