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 projects

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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)