For simulation, there is no harm for a cooling system to operate in Winter. This is one reason to do simulation, to find out the system demand conditions for a typical year with assumed loading conditions.
In practice, the unitary system do not have a type 4 thermostat control. The heating and the cooling unit cannot be on at the same time, by using a switch on the thermostat. You will simply open some windows to keep cool.
The outside compressor unit has an extra lock out switch and the unit is usually covered up to protect it from snow accumulation inside the casing.
Heat pumps have sump and auxilairy heaters etc. for them to operate in regions with a mild Winter. The economizer mode can then be applied.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: em@xxxxxxxxxxxxxxxxxxxx
Date: Wed, 18 Jan 2012 12:20:58 -0600
Subject: RE: [EnergyPlus_Support] Warning for Coil:Cooling:DX:SingleSpeed
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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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In practice, the unitary system do not have a type 4 thermostat control. The heating and the cooling unit cannot be on at the same time, by using a switch on the thermostat. You will simply open some windows to keep cool.
The outside compressor unit has an extra lock out switch and the unit is usually covered up to protect it from snow accumulation inside the casing.
Heat pumps have sump and auxilairy heaters etc. for them to operate in regions with a mild Winter. The economizer mode can then be applied.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: em@xxxxxxxxxxxxxxxxxxxx
Date: Wed, 18 Jan 2012 12:20:58 -0600
Subject: RE: [EnergyPlus_Support] Warning for Coil:Cooling:DX:SingleSpeed
I saw this post earlier but I still don't understand why the DX cooling is running in the wintertime. I followed the example for Packaged Unitary systems and the thermostats are set. Is the problem the Cooling Coil Schedules? I would assume the the coiling coils should be allowed to stay "always on."
** Warning ** Coil:Cooling:DX:SingleSpeed "RTU-4 COOLING COIL" - Air-cooled condenser inlet dry-bulb temperature below 0 C. Outdoor dry-bulb temperature = -2.93
** ~~~ ** ... Occurrence info = CHICAGO WEATHER, 01/03 12:30 - 12:45
** ~~~ ** ... Operation at low ambient temperatures may require special performance curves.
** Warning ** Coil:Cooling:DX:SingleSpeed "RTU-5 COOLING COIL" - Air-cooled condenser inlet dry-bulb temperature below 0 C. Outdoor dry-bulb temperature = -2.80
** ~~~ ** ... Occurrence info = CHICAGO WEATHER, 01/03 12:45 - 13:00
** ~~~ ** ... Operation at low ambient temperatures may require special performance curves.
** Warning ** Coil:Cooling:DX:SingleSpeed "RTU-1 COOLING COIL" - Air-cooled condenser inlet dry-bulb temperature below 0 C. Outdoor dry-bulb temperature = -2.80
** ~~~ ** ... Occurrence info = CHICAGO WEATHER, 01/03 13:00 - 13:15
** ~~~ ** ... Operation at low ambient temperatures may require special performance curves.
** Warning ** Coil:Cooling:DX:SingleSpeed "RTU-3 COOLING COIL" - Air-cooled condenser inlet dry-bulb temperature below 0 C. Outdoor dry-bulb temperature = -2.80
** ~~~ ** ... Occurrence info = CHICAGO WEATHER, 01/03 13:00 - 13:15
** ~~~ ** ... Operation at low ambient temperatures may require special performance curves.
Any reply would help.
Thanks,
Laurent Kanago
Technology Director
Office: (312) 235-2225
Fax: (773) 989.8679
Cell: (312) 730-2419
5030 N. Marine Dr #807
Chicago, IL 60640
http://www.ecohillsolutions.com/
?Please consider the environment before printing this e-mail. Thank you.?
From: YuanLu Li <yli006@xxxxxxxxxxx>
Reply-To: <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Date: Wed, 28 Dec 2011 07:47:03 -0500
To: EnergyPlus_Support <energyplus_support@xxxxxxxxxxxxxxx>
Subject: RE: [EnergyPlus_Support] Warning for Coil:Cooling:DX:SingleSpeed
Reply-To: <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Date: Wed, 28 Dec 2011 07:47:03 -0500
To: EnergyPlus_Support <energyplus_support@xxxxxxxxxxxxxxx>
Subject: RE: [EnergyPlus_Support] Warning for Coil:Cooling:DX:SingleSpeed
As indicated by the error message, you are running DX cooling in Winter. Jan 14 in Chicago.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: eee.javed@xxxxxxxxx
Date: Wed, 28 Dec 2011 12:32:54 +0000
Subject: [EnergyPlus_Support] Warning for Coil:Cooling:DX:SingleSpeed
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: eee.javed@xxxxxxxxx
Date: Wed, 28 Dec 2011 12:32:54 +0000
Subject: [EnergyPlus_Support] Warning for Coil:Cooling:DX:SingleSpeed
Hi All,
I am trying to run DX cooling coil and getting following repetitive error , what could be the possible solution for the same.
** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE5-1 PTAC COOLING COIL" - Full load outlet air dry-bulb temperature < 2C. This indicates the possibility of coil frost/freeze. Outlet temperature = -4.83 C.
** ~~~ ** ...Occurrence info = Chicago Ohare Intl Ap IL USA TMY3 WMO#=725300, 01/14 08:38 - 08:45
** ~~~ ** ... Possible reasons for low outlet air dry-bulb temperatures are: This DX coil
** ~~~ ** 1) may have a low inlet air dry-bulb temperature. Inlet air temperature = 10.835 C.
** ~~~ ** 2) may have a low air flow rate per watt of cooling capacity. Check inputs.
** ~~~ ** 3) is used as part of a HX assisted cooling coil which uses a high sensible effectiveness. Check inputs.
** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE3-1 PTAC COOLING COIL" - Air-cooled condenser inlet dry-bulb temperature below 0 C. Outdoor dry-bulb temperature = -4.40
** ~~~ ** ... Occurrence info = Chicago Ohare Intl Ap IL USA TMY3 WMO#=725300, 01/14 10:00 - 10:15
** ~~~ ** ... Operation at low ambient temperatures may require special performance curves.
** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE3-1 PTAC COOLING COIL" - Full load outlet air dry-bulb temperature < 2C. This indicates the possibility of coil frost/freeze. Outlet temperature = 8.52E-002 C.
** ~~~ ** ...Occurrence info = Chicago Ohare Intl Ap IL USA TMY3 WMO#=725300, 01/14 10:00 - 10:15
** ~~~ ** ... Possible reasons for low outlet air dry-bulb temperatures are: This DX coil
** ~~~ ** 1) may have a low inlet air dry-bulb temperature. Inlet air temperature = 15.011 C.
** ~~~ ** 2) may have a low air flow rate per watt of cooling capacity. Check inputs.
** ~~~ ** 3) is used as part of a HX assisted cooling coil which uses a high sensible effectiveness. Check inputs.
** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE1-1 PTAC COOLING COIL" - Air-cooled condenser inlet dry-bulb temperature below 0 C. Outdoor dry-bulb temperature = -4.40
** ~~~ ** ... Occurrence info = Chicago Ohare Intl Ap IL USA TMY3 WMO#=725300, 01/14 10:45 - 11:00
** ~~~ ** ... Operation at low ambient temperatures may require special performance curves.
** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE1-1 PTAC COOLING COIL" - Full load outlet air dry-bulb temperature < 2C. This indicates the possibility of coil frost/freeze. Outlet temperature = 1.79 C.
** ~~~ ** ...Occurrence info = Chicago Ohare Intl Ap IL USA TMY3 WMO#=725300, 01/14 15:00 - 15:15
** ~~~ ** ... Possible reasons for low outlet air dry-bulb temperatures are: This DX coil
** ~~~ ** 1) may have a low inlet air dry-bulb temperature. Inlet air temperature = 15.972 C.
** ~~~ ** 2) may have a low air flow rate per watt of cooling capacity. Check inputs.
** ~~~ ** 3) is used as part of a HX assisted cooling coil which uses a high sensible effectiveness. Check inputs.
************* Simulation Error Summary *************
*************
************* ===== Recurring Error Summary =====
************* The following recurring error messages occurred.
*************
************* ** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE5-1 PTAC COOLING COIL" - Low condenser dry-bulb temperature error continues...
************* ** ~~~ ** This error occurred 45 total times;
************* ** ~~~ ** during Warmup 0 times;
************* ** ~~~ ** during Sizing 0 times.
************* ** ~~~ ** Max=-2.8 [C] Min=-7.2 [C]
*************
************* ** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE5-1 PTAC COOLING COIL" - Full load outlet temperature indicates a possibility of frost/freeze error continues. Outlet air temperature statistics follow:
************* ** ~~~ ** This error occurred 45 total times;
************* ** ~~~ ** during Warmup 0 times;
************* ** ~~~ ** during Sizing 0 times.
************* ** ~~~ ** Max=-2.888928 Min=-4.833602
*************
************* ** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE3-1 PTAC COOLING COIL" - Low condenser dry-bulb temperature error continues...
************* ** ~~~ ** This error occurred 26 total times;
************* ** ~~~ ** during Warmup 0 times;
************* ** ~~~ ** during Sizing 0 times.
************* ** ~~~ ** Max=-2.8 [C] Min=-4.75 [C]
Any help is appreciated.
