Cooling coil and Direct Evaporative Cooler

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Hello All,

I am interested in calculating the energy savings obtained by using
combination of chilled water cooling coil and direct evaporative cooler
when compared to using only the cooling coil for a dry climate.

In this set up the direct evaporative cooler would be placed after the
cooling coil. The return air would be cooled by cooling coil and then
passes through the direct evaporative cooler and then to the respective

I would like to have some suggestion on how to model this in eQuest.



R Ganesh's picture
Joined: 2011-09-30
Reputation: 0


I think this is the setup you're talking about:

Baseline - VAV AHU, Chilled water cooling coil, no evaporative cooling

Energy Conservation Measure - VAV AHU, Chilled water cooling coil with
direct evaporative cooler.

When you say that the return air would be cooled by the cooling coil, do you
mean that there will be some form of heat recovery, or just that the air
handler is equipped with an economizer and can recirculate return air? It
may be helpful to attach a rough sketch of the proposed system schematics.

In any case, see the screenshot & help file excerpts below:


For SYSTEM:TYPE = EVAP-COOL or for an add-on unit, takes a code-word that
specifies the type of evaporative cooling elements. See Figure

DIRECT There is only a direct evaporative cooling

INDIRECT There is only an indirect evaporative cooling

INDIRECT-DIRECT There are both direct and indirect evaporative cooling


Takes a code-word that specifies whether the evaporative precooler can or
cannot operate in conjunction with mechanical cooling. In either case the
evaporative cooler will cycle off if OA-CONTROL = TEMP and the outside air
is cool enough to handle the entire cooling load.

SEPARATE The evaporative cooler operates only when it
meets the entire cooling load.

TOGETHER The evaporative cooler does as much cooling as
possible; mechanical cooling handles the remaining load (plus any
dehumidification that is needed).

You should also have a look at the help files, search under EVAP.


Steven Savich's picture
Joined: 2011-09-30
Reputation: 0