[bldg-sim] eQuest 3.52

[Sheila Sagerer]

Hi Christine,

The HVAC system fan is controlled by the fan schedule which you have to
create (or you can use a default from the library).  The schedule is an
on/off or on/off/flag type schedule.  A "1" in the schedule means the fan is
"on" - I use this when the building is occupied -, a "0" means the fan is
off but can cycle on if there is a call for heating or cooling, a flag of
"-999" is used to define an optimum start period.  We usually use the OA
minimum schedule to control the ventilation air and economizer use for each
AHU.  You may want to check the help screens at both the thermal zone level
AND the system level.  These help screens give information on the order of
preference that the program uses if data is entered at more than one level
to control ventilation.  The help screen for the min OA air schedule also
gives good info on several ways to control the ventilation air at the system
level.

Two things I use to control and/or eliminate heating during the summer
months are the "Heat Availability" and Space "Heating Temperature"
Schedules.  In the space temperature schedule, I specify that thermostat
setpoint is 55F from say May through Sept - this will change per type of
building and where it is located at.  Then in the availability schedule I
say that heat is only if the OD temp is below say 65F during fall and spring
months, heat is always available in the winter months and never available
during the summer.  If you want reheat available during the warmer months,
just set heat always available and just use the temperature schedule to
limit the heating energy use just to reheat coils.

As for infiltration, I find it easier to set the infiltration to ACH (air
changes/hour) and use the schedule to determine when infiltration applies.
Generally, we have infiltration on the perimeter of the building only and
even then only during unoccupied periods when the fan is scheduled off.  We
assume that if the fan is on, then the building is pressurized and
infiltration is limited.

CHECK the help screens for each schedule that you use.  The help screens
have useful info that tells the type needed for that particular application
as well as some examples and cautions.

Sorry, I don't have an answer to your last question since I usually use the
Design Development wizard.

I hope this helps.

Sheila Sagerer
Energy Engineer
Energy Opportunities, Inc
Ph: 717-880-9069
Fax: 717-291-9497

-----Original Message-----
From: postman at gard.com [mailto:postman at gard.com]On Behalf Of Christine
Lee
Sent: Thursday, December 30, 2004 4:43 PM
To: bldg-sim at gard.com
Subject: [bldg-sim] eQuest 3.52


Hello group,

I am so glad to have found out about this forum!  I hope some of you
will be able to answer my questions.

How does the HVAC system fan (and schedule) work?  Does this unit
control the building air flows/ventilation rates?  I wasn't able to
turn off or reduce space heating during the summer months.  Is there a
place to resolve this?

The infiltration rates appear to be controlled by two inputs -- air
change (per hour?) and cfm/ft^2.  However, when one value is
specified, it seems as though the program shoudl be calculating the
other, just because it has the information such as building volume and
square footage to do so.  The end reports yield different values when
one or the other or both are entered, even though they should be
dependent on each other.  Is there a way to input the building
infiltration to ensure accurate end calculations?

In the Schematic Wizard, I am allowed to specify values for both
nonresidential and residential domestic water heating in two different
windows.  Do these specifications result from the same heating unit?
For example, I am able to input two different tank capacities, but am
uncertain whether this means I have two tanks or one.

Thank you so much.  Your help is greatly appreciated.
Christine

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