[TRNSYS-users] cooling coil

[David Bradley]

Ming,
   There are three cooling coil models available in the TESS HVAC Library.

Type508 models a cooling coil using one of four control modes. The cooling 
coil is modeled using a bypass approach in which the user specifies a 
fraction of the air stream that bypasses the coil. The remainder of the air 
stream is assumed to exit the coil at the average temperature of the fluid 
in the coil and at saturated conditions. The two air streams are remixed 
after the coil. In its unrestrained (uncontrolled) mode of operation, the 
coil cools and dehumidifies the air stream as much as possible given the 
inlet conditions of both the air and the fluid streams. The model is 
alternatively able to internally bypass fluid around the coil so as to 
maintain the outlet air dry bulb temperature above a user specified 
minimum, to maintain the air outlet absolute humidity ratio above a user 
specified minimum or to maintain the fluid outlet temperature below some 
user specified maximum.

Type752 component models a simple cooling coil where the air is cooled as 
it passes across a coil containing a cooler fluid (typically water or a 
refrigerant). This model uses the bypass fraction approach for cooling 
coils to solve for the outlet air conditions. The bypass factor approach 
assumes that a portion of the air stream comes to temperature equilibrium 
with the coil fluid and the other portion of the air stream (the bypass 
fraction) is thermally unaffected by the coil in the air stream. These two 
flows then mix to produce the outlet air condition. This coil may operate 
in 1 of 4 control modes:
1 - The outlet air temperature is controlled to be at a user-specified 
temperature
2 - The outlet air temperature and outlet air humidity ratio are controlled 
to be at user-specified conditions
3 - The outlet air temperature and outlet relative humidity are controlled 
to be at user-specified conditions
4 - The outlet air humidity ratio is controlled to be at a user-specified 
condition
The big difference between Type508 and Type752 is that Type508 fully solves 
both the outlet air stream and outlet liquid stream conditions while 
Type752 solves for onlyt the air stream outlet conditions and reports the 
load on the liquid stream.

Type697 models a cooling coil where the air is cooled as it passes across a 
coil containing a cooler fluid (typically water). This model relies on 
user-provided external data files which contain the performance of the coil 
as a function of the entering air and fluid conditions. Sample data files 
accompany to show the format of these external files.

Kind regards,
  David


At 21:03 9/17/2006, Liu, Ming - liumy008 wrote:
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>
>Hello everyone,
>
>I need a component "Cooling Coil" to setup my model. One side is the 
>secondary coolant; its inlet temperature is about -29C. The other side is 
>air; its inlet temperature is about -22C. However, in the Cooling Coil 
>(Type32 & Type52) in TRNSYS, air is assumed to exchange heat with water. I 
>can not set the inlet water temperature to a minus value.
>
>Is there anyone know what component I can use instead of Type 32 and Type 52?
>
>Thanks in advance!
>
>Ming
>
>_______________________________________________
>TRNSYS-users mailing list
>TRNSYS-users at engr.wisc.edu
>https://www.cae.wisc.edu/mailman/listinfo/trnsys-users

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Thermal Energy System Specialists (TESS), LLC
David BRADLEY                           2916 Marketplace Drive - Suite 104
Partner                                        Madison, WI 53719
Phone: (608) 274-2577 USA
Fax: (608) 278-1475
E-mail: bradley at tess-inc.com
Web Pages:  http://www.tess-inc.com     and      http://www.trnsys.com

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