[EnergyPlus_Support] Re: Problem with removing reheat coils in VAV

["n_junk" <n_junk@xxxxxxxxxxxxxx>]

Hi! You are refering to "Central Heating Design Supply Air Temperature", right? I forgot to tell that I already had changed it to 20, 30, 40, 50 and even 70ºC and none of them hadn't change at all the interior temperature. If I use a high temperature and put again the reheat coils, the rooms sometimes even overheat, but without them the temperatures continues under 20ºC.

This is really odd, I don't know what is happening.



--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Vinay Devanathan <vinay.devanathan@...> wrote:
>
> The main heating coils setpoint temperature will be set such that it only
> heats air to a certain temp, (say around 15 - 16 C), so that the reheat
> coils can be sized for proper capacity to meet the load. When you remove the
> reheat coils, your supply air will obviously be under-heated as the main
> heating coil is not sized for that high capacity and will end up providing
> supply air at the setpoint temperature. You can look at what the heating
> coils design leaving air temperature by viewing the expidf file under
> Sizing:System object.
> 
> On Mon, Jul 11, 2011 at 1:02 PM, n_junk@... <
> n_junk@...> wrote:
> 
> > **
> >
> >
> > Hi!
> >
> > I'm trying to simulate an existing HVAC system which is similar to a VAV,
> > only with heating, without cooling coil or reheat coils. I'm using the HVAC
> > Template VAV Packaged.
> > The rooms' temperatures stay above 20ºC, like I configured in the
> > Thermostat, until I remove the reheat coils. When I do that the temperature
> > drops under 20ºC and only reaches it if there are internal loads.
> >
> > I have almost everything in autosize, except the maximum flow of the input
> > air (but autosize never reaches it, so I think the problem is not from
> > there).
> >
> > To see my problem just open this example file that comes with EnergyPlus:
> > HVACTemplate-5ZonePackagedVAV.idf. Then run a simulation and consult the
> > evolution of Zone Air Temperature for any of the conditioned zones and see
> > that it stays inside the temperatures of the Thermostat. After that go to
> > the file, remove the reheat coils of every zone (and deactivate the system
> > cooling coil), run the simulation again and compare the temperatures. You'll
> > see that now the temperatures stay under the Thermostat limit and only reach
> > it when the internal loads harm the room enough.
> >
> > I'm looking in the expidf file for days and I still don't know what is
> > wrong with it. Since I really have to remove the reheat coils, what can I do
> > to correct this problem?
> >
> > Thanks in advance!
> >
> > 
> >
>




------------------------------------

Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx

The primary EnergyPlus web site is found at:
http://www.energyplus.gov

The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/

Attachments are currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/join
    (Yahoo! ID required)

<*> To change settings via email:
    EnergyPlus_Support-digest@xxxxxxxxxxxxxxx 
    EnergyPlus_Support-fullfeatured@xxxxxxxxxxxxxxx

<*> To unsubscribe from this group, send an email to:
    EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/