I think, dew point temperature is the same as the wet-bulb temperature.
At 100% reletive humidity, the dry-bulb, web-bulb, and dew point are all the same.
===================
If the humidity ratio in a zone is fixed, the dew point is the web-bulb temperature at this humidity ratio. I.e. 100% humidity at this temperature.
When a surface is cooled to this temperature, the moisture starts to condense on the surface. EPlus calculate and report this temperature for the radiant panel. The condensation will not continue, when the cooling source is stopped. (the heat released by condensation is not removed at the panel.)
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With outside air of a certain RH, the water vapour become dew on the ground at dew point temperature, and hence the name. When there is wind, dew would not form.
This is the reason why the neutral comfort temperature can be increased with air movement over the exposed human skin.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: jeannieboef@xxxxxxxxx
Date: Mon, 1 Aug 2011 11:31:52 +0000
Subject: [EnergyPlus_Support] Can't find room dew-point in rdd
__._,_.___
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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At 100% reletive humidity, the dry-bulb, web-bulb, and dew point are all the same.
===================
If the humidity ratio in a zone is fixed, the dew point is the web-bulb temperature at this humidity ratio. I.e. 100% humidity at this temperature.
When a surface is cooled to this temperature, the moisture starts to condense on the surface. EPlus calculate and report this temperature for the radiant panel. The condensation will not continue, when the cooling source is stopped. (the heat released by condensation is not removed at the panel.)
========================
With outside air of a certain RH, the water vapour become dew on the ground at dew point temperature, and hence the name. When there is wind, dew would not form.
This is the reason why the neutral comfort temperature can be increased with air movement over the exposed human skin.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: jeannieboef@xxxxxxxxx
Date: Mon, 1 Aug 2011 11:31:52 +0000
Subject: [EnergyPlus_Support] Can't find room dew-point in rdd
Hi All, When I run certain scenarios with my chilled ceiling, I get this niffty error, which gives the room dew-point when the ceiling is deactivated due to condensation. I looked for a variable like this in the rdd file, but don't find it. Can one output this zone dew-point?
** Warning ** Surface temperature below dew-point temperature--potential for condensation exists
** ~~~ ** Flow to the following radiant system will be shut-off to avoid condensation
** ~~~ ** Hydronic Radiant System Name = PIERW%E03:PIERW%E03 RF
** ~~~ ** Predicted radiant system surface temperature = 16.83
** ~~~ ** Zone dew-point temperature= 16.84
** Warning ** Surface temperature below dew-point temperature--potential for condensation exists
** ~~~ ** Flow to the following radiant system will be shut-off to avoid condensation
** ~~~ ** Hydronic Radiant System Name = PIERW%E03:PIERW%E03 RF
** ~~~ ** Predicted radiant system surface temperature = 16.83
** ~~~ ** Zone dew-point temperature= 16.84
__._,_.___
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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