Sorry David, my wording was very
poor.
What I was trying to get at is
that the approach temperatures appear too small.
I have 22C air entering the coil
and 29C air leaving the coil.
I have 32C water entering the
coil and 25C water leaving the coil.
That is a delta T of just 3C, or
5.4F between the air entering and the water leaving.
It should be about 7-10F based
on project experience.
This might be splitting hairs,
but with 500,000 CFM of air flow, 1 degree means thousands of dollars. Therefore,
every item gets scrutinized.
Also, I was hoping there was a
way to set the effectiveness on the cooling coil like I was able to on the
heating coil.
Thanks,
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: David Bradley
[mailto:bradley@tess-inc.com]
Sent: Monday, March 29, 2010 4:18 PM
To: Fred Betz
Cc: trnsys-users@cae.wisc.edu
Subject: Re: [TRNSYS-users] Heating Coil: Type 670-1 bug
Fred,
I think you might be confusing efficiency and effectiveness.
Effectiveness is actual energy transfer divided by maximum theoretically
possible energy transfer. The air and water side heat transfers need to be
equal or else there is an energy imbalance across the coil.
Best,
David
Fred Betz wrote:
All,
There appears to be a bug in the Type 670-1 heating coil.
I set the effectiveness of the coil to 0.70, but the air and
water side heat transfer rates are approximately equal.
Anyone have a fix?
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
|
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