[Equest-users] Schedule for zone reheat and pre-heat

[Bruno Lee]

1) T-stat could be set to undefined, if you want to turn re-heat OFF  
all the time. If you want to schedule the re-heat coil OFF at the same  
schedule as min outside air ratio (such that, say at night, when min  
OA = 0, re-heat is OFF), set it inside "user input expression".

2) When min outside air ratio set to "0", the system intakes  
absolutely no OA (not just minimum ratio, although the variable name  
implies so). I am not sure if that's what you want since you mentioned  
you want to "shut off the outside air damper".

However, as mentioned, some zones may experience too many unmatched  
hours if zone re-heat is OFF.

There may be other better ways to achieve your goals, please let me  
know. Thanks.

Bruno


On Sep 3, 2008, at 1:33 PM, Hernandez, Arturo wrote:

> Thank you for your input.  However I have these coments.
>
> 1) I need the zones to maintain at least 65F but only via the preheat
> furnace.  No electric re-heat via VAV boxes...  I am not following how
> setting the t-stat in the zone will help out.
>
> 2) The min outside air ratio is set to 0% but shouldn't at night but
> that is just the Minimum.... wouldn't I want the maximum ratio (if it
> exist)?
>
>
> ARTURO HERNANDEZ, Mechanical
> OWP/P
>
> 111 West Washington Street | Suite 2100
> Chicago , Illinois 60602-2714
> 312.960.8324 Direct | 312.827.8324 Fax | ahernandez at owpp.com |
> www.owpp.com
>
> ARCHITECTURE | INTERIORS | ENGINEERING | PLANNING | CONSULTING |
> DESIGN/BUILD
>
> PLEASE CONSIDER THE ENVIRONMENT BEFORE PRINTING THIS EMAIL
>
>
> -----Original Message-----
> From: Bruno Lee [mailto:brunolee at psu.edu]
> Sent: Wednesday, September 03, 2008 11:42 AM
> To: Hernandez, Arturo
> Cc: equest-users at lists.onebuilding.org
> Subject: Re: [Equest-users] Schedule for zone reheat and pre-heat
>
> 1) Air-side HVAC Zone Parameters > Heating > Heating T-stat schedule
> 	the schedule setting is temperature type, you could manipulate
> the
> set-point such that it acts according to your design.
>
> 2) Air-side HVAC System Parameters > Outdoor Air > Minimum Air  
> Schedule
> 	the schedule setting is Frac/Design type, you could set it to
> "0" if
> you want to shut off OA.
>
> Schedule can be defined by right clicking on the schedule folder, then
> "create schedule". Create Daily first, then Weekly, then Annual.
>
> The system is supposed to run as an integrated unit, by changing
> schedule of any individual component may result in too many unmatched
> hours, you should check the SS-F report to see if that is the case. If
> so, you might also want to check hourly result to see in details the
> reason behind, and modify your schedule accordingly.
>
> I hope I haven't misinterpreted your questions.
>
> Bruno Lee
> M.S. Student
> Department of Architectural Engineering
> Penn State University
>
>
> On Sep 3, 2008, at 9:31 AM, Hernandez, Arturo wrote:
>
>> I am having a problem modeling a building which has a PVAV with a
>> pre-heat furnace and VAV electric reheat boxes.  The pre-heat
>> furnace is intended to raise the temperature up to 55F while the
>> heating is done locally at the VAV electric reheat box. (This is
>> where I have the problem) At night (and weekend) the electric re-
>> heat on the boxes are shutoff and  outside air is shut off.  The
>> building is set back in temperature and heated via the preheat
>> furnace.  This is what I am trying to find out:
>>
>> 1.       Is there a way to schedule the electric reheat coils on the
>> VAV boxes?
>> 2.       Is there a way to shut off the outside air damper at night/
>> weekend?
>>
>> Any help will be appreciated.
>>
>> Thank you in advance,
>>
>> ARTURO HERNANDEZ
>> _______________________________________________
>> Equest-users mailing list
>> http://lists.onebuilding.org/listinfo.cgi/equest-users- 
>> onebuilding.org
>> To unsubscribe from this mailing list send  a blank message to
> EQUEST-USERS-UNSUBSCRIBE at ONEBUILDING.ORG
>
>