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existing HVAC systems analysis
SEI
mechanical and electrical engineers are hands-on experienced with
analyzing existing HVAC systems, diagnosing operational problems, and
proposing long term and short term solutions to these problems. Our staff
of engineers are particularly well acquainted in building
operations and communicate very well with operating and maintenance
personnel. You will find that our staff is at home with tools and
instruments, as compared to the clean hands ivory tower type of engineer or
architect. This attitude generally shows through and makes our personnel
more compatible with your operating and maintenance personnel. We always
take the time to explain any changes in operating and maintenance procedures
to your personnel so that they will fully understand and believe in any
procedures that we recommend.
SEI has
extensive experience determining HVAC system requirements. SEI has had
in-house HVAC load calculating capability since 1979. SEI engineers have performed analysis of the
following HVAC systems:
A. LACKLAND
AFB HVAC STUDY BUILDINGS 1351, 1250, 1354, 1251, 1355, 6329 and 6359 - Sept,
2002 - Project No. MPLS-00-1062 Lackland
AFB, Texas 78236-5253
- We performed a formal study and written report to determine why these
recently air conditioned buildings did not control the indoor humidity
properly, and was growing mold on the indoor surfaces. We then
prepared a report to correct the apparatus configurations so that the
systems would have inherent humidity control plus positive humidity control
when abnormal conditions occur. Abnormal conditions might be when
someone holds the doors open for extended periods of time, or during system
startup after a power failure or system shutdown.
All of these buildings have extreme mold
and mildew problems resulting from the high room relative humidity that is
normally present indoors since the HVAC systems replacement. The resulting
high relative humidity has caused mold, mildew and rust on the relatively
new walls, ceiling grids, the ceiling supply air diffusers, and the return
air grilles. Most of these buildings have recently installed new HVAC
systems, and the occupants refused to work in these buildings due to the
humidity and mold problems.
The problem was with the basic design configuration of the recently
installed new HVAC apparatus which did not feature inherent humidity control
or even positive control for removal of humidity during abnormal or upset
conditions. The existing systems will require that the chiller be operated
at essentially full load whenever the building cooling requirement is less
than 90% of the full capacity for humidity control, and that the boiler also
be operated at all times to reheat the room air supply sufficiently to
prevent the rooms from getting too cold. The annual operating costs of this
system if operated for humidity control would be several times the cost of a
modified apparatus with face & by-pass or maybe return air by-pass to the
fan section.
We proposed to vary the apparatus leaving air temperature by blending
dehumidified return air in the draw-through fan section as required to not
overcool the occupied space. This will eliminate the reheat requirement. We
recommend cutting an opening into the fan plenum and adding a motor operated
damper to allow dehumidified return air (RA) to enter the fan plenum without
passing through the cooling coil except when it is needed to cool the
occupied space, or when dehumidification and reheat is required. We will
remove the control valve from the chilled water coil and allow the chilled
water coil to circulate uncontrolled and have the cooling coil leaving air
temperature to be constant at or below the desired dew point. This removal
of the chilled water control valve will also decrease the possibility of
wintertime chilled water coil freezing, if the chilled water pumps are
operated at all temperatures below freezing. Dehumidification and reheat
will not be required except under extreme conditions, such as when someone
blocks the exterior doors open. The modified apparatus would have inherent
control of the maximum room relative humidity due to the revised
configuration with inherent maximum dew point control. Rough estimations for
office occupancy for San Antonio gives 2200 full load equivalent hours of
cooling capacity operation.
The occupants complain that the rooms at the ends of the duct runs of the
recently air conditioned "I" buildings have no air flow. The contract MPLS
96-8011 drawings indicate that the ducts were sized at constant friction
without using any static regain consideration. Speeding up the fan to
overcome the additional static friction from the first air outlet to the
last air outlet and would be less expensive than replacing the ductwork with
larger ductwork, but would cause additional fan noise in the rooms closest
to the fan rooms.
The exterior of these wooden framed buildings have been up-graded or dressed
up by the application of EFIS on top of the existing exterior wood siding.
This was probably intended to change the appearance of these structures and
give them the appearance of modern office buildings. EIFS added to new or
existing wood substrate sometimes causes the wood to rot and fail. These
failures normally occur within eight to ten years. EFIS added to wooden
framed structures has caused many failures around the country, and many
lawsuits. The moisture trapped behind the EFIS panels in the wood substrate
causes the wood substrate to rot. We recommend modifying the existing
apparatus to maintain a constant chilled water cooling coil leaving dew
point.
B. LACKLAND AFB CHILLED WATER PLANT PIPING REVISIONS - 1998 - We
performed a study to determine why the plant chilled water would not
circulate the water to the buildings properly, and then prepared drawings to
correct the piping so that the piping would flow to the buildings in the
quantity needed.
C. POSTAL SERVICE - Main Post Office, Houston - Replace open drive motor,
replace transmission, revise piping for variable chilled water flow,
reconfigure plant for primary-secondary pumping, start-up & commissioning,
operating procedures, and balancing.
