FINAL TACTICAL ENERGY AUDIT REPORT FOR THE
SAN FRANCISCO UNIFIED SCHOOL DISTRICT Prepared for:
THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION
OCTOBER 11, 2010 Prepared by:
Cogent Energy, Inc. 2300 Clayton Road, Suite 480 Concord, CA 94520 925-521-9600 www.enernoc.com
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION
DISCLAIMER
This Tactical Energy Audit serves to investigate and recommend energy conservation opportunities for the San Francisco Unified School District. Based on the available building plans, field work, and interviews of site operating and maintenance personnel, the recommendations are based on an analysis of conditions observed and information gathered at the time of the survey. Project cost estimates are based on vendor quotes, cost data publications and experience with similar projects. Energy savings are dependent upon many factors, including conservation measures implemented, seasonal weather variations, fuel price, and specific energy use practices of the facility occupants and workers. Additionally, many of these energy efficiency measures (EEMs) are interactive and may produce fewer savings than identified if implemented as a group. If the EEMs have been cascaded, this interdependence has been incorporated into the savings calculated and reported. Note that changing the order of implementation will affect the savings associated with some measures. This report, by itself, is not intended as a basis for the engineering required to adopt and implement any of these recommendations. Its intent is to inform the client as to the potential cost savings of the recommendations. Development of design documents and specifications will be required, conforming to the details of this audit, to successfully implement the EEMs. Disturbance, removal or replacement of building material, insulation systems, high intensity discharge and fluorescent lamps, lamp ballasts, power factor correction capacitors, starting and running capacitors of motors and potentially other components which may contain asbestos, mercury, or PCB’s require handling and disposal in accordance with applicable Federal and State laws and regulations.
COGENT ENERGY, INC.
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION
Table of Contents 1. Executive Summary..................................................................................................... 3 2. Facility Descriptions .................................................................................................... 8 Robert Louis Stevenson Elementary School........................................................... 8 Everett Middle School ............................................................................................ 9 Burton High School .............................................................................................. 11 3. Utility Baseline Analysis ........................................................................................... 14 Robert Louis Stevenson Elementary School......................................................... 15 Everett Middle School .......................................................................................... 16 Burton High School .............................................................................................. 16 4. Energy Efficiency Measures and Energy Analysis ................................................... 17 Robert Louis Stevenson Elementary School......................................................... 21 Everett Middle School .......................................................................................... 24 Burton High School .............................................................................................. 26 5. Conclusion ................................................................................................................. 30 APPENDIX A: Non-Cascaded Recommended Energy Efficiency Measures ($0.038/kWh) .................................................................................................................... 32 APPENDIX B: Cascaded Recommended and Non-Recommended Energy Efficiency Measures ($0.038/kWh) .................................................................................................... 33 APPENDIX C: Identified Maintenance Measures ........................................................... 35 APPENDIX D: Utility Consumption Profiles .................................................................. 36
2
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION 1. EXECUTIVE SUMMARY Cogent Energy has partnered with the San Francisco Public Utilities Commission (SFPUC) to perform Tactical Energy Audits at various school buildings within the San Francisco Unified School District (SFUSD). The SFUSD intends these Energy Audits to identify and evaluate improvements in the buildings’ mechanical equipment and systems in order to reduce energy consumption and cost as well as to mitigate greenhouse gas emissions. In addition to reduced annual energy costs and environmental impact, the identified improvements provide the SFUSD with a unique opportunity to upgrade outdated equipment, reduce operations and maintenance demands, reduce electricity demand, improve indoor environmental quality, and provide more efficient operation of energy consuming systems. Beyond reducing energy consumption and cost at the audited schools, the SFUSD is preparing to issue a bond to fund energy efficiency and energy cost curtailment projects district-wide. The SFUSD intends that the results from this tactical energy audit will assist in identifying attractive energy efficiency measure types, quantifying potential savings that may be realized through a district-wide implementation of energy efficiency measures, and determining a scope of costs that would be needed in order to realize district-wide energy savings. Because the SFUSD plans to extrapolate the potential savings of a district-wide energy efficiency program based on the results of this audit, Cogent Energy has tailored the audits and this report to reflect energy savings opportunities that it expects would be found at similar SFUSD facilities. Towards this goal, Cogent Energy performed energy audits at Robert Louis Stevenson Elementary School, Everett Middle School, and Burton High School. The audits’ objective was to identify a comprehensive package of Energy Efficiency Measures (EEMs) with the potential to generate energy savings and provide a net positive investment for the District. Site surveys were conducted at each school facility in order to inspect and evaluate the energy consuming electrical and natural gas mechanical systems, as well as to conduct interviews with maintenance personnel and facility occupants. Based on this work, an initial list of EEMs was generated for each of the three school buildings, and analyses were conducted for each EEM to estimate the potential energy savings available to the SFUSD. Cost estimates were then developed to evaluate the financial viability of the measures. Using historical utility billing data from March 2007 through February 2010, it was determined that the three school buildings together represent approximately $241,000 per year in utility costs, including $59,760 per year for electricity and $181,000 for natural gas. This report describes a package of recommended EEMs that in aggregate are estimated to result in approximately 149,500 kWh/yr in electricity savings and 37,460 therms/yr in natural gas savings.