Thanks!
I am trying to run DX cooling coil and getting following repetitive error , what could be the possible solution for the same.
** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE5-1 PTAC COOLING COIL" - Full load outlet air dry-bulb temperature < 2C. This indicates the possibility of coil frost/freeze. Outlet temperature = -4.83 C.
** ~~~ ** ...Occurrence info = Chicago Ohare Intl Ap IL USA TMY3 WMO#=725300, 01/14 08:38 - 08:45
** ~~~ ** ... Possible reasons for low outlet air dry-bulb temperatures are: This DX coil
** ~~~ ** 1) may have a low inlet air dry-bulb temperature. Inlet air temperature = 10.835 C.
** ~~~ ** 2) may have a low air flow rate per watt of cooling capacity. Check inputs.
** ~~~ ** 3) is used as part of a HX assisted cooling coil which uses a high sensible effectiveness. Check inputs.
** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE3-1 PTAC COOLING COIL" - Air-cooled condenser inlet dry-bulb temperature below 0 C. Outdoor dry-bulb temperature = -4.40
** ~~~ ** ... Occurrence info = Chicago Ohare Intl Ap IL USA TMY3 WMO#=725300, 01/14 10:00 - 10:15
** ~~~ ** ... Operation at low ambient temperatures may require special performance curves.
** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE3-1 PTAC COOLING COIL" - Full load outlet air dry-bulb temperature < 2C. This indicates the possibility of coil frost/freeze. Outlet temperature = 8.52E-002 C.
** ~~~ ** ...Occurrence info = Chicago Ohare Intl Ap IL USA TMY3 WMO#=725300, 01/14 10:00 - 10:15
** ~~~ ** ... Possible reasons for low outlet air dry-bulb temperatures are: This DX coil
** ~~~ ** 1) may have a low inlet air dry-bulb temperature. Inlet air temperature = 15.011 C.
** ~~~ ** 2) may have a low air flow rate per watt of cooling capacity. Check inputs.
** ~~~ ** 3) is used as part of a HX assisted cooling coil which uses a high sensible effectiveness. Check inputs.
** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE1-1 PTAC COOLING COIL" - Air-cooled condenser inlet dry-bulb temperature below 0 C. Outdoor dry-bulb temperature = -4.40
** ~~~ ** ... Occurrence info = Chicago Ohare Intl Ap IL USA TMY3 WMO#=725300, 01/14 10:45 - 11:00
** ~~~ ** ... Operation at low ambient temperatures may require special performance curves.
** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE1-1 PTAC COOLING COIL" - Full load outlet air dry-bulb temperature < 2C. This indicates the possibility of coil frost/freeze. Outlet temperature = 1.79 C.
** ~~~ ** ...Occurrence info = Chicago Ohare Intl Ap IL USA TMY3 WMO#=725300, 01/14 15:00 - 15:15
** ~~~ ** ... Possible reasons for low outlet air dry-bulb temperatures are: This DX coil
** ~~~ ** 1) may have a low inlet air dry-bulb temperature. Inlet air temperature = 15.972 C.
** ~~~ ** 2) may have a low air flow rate per watt of cooling capacity. Check inputs.
** ~~~ ** 3) is used as part of a HX assisted cooling coil which uses a high sensible effectiveness. Check inputs.
************* Simulation Error Summary *************
*************
************* ===== Recurring Error Summary =====
************* The following recurring error messages occurred.
*************
************* ** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE5-1 PTAC COOLING COIL" - Low condenser dry-bulb temperature error continues...
************* ** ~~~ ** This error occurred 45 total times;
************* ** ~~~ ** during Warmup 0 times;
************* ** ~~~ ** during Sizing 0 times.
************* ** ~~~ ** Max=-2.8 [C] Min=-7.2 [C]
*************
************* ** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE5-1 PTAC COOLING COIL" - Full load outlet temperature indicates a possibility of frost/freeze error continues. Outlet air temperature statistics follow:
************* ** ~~~ ** This error occurred 45 total times;
************* ** ~~~ ** during Warmup 0 times;
************* ** ~~~ ** during Sizing 0 times.
************* ** ~~~ ** Max=-2.888928 Min=-4.833602
*************
************* ** Warning ** Coil:Cooling:DX:SingleSpeed "SPACE3-1 PTAC COOLING COIL" - Low condenser dry-bulb temperature error continues...
************* ** ~~~ ** This error occurred 26 total times;
************* ** ~~~ ** during Warmup 0 times;
************* ** ~~~ ** during Sizing 0 times.
************* ** ~~~ ** Max=-2.8 [C] Min=-4.75 [C]
Any help is appreciated.
Thanks!
__._,_.___
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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