I do not know why so many users are cmplaining about DX coil freezing warnings.
Heat first before cooling, the cold OD air will never reach the DX cooling coil. Warnings are given to the operation of the heat pumps at low OD temperatures. Glycol anti-freeze is needed for OD solar collector in Winter, ehrn it is subject to frost at night. Wen hardware required special protection, warnings in EPlus is good.
EMS may remove the warnings, and it may not provide the real equipment protection or correct operation. A real life computer control program in a computer controlled system may not be able to correct a real hardware problem due to environment condition. It is not an EPlus problem.
If the supply air temperture required is 16°C or more, 14°C for those with VAV setpoint manager, why size it to 12.8°C, which was really for chillers.. When the OD air is heated to 14°C, the DX cooling coil will never be subjected to low temperature start-up.
Many template users do not know what is in the zone and system sizing objects, and do not care how the numbers was filled in and got into the sizing objects.
Refridgerator would turn on the defrosting cycle, when the evaporator is frozen. The air circulating fan stops, when the frig. door is open. Without the auto defrost, the user turns off the power manually. Auto-degrost and warm butter compartment models are still being certified as energy saving models.
Just some of my random views on energy saving certification.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: brent.griffith@xxxxxxxx
Date: Fri, 6 Jul 2012 10:11:20 -0600
Subject: RE: [EnergyPlus_Support] Re: Learn from my mistakes - EMS to avoid DX coil freeze - bad implementation
__._,_.___
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.
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Heat first before cooling, the cold OD air will never reach the DX cooling coil. Warnings are given to the operation of the heat pumps at low OD temperatures. Glycol anti-freeze is needed for OD solar collector in Winter, ehrn it is subject to frost at night. Wen hardware required special protection, warnings in EPlus is good.
EMS may remove the warnings, and it may not provide the real equipment protection or correct operation. A real life computer control program in a computer controlled system may not be able to correct a real hardware problem due to environment condition. It is not an EPlus problem.
If the supply air temperture required is 16°C or more, 14°C for those with VAV setpoint manager, why size it to 12.8°C, which was really for chillers.. When the OD air is heated to 14°C, the DX cooling coil will never be subjected to low temperature start-up.
Many template users do not know what is in the zone and system sizing objects, and do not care how the numbers was filled in and got into the sizing objects.
Refridgerator would turn on the defrosting cycle, when the evaporator is frozen. The air circulating fan stops, when the frig. door is open. Without the auto defrost, the user turns off the power manually. Auto-degrost and warm butter compartment models are still being certified as energy saving models.
Just some of my random views on energy saving certification.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: brent.griffith@xxxxxxxx
Date: Fri, 6 Jul 2012 10:11:20 -0600
Subject: RE: [EnergyPlus_Support] Re: Learn from my mistakes - EMS to avoid DX coil freeze - bad implementation
That output variable would be ?System Node Temp.? But if this about eliminating coil warnings, then some of them are for the condenser side. So a really robust EMS program might look at both the outdoor air and the coil inlet.
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Jia Hu
Sent: Friday, July 06, 2012 10:01 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Re: Learn from my mistakes - EMS to avoid DX coil freeze - bad implementation
Thanks, do you know how to implement your method? specifically, which variable should I use to in the EMS:Sensor? or which variable is used to measure DX coil inlet node ?
Thanks,
On Fri, Jul 6, 2012 at 6:59 AM, Jean marais <jeannieboef@xxxxxxxxx> wrote:
Yip, ideally each coil...that's a lot of work, but I think soon eplus will work coil freeze protection into the coil model. I'm monitoring just one worst case coil at the moment in one of my models and applying the manipulated schedule to all coils as a "less work" work around. Should do the job though.
__._,_.___
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.
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