3
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION It is important to note that the SFUSD receives electricity from the SFPUC billed at a discounted rate of $0.0375/kWh, below the SFPUC’s cost of service rate of $0.0882/kWh, and well below the PG&E market rate of $0.1604/kWh1. As mentioned, with the discounted rate offered by the SFPUC as a community benefit to the SFUSD, the aggregate electric utility bill for these three schools is approximately $59,756. At the cost of service rate, the SFUSD would pay approximately $140,500 per year for electricity, and at the PG&E market rate, the SFUSD would pay approximately $255,600 per year. The SFUSD receives natural gas from PG&E at the rate of approximately $1.11/therm. The discounted rate for electricity affects not only the utility bills, but also the economic impact of energy efficiency projects. Given the discounted rate for electricity, the EEM’s indentified in this report represent a total utility savings for electricity and natural gas of $47,260 per year, a 20% reduction from current costs. Given the SFPUC rate of service, the EEM’s represent a total utility savings of $54,770 per year. If the PG&E market rate is considered, the EEM’s represent a savings of $65,561 per year. The capital investment required to achieve these savings is estimated to be $880,100. Incentives offered by PG&E for therms savings amount to approximately $37,010, reducing the District’s outlay to approximately $843,080. The resulting simple payback periods are 17.8 years at the discounted rate, 15.4 years at the cost of service rate, and 12.9 years at the PG&E market rate. Tables 1.1 through 1.3 summarize the package of recommended EEMs identified through this Tactical Energy Audit. A full list of recommended and non-recommended measures is included in Appendix B. The savings detailed in this report would result from the implementation of the identified EEM’s as singular retrofit projects. However, the SFUSD would realize significantly greater energy reduction and cost savings by pursuing a more comprehensive districtwide energy efficiency program that emphasized retrocommissioning (RCx) of existing HVAC and mechanical systems. RCx would include necessary systems testing to identify low cost and no cost EEMs, systems maintenance and repair, optimization of the buildings’ energy management systems, and capital equipment replacement measures. Immediately following RCx, the SFUSD would arrange with a mechanical contractor to implement the identified measures in a systematic process. Finally, new equipment and systems would be commissioned (Cx), which would include functional performance testing of the systems after they have been upgraded to ensure optimal operation. An energy efficiency program would offer significant advantages over individual retrofit projects as it would provide the best integration of retrofits, system optimization, and quality assurance in the most expedited and cost effective manner. 1
The $0.1604/kWh assumes an A-10 rate schedule, and is taken from the June 2010 – Present tariff book listed by PG&E, and reviewed on October 05, 2010. This rate includes meter charges, Time-of-Use escalation rates, transmission charges, and demand charges. (http://www.pge.com/tariffs/electric.shtml#COMMA10)
4
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION Table 1.1: Recommended Energy Efficiency Measures at the SFPUC Discounted Rate of $0.038/kWh ECM Number Robert Louis Stevenson Elementary
kWh/yr Saved
ECM Title
ST.01
Convert HV-1 from constant volume to variable volume through the installation of a Variable Frequency Drive.
7,475
ST.02
Upgrade EMS to include control of AC units to prevent loss of scheduling. Upgrade EMS to include control of heating & ventilating unit HV-1.
26,221
ST.03
Install a CO2 sensor in the Auditorium to control HV-1 based on space occupancy.
Install lighting occupancy control to turn off lights in rooms that are ST.04 not in use. TOTALS Everett Middle School EV.01
Install daylighting control in classrooms and offices. TOTALS
kW Saved
-
1,960
$284.05
$2,175.60
$2,459.65
13.7
$22,866.42
$1,960.00
$20,906.42
8.5
1,305
$996.40
$1,448.97
$2,445.37
14.2
$30,675.00
$1,305.38
$29,369.62
12.0
1,412
$0.00
$1,566.86
$1,566.86
8.6
$1,200.00
$960.00
$240.00
0.2
4,677
$355.70 $1,636.16
$0.00 $5,191.43
$355.70 $6,827.59
2.2 39
$4,181.24 $58,922.66
$0.00 $4,225.38
$4,181.24 $54,697.29
11.8 8.0
$489.03 $489.03
$0.00 $0.00
$489.03 $489.03
3.1 3
$7,989.72 $7,989.72
$0.00 $0.00
$7,989.72 $7,989.72
16.3 16.3
7,622
$2,206.09
$8,460.42
$10,666.51
60.3
$344,519.12
$7,622.00
$336,897.12
31.6
15,459
$515.20
$17,159.49
$17,674.69
97.5
$286,470.00
$15,459.00
$271,011.00
15.3
1,251
$472.42
$1,388.61
$1,861.03
10.6
$47,946.93
$1,251.00
$46,695.93
25.1
2
-
-
9,361 43,057
-
12,869 12,869
2
-
Annual Electrical Cost Saved
0
0
Annual Annual Natural Gas Energy Cost Cost Saved Saved
Greenhouse Gas Reduction* (tons CO2)
Natural Gas Saved (therms/yr)
Project Cost Estimate
Potential Rebates
Net Project Estimate
Simple Payback (years)
Burton High School
BT.01
Convert the main building supply fan SF-1 from constant volume to variable volume through the installation of a Variable Frequency Drive. Install VAV boxes in ducts connected to SF-1.
58,055
BT.02
Upgrade the EMS to include control of all building equipment and systems.
13,558
BT.03
Convert the air systems serving the Gymnasium from constant volume to variable volume through the installation of Variable Frequency Drive control.
12,432
BT.05
Convert supply fans SF-2, SF-3, and SF-4 from constant volume to variable volume through the installation of a Variable frequency Drive. Convert heating & ventilating unit HV-1 from constant volume to variable volume through the installation of a Variable Frequency Drive.
BT.06
Replace the three (3) fan coil units serving the radio station area with split system heat pumps .
BT.07
Install daylighting control and occupancy sensors
BT.08
Install solenoid control valves for the four (4) fan coil units serving the first floor lab areas in the Science Building.
BT.04
22 -
4
7,944
-
3,601
$301.87
$3,997.11
$4,298.98
23.9
$75,279.71
$3,601.00
$71,678.71
16.7
1,724
-
2,046
$65.51
$2,271.06
$2,336.57
12.9
$18,458.51
$2,046.00
$16,412.51
7.0
(13,002)
-
2,773
-$494.07
$3,078.03
$2,583.96
13.8
$27,960.00
$2,773.00
$25,187.00
9.7
12,869
-
-
$489.03
$0.00
$489.03
3.1
$8,877.71
$0.00
$8,877.71
18.2
32 $0.00 TOTALS 93,581 26 32,784 $3,556.06 TOTALS 149,507 28 37,460 $5,681.25 * (kWh * 0.524 lbs per kWh + Therms * 13.446 lbs per therm) / (2204.6 lbs per Tonne) http://www.pge.com/myhome/environment/calculator/assumptions.shtml ** Project costs do not include markups for Engineering, Project Management, Project Administration and Contingencies
$34.97 $36,389.69 $41,581.12
$34.97 $39,945.74 $47,262.37
0.2 222 264
$3,660.00 $813,171.96 $880,084.34
$31.50 $32,783.50 $37,008.88
$3,628.50 $780,388.46 $843,075.47
103.8 19.5 17.8
5
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION Table 1.2: Recommended Energy Efficiency Measures at the SFPUC Rate of Service of $0.0882/kWh ECM Numbe r
kWh/yr Save d
ECM Title
Annual Natural Gas Annual Natural Save d Ele ctrical Gas Cost (the rms/yr) Cost Save d Save d
kW Save d
Gre e nhous Annual e Gas Ene rgy Re duction* Proje ct Cost Cost Save d (tons CO2) Estimate
Pote ntial Re bate s
Ne t Proje ct Estimate
Simple Payback (ye ars)
Robe rt Louis Ste ve nson Ele me ntary
ST.02
Convert HV-1 from constant volume to variable volume through the installation of a Variable Frequency Drive. Upgrade EMS to include control of AC units to prevent loss of scheduling. Upgrade EMS to include control of heating & ventilating unit HV-1.
