At the pre-VAV days. Many people asked for VAV, although I pointed out at that them there is no variable speed fan motor in use.
You need a variable frequency drive or a DC motor with some speed controlling device to use the system.
There are two VAV configurations introduced in EPlus. First was the variable damper, then the variable speed fan.
VAV requires more control, therefore they are used as examples.
If you set the coefficients for curve to 0, 1, 0, 0, 0, and allow the fan to be stopped (intermittent), the variable speed fan object behaves like a constant volume fan with on/off. I think, you can also set speed to low, medium and high in the object..
Any example using the variable fan object is capable of modelling a VAV system. But not necessary to be running in the VAV mode. Not all the fields in the VAV variable speed fan object need to be used. Check the last field of this object.
The constant speed fan object is still available. The choice is yours.
=================================
Sizing of a zone and system and plant is not done based on one object.
When the sizing is run, the IDF already has the fan object fixed as VAV or CAV. EPlus knows which component to choose to be attached to the Zone thermostat. If there is an error, you will be informed.
That is why the 100% fresh air user does not know how to control the system, because there is no thermostat properly linked to it in the IDF
===========================
People are now asking for VRV for the compressor. Is it really better and save energy?
It does not matter, and the simulation object will be make available for those who wanted to try in the near future. I have experience with a real VRV system and VSD fan and thermostat controlled VAV diffuser in each room, computer controlled sensors for the whole building. The system works, but the building is not designed for energy saving.
==========================================
Fan in the fan unit or AHU has nothing to do with the way the cooling water is chilled. Fan is not the only device that the zone thermostat can control. If you leave the fan in the continuous mode, it is not controlled. The thermostat controls the coil. When all the fan coils are turned off, the chiller will stop, because the cooling water temperature will fall, etc.
========================
========================
Assembled CAV units with a chilled water coil. Yes. You will find it in every condo. unit. Each one has one thermostat control. There are many fan coil examples in the exampleFiles folder.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: jippnojunk@xxxxxxxxx
Date: Tue, 19 Apr 2011 21:36:59 +0000
Subject: [EnergyPlus_Support] Re: HVAC Template
Hello,
I am taking this old 2009 question out of the dust to ask for a bit more details.
"YLI006 > If so, all non VAV templates are CAV's. Any VAV system running at constant air volume is a CAV. I.e., air volume not controlled by theremostat in the zone."
I pretty much had the same question in mind since I could not find a system that use chilled water except for VAV.
Only VAV systems can used CHilledWater in the HVAC:Template's.
Are you proposing to size a VAV system min and max flows to the same values to convert a VAV to CAV? I bet not since I don't see how E+ would know what to do to modulate cooling to meet the varying load. right?
Do these things exist? i.e. Assembled CAV units with a chilled water coil.
Maybe I am off track and the system is just not a CAV?
JP Beaulieu,
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu 元六 Li <yli006@...> wrote:
>
>
> What is SDCAV and DDCAV?
>
>
>
> Single Duct constant air volume and dual duct constant air volume?
>
>
>
> If so, all non VAV templates are CAV's. Any VAV system running at constant air volume is a CAV. I.e., air volume not controlled by theremostat in the zone.
>
>
>
>
>
> How do you intend to use the dual duct? One for conditioned air and one for return air? One for heating and one for cooling?
>
>
>
> HVACTemplate:Thermostat
> HVACTemplate:Zone:Unitary
> HVACTemplate:System:Unitary
>
> combination is a constant volume single duct equivalent.
>
>
>
> PTAC is also a constant volume single duct equivalent..
>
>
>
> There are examples in the exampleFiles folder.
>
>
>
> Is there any zone equipment? Dampers, fans, or coils. How do you intend to control the zone temperature and humidity? What do you want to use as cooling and heating sources?
>
>
> I may be wrong, as I have not run all these simulations myself.