D. MDACC - SMITH RESEARCH BUILDING - HOUSTON, TEXAS - We Studied
and documented the existing HVAC, Electrical Service, Air, Vacuum, Deionized
Water, Instrument Air, Steam Supply, Chilled Water Supply, and other
services to the laboratory. We documented the present, future, and
ultimate requirements for these utilities as required to serve the existing
and proposed laboratories, and the future ultimate building utility
requirements for these services. Our study documented specific
modifications to the building that allowed the building to be fully
developed into laboratory space plus the addition of 60,000 SF of new
research laboratory space.
E. EXXON PRODUCTION RESEARCH LABORATORY BUILDING - 1976 - We performed
an analysis of the HVAC system and recommended energy conservation measures
such as Variable Volume Chemical Hood Exhaust, Chilled Water Reheat for OSA
Make-up, and several other unique HVAC modifications for that project.
F. SEI has
performed many analysis of small existing HVAC systems for the US Postal
Service. Contact Mr. Marshall Cantor (713) 226-3471 with the USPS. SEI has
all of the tools & instruments to analyze HVAC systems, and regularly uses
these instruments to determine non operation problems, and operational
problems with HVAC systems. SEI has corrected small problems if they are
easy to fix.
1.
COLLEGE STATION PO
- REPLACE CHILLER - USPS - CANTOR (713) 226-3471 REPLACE CHILLER - 1994
- $38,686
2.
VIDOR PO - REPLACE
HVAC EQUIPMENT - USPS - CANTOR (713) 226-3471 - REPLACE HVAC EQUIPMENT -
1994 - $21,000
3.
MEMORIAL PARK STA -
REPLACE CHILLER - USPS - SIMS (214) 819-7236 - REPLACE CHILLER - 1994 -
$98,360
4.
BAYTOWN MPO COMPRESSOR REPL - USPS - SIMS (214) 819-7236 - REPLACE
COMPRESSOR 1993 - $5,350
5.
LAKE JACKSON, TX MPO - REPLACE HVAC - USPS - CANTOR (713) 226-3471 -
REPLACE HVAC EQUIPMENT - 1993
6.
ROY ROYALE STA - REPLACE HVAC - USPS - SIMS (214) 819-7236 - REPLACE
HVAC EQUIPMENT - 1993 - $97,000
7.
GREENS NORTH STATION, TX - USPS - CANTOR (713) 226-3471 - EMERGENCY
GAS LINE REPAIR - 1993
8.
LONG POINT STA HVAC REPLACEMENT - USPS - CANTOR (713) 226-3471 -
REPLACE HVAC EQUIPMENT - 1993
9.
ORANGE, TX MPO - REPLACE CHILLERS - USPS - CANTOR (713) 226-3471 -
REPLACE CHILLERS - 1993
10.
PASADENA COOLING TOWER REPAIRS - USPS - CANTOR (713) 226-3471 - HVAC
R&A REPAIRS - 1993
11.
FOSTER PLACE
STATION - HVAC REPLACE - USPS - CANTOR (713) 226-3471 HVAC EQUIPMENT
REPLACEMENT - 1993
12.
DENVER HARBOR STA -
HVAC REPLACE - USPS - CANTOR (713) 226-3471 - HVAC EQUIPMENT REPLACEMENT -
1993
13.
S POST OAK STATION
- HVAC REPLACE USPS - CANTOR (713) 226-3471 HVAC EQUIPMENT
REPLACEMENT - 1993
14.
MISSOURI CITY
STATION - HVAC REPLACE - USPS - CANTOR (713) 226-3471 - HVAC EQUIPMENT
REPLACEMENT - 1993
15.
BEECHNUT STATION -
HVAC REPLACE - USPS - CANTOR (713) 226-3471 - HVAC EQUIPMENT REPLACEMENT -
1993
16.
WESTFIELD STATION -
HVAC REPLACE USPS - CANTOR (713) 226-3471 - HVAC EQUIPMENT REPLACEMENT
- 1993
17.
HOUSTON, TX MPO -
CH REPAIRS - USPS - CANTOR (713) 226-3471 - CHILLED WATER SYSTEM MOD - 1992
G.
preventative maintenance plans and manuals:
SEI
prepares operation & maintenance manuals for projects that have other than
normal operating and maintenance procedures. Normal projects without
complicated operating or complicated maintenance procedure requirements can
be documented by the construction contractor. SEI specifications always
include a maintenance program outline, operational program outline, and
other scope requirements so that the contractor fills in the blanks with the
equipment that he selects to install, and submits the completed data for the
AE review. SEI has extensive
experience reviewing contractor prepared O&M plans and manuals. SEI
mechanical and electrical engineers are hands-on experienced with
analyzing existing HVAC systems, diagnosing operational problems, and
proposing long term and short term solutions to these problems. Our staff
of engineers (and architects) are particularly well acquainted in building
operations and communicate very well with operating and maintenance
personnel. You will find that our staff is at home with tools and
instruments, as compared to the clean hands ivory tower type of engineer.
This attitude generally shows through and makes our personnel more
compatible with your operating and maintenance personnel. We always take
the time to explain any changes in operating and maintenance procedures to
your personnel so that they will fully understand and believe in any
procedures that we recommend.
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