ST.03
Install a CO2 sensor in the Auditorium to control HV-1 based on space occupancy.
ST.04
Install lighting occupancy control to turn off lights in rooms that are not in use.
ST.01
TOTALS
7,475
-
26,221
2
-
-
9,361
-
43,057
2
1,960
$659.30
$2,175.60
$2,834.90
13.7
$22,866.42
$1,960.00
$20,906.42
7.4
1,305
$2,312.71
$1,448.97
$3,761.67
14.2
$30,675.00
$1,305.38
$29,369.62
7.8
1,412
$0.00
$1,566.86
$1,566.86
8.6
$1,200.00
$960.00
$240.00
0.2
$825.61
$0.00
$825.61
4,677
$3,797.61
$5,191.43
$8,989.04
2.2 39
$4,181.24
$0.00
$4,181.24
5.1
$58,922.66
$4,225.38
$54,697.29
6.1
Eve re tt Middle School EV.01
Install daylighting control in classrooms and offices.
12,869 TOTALS
Burton High School Convert the main building supply fan SF-1 from constant volume to variable volume through the installation of a Variable Frequency Drive. BT.01 Install VAV boxes in ducts connected to SF-1.
-
12,869
-
$1,135.07
$0.00
$1,135.07
3.1
$7,989.72
$0.00
$7,989.72
7.0
$1,135.07
$0.00
$1,135.07
3
$7,989.72
$0.00
$7,989.72
7.0
7,622
$5,120.45
$8,460.42
$13,580.87
60.3
$344,519.12
$7,622.00
$336,897.12
24.8
15,459
$1,195.82
$17,159.49
$18,355.31
97.5
$286,470.00
$15,459.00
$271,011.00
14.8
1,251
$1,096.50
$1,388.61
$2,485.11
10.6
$47,946.93
$1,251.00
$46,695.93
18.8
0
58,055
22
0
BT.03
Upgrade the EMS to include control of all building equipment and systems. Convert the air systems serving the Gymnasium from constant volume to variable volume through the installation of Variable Frequency Drive control.
BT.04
Convert supply fans SF-2, SF-3, and SF-4 from constant volume to variable volume through the installation of a Variable frequency Drive.
7,944
-
3,601
$700.66
$3,997.11
$4,697.77
23.9
$75,279.71
$3,601.00
$71,678.71
15.3
BT.05
Convert heating & ventilating unit HV-1 from constant volume to variable volume through the installation of a Variable Frequency Drive.
1,724
-
2,046
$152.06
$2,271.06
$2,423.12
12.9
$18,458.51
$2,046.00
$16,412.51
6.8
BT.06
Replace the three (3) fan coil units serving the radio station area with split system heat pumps .
(13,002)
-
2,773
-$1,146.75
$3,078.03
$1,931.28
13.8
$27,960.00
$2,773.00
$25,187.00
13.0
BT.07
Install daylighting control and occupancy sensors
12,869
-
-
$1,135.07
$0.00
$1,135.07
3.1
$8,877.71
$0.00
$8,877.71
7.8
BT.08
Install solenoid control valves for the four (4) fan coil units serving the first floor lab areas in the Science Building.
-
-
$0.00
$34.97
$34.97
0.2
$3,660.00
BT.02
13,558
-
12,432
4
$31.50
$3,628.50
103.8
$8,253.80 $36,389.69 $44,643.49
222 $813,171.96 $32,783.50
$780,388.46
17.5
TOTALS 149,507 28 37,460 $13,186.48 $41,581.12 $54,767.60 * (kWh * 0.524 lbs per kWh + Therms * 13.446 lbs per therm) / (2204.6 lbs per Tonne) http://www.pge.com/myhome/environment/calculator/assumptions.shtml ** Project costs do not include markups for Engineering, Project Management, Project Administration and Contingencies
264 $880,084.34 $37,008.88
$843,075.47
15.4
TOTALS
93,581
26
32 32,784
6
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION Table 1.3: Recommended Energy Efficiency Measures at the PG&E Market Rate of $0.1604/kWh ECM Numbe r
kWh/yr Save d
ECM Title
Annual Natural Gas Annual Natural Save d Ele ctrical Gas Cost (the rms/yr) Cost Save d Save d
kW Save d
Gre e nhous Annual e Gas Ene rgy Re duction* Proje ct Cost Cost Save d (tons CO2) Estimate
Pote ntial Re bate s
Ne t Proje ct Estimate
Simple Payback (ye ars)
Robe rt Louis Ste ve nson Ele me ntary ST.01
Convert HV-1 from constant volume to variable volume through the installation of a Variable Frequency Drive.
7,475
ST.02
Upgrade EMS to include control of AC units to prevent loss of scheduling. Upgrade EMS to include control of heating & ventilating unit HV-1.
26,221
ST.03
Install a CO2 sensor in the Auditorium to control HV-1 based on space occupancy.
ST.04
Install lighting occupancy control to turn off lights in rooms that are not in use. TOTALS
-
2
-
-
9,361
-
43,057
1,960
$1,198.99
$2,175.60
$3,374.59
13.7
$22,866.42
$1,960.00
$20,906.42
6.2
1,305
$4,205.88
$1,448.97
$5,654.84
14.2
$30,675.00
$1,305.38
$29,369.62
5.2
1,412
$0.00
$1,566.86
$1,566.86
8.6
$1,200.00
$960.00
$240.00
0.2
$0.00
$1,501.45
4,677
$6,906.32
$1,501.45 2
$5,191.43 $12,097.75
2.2 39
$4,181.24
$0.00
$4,181.24
2.8
$58,922.66
$4,225.38
$54,697.29
4.5
Eve re tt Middle School EV.01
Install daylighting control in classrooms and offices.
