Re: [EnergyPlus_Support] High-Temp Radiant System coupled with dummy primary system (how???)

["Michael J. Witte" <mjwitte@xxxxxxxx>]

Sorry about the confusion.  Would you please send me the specific place that 
you read this, so we can edit it?

The high-temp radiant system can be used alone.  You need a thermostat, a 
controlled zone equipment configuration, and a zone equipment list which lists 
the high-temp radiant heater.

To answer your other questions:

When a zone is served by more than one system, each system is simulated in 
priority order.  Any load remaining after the first piece of equipment is 
modeled will be passed to the next piece of equipment.

Autosizing does not understand the presence of multiple systems serving the 
same zone.  Each piece of equipment will be autosized to meet the full load.

Mike


On 11 May 2007 at 1:57, Kristin Field wrote:

> Hi, I'm trying to model a zone that has a high-temp. radiant system
> only.  Basically, it is a semi-conditioned space - a space that has
> very low heating setpoints and no cooling setpoints.  The only
> elements providing heat to meet the heating setpoint should be these
> tube heaters.  Oh, and it's single-zone.
> 
> In the EP documentation, the high-temp. radiant systems are described
> as supplemental zone equipment to a primary system.  I have tried
> using the purchased air system and also creating a "dummy" system
> (zero energy, flows, very low setpoints, etc.), and neither one works.
>  In the purchased air system with very low setpoint, the sizing
> algorithm determines that there's no heating load, so the radiant
> system isn't deployed.  In the compact DX system with very low
> setpoints and zero energy (but not zero flows), the same thing
> happens.  In the compact DX system with low setpoints, zero energy,
> and zero flows, it terminates the run due to flows of zero.
> 
> Can anyone tell me how to accomplish what I want to in this model?  A
> tube-heater-only heating system.
> 
> On a related note, this got me thinking about another question:
> pretending that I wanted to use a high-temp. radiant system as it was
> intended, as a supplement to a central HVAC system, how does EP decide
> when to deploy the central heating and when to deploy the radiant
> system (as long as they have the same setpoint schedules)?  I know
> that the controller gives priorities 1 and 2, but if the equipment is
> autosized, then does the auto-sizing take into account that there is
> priority 2 equipment there and size the priority 1 equipment to be
> smaller?  If it doesn't, and it sizes the priority 1 equipment to meet
> all the heating load, then why would the 2nd priority equipment ever
> be called?  This is just something that I would be interested to know.
> 
> Thanks for the help!
> 
> Kristin Field
> 
> 
> 
> 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.pdf under the
> Documentation link and press the "search" button.
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 


========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx





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