[Equest-users] evaporative coolers in equest

Nick Caton ncaton at smithboucher.com
Wed Aug 17 07:56:18 PDT 2011


Patrick, thanks for the heads up!

 

My experience applying evap. coolers has been on a limited basis
explicitly for space comfort, operated staged & cycled off via
thermostat, so my brainstorming for Deepika was tailored to my past
experience.  In those cases (auto garages), a mechanical ventilation
system was provided as an entirely separate system, so the 62.1/IMC
requirements for ventilation during occupancy were addressed elsewhere.

 

If one is in fact using a swamp cooler functionally to supply required
ventilation air, then I would agree it makes complete sense to operate
continuously during occupied hours.  

 

I recall evap. coolers being a breath of fresh air (har har) to design
around as they do make you rethink how you use your psych charts =).
I'll defer any specific swamp cooler application queries to the Arizona
engineer below me though - we don't use them quite so often locally,
outside of the desert ;).

 

~Nick

 

 

 

NICK CATON, P.E.

SENIOR ENGINEER

 

Smith & Boucher Engineers

25501 west valley parkway, suite 200

olathe, ks 66061

direct 913.344.0036

fax 913.345.0617

www.smithboucher.com 

 

From: Patrick J. O'Leary, Jr. [mailto:poleary1969 at gmail.com] 
Sent: Tuesday, August 16, 2011 5:48 PM
To: Nick Caton
Cc: deepika khowal; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] evaporative coolers in equest

 

i would agree with nick on this except for part #3.  if you're using
ashrae 62, or the 2000/2003/2006 imc (at least the way it is enforced in
southern arizona), the evaporative cooler fan is required to run while
the building is occupied so despite glazing upgrades you shouldn't be
seeing any savings from the hvac system during occupied hours.  you
would probably see some during night setback if the building there's
some thermostat setting that will operate the evap coolers to remove air
(and the associated heat build up) but i would not think it to be that
significant of a savings compared to heat gain during occupied hours.

i would think, as nick mentions in point 5, that the ummet cooling hours
might be a better measure of what you are looking for.  improved glazing
should help reduce the rate of heat gain so the evap coolers should be
able to meet whatever setpoint you are using with less unmet cooling
hours.  in reality i would think it would be more obvious by an occupant
working proximity to the windows - if they're currently affected by the
solar heat gain.  i don't know your climate but in southern arizona you
don't really want to be seated right next to a window with a direct sun
exposure and insufficient airflow (evap) or mechanical cooling and poor
windows.

On 8/16/11 2:22 PM, Nick Caton wrote: 

I hope we're at a simple vocabulary disconnect here...

 

Upgrading the windows will reduce your solar cooling loads.

Reducing your solar cooling loads will reduce the amount of heat to be
removed from the building.

Reducing the amount of heat to remove will reduce the required hours of
operation of your HVAC system (in this case, evaporative coolers) to
maintain comfort.

Reducing the runtime of your evaporative coolers will result in reduced
energy consumption.  Fan energies primarily, in the case of evaporative
coolers.

In the event the existing system is not of sufficient capacity to begin
with, you may also/instead observe a reduction in unmet cooling hours.

 

The reduction of solar loads with a glazing upgrade could be negligible
for a variety of possible reasons, but it's unlikely the net effect is
absolutely zero.  

 

~Nick



 

NICK CATON, P.E.

SENIOR ENGINEER

 

Smith & Boucher Engineers

25501 west valley parkway, suite 200

olathe, ks 66061

direct 913.344.0036

fax 913.345.0617

www.smithboucher.com 

 

From: deepika khowal [mailto:deepika.khowal at gmail.com] 
Sent: Tuesday, August 16, 2011 3:11 PM
To: Nick Caton
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] evaporative coolers in equest

 

 

This is an existing building with evaporative coolers.

the proposed design  to upgrade the windows and check the relative
benefits.

I dont see much benefits in energy because  evaporative coolers are
sized based on Cfm and not btus, the savings will be in cfms.

correct me if I am wrong.

is there any other way I can show the benefit in the proposed case if
not HVAC benefits?

Thanks

On Tue, Aug 16, 2011 at 1:00 PM, Nick Caton <ncaton at smithboucher.com>
wrote:

Hi Deepika,

 

I'm not certain any increase/decrease in cooling loads (such as solar
loads affected by changing glazing) should have any effect on the
reported "space cooling energy" when you're using evaporative coolers.
Direct evaporative (swamp) coolers of the simplest sort have only fan
and pump energies to consider -  no refrigerant!  I would advise looking
up the Detailed Simulation Reports Summary page 158/160 to review end
use categories and what they cover. 

 

I am unfamiliar with Bridgeport's climate, but as a general rule if I
observed a significant amount of glazing in a space served by a direct
evaporative cooler... I'd be extra cautious to ensure the HVAC designer
is carefully considering condensation and potential for other
humidity-driven issues along the way.  I'm most used to seeing them
applied to well-ventilated and/or open-air spaces such as garages and
gyms/hangars.

 

~Nick

 



 

NICK CATON, P.E.

SENIOR ENGINEER

 

Smith & Boucher Engineers

25501 west valley parkway, suite 200

olathe, ks 66061

direct 913.344.0036

fax 913.345.0617

www.smithboucher.com <http://www.smithboucher.com>  

 

From: equest-users-bounces at lists.onebuilding.org [mailto:
equest-users-bounces at lists.onebuilding.org] On Behalf Of deepika khowal
Sent: Tuesday, August 16, 2011 1:36 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] evaporative coolers in equest

 

Hello all

I am modeling a building in Bridgeport, CA which has evaporative
coolers.

I dont see any benefits if I replace existing clear glass with low-e in
cooling energy consumption.

Did anyone model evaporative coolers/swamp coolers before?

I want to know whether there is a way to show cooling benefit with such
HVAC system.

Thanks

Regards

Deepika

 

 
 
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