[Bldg-rate] [Bldg-sim] PSZ-AC

[Eric Youngson]

Kendra,

                You are right. The user-guide specifies on page G-27:

 

Systems 3 and 4 are single zone

packages with either gas or heat pump

heating. Whether the baseline building

system has an economizer depends on the

area served by the system, whether the

zone served is a perimeter or an interior

zone, and climate. Table G3.1.2.6A gives

the floor area served by the system, above

which an economizer is needed. For the

purposes of defining interior and

perimeter zones, any thermal zone that

has more than half of its floor area located

more than 15 ft from an exterior wall is to

be considered an interior zone, otherwise,

it is a perimeter zone.

 

Thanks!

 

Eric

 

From: Kendra Tupper [mailto:ktupper at rmi.org] 
Sent: Friday, September 05, 2008 7:34 AM
To: Dan Russell; Eric Youngson; bldg-sim at lists.onebuilding.org
Cc: bldg-rate at lists.onebuilding.org
Subject: RE: [Bldg-sim] PSZ-AC

 

I agree with Dan.  The 90.1 User's Manual is a bit more clear on this
subject, and references that a PSZ unit is created for each thermal
zone.

 

________________________________

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Dan Russell
Sent: Thursday, September 04, 2008 4:12 PM
To: Eric Youngson; bldg-sim at lists.onebuilding.org
Cc: bldg-rate at lists.onebuilding.org
Subject: Re: [Bldg-sim] PSZ-AC

 

Eric, 

 

I understand System 3 (PSZ-AC) to be a standard packaged rooftop that
may serve multiple "spaces", but only serves a single "thermal zone".
In other words, there is only one thermostat that controls the entire
unit.

 

Your baseline should have a separate PSZ-AC for each thermal zone
depicted by your HVAC drawings.  Note that adjacent thermal zones with
similar load characteristics (light/equip gain, people count, exterior
exposure, etc.) may be lumped into a single thermal zone for modeling
purposes (i.e. less zones = simpler model).

 

Hope that helps.

 

 Dan Russell, EIT 

 

 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Eric
Youngson
Sent: Thursday, September 04, 2008 3:33 PM
To: bldg-sim at lists.onebuilding.org
Cc: bldg-rate at lists.onebuilding.org
Subject: [Bldg-sim] PSZ-AC

 

Sim List,

                ASHRAE system 3 is, Packaged Single Zone Air Conditioner
(PSZ-AC). The description of PSZ-AC says, "Packaged rooftop air
conditioner". I assume that this means a single unit serving multiple
zones. This doesn't seem to make sense since the name contains the
phrase 'single zone'.

                I have a building with baseline system 3, PSZ-AC and I'm
not sure how to apply this system. The proposed building has a variety
of systems. Should I have a system per zone or a single unit for the
building?

 

Thanks

 

  <http://www.pae-engineers.com/> 

Eric Youngson 

 

PAE Consulting Engineers, Inc. 



503.226.2921 Main
503.542.0567 Direct
503.226.2930 Fax
ericy at pae-engineers.com 

Mechanical 

808 SW Third Avenue - Suite 300
Portland, OR 97204-2426
www.pae-engineers.com 

inspire  interpret  integrate 







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