12,869 TOTALS
-
12,869
-
$2,064.23
$0.00
$2,064.23
3.1
$7,989.72
$0.00
$7,989.72
3.9
$2,064.23
$0.00
$2,064.23
3
$7,989.72
$0.00
$7,989.72
3.9
7,622
$9,312.02
$8,460.42
$17,772.44
60.3
$344,519.12
$7,622.00
$336,897.12
19.0
15,459
$2,174.70
$17,159.49
$19,334.19
97.5
$286,470.00
$15,459.00
$271,011.00
14.0
1,251
$1,994.09
$1,388.61
$3,382.70
10.6
$47,946.93
$1,251.00
$46,695.93
13.8
0
0
Burton High School
BT.01
Convert the main building supply fan SF-1 from constant volume to variable volume through the installation of a Variable Frequency Drive. Install VAV boxes in ducts connected to SF-1.
58,055
BT.02
Upgrade the EMS to include control of all building equipment and systems.
13,558
BT.03
Convert the air systems serving the Gymnasium from constant volume to variable volume through the installation of Variable Frequency Drive control.
12,432
BT.04
Convert supply fans SF-2, SF-3, and SF-4 from constant volume to variable volume through the installation of a Variable frequency Drive.
7,944
-
3,601
$1,274.22
$3,997.11
$5,271.33
23.9
$75,279.71
$3,601.00
$71,678.71
13.6
BT.05
Convert heating & ventilating unit HV-1 from constant volume to variable volume through the installation of a Variable Frequency Drive.
1,724
-
2,046
$276.53
$2,271.06
$2,547.59
12.9
$18,458.51
$2,046.00
$16,412.51
6.4
BT.06
Replace the three (3) fan coil units serving the radio station area with split system heat pumps .
(13,002)
-
2,773
-$2,085.48
$3,078.03
$992.55
13.8
$27,960.00
$2,773.00
$25,187.00
25.4
BT.07
Install daylighting control and occupancy sensors
12,869
-
-
$2,064.23
$0.00
$2,064.23
3.1
$8,877.71
$0.00
$8,877.71
4.3
BT.08
Install solenoid control valves for the four (4) fan coil units serving the first floor lab areas in the Science Building.
-
-
$0.00
$34.97
$34.97
0.2
$3,660.00
22 -
4
$31.50
$3,628.50
103.8
32,784 $15,010.32 $36,389.69 $51,400.00
222 $813,171.96 $32,783.50
$780,388.46
15.2
TOTALS 149,507 28 37,460 $23,980.86 $41,581.12 $65,561.98 * (kWh * 0.524 lbs per kWh + Therms * 13.446 lbs per therm) / (2204.6 lbs per Tonne) http://www.pge.com/myhome/environment/calculator/assumptions.shtml ** Project costs do not include markups for Engineering, Project Management, Project Administration and Contingencies
264 $880,084.34 $37,008.88
$843,075.47
12.9
TOTALS
93,581
26
32
7
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION 2. FACILITY DESCRIPTIONS ROBERT LOUIS STEVENSON ELEMENTARY SCHOOL Robert Louis Stevenson Elementary School was constructed in 1953 and is comprised of a two-story main building which includes classrooms, offices, bathrooms, an auditorium, and cafeteria. Located in San Francisco at 2051 34th Avenue, the building contains 47,500 square feet of interior space and has a large outdoor area for basketball courts. Five portable classrooms in the North East provide additional space for the school. During the school year, the average daily attendance including faculty presence totals 451 persons corresponding mainly to normal school day hours. The building is constructed of brick and concrete, and currently has single-pane clear glass windows within wood frames.
Image 1: Wooden Framed Windows
HVAC Systems The building has two steam boilers that provide heat to the entire building, and the heat is delivered to the rooms through baseboard convectors. Ventilation is provided by operable windows, and the school does not have mechanical cooling. The auditorium receives heating and ventilation (HV) from HV-1 which is controlled by a local thermostat. Domestic hot water is provided to the building by a water heater piped to a hot water storage tank. There are five heat pumps which serve the portable classrooms and are controlled locally by programmable thermostats. 8
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION Lighting New T8 fluorescent lighting was installed in 2005 during a district-wide lighting renovation. High efficiency ballasts and T8 lamps are installed throughout the classrooms and offices, however it was reported by facility staff during the site-visit that lighting components are reaching the end of their useful life, as failed ballasts and lamps have become a recent and ongoing problem. All lighting is controlled manually by wallmounted toggle switches. Occupancy Schedule and Operating Hours The school year consists of approximately 180 school days, and a summer vacation that last about two months from July to August. The majority of building occupancy occurs during regular school hours, and school is in session between the hours of about 8:00 AM to 3:00 PM. The operating hours of the main mechanical equipment is divided into three systems. Heating hot water system: Monday - Friday 5:00 AM to 6:30 PM. Domestic hot water system: 24/7 Operation Air compressor: Tuesday–Friday, 5:15AM to 5:30PM; Monday 3:15 AM to 5:30PM. Building Energy Management System (EMS) The two steam boilers are programmed to operate in a lead-lag arrangement based on steam pressure in the supply line. In the EMS, various components and settings are defined such as lead-lag designation, boiler lockout temperatures, overrides, pump and boiler enabling, and schedule modes. Status, faults, and runtime are also displayed. The current EMS configuration offers minimal online trending capabilities.
EVERETT MIDDLE SCHOOL Everett Middle School was constructed in 1928 and is one contiguous building that contains offices, an auditorium, a library, classrooms, a cafeteria, locker rooms and gyms. Located in San Francisco at 450 Church Street, the three story building’s total square footage is approximately 135,000 square feet and it encloses two courtyards and a parking lot. During the school year, the average daily attendance including faculty totals approximately 450 persons during normal school day hours. The 9
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION facility experiences varying afternoon and weekend occupancy due to college classes and afterschool programs that are held on-site. The building is constructed of block and concrete with a tile roof, and a majority of the original wooden frame windows were replaced with new window glass and aluminum frames. HVAC Systems The building has two steam boilers that provided heating to the entire building through baseboard convectors and radiators. The auditorium and library have additional heating and ventilating units that are infrequently used for large events or meetings. Ventilation is provided by operable windows, and the school does not have mechanical cooling. Ventilation for the auditorium is provided from ducted supply fans located in the basement, however these units are operated on time clocks and have been converted to only function through manual on/off switches.
