[BLDG-SIM] Evaporative precooling increases system peak cooling load?

[Zhou, Anna]

Vikram,

I tried to use indirect evaporative cooling only, the peak cooling load
decreases from the (indirect/direct case) but still larger than the base
case (without evap.precooling.)
Also, if change the fraction of the air that's evaporative precooling to be
a smaller value, same as above.
So, the latent load does play a role in the increasing of the peak load but
should not be the only reason.

Hourly report shows :

1. if total system flow rate is autosized, the total system flow is lower in
the evap. precooling case than the normal case. And during the peak day, for
the test building, the evap. precooling allways uses 100% OA, while the
normal case uses the minimum OA.
2. if the total system flow is manually defined. The total peak system flow
is same for both cases. But the evap. precooling still uses 100% OA on the
peak day.

So, I suspect, another reason might be the more amount of OA, or less amount
of total system air?

Anna

-----Original Message-----
From: Vikram Sami [mailto:Vikram at ensargroup.com]
Sent: Tuesday, June 08, 2004 9:05 AM
To: annazhou at geopraxis.com
Subject: RE: [BLDG-SIM] Evaporative precooling increases system peak
cooling load?


Anna,
I'm not sure, but it could be that since you are using evap cooling, the
latent loads might be adding to the overall peak cooling loads. What is
the dry bulb high limit that you have set? Does the overall building
energy reduce?

Vikram Sami

Ensar Group Inc.
2305 Broadway
Boulder, CO 80304
Tel: (303) 449-5226
Fax: (303) 449-5276




-----Original Message-----
From: postman at gard.com [mailto:postman at gard.com] On Behalf Of Zhou, Anna
Sent: Tuesday, June 08, 2004 10:16 AM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] Evaporative precooling increases system peak cooling
load?


Hello everyone,

While using eQuest (DOE2.2), I have noticed that each time evaporative
precooling is used (indirect, or indirect/direct), the system peak
cooling load increases (from ss-d report).

Can anyboby give me some insight why this is happenning?

Thanks a lot!

Anna



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