Dear Lori,
A couple of thoughts:
I’ve recently completed some models using indirect evap
with DX. E+ works OK for some configurations, but not all (at least not
without some “Workarounds”). Generally, it’s not a good
idea to couple direct evap and DX because of the fact that a direct evap
cooler removes no energy from the air (it’s adiabatic).
There are a couple of manufacturers who make the indirect + DX
type of equipment currently, and they generally use either:
·
A constant volume supply fan with constant volume exhaust
fan. The exhaust fan draws evaporatively cooled air across the DX
condenser for additional performance improvement.
·
An all-variable-volume version of the above.
E+ models the first version fairly straightforwardly. The second
version needs some help from you, largely because E+ doesn’t know how to
make the exhaust fan Variable speed.
I recently completed a paper for the upcoming ASHRAE Winter
conference in which I compared performance for traditional DX against a couple
versions of indirect evap plus DX in dry climates. I don’t think I
can share the paper yet, but I can send you an IDF or two to help you. In
short, it appears that you can’t save much energy by using a cycling (on/off)
fan control. For variable speed fans, it appears that you can save
substantial energy if your indirect evap effectiveness exceeds 75% or so.
For a very high effectiveness indirect evap system, check out www.coolerado.com. (Other such systems may
be available, but I don’t know about them.)
Please send me a private message and I’ll attach the IDFs.
p.s., If anyone else has interest, I’ll post it to the E+
files on Yahoo.
The Building Performance Team
James V. Dirkes II, P.E., LEED AP
1631 Acacia Drive NW
Grand Rapids, MI 49504
616 450 8653
From: EnergyPlus_Support@xxxxxxxxxxxxxxx
[mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of jorehome
Sent: Wednesday, October 13, 2010 5:02 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] DirectIndirectEvapCoolers.idf
I'm looking for help with setting up an evaporative cooler
that is used in combination with a DX unit. I'm attempting to use the
DirectIndirectEvapCoolers.idf example file to set this up.
Question: How do I combine this example with my model that I assembled with
DesignBuilder? I know that I can open both with the EP-Launch software and find
the sections that I need to add to my file but how do I get the node naming
right? Is there any software available to make this easier?
Thanks in advance.
Lori Jore
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