Image 2: Typical Radiator
Lighting New T8 fluorescent lighting was installed in 2005 during a district-wide lighting renovation. High efficiency ballasts and T8 lamps are installed throughout the classrooms and offices, however it was reported by facility staff during the site-visit that lighting components are reaching the end of their useful life as failed ballasts and lamps have become a recent and ongoing problem. All lighting is controlled manually by wallmounted toggle switches. Occupancy Schedule and Operating Hours The school year is about 180 days and there is a summer vacation that last about two months from July to August. School is in session between the hours of approximately 8:00 AM to 3:00 PM, but after school programs and night classes occur frequently on both weekdays and weekends. The operating hours of the HV equipment is as follows: 10
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION
Heating hot water system: Monday - Friday 5:00 AM to 8:00 PM, with the system disabled between 12:00PM and 3:30PM. Domestic hot water system: Monday - Friday 4:00 AM to 8:00 PM Building Energy Management System (EMS) The steam boilers are programmed to operate in a lead-lag arrangement based on steam pressure in the supply line. In the EMS, various components and settings are defined such as lead-lag designation, boiler lockout temperatures, overrides, pump and boiler enabling, and schedule modes. Status, faults, and runtime are also displayed. There are also simple descriptions of the equipment operation and simple online trending available.
BURTON HIGH SCHOOL Phillip and Sala Burton Academic High School was constructed in 1963 with approximately 230,600 square feet of interior space, and is located in San Francisco at 400 Mansell Street. During the academic school year, the high school typically holds approximately 900 students and faculty during the school day. This facility is comprised of five distinct buildings; a Main Building, a Science Building, a Cafeteria, a Gymnasium with locker rooms, and an Auditorium. The main building contains classrooms, offices and a library. The science building contains classrooms, a weight and workout room, and a radio station that uses about 4 rooms for production. The radio station is operated 24/7, and therefore requires 24/7 operation of the HV equipment. The cafeteria has a large dining area equipped with tables and a kitchen. The gym building has a large basketball court with two dance rooms and two locker rooms. The auditorium has a large seating capacity and has two large rooms that serve as music and performing arts classrooms. The buildings are made of block and concrete with a medium gray roof. HVAC Systems Burton High School has a variety of HV units serving various parts of the campus. The core of the main building is primarily served by a large supply fan with heating coils accompanied by several exhaust fans. Four boilers and six heating hot water (HHW) pumps circulate HHW throughout the building. The classrooms around the perimeter of 11
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION the building are heated through baseboard convectors with thermostatic valves, and operable windows provide ventilation. The science building is provided with heating from ceiling-hung fan coil units. The cafeteria is heated by a ducted HV unit installed on the roof. The gym and locker rooms are conditioned by HV units of various sizes. The auditorium is served by three supply fans and three exhaust fans which are located in a mechanical room behind the stage, and small fume hood exhaust fans serve science laboratories. Ventilation is provided by operable windows, and the school does not have mechanical cooling.
Image 3: Fume Hood Exhaust Fans
Image 4: HHW Pumps
Lighting New T8 fluorescent lighting was installed in 2005 during a district-wide lighting renovation. High efficiency ballasts and T8 lamps are installed throughout the classrooms and offices, however it was reported by facility staff during the site-visit that lighting components are reaching the end of their useful life as failed ballasts and lamps have become a recent and ongoing problem. All lighting is controlled manually by wallmounted toggle switches. Occupancy Schedule and Operating Hours The school year is about 180 days and there is a summer vacation that last about two months from July to August. The majority of the facility is occupied from 7:00 AM to 6:00 PM. However, the radio station in the science building may be occupied 24 hours per day throughout the week, and therefore the heating hot water system is run 24/7 to account for this potential load. The operating hours of the equipment is divided into four schedules. Heating hot water system and domestic hot water system: 24/7 operation. Auditorium and cafeteria: Weekday 4:00 AM to 6:00 PM. Gym and main building: Weekday 4:00 AM to 9:00 PM. 12
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION Science building: Weekday 2:30 AM to 8:30 PM Building Energy Management System (EMS) Burton operates an active EMS which controls all central HV components. The EMS controls various points including but not limited to temperature sensors (zone, outside air temperature (OAT), building, water, etc.), start/stop status, valve positions, setpoint resets, override controls, and general fault statuses. There is also a simple description of equipment operation and a basic level of online trending available.
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FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION 3. UTILITY BASELINE ANALYSIS SFUSD provided Cogent Energy with utility billing information for the three schools covering the period from March 2007 through February 2010. The utility billing information included the following: Electricity consumption (kWh) and cost ($) Electric demand (kW) Natural gas consumption (therms) and cost ($) Total energy consumption (MMBtu) and cost ($) In order to perform the analysis, a monthly average was taken from the three years of data available in order to even out any deviations due to weather and load variations. Once the average for each month was calculated, the data was compiled and graphed. The area of each school building was also taken into account to get the energy use per square foot of gross area. The annual energy profiles are summarized in Tables 1 and 2. Table 1 summarizes the square footage, total annual energy, demand, electricity and gas consumption and costs for each of the schools. Table 2 shows the annual electricity, gas and total energy consumption on a per square foot basis for these school buildings. Details are available for each of the buildings in Section 3 of this report. Table 1: School Building Electrical Usage, Natural Gas Usage, and Utility Costs
School Name Stevenson ES Everett MS
Electricity (kWh) 120,540 492,767
Peak Demand (kW) 40 146
Total Electricity Cost ($) $4,520 $18,479
Natural Gas (therms) 26,277 63,224
Natural Gas Cost ($) $29,843 $67,303
Total Energy (MMBtu) 3,052 8,004
Total Energy Cost ($) $34,707 $85,783
Burton HS
980,197
267
$36,757
78,211
$83,894
11,166
$120,653
Benchmark Gas Consumption* (%) 158 % 134 % 97 %
Total Energy (MMBtu/sq. ft.) 0.064 0.059 0.048
Table 2: School Building Energy Usage Indices
School Name Stevenson ES Everett MS Burton HS
Building Area (sq. ft.) 47,500 135,000 230,600
Electricity (kWh/sq. ft.) 2.538 3.650 4.251
Benchmark Electricity Consumption* (%) 41 % 59 % 69 %
Natural Gas (therms/sq. ft.) 0.553 0.468 0.339
* Averaged end-use intensity was determined to be 6.16 kWh/ft 2/yr for electrical energy consumption and 0.35 therms/ft2/yr for gas consumption.
