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This site seeks to support the 6 points listed below:
1) It is almost impossible to verify that the ASHRAE ventilation standard
62.1-2007 has been met with
an all-air system.
2) Therefore a dedicated outdoor air system (DOAS) is required for verifiable ventilation air distribution.
3) Once the use of DOAS is in place, it is one small step to decouple the space sensible and latent
loads by supplying dry
Outdoor Air (OA) at a low (45-50 F) Dew Point Temperature (DPT).
This
results in a significant improvement in the Indoor Air
Quality (IAQ), with a potential savings to US
businesses
of $208 billion/year (in 1996 dollars when the Gross Domestic Product (GDP) was
$8,000 Billion) through reduced medical expenses and lost productivity. (source: LBL)
Note: The US GDP had grown to over
$14,264 Billion/yr by
the end of the forth quarter 2008.
4) That leaves sensible only cooling for the parallel system since all of the moisture is removed with
the ventilation air, eliminating high humidity conditions.
5) There are many design choices for the parallel space sensible cooling system. At this site,
ceiling
radiant cooling panels (CRCP)/chilled ceiling or
chilled beams (technologies that
are expanding
here in the US,
as of 8/9/08)
are favored. With the DOAS-Radiant system, contaminants
generated or released in one space are not
distributed throughout the building by the HVAC sys.
6)
THE BENEFITS OF THIS APPROACH: This mechanical system design concept, when compared
to the conventional all air VAV system, results
in
lower first
and operating costs, provides
superior IAQ and thermal & acoustical comfort, reduces the
hazard of a biological or
chemical attack in the building, reduces the required plenum depth, and is easier to
balance and maintain.
The challenge of conforming to ASHRAE Standard 62.1-2007 in an energy efficient manner has led some HVAC practitioners to the conclusion that using
dedicated outdoor air systems (DOAS) in conjunction with sensible cooling at terminal units offers the best solution.
To comment on the material on this site please send email to:
Stanley A. Mumma, Ph.D.,
P.E.
¤Dr. Mumma, ASHRAE Fellow
and Distinguished Lecturer, is currently Professor
Emeritus,
Architectural Engineering Department,
College of Engineering at
The Pennsylvania State University, University
Park, PA..
¤This site was designed by
Robert V. Hedman,
E.I.T., LEED
Certified Professional, & ASHRAE member while an MS Candidate in the Architectural
Engineering Department at the Pennsylvania State University.
Dedicated Outdoor Air Systems (DOAS) section
This section contains information on dedicated outdoor air systems.
Environmental Safety section
This section contains information about the strong health and safety benefits of the system,
including during chemical and biological events.
Radiant Ceiling Panels section
This section contains information on ceiling radiant cooling panels (CRCP), also referred to as chilled ceilings.
Economic Considerations section
This section contains a first cost and operating cost analysis; for a 6 story office building; utilizing a dedicated outdoor air system (DOAS)-radiant system,
with a comparison to a conventional all air VAV system serving the same facility.
Proof of Concept section
This section identifies the Contributors to the project. It also provides links
to: The Project Description and System Schematic, The System Control Overview, The Project Goals,
and A Virtual Tour.
Technical Papers section
This section contains copies of archival technical papers ASHRAE published papers and
technical papers on dedicated outdoor air systems (DOAS) and radiant ceiling
panels.
You will need Adobe Acrobat Reader to view these files.
Download a free version of Adobe Acrobat Reader.
PPT Presentations @ ASHRAE
Meetings
This section contains PowerPoint presentations on dedicated outdoor air systems (DOAS)
and radiant ceiling panels.
Links section
This section contains links to pages dealing with dedicated outdoor air systems and radiant ceiling panels. They are all worth taking a look at.
LEED Green Building section
This section is intended to explore the potential rating points that the DOAS-radiant mechanical system design could contribute to the overall Green Building rating. The
DOAS-radiant system is significant for its energy and environmental benefits.
Dedicated Outdoor Air
l Home l
Dedicated Outdoor Air Systems (DOAS) l Environmental
Safety l Radiant Panels l Economic
Considerations l Proof of Concept l Technical
Papers l ASHRAE Presentations l Links l
LEED Green Building l Email l
Section
descriptions are below.
