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[EnergyPlus_Support] problems about vav simulation
Dear,
I have check as the following two suggestion. However, the results seem still unreasonable. For VAVsystems, it appears constant flowrate at fixed supply temperature. Please help me to inspect this problem.
The simulated system is very simple: mixed air flow through a cooling coil and then suppied into room, using Hong Kong weather data file. I have uploaded the folder: single room vav simulation
Thanks very much.
Rgs,
Xu
----- Original Message -----
From: Michael J. Witte
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Sent: Monday, June 28, 2004 2:17 AM
Subject: Re: [EnergyPlus_Support] one about vav system
This behavior indicates the coil is not large enough. Suggestions:
1. Make sure the OA flow rate and the supply air temperatures in teh ZONE
SIZING and SYSTEM SIZING objects are consistent with the simulation OA flow and
temperature setpoints.
2. Use COIL:Water:DetailedFlatCooling, do not use COIL:Water:SimpleCooling.
If this does not fix the problem, please upload the input file to the files
area in the Yahoo group or e-mail zipped idf to energyplus-support@xxxxxxxx.
Mike
On 24 Jun 2004, at 16:24, Xu H.T wrote:
> Like the following email.
>
> I do a simulation for VAV system. The design day is used for sizing of zone,
> system and plant. I set the supply air temperature to 19C. I find with the
> design day simulation, the supply air temperature isn't 19 (20.5 actually) and
> the air flowrate is constant. However, for the run period simulation, the
> supply air temperature is actually 19 and the supply air flowrate is also
> constant. Why? Any suggestion for this problem. Thanks.
>
> Xu
>
> ----- Original Message -----
> From: zhaicq98
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Sent: Thursday, June 24, 2004 8:51 AM
> Subject: [EnergyPlus_Support] questions about dx vav system
>
>
> I have two questions here.
>
> First, I am simulating a VAV system with no terminal reheat. I
> specify the supply air temperature to be 12.8oC in cooling season and
> 35oC in heating season. According to results I got, it works well in
> cooling season, trying to keep the indoor temperature under 23oC by
> varing the supply air flow rate. While in winter, it keeps heating
> the space to a high temperature. In heating season, the supply air
> flow rate is always at its maximum value. I can not understand why
> the supply air flow rate in heating season does not vary.
>
> Second question is about the iteration. I am using a multispeed DX
> coil. The program terminates when simulating the system in May. There
> is a fatal error which says the iteration limit is exceeded when
> calculating the speed of the compressor. I have no idea how to
> resolve the problem.
>
> I have uploaded the file named BOX4_VAV.idf to the files area.
>
> Thanks.
----- Original Message -----
From: Michael J. Witte
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Sent: Wednesday, July 21, 2004 11:09 PM
Subject: Re: [EnergyPlus_Support] Glare index
My guess is that the coordinates or facing angle of the daylighting reference
point in these zones is incorrect. Remember that daylighting reference points
are always relative to the zone origin, even when World Coordinates have been
specified. In the dxf drawing file, the daylighting reference points are drawn
as a small red circle to help you verify the location. You may need to comment
out all of the daylighting objects and then add them back one by one to make
sure each reference point is within the appropriate zone. If you are unable to
resolve this, please submit your input file.
Mike
On 8 Jul 2004, at 4:26, leeslwong wrote:
> Hi,
>
> I've simulated the daylight performance of a residential block which
> includes a kitchen, a living room, 2 bedrooms and a master bedroom. I
> called out the annual glare index with hourly basis of each rooms.
> The results show that there is no glare (means '0') in the kitchen, a
> bedroom and a living room. What situations would have these results?
> But there are glare index in other two rooms. Those five room have a
> window facing with the same direction (east). As I know glare index
> never reaches '0'. Anybody can tell me what's happening and how to
> solve it?
>
> Thanks
>
> lee
>
>
>
>
> 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.
>
> Yahoo! Groups Links
>
>
>
>
>
>
========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support
EnergyPlus-Support@xxxxxxxx
The primary EnergyPlus web site is found at:
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