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FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION Based on the historical data summarized in Tables 1 and 2, the SFUSD pays approximately $0.0375/kWh, and approximately $1.04/therm. These costs are in line with current rate schedule utility charges identified by SFUSD personnel, specifically $0.0375/kWh and a range between $1.00/therm and $1.11/therm. The $0.0375/kWh includes electricity, as well as transmission and distribution fees and the rate does not vary by season. The SFUSD does not currently pay electric demand charges. The SFUSD procures electricity from the San Francisco Public Utilities Commission and procures natural gas from Pacific Gas &Electric. The 1999 Commercial Building Survey Report2 issued by Pacific Gas & Electricity details energy intensities per square foot for various building types within PG&E’s electric service territory. Based on this report, schools such as the three surveyed in this audit would be expected to operate at an averaged end-use intensity of 6.16 kWh/ft2/yr for electrical energy consumption. This value is representative of schools with no mechanical cooling equipment or systems, average cooking loads, interior and exterior lighting, and assorted miscellaneous plug loads such as computers and AV equipment. Similarly for natural gas, school buildings are expected to operate at an averaged end-use intensity of 0.353 therms/ft2/yr. Although these end-use intensity values fail to account for such factors as the specific number of computers in a school, lighting system types, EMS control, etc., they provide a reasonable framework for comparing the audited schools to a generalized index. The following sections detail the energy usage at the individual schools, and compare the schools to the average end-use intensity. ROBERT LOUIS STEVENSON ELEMENTARY SCHOOL Robert Louis Stevenson in comprised of approximately 47,500 sq. ft. of interior area. As per Table 2, the building uses approximately 2.5 kWh/ft2/yr of electricity and approximately 0.55 therms/ft2/yr of natural gas. The total energy consumed per square feet is about 0.06 MMBtu. Compared to the end-use intensity value of 6.16 kWh/ft2/yr, Stevenson represents approximately 41% of the averaged electrical energy consumption typical for a school, and compared to the EUI value of 0.353 therms/ft2/yr, it represents 156% of the averaged natural gas consumption typical for a school. Based on these enduse intensity profiles, it is expected that natural gas savings will be seen to a greater degree than electricity savings. Further, because the SFUSD pays a low rate for electricity through the SFPUC, it is expected that EEMs with significant natural gas savings would offer more attractive simple payback periods to SFUSD than EEMs wherein the savings are confined to electricity, and the findings of this audit confirm these expectations. The annual utility consumption profiles for this school are provided in Appendix B. 2
The 1999 Building Report issued by PG&E describes the results from a data collection effort involving surveys of almost 1,000 commercial buildings in PG&E’s electric service territory. This information collected included building structures, facility operations, equipment types, fuel choices, operating schedules, and billing data. The collected information was used to produce simulated end-use intensities and simulated end-use sales.
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FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION EVERETT MIDDLE SCHOOL Everett Middle School is a large school building with 135,000 sq. ft. of interior area. As per Table 2, the building uses about 3.7 kWh/ft2/yr of electricity and about 0.47 therms/ft2/yr of natural gas. The total energy consumed per square feet is about 0.06 MMBtu. Compared to the EUI value of 6.16 kWh/ft2/yr, Everett represents approximately 59% of the averaged electrical energy consumption typical for a school, and compared to the EUI value of 0.353 therms/ft2/yr, it represents 132% of the averaged natural gas consumption typical for a school. Based on these end-use intensity profiles, it is expected that natural gas savings will be seen to a greater degree than electricity savings. Further, because the SFUSD pays a low rate for electricity, it is expected that EEMs with significant natural gas savings would offer more attractive simple payback periods than EEMs wherein the savings are confined to electricity, and the findings of this audit confirm these expectations. The annual utility consumption profiles for this school are provided in Appendix B. BURTON HIGH SCHOOL Burton High School is a 230,600 sq. ft. school building. As per Table 2, the building uses approximately 4.3 kWh/ft2/yr of electricity and about 0.34 therms/ft2/yr of natural gas. The total energy consumed per square feet is about 0.048 MMBtu/yr. Compared to the EUI value of 6.16 kWh/ft2/yr, Burton represents approximately 61% of the averaged electrical energy consumption typical for a school, and compared to the EUI value of 0.353 therms/ft2/yr, it represents 96% of the averaged natural gas consumption typical for a school. Overall, the natural gas end-use intensity at Burton is in-line with similar school buildings, whereas the electrical end-use intensity is well below that of similar school buildings. Due to the relatively low end-use intensities, one would not anticipate significant opportunities for energy use reduction. However, cost effective measures were found at this site. The annual utility consumption profiles for this school are provided in Appendix B.
