[Equest-users] Heating is not on for System Type Pkgd Va

[Daric Adair]

Jing;

John Aulbach is right on.
This may be an issue of modeling vs reality then. With a ‘Packaged VAV’ eQuest believes that there are VAV boxes downstream, so it will put out cold air to provide cooling and depend on the VAV Boxes to reheat and prevent over-cooling.

You may want to try a PVVVT system since that requires specifying a control zone, and that will allow the System to provide hot/cold air based on the control zone. The other 2 zones will be slaved along to them, providing either heating or cooling – whatever the control zone dictates it needs. But it doesn’t require VAV boxes (as your system doesn’t have them)

The Thermostat Control should not enable/disable/prevent heat. A Single Max VAV system uses ‘Proportional’ and a Dual Max VAV System needs ‘Reverse Acting’. Proportional just allows eQuest to provide CFM up to the max durring cooling and turn down to the minimim ratio as coolng load ecrease and then jump to the minimum heating ratio (if a dual min box. If single min box, then the min ratio and min-heatig-ratio will be the same). Reverse acting just means that as the heating load increases, the box can allow more airflow up to the Heating Maximum Airflow (making it a dual max box.)

The main issue may be the incorrect system type in eQuest vs the actual system type that is attempting to be modeled.



Thanks,
DARIC R ADAIR PE, CEM, BEMP
Mechanical Engineer, Energy Analyst

Henderson Engineers

daric.adair at hendersonengineers.com<mailto:daric.adair at hendersonengineers.com>

Licensed in KS

From: John Aulbach <jra_sac at yahoo.com>
Sent: Tuesday, November 13, 2018 4:01 PM
To: Jing Hong <hongjing.shirley at gmail.com>; Jing Hong via Equest-users <equest-users at lists.onebuilding.org>; mbusman04 at gmail.com
Cc: equest-users at lists.onebuilding.org; Daric Adair <daric.Adair at hendersonengineers.com>; equest-users at onebuilding.org
Subject: Re: [Equest-users] Heating is not on for System Type Pkgd Va

reheat You need a reheat coil for VAV !!!
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On Tue, Nov 13, 2018 at 1:59 PM, Jing Hong via Equest-users
<equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>> wrote:
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