Dear Alaa,
The paper is called “ Energy Simulation Results for
Indirect Evaporative-Assisted DX Cooling Systems” and will be presented at the
ASHRAE winter conference in Las Vegas. I hope to see you there and compare
notes!
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 alaa kandil
Sent: Wednesday, October 13, 2010 5:30 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] DirectIndirectEvapCoolers.idf
Hi
James, Lorie,
I am
very interested in this paper. Currently, I am working on a data center project
in a cold-dry region that combines DX and direct evaporative cooling.
Simulation expected great savings, these savings are basically because of
humidification energy as the building has to be controlled between 30% and 40%
RH.
Regarding
Lorie's question,
- I
advice you to use RESEARCHSPECIALDIRECTEVAPORATIVE object. It is away easier to
define.
- I
don't advice you to start with an HVAC system defined in Design Builder.
Get only the geometry from Design builder.
-
Start with a base system using "UNITARY:COOLING ONLY"
- Add
the evaporative cooler between outdoor air mixer and cooling coil.
-
Each component have inlet and outlet node, so when you add it make sure
that evaporative inlet node is outlet node of outdoor mixer and outlet node is
inlet node of DX coil.(track node names allover the file, you may do
that easier in the text editing mode instead of IDF editor).
-
You also need to add it to the main air loop branch object
- In
the evaporative cooler component, select the sensor node in the way you like to
control the cooler.
1-If you want it to work on te same time with the DX coil (pre-cooling),
then the evaporative outlet node should be the sensor node with a pre
cooling set point (you need to define that through a set point manager).
2-If you want it to carry all the load if it can, then set point node should be
the Air Loop outlet node (Same node for DX coil and it should have a set point
manager as well)
Please
feel free to contact me directly if you need more help.
Alaa
Kandil
Energy
Analysis Specialist
MA,
LEED® AP
MechWave
Engineering Ltd.
Suite
200, 1518 7th Street SW
Calgary,
Alberta T2R 1A7
Phone:
403-802-1090 Facsimile: 403-244-4440
From: "James V Dirkes II, PE"
<jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Sent: Wed, October 13, 2010 7:38:03 AM
Subject: RE: [EnergyPlus_Support] DirectIndirectEvapCoolers.idf
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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