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FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION 4. ENERGY EFFICIENCY MEASURES AND ENERGY ANALYSIS
ENERGY ANALYSIS METHODOLOGY Two methods of energy calculations were used to determine energy savings for this audit. The first method involved energy calculations using a modified bin weather analysis. Data used in the analysis includes equipment information obtained from the site survey and As-Built drawings, as well as field measured data. The bins are separated into 24 hour increments for 5 day types per month (1,440 bins). The day types are based on temperature distribution for four weekday-types for each month and an average weekend day for each month. The four temperature distribution day types include a peak temperature day, an upper third temperature day (i.e., a hot day), an intermediate third temperature day (i.e., a moderate day) and a lower third temperature day (i.e., a mild day). The number of these days each month varies from bin to bin based on how they align with the temperature profiles. These calculation routines provide a degree of accuracy approaching an 8,760 hour analysis and are 24-hour based to assess time-of-use and seasonal rate structures. Furthermore, the models are very adaptable to incorporating field-collected metering data. The analysis was performed by developing an energy model of the building using 8,760 hour weather data from TMY2 data for California climate zone 3. The weather data was used to determine the number of mild, moderate and hot days in each month. The weather-dependent loads were modeled based on measured data, system configuration and control sequences. Assumptions were made to estimate the nonweather dependent loads such as computer equipment, lighting and miscellaneous plug loads. The EEM analysis, based on the above energy model, predicts the electric energy, gas energy and electric demand savings associated with the implementation of each proposed measure. Because weather conditions vary from year to year, the calculated annual energy consumption and cost will not (and should not) be exactly equal to the actual energy consumption over the past year. However, the calculated results should be close in value to the actual consumption and cost. Moreover, the calculated relative energy consumption per energy system (e.g., space cooling) should be very representative of the actual usage distribution between energy systems. The second method used to determine energy savings was energy modeling through DOE-2 eQuest software. eQuest models were created for Robert Louis Stevenson and Everett in order to investigate the feasibility of building envelope EEMs, including 17
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION window replacements, weather stripping, and cool roofing retrofits. The following screenshots show the models created for this audit.
Image 5: Overview of eQuest Model for Everett
Image 6: Close-Up View of Windows at Everett
Image 7: Overview of eQuest Model for Stevenson
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FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION
Image 8: Close-Up View of Windows at Stevenson
Data Collection
The following data was collected during the audits and then used in the analysis: Annual campus electricity and gas usage. Existing system data including quantities, layouts, flow rates, coil capacities and design ratings from the building mechanical plans. Sequences of Operation from mechanical drawings, EMS As-Built documentation, and interviews with building engineers. Nameplate data from the air handler units such as manufacturer, model number, fan motor power (kW), electrical data (volts, amps and phases), fan type etc. Operation schedules for buildings and independent zones. The building architectural, electrical and mechanical plans were also used to gather information on system types and configuration. Interactive Effects An important step in the energy audit process is to take into account the interactive effects of installing various EEMs. Interactive effects is the term given to describe the fact that if two or more energy efficiency measures are installed, the realized savings may be less than the estimated savings for the individual measures as stand-alone EEMs. Consider the example of two EEMs; #1 where a new, more efficient air conditioner is installed and #2, where a new EMS is installed to shut off the air conditioner at nights and on weekends. Either measure will save energy but if they are both installed, the realized savings will be less than the sum of the two measures as estimated independently. To understand this effect, let us assume the new air conditioner is 19
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION installed first and the savings are estimated by assuming that the efficiency gains are realized 24 hours per day, seven days per week. However, if the new EMS is installed and the air conditioner is shut down on nights and weekends, the air conditioner will run less hours and therefore the realized savings will be less than anticipated for the new air conditioner project alone. Conversely, consider the situation if the new EMS is installed first. The EMS savings would be based on shutting down the old, inefficient air conditioner on nights and weekends. However, if the old air conditioner is then replaced, the energy required to condition the zone would be less and therefore the savings realized by the new EMS system would be reduced. To account for this effect, Cogent Energy cascaded the EEM analyses such that each measure’s energy savings calculation assumes that the previous measures have been implemented. Using the example above, the savings for the new air conditioner would be estimated using the old controls and then the realized savings for the new EMS would be estimated but based on reduced energy consumption to serve the zone. The disadvantage with this methodology is that the attractiveness of various measures is highly dependent on the order on which the measures are cascaded. In other words, some EEMs will appear superior to others just because they were analyzed first. The advantage is that if the sequence of the measures to be implemented is known, the measures can be cascaded in that order, and the savings will reflect the actual sequencing of the projects. For this report, Burton High School was the only school requiring the cascading of measures. For Burton, measures consisting of controls upgrades were cascaded first, conversions from constant volume to variable volume of air-side and water-side systems were cascaded second, and equipment replacement measures were cascaded third. A matrix is provided in Appendix A showing the results of the non-cascaded analysis. Recommended and Non-Recommended Measures Following the site-visits, Cogent Energy compiled a preliminary list of potential EEMs. After calculating energy savings impact, the EEMs were separated into recommended and non-recommended measures. Recommended measures are those whose implementation can be funded through the cost savings made available through their implementation. In general, EEMs with simple paybacks greater than approximately 50 years were identified as non-recommended. Certain measures with simple paybacks greater than 50 years were identified as recommended EEMs due to their low implementation cost. Maintenance Measures Cogent Energy identified numerous maintenance measures that are listed in Appendix C. While these measures are not expected to have a substantial and directly quantifiable energy savings component, the proper maintenance of equipment and systems will lead to reduced energy consumption over time. Further, proper maintenance will extend the useful lifetime of equipment. 20
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION ENERGY EFFICIENCY MEASURES AND RESULTS
ROBERT LOUIS STEVENSON ELEMENTARY SCHOOL Recommended Measures ST.01 Convert HV-1 from constant volume to variable volume through the installation of a Variable Frequency Drive. Heating & Ventilating Unit HV-1 is a constant volume unit. By converting to variable volume flow through the installation of a Variable Frequency Drive (VFD), the load on the fan can be reduced to better track the actual thermal load of the auditorium space which it serves. As a part of this measure, a thermostat should be installed in order to implement setpoint control. ST.02 Upgrade EMS to include control of AC units to prevent loss of scheduling. Upgrade EMS to include control of heating and ventilating unit HV-1. The current operating schedule of the AC units is unreliable, as the internal batteries frequently fail during power outages. This failure causes the programming of the AC units to be lost, resulting in the units operating at unoccupied times, for example nighttime and weekends. EMS control should be installed on the AC units to allow for consistent scheduling, operation and monitoring. The EMS does not currently control heating and ventilating unit HV-1. HV-1 serves the auditorium area which is infrequently occupied. By incorporating HV-1 into the EMS, a more targeted and reduced operation schedule can be implemented. ST.03 Implement Demand Ventilation through the installation of a CO2 sensor in the Auditorium to control HV-1 based on space occupancy. The installation of CO2 sensors would allow the unit to minimize the amount of outside air intake during periods of no or low occupancy; therefore reducing the heating load related to cold outside air. The CO2 sensors would modulate the outside air dampers as necessary to provide adequate ventilation when needed. ST.04 Install lighting occupancy control to turn off lights in rooms that are not in use. Lighting was observed to be turned on in numerous rooms which were unoccupied, including classrooms and offices. The school should install occupancy sensors in classrooms and offices for which there is intermittent occupancy in order to better match lighting use to occupancy.
