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We're
counting down our Top 10 list in the next 10 editions of INNOVATIONS
#10
- Life-Cycle-Cost Based Decision-Making - October/November 2002
#9 DOAS (Dedicated Outdoor Air Systems) - December/January
2003
#8 - RADIANT
COOLING
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Our
last issue discussed the many advantages of using dedicated outdoor air
systems (DOAS) to provide all ventilation and dehumidification for a
building. The remainder of the room cooling and heating needs to be
done by a secondary, sensible-only system -- fan coils, water-source heat pumps, or a
radiant system. All secondary systems run dry (no condensation),
since the building moisture removal is already accomplished by the DOAS.
The DOAS provides a modest amount of room air circulation via high-aspiration
diffusers. |
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A radiant
system could consist of hydronic tubing imbedded in the structure
(plastic tubing in concrete decking or plaster) like the European
"batiso" (constant temperature) concept or tubing bonded to
metal panels integrated into the suspended ceiling grid. In either
case, cooling is accomplished by supplying chilled water to the
tubing at a temperature less than the room temperature but greater than
the room dew point (usually in the range of 57-63F). Heating is accomplished by
circulating warm water. A two-pipe or four-pipe system can be
used. Metal radiant panels are more
popular and offer greater flexibility than imbedded systems. |
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Pictures: Radiant
panels have been used successfully in over 500
recently-constructed European buildings. |
Radiant
panels can achieve approximately 30 BTU/hr of cooling per square foot.
After accounting for the sensible cooling contribution of the DOAS air
stream, about 50% of a typical office ceiling area must be active panels to provide the
same cooling effect as a conventional air system. The
advantages of radiant panels compared to conventional air systems include:
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No floor space for
equipment: all components are in the ceiling
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Aesthetically
pleasing: tubing can be bonded to a wide range of ceiling
panels from several manufacturers; panels can be
sound-attenuating, colored, textured, integrated with lights and
sprinklers
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Superior comfort:
50% of the energy exchange by our bodies is by radiation;
radiant exchange feels more comfortable than the cold drafts caused by
conventional air systems, particularly when there are large solar
radiation gains to the rooms
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Low maintenance:
long life components, no moving parts other than a control valve, no
complex controls like on VAV boxes, no filters to change
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“Passive”
response: panel cooling and heating capacity inherently
increases if there are radiant gains or losses to the room
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Quiet: no fans
or compressors in the rooms
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Complementary to
DOAS: small diameter DOAS ducts require little ceiling plenum
depth; radiant panels and piping fit in the same space
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Efficient:
due to the radiant exchange process, warmer chilled water and cooler
hot water can be used than conventional systems; for the same
reason, the space temperature can be kept higher in summer (75-80F), lower in
winter
Life-cycle
costs of DOAS/radiant systems are less than conventional systems and can be
competitive on a first-cost basis. The radiant panel piping can be
integrated with the sprinkler system piping for even greater savings.
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Project Spotlight:
Engineer-Led
Turnkey™ Project - Sunnex Inc. (Springboro, Ohio) Process Equipment
Installation
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ThermalTech
recently
completed an Engineer-Led TurnkeyTM electrical project for a new chemical process
line in a manufacturing facility. We provided design,
scheduling, equipment purchase, and subcontractor management. We
worked for the mechanical contractor and provided mechanical
system design for them as well.
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Scope of Work:
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Upgraded
electrical service equipment through installation of a new
1000-kVA transformer, 2000A pad-mounted switchboard, and the
back-feed of an existing 1200A switchboard
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Installed 800-amp
motor control center, lighting fixtures and switches, power
and control conduits, solenoid J-boxes, and wiring systems
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Installed new PLC
panel with touch screen remote PLC operator interface, PLC weight
scale interface, and Syscon control panel
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Systems
compliant with Class 1, Division 1 and Division 2 construction
methods
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New electric service |
PLC Control Panel |
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Success Factors:
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Increased
facility's electrical capacity
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Doubled
the company's production facilities
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Project completed on tight time schedule and within budget
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Contractors
managed in field by design engineers, enabling construction
process to run smoothly
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A
LIFE-SAVING Tech Tip
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Gary R. Davies,
P.E.
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This is not my usual
engineering tech tip, but it may be the most important advice I'll
ever be able to give you. I was recently diagnosed with prostate
cancer, just two days after my 50th birthday. Fortunately, as
the result of routine periodic PSA testing by my family doctor over the past seven
years, I had early warning of the cancer
development. I arranged to have surgery in December at
Washington University in St. Louis. Three weeks later,
after excellent care and support from family and friends, I was back
at work. I'm relieved to say that the probability of the cancer
recurring is very low. My hope is that you can benefit
from my experience. |
How prevalent is
prostate cancer? The lifetime risk of a man developing it is 1
in 6 (versus 1 in 8 for a woman developing breast cancer). There
were almost 200,000 new cases and 31,000 deaths in 2001.
Awareness of the pervasiveness of the disease and promotion of
screening tools is not as widespread as it should be.
My advice to all men:
-
Take control of your
health management. Tell your doctor you want a
periodic PSA test, beginning in your early 40's (I've been surprised by
the number of men in their 40's I have met that have had prostate
cancer). It's
a painless, inexpensive blood test that can be done at the same
time you check your cholesterol. Pay for it yourself if you
have to (it only costs about $75). It is the only tool available for detecting prostate cancer in its
earliest--and most curable--stages while it is contained within the
prostate. If you wait for other
physical symptoms to appear, it's too late.
-
Pay
particular attention if you have any family history of prostate
cancer or if you are African-American -- the incidence rates are
much higher.
-
Take early
aggressive action (free-PSA test and/or a biopsy) if your test results become
even moderately high (PSA>2.5 in your 40's, >3.5 in your
50's),
even if your doctor doesn't seem concerned. Some
doctors and insurance companies use 4.0 as the trigger level,
which may allow the cancer to develop a dangerous
grasp.
-
If your PSA levels
are increasing, read up on your options. There are many
informative web sites and books available. Here are a few:
www.drcatalona.com,
www.hopkinsprostate.com,
www.prostate-help.org,
Dr. Patrick Walsh's Guide to Surviving Prostate Cancer, Warner
Books.
-
If
cancer is confirmed, seek help from the best experts you can find,
even if outside your provider network. Read up on who the
specialists are and which institutions are rated the highest for
skill and care. Ask for their outcomes data.
-
Don't
worry about the pain and discomfort of the tests and
treatments. It's not as bad as you might think. Keep a
positive attitude. The risk from procrastinating due to fear
can be the most devastating aspect.
I
met many men who had
been through what I was facing. Their help was a blessing.
Feel free to contact me if I can do the same for you. And get
that PSA test now!
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Gary R. Davies, Managing
Principal, is proud to announce the appointment of ThermalTech's new principals:
SHERRY BURNSIDE
JEFFREY D. CELUCH
DANA P. CONNOLLY
JAMES W. DRYE
THOMAS E. KENNEDY
STEPHEN D. WILLIAMS
Collectively, the new
Principals have provided over 85 years of service to ThermalTech.
Congratulations to
ThermalTech's new principals!
     
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