[TRNSYS-users] Heating Coil: Type 670-1 bug

[Fred Betz]

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 at aeieng.com<mailto:fbetz at aeieng.com>  |  www.aeieng.com<http://www.aeieng.com/>



From: David Bradley [mailto:bradley at tess-inc.com]
Sent: Monday, March 29, 2010 4:18 PM
To: Fred Betz
Cc: trnsys-users at 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 at aeieng.com<mailto:fbetz at aeieng.com>  |  www.aeieng.com<http://www.aeieng.com/>









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Thermal Energy System Specialists (TESS), LLC

David BRADLEY                      22 N. Carroll Street - Suite 370

Partner                            Madison, WI 53703

                                   USA

P: +1.608.274.2577

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