The way to correlate bypass fraction with the manufacturer’s data sheet is through the approach temperature.
You adjust the bypass fraction so that the approach temperatures match the selection of the coil.
It’s somewhat iterative so I’ve created a separate small model with a constant air flow and water flow that I input and then adjust the bypass fraction until
the approach temperature is about right for my actual selection.
Fred
|
Fred Betz
PhD., LEED AP
Sustainable Systems Analyst
|
|
AEI |
AFFILIATED ENGINEERS, INC.
5802 Research Park Blvd. | Madison, WI 53719
P: 608.236.1175 | F: 608.238.2614
fbetz@aeieng.com |
www.aeieng.com
|
From: Jean Marais [mailto:jeannieboef@gmail.com]
Sent: Wednesday, September 05, 2012 6:39 AM
To: TRNSYS-users@cae.wisc.edu
Subject: [TRNSYS-users] Coil ByPass Fraction
Dear Group,
I would love to know how you go about assigning the parameter "coil bypass fraction" for cooling coils that cool air. This parameter must be affected by the physical coil dimensions (pipe diameter, fins, number of rows, etc.) as well as by mass flow rate of
the air and the overall dimensions of the coil. I've never seen this on a manufacturer's data sheet. Please advise.
Regards,
Jean.
PS I had hoped this was internally calculated without user input.