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School District of Cambridge. A Business Relationship Presentation. North American Mechanical Inc. Use our energy to save yours®. Tonight’s Goals. Summary and general condition of the HVAC systems in the three district school buildings - PowerPoint PPT PresentationTRANSCRIPT
North American Mechanical Inc.
School District of CambridgeA Business Relationship Presentation
Use our energy to save yours®
Tonight’s Goals
Summary and general condition of the HVAC systems in the three district school buildings
Expected useful life of the HVAC systems at all three schools
Our Recommendations2
Our History
Entered into a 3 year HVAC Proactive Maintenance Agreement in Dec 2009
Provide Energy related services including reports upon request
Installed new pool boiler/heat exchanger in the Elementary School pool to improve performance and system longevity as well as many other system improvement projects3
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Nikolay MS
Built in 1955
Addition in 1964
1990 (small addition)
1998 (Major Electrical/Mechanical upgrades)
2003 (Control system upgrade)
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Nikolay MS
Description of systems
HW – CW (Chiller/Boiler System)
Unit Ventilators
Pneumatic Control system with digital front end (Johnson Controls)
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Nikolay MS
Assessment of systems
Major equipment is in very good condition
Since NAMI’s involvement, several significant issues have been resolved to improve system performance and improve system longevity. (I.E. Boiler/Chiller starts – Short cycling)
Controls are all pneumatic – Regular control issues, leaking air.
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Nikolay MS
ENERGY Review
The total cost of energy for 2010/2011 for the middle school was $82,414 compared to $86,843 in 2008/2009. The cost per square foot in 08/09 was $0.987 and $0.937/sf in 2010/2011. Like the high school, this performance is very good. The building does not have as much after-hour use as the high school, so the expectations would be to operate at a slightly lower cost/sf. One concern warranting further investigation is the electrical usage has increased by almost 16% from 2008/2009 to 2010/2011. This is significantly higher than the increase for the entire district.
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Nikolay MS
Recommendations
Replace the HVAC system controls with one that provides better air quality, comfort, and is more efficient
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Cambridge ES
Built in 1998
2003 (control system upgrade)
New Pool Boiler/Heat Exchanger Dec 2010
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Description of systems
HW – CW (Chiller/Boiler System)
VAV (Variable Air Volume)
Pneumatic Control system with digital front end (Johnson Controls)
Cambridge ES
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Assessment of systems
Major equipment is in very good condition
Since NAMI’s involvement, several significant issues have been resolved to improve system performance and improve system longevity. (I.E. Boiler/Chiller starts – Short cycling)
Controls are all pneumatic – Regular control issues, leaking air.
Cambridge ES
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ENERGY Review
The energy use at the elementary school is much higher than the other two schools. In 2010/2011, the total cost of energy was $183,188 or $1.53/sf (compared with approximately $0.95/sf for the Middle and High Schools). It should be noted that the elementary school is fully air-conditioned and has a swimming pool and that the usage is down significantly from 2008/2009 ($208,471, $1.73/sf).
Cambridge ES
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Recommendations
Replace the HVAC system controls with one that provides better air quality, comfort, and is more efficient
Cambridge ES
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1969 Original High School HVAC SystemsDescription of systems
One large, central gas heating furnace (June Aire)
Dual duct, under floor air distribution system
A/C for interior core area
No A/C for exterior areas
Cambridge HS (1969)
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Cambridge HS (1969)
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Assessment of systems
At 43 years old the HVAC system has well exceeded its expected useful life
The A/C condensing unit is in need of replacement in the near future
Major repairs to furnace refractory are needed in the near future
Cambridge HS (1969)
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Assessment of systems
Air tunnels need to be cleaned, some repairs made and measures need to be taken to keep ground water from entering them
Buried ductwork is corroding
Controls are all pneumatic – Regular control issues, leaking air.
Cambridge HS (1969)
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Picture 1 – Insulation on Tunnel Floor
Cambridge HS (90-98)
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Picture 2 – Water in Tunnel
Cambridge HS (90-98)
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Picture 3 – Frog Carcass
Cambridge HS (90-98)
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Picture 4 - Trash
Cambridge HS (90-98)
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Picture 5 – Dirty ductwork, damaged fiberglass
Cambridge HS (90-98)
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Picture 6 – Dirty ductwork, damaged fiberglass
Cambridge HS (90-98)
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Recommendations
Replace the HVAC system (and controls) with one that provides better air quality, comfort, and is more efficient
Add A/C for the exterior classrooms
Cambridge HS (1969)
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1990 Additions & 1998 Alterations to HVAC SystemsDescription of Systems
Hot water boilers
Air handling units (AHU’s)/variable air volume (VAV)
A/C for interior areas and music area
Cambridge HS (90-98)
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Assessment of systems
The system is generally in good condition
Pneumatic Control system with digital front end (Johnson Controls)
The overall HVAC system can be expected to last another 10 to 20 years. Controls, boilers, and possibly other minor equipment may need to be replaced sooner depending on wear
Cambridge HS (90-98)
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ENERGY Review
Total energy cost for the high school for 2008/2009 was $115,294 or $0.97/sf. For the school year 2010/2011, the total energy cost was $113,355 or $0.953/sf; a decrease of 1.7%. This performance is very good. The electrical use/sf for 10/11 was 5.24 kWh/sf and the natural gas was .39 therms/sf. Considering all of the after-hours use of a high school, the energy costs are well under control and shows the building is well operated. Please note that older HVAC systems may not be set-up to bring in as much ventilation air as required by today’s building codes. The heating/cooling of ventilation air may be a significant part of any building’s energy use.
Cambridge HS (90-98)
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Recommendations
Replace the temperature control system to make it compatible with the controls recommended for replacement in the 1969 building
Consider adding A/C for the exterior classrooms
Continue to maintain the HVAC system
Cambridge HS (90-98)
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Thank You!
Questions?
Cambridge HS (90-98)