Re: [EnergyPlus_Support] Basic principle question

["Jean Marais jeannieboef@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx>]

Imagine that surface of the pipes of the coil could be below the dewpoint of the air. A certain fraction of the air passes through the coil without direct or film contact with the pipe surface will some air does. This concept is referred to as bypass fraction.

The pipes may condense out some water this way and after the pipes the saturated and non-saturated fractions of the air mix again.

So you can't just use the psychometric chart to determine the outlet conditions without considering the SHR and bypass factor of the coil.

I hope this helps.

On 1 Dec 2015 4:20 pm, "alyelhefni@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

 

Hi ,

I know that for a cooling water coil to make air output temperature at certain setpoint , it will either cool it sensibly or cool and dehumidify it to reach that setpoint .

Therefore there is one humidity ratio where the coil would cool only sensibly (constant w) and a point of any other humidity ratio above that would need to be cooled and dehumidified to reach such temperature setpoint.

The strange thing that happened here is that in excel sheet results some points show that the coil have cooled and reached setpoint sensibly although those points are of different humidity ratios and all above the line of setpoint temp at 100% RH .

Can anyone explain that ?

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Posted by: Jean Marais <jeannieboef@xxxxxxxxx>

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