Re: looking for TRNSYS components

[David Bradley <bradley@xxxxxxxxxxxx>]

Dear Anil,

> I want to
> know:
> 1. If the evaporative cooler component is available free of
> cost? How to procure and use it?

  You can get the evaporative cooler model for free from the TRNLIB
section of the Solar Lab website. The ASHRAE Toolkit that was mentioned
in an earlier email is also included in the TRNLIB section. In order to
download those components, you should only have to provide the same user
ID and password that you would to download a TRNSYS update from the SEL
site. Please contact me directly (bradley@tess-inc.com) and I can provide
you with these if you do not already have them. Simply click on the name
of the component, and then on the ".for" icon and the code
should be viewable. After downloading it, you would have to add the model
to your trnlib.dll using a Fortran compiler. Alternatively, we have
developed a number of evapoartive cooler models (swamp coolers and
fogging devices) that we are working on for version 2 of the TESS
libraries. Below is a very brief overview of what they do.

Swamp Cooler:
This routine models an evaporative cooling device which cools an inlet
air stream by passing the air through or across a wetted surface;
evaporating the water from the surface and cooling the air stream in the
process. The ideal exiting air state for an evaporative cooler is if the
air exits with a dry-bulb temperature equal to its inlet wet-bulb
temperature.  The model takes the saturation efficiency of the
device as an input in order to calculate the air outlet conditions. The
saturation efficiency is defined as:
Saturation Efficiency =
(Tair,db,in
-
Tair,db,out)
/
(Tair,db,in
-
Tair,wb,in)
where in refers to the inlet condition, out refers to the
air outlet condition, db refers to the air dry-bulb temperature
and wb refers to the air wet bulb temperature.
The power output is simply the parasitic power if the machine is
operating.  The machine is assumed to be off (inlet conditions =
outlet conditions) if the control signal is less than 0.5 or if the inlet
air flow rate is zero.

Fogging Device:
This routine models an evaporative cooling device which cools an inlet
air stream by injecting tiny droplets of water into the air stream -
causing the water to evaporate and removing sensible energy from the flow
stream. The user must supply the inlet air conditions, and the desired
relative humidity for the outlet air stream. The model then iterates on
outlet dry bulb temperature until the desired outlet relative humidity is
met given the wet bulb temperature.  This model is similar to the
Type 506 evaporative cooler but includes internal controls to keep the
outlet air at the user-defined relative humidity set-point.  The
power used by the machine is the parasitic power (Parameter 1) whenever
the machine is operating and zero otherwise.

> 3. Is a
> "Flat-plate Air to Air heat Exchanger" component available
> anywhere in the TRNSYS library?

If one of the standard heat exchangers is not appropriate, you could use
Type667 in your HVAC library (air to air heat recovery device). It takes
both sensible and latent effectiveness as an input.
Kind regards,
  David

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

"Providing software solutions for today's energy engineering projects"
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