>
>
>
>
> Dr. Li
>
>
>
>
>
>
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: wangleihello@...
> Date: Mon, 17 Aug 2009 21:46:26 +0800
> Subject: [EnergyPlus_Support] HVAC Template
>
>
>
>
>
>
> Hi,
> The HVAC Template objects are very useful for creating the HVAC siumlation model. But I have some quesitons on how to create the SDCAV or DDCAV system using the HVAC template objects. Based on the help document, There only are Simple ideal loads system, Package terminal air conditioner(PATC), Pacage terminal air-to-air heat pump (PTHP) systems,Pacakged and split system and VAV system.
> Onyone can tell me how to create the SDCAV and DDCAV system usint template objects
> Thanks
> Lei Wang
>
>
>
> 没有广告的终身免费邮箱,www..yeah.net
>
>
>
>
>
>
>
>
> __________________________________________________________
> Stay in the loop and chat with friends, right from your inbox!
> http://go.microsoft.com/?linkid=9671354
>
I am taking this old 2009 question out of the dust to ask for a bit more details.
"YLI006 > If so, all non VAV templates are CAV's. Any VAV system running at constant air volume is a CAV. I.e., air volume not controlled by theremostat in the zone."
I pretty much had the same question in mind since I could not find a system that use chilled water except for VAV.
Only VAV systems can used CHilledWater in the HVAC:Template's.
Are you proposing to size a VAV system min and max flows to the same values to convert a VAV to CAV? I bet not since I don't see how E+ would know what to do to modulate cooling to meet the varying load. right?
Do these things exist? i.e. Assembled CAV units with a chilled water coil.
Maybe I am off track and the system is just not a CAV?
JP Beaulieu,
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu 元六 Li <yli006@...> wrote:
>
>
> What is SDCAV and DDCAV?
>
>
>
> Single Duct constant air volume and dual duct constant air volume?
>
>
>
> If so, all non VAV templates are CAV's. Any VAV system running at constant air volume is a CAV. I.e., air volume not controlled by theremostat in the zone.
>
>
>
>
>
> How do you intend to use the dual duct? One for conditioned air and one for return air? One for heating and one for cooling?
>
>
>
> HVACTemplate:Thermostat
> HVACTemplate:Zone:Unitary
> HVACTemplate:System:Unitary
>
> combination is a constant volume single duct equivalent.
>
>
>
> PTAC is also a constant volume single duct equivalent..
>
>
>
> There are examples in the exampleFiles folder.
>
>
>
> Is there any zone equipment? Dampers, fans, or coils. How do you intend to control the zone temperature and humidity? What do you want to use as cooling and heating sources?
>
>
> I may be wrong, as I have not run all these simulations myself.
>
>
>
>
> Dr. Li
>
>
>
>
>
>
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: wangleihello@...
> Date: Mon, 17 Aug 2009 21:46:26 +0800
> Subject: [EnergyPlus_Support] HVAC Template
>
>
>
>
>
>
> Hi,
> The HVAC Template objects are very useful for creating the HVAC siumlation model. But I have some quesitons on how to create the SDCAV or DDCAV system using the HVAC template objects. Based on the help document, There only are Simple ideal loads system, Package terminal air conditioner(PATC), Pacage terminal air-to-air heat pump (PTHP) systems,Pacakged and split system and VAV system.
> Onyone can tell me how to create the SDCAV and DDCAV system usint template objects
> Thanks
> Lei Wang
>
>
>
> 没有广告的终身免费邮箱,www..yeah.net
>
>
>
>
>
>
>
>
> __________________________________________________________
> Stay in the loop and chat with friends, right from your inbox!
> http://go.microsoft.com/?linkid=9671354
>
__._,_.___
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
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
__,_._,___
=======
Email scanned by PC Tools - No viruses or spyware found.
(Email Guard: 7.0.0.21, Virus/Spyware Database: 6.17340)
http://www.pctools.com
=======