[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [EnergyPlus_Support] Humidity Control
Your cooling coil may not have sufficient capacity to meet the
dehumidification load. If the coil was autosized, it was sized to meet
the thermostat set point. A future release will allow the coil to be
autosized to meet both the thermostat and humidistat set points. You may
need to manually increase the cooling coil capacity.
If you are using a Controller:Simple object to control the cooling coil,
the control variable should be set to TEMPandHUMRAT.
Report the set point at the fan outlet node and compare this value with
the fan outlet node temperature.
Report Variable,
Fan Outlet Node Name, !- Key_Value
System Node Setpoint Temp, !- Variable_Name
Timestep; !- Reporting_Frequency
Report Variable,
Fan Outlet Node Name, !- Key_Value
System Node Temp, !- Variable_Name
Timestep; !- Reporting_Frequency
When the actual temperature is above the set point, is the coil at its
maximum capacity?
You will need to add a report variable for your specific coil's
capacity, you can find this report variable in the rdd file.
When the humidity is above the humidistat set point, the set point
temperature calculated by the Set Point Manager:Single Zone Max Hum
object will overwrite the set point temperature placed on the node by
the Set Point Manager:Single Zone Cooling object. Does the set point
temperature at the fan outlet node continue to decrease as the humidity
rises further above the humidistat set point?
An alternative method would be to add a Set Point Manager:Mixed Air
object and use the cooling coil outlet node as the set point node and
the fan outlet node as the reference set point node (leave the Set Point
Manager:Single Zone Cooling object set point node name as the fan outlet
node). Then move the name of the set point node for the existing Set
Point Manager:Single Zone Max Hum object to the cooling coil outlet
node. The same guidance given above also applies to this configuration
(except you would add report variables for the System Node Setpoint Temp
and System Node Temp using the cooling coil outlet node as the key value
to help you debug this).
civilnug wrote:
> Hi All,
>
> I have a single zone single duct : constant volume : reheat system,
> with a cooling coil, followed by a fan, followed by a humidifier on
> the air loop and a reheat coil just before the zone. In winter the
> temperature and RH are at their set levels but in the summer the RH
> levels are too high. (I need the RH to be 50% +/- 5% year round as the
> zone is a gallery storage area). I have SET POINT MANAGER:SINGLE ZONE
> MAX HUM with the control node set to the fan outlet and SET POINT
> MANAGER:SINGLE ZONE MIN HUM with the control node set to the
> humidifier outlet. I also have SINGLE ZONE COOLING with the control
> node set to the fan outlet node.
>
> I was wondering could it be a clash of control nodes causing the
> problem or is it something else entirely.
>
> Thanks,
> John.
>
>
>
>
>
>
> 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 not allowed -- please post any files to the
> appropriate folder in the Files area of the Support Web Site.
>
> EnergyPlus Documentation is searchable. Open EPlusMainMenu.idf and
> press the "search" button.
>
>
>
> ------------------------------------------------------------------------
> YAHOO! GROUPS LINKS
>
> * Visit your group "EnergyPlus_Support
> <http://groups.yahoo.com/group/EnergyPlus_Support>" on the web.
>
> * To unsubscribe from this group, send an email to:
> EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
> <mailto:EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx?subject=Unsubscribe>
>
> * Your use of Yahoo! Groups is subject to the Yahoo! Terms of
> Service <http://docs.yahoo.com/info/terms/>.
>
>
> ------------------------------------------------------------------------
>
--
Richard A. Raustad
Senior Research Engineer
Florida Solar Energy Center
University of Central Florida
1679 Clearlake Road
Cocoa, FL 32922-5703
Phone: (321) 638-1454
Fax: (321) 638-1439 or 1010
Visit our web site at: http://www.fsec.ucf.edu
UCF - From Promise to Prominence: Celebrating 40 Years
[Non-text portions of this message have been removed]
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 not allowed -- please post any files to the appropriate folder in the Files area of the Support Web Site.
EnergyPlus Documentation is searchable. Open EPlusMainMenu.idf and press the "search" button.
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/EnergyPlus_Support/
<*> 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/