[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [EnergyPlus_Support] Re: Low Temperature Radiant System





Hello,

Can anyone please help me out with the below mentioned query. I have tried various things (Unitary DX System with Low temp radiant sys) but keep getting the following problems:

1. My radiant system is never ON even when i schedule the DX system as always off. the CSV file shows no cooling rate for DX system but it shows the same for Radiant System as well. Moreover its not that my setpoints are met due to ventilation and infiltration. Almost the entire time of run period the setpoints are not met.

2. I am getting the following warning which I think is the crux of the problem.

** Warning ** No valid range found for Loop Demand=-24846.35 in Load Range Based Operation Scheme=EQUIPMENTOPERATION.
   **   ~~~   ** All equipment will be turned off. Other cases of this condition will not be reported.


Thanks a lot in advance.


--- On Sat, 17/7/10, Nikhil Sehgal <nickus_1986@xxxxxxxxxxx> wrote:

From: Nikhil Sehgal <nickus_1986@xxxxxxxxxxx>
Subject: Re: [EnergyPlus_Support] Re: Low Temperature Radiant System
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Date: Saturday, 17 July, 2010, 3:28 PM

 

Hello,

I have tried a similar system - AirLoopHVAC: Unitary:HeatCool with a LowTemperatureRadia nt:Variable flow.

Now, I am facing a peculiar problem. When I model my building only with the Unitary system i get a design load of around 20 TR (which is fine). But when I use radiant cooling (on roof) my design load increases by 3TR. Moreover when I use the same radiant cooling on floor the design load output is less than 3 TR! Also since my Unitary system takes all the load the radiant system is OFF. So why is there a variation in load?

Basically what I am trying to do is compare the power consumption when (1) Only a Unitary System is installed and (2) When a unitary system works with a radiant cooling system. So how do i go about it to get proper outputs?

Thanks a lot

Nikhil

--- On Tue, 6/7/10, M�¡rio <mneves32@yahoo. com> wrote:

From: M�¡rio <mneves32@yahoo. com>
Subject: [EnergyPlus_ Support] Re: Low Temperature Radiant System
To: EnergyPlus_Support@ yahoogroups. com
Date: Tuesday, 6 July, 2010, 3:50 AM

 

No, usualy the outside air is neutral in termos o load witch means that the actual load of the space is tacken by the radiant system. Try using the system sizing in ventilation mode.

--- In EnergyPlus_Support@ yahoogroups. com, "O. Tugrul Karaguzel" <tugrulkaraguzel@ ...> wrote:
>
> Thanks so much.
> I think I locate the source of my problem now. My ventilation air is treated to satisfy the whole zone's heating load nothing left to radiant system. (Meanwhile according to E+ documentation radiant systems can only be controlled at priority # 2 which means as a secondary system). I have AHUs serving each floor of the building having several thermal zones. I'll have to work on AHUs to adjust zone loads.
> My radiant system is variable flow. AHUs have variablevolume fans.
> Do you mean radiant heating set-points temps are 1C cooler than zone heating-setpoints?
> thanks.
>
> Omer T. Karaguzel PhD Candidate
> Center for Building Performance & Diagnostics (CBPD)
>
> Carnegie Mellon University Pittsburgh, PA 15213
>
>
> --- On Mon, 7/5/10, MÃ?Æ?Ã?¡rio <mneves32@...> wrote:
>
> From: MÃ?Æ?Ã?¡rio <mneves32@...>
> Subject: [EnergyPlus_ Support] Re: Low Temperature Radiant System
> To: EnergyPlus_Support@ yahoogroups. com
> Date: Monday, July 5, 2010, 5:31 PM
>
>
>
>
>
>
>
> Ã? 
>
>
>
>
>
>
>
>
>
> Hello.
>
>
>
> First, could it be that you ventilation air witch, usualy is treted is suficient to overcome your Load?
>
>
>
> Second is it a variable or constante flow system, you used the direct duct object, is your fan constante volume?
>
>
>
> Have you tried to setpoint the air tempreture about 1�ºC colder than your space, if everything else is OK the radiant system has to be activated.
>
>
>
> Best Regards
>
>
>
> MN
>
>
>
> --- In EnergyPlus_Support@ yahoogroups. com, "O. Tugrul Karaguzel" <tugrulkaraguzel@> wrote:
>
> >
>
> > Hi there,
>
> > In my model zone ventilation is supplied by AHU as well as load function. I also realized that ventilation should be separated from air conditioning so as to couple radiant system. Can it be done by changing parameters of the heating coil of the central system since there should be some sort of pre-heating of outdoor air to be used for ventilation purposes?
>
> > Best.
>
> >
>
> > Omer T. Karaguzel PhD Candidate
>
> >
>
> > Center for Building Performance & Diagnostics (CBPD)
>
> >
>
> > Carnegie Mellon University
>
> > Ã??Ã? Pittsburgh, PA 15213
>
> >
>
> > --- On Mon, 7/5/10, MÃ?Æ?Ã?'Ã??Ã?¡rio <mneves32@> wrote:
>
> >
>
> > From: MÃ?Æ?Ã?'Ã??Ã?¡rio <mnevves32@>
>
> > Subject: [EnergyPlus_ Support] Re: Low Temperature Radiant System
>
> > To: EnergyPlus_Support@ yahoogroups. com
>
> > Date: Monday, July 5, 2010, 5:04 PM
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> > Ã??Ã? 
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> > Hello
>
> >
>
> >
>
> >
>
> > What is the AHU set for, load or ventilation functions?
>
> >
>
> >
>
> >
>
> > --- In EnergyPlus_Support@ yahoogroups. com, "O. Tugrul Karaguzel" <tugrulkaraguzel@> wrote:
>
> >
>
> > >
>
> >
>
> > > Hi,
>
> >
>
> > > In my Energy Plus model, I have a low temp (hydronic) radiant system and a single duct uncontrolled air terminal (connected to an AHU with a heating & cooling coil) serving the same thermal zone. I want the radiant system to be the main heating component and any remaining zone loads to be met by the other equipment. So as to do this, I already defined heating priority # 1 to radiant heating system and # 2 to single duct air terminal. However, my simulation results show that radiant system is not operating at all and all the zone loads are still met by air terminal units. How can I reverse this operation? Is there any other settings that can successfully couple these two systems?
>
> >
>
> > > Thanks in Advance.
>
> >
>
> > >
>
> >
>
> > > Omer T. Karaguzel PhD Candidate
>
> >
>
> > > Center for Building Performance & Diagnostics (CBPD)
>
> >
>
> > > Carnegie Mellon University
>
> >
>
> > > Pittsburgh, PA 15213
>
> >
>
> > >
>
> >
>





__._,_.___


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.




Your email settings: Individual Email|Traditional
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe

__,_._,___