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FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION Energy Analysis Results for Recommended Measures
ECM Number
kWh/yr Saved
kW Saved
ST.01
7,475
ST.02
26,221
ST.03
-
-
ST.04
9,361
-
TOTALS
43,057
Greenhouse Natural Gas Annual Annual Annual Gas Saved Electrical Natural Gas Energy Cost Reduction* Project Cost (therms/yr) Cost Saved Cost Saved Saved (tons CO2) Estimate
-
2
2
Potential Rebates
Net Project Estimate
Simple Payback (years)
1,960
$284.05
$2,175.60
$2,459.65
13.7
$22,866.42
$1,960.00
$20,906.42
8.5
1,305
$996.40
$1,448.97
$2,445.37
14.2
$30,675.00
$1,305.38
$29,369.62
12.0
1,412
$0.00
$1,566.86
$1,566.86
8.6
$1,200.00
$960.00
$240.00
0.2
$355.70
$0.00
$355.70
2.2
$4,181.24
$0.00
$4,181.24
11.8
$1,636.16
$5,191.43
$6,827.59
39
$58,922.66
$4,225.38
$54,697.29
8.0
4,677
Non-Recommended Measures ST.05 Replace existing windows with new windows and insulation. The school was constructed with wooden frame windows which have deteriorated over time. Currently, the windows are difficult to open, some are inoperable, and there is significant air infiltration through the window frames throughout the building. Cogent Energy investigated the feasibility of replacing the existing wooden frame, single pane windows with new metal frame windows and new insulation. The energy savings were found to be negligible due to moderate temperatures in San Francisco and the facilities dependence on operable window ventilation throughout the year. Given the large capital cost of a windows retrofit project, the measure could not be recommended. Further Cogent Energy modeled a retrofit wherein the SFUSD would install low-E windows, which would reflect sunlight off the window’s exterior face and prevent heating in the interior spaces. It was found that this type of retrofit would actually increase annual natural gas consumption due to the removal of the natural thermal gain.
Image 9: East Facing Windows
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FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION ST.06 Install a new Domestic Hot Water heater. Domestic hot water heater, WH-1, has a rusted and cracked flue due to a leaky pipe above WH-1 and has reached the end of its useful life. The facility should replace WH-1 with (2) 200 MBH condensing hot water heaters, however this project is not justified based on energy savings alone.
Image 10: WH-1 with Rusted Flue
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FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION EVERETT MIDDLE SCHOOL Recommended Measures EV.01 Install daylighting control in classrooms and offices. Lights were observed to be turned on in numerous classrooms and offices which also have windows that allow substantial daylight. The school should install daylighting control with occupancy sensors in order to turn lighting off during times of adequate daylighting or unoccupancy. Energy Analysis Results for Recommended Measures
ECM Number EV.01 TOTALS
kWh/yr Saved
Greenhouse Natural Gas Annual Annual Annual Gas Saved Electrical Natural Gas Energy Cost Reduction* Project Cost (therms/yr) Cost Saved Cost Saved Saved (tons CO2) Estimate
kW Saved
12,869 12,869
-
0
0
Potential Rebates
Net Project Estimate
Simple Payback (years)
$489.03
$0.00
$489.03
3.1
$7,989.72
$0.00
$7,989.72
16.3
$489.03
$0.00
$489.03
3
$7,989.72
$0.00
$7,989.72
16.3
Non-Recommended Measures EV.02 Replace the existing windows in the Gymnasium with operable windows. The windows in the Gymnasium are typically left closed due the inaccessibility of the open/close mechanisms. This situation results in little to no ventilation air available to the space. Cogent Energy created an eQuest model to investigate the energy impact of installing new windows with access to the open/close mechanisms which will allow increased ventilation to the space. It was determined that a windows replacement retrofit would have negligible impact on energy savings, and given the high cost of a windows replacement project, this measure does not offer a justifiable payback.
Image 11: Gymnasium Windows and Radiators
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FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION EV.03 Repair broken automatic and manual valves serving the steam radiators with new automatically controlled valves. Manual control valves were found serving steam radiators in various rooms throughout the school. Manual valves are frequently left-open to operate during periods of unoccupancy, and during time periods for which the temperature setpoints have been met. Additionally, numerous automatic and manual control valves were found to be damaged and broken due to misuse. Automatic control valves operate the radiators based strictly to meet temperature setpoints and as such may be installed in place of the existing manual valves and damaged automatic valves.
Image 12: Broken Radiator Valve
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FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION BURTON HIGH SCHOOL Recommended Measures BT.01 Convert the main building supply fan SF-1 from constant volume to variable volume through the installation of a Variable Frequency Drive. Install VAV boxes in ducts connected to SF-1. The existing supply fan SF-1 is a constant volume system, and does not provide reliable heating to the main building. Further, there is an unequal distribution of air throughout the SF-1 system. In order for the SF-1 system to better meet the specific load, the school should install a variable frequency drive on SF-1, and VAV boxes in the ducts connected to SF-1. The VFD and VAV boxes should be tied to the EMS. BT.02 Upgrade the EMS to include control of all building equipment and systems. The current EMS configuration does not include all of the HVAC components in the facility. The EMS should be upgraded to include the building's central HVAC equipment, and the equipment should be integrated into EMC optimized control. The Auditorium, Cafeteria, Gym, and Main Building's time-of-day schedules can be reduced through integration of EMS control. BT.03 Convert the air systems serving the Gymnasium from constant volume to variable volume through the installation of Variable Frequency Drive control. The heating and ventilating units, HV-4, HV-5, HV-6, and HV-7, and the exhaust fans, EF-13, EF-14, EF-15, and EF-16 serving the Gymnasium are constant volume units. The current supply and exhaust fans do not provide proper ventilation to Gymnasium. This measure would convert the constant volume system to variable volume through the installation of a 7.5 HP VFD to control all the fans, and incorporate demand ventilation through the installation of a CO2 sensor to control the VFD per the ventilation requirements of the space. The VFDs should be controlled by the EMS. BT.04 Convert supply fans SF-2, SF-3, and SF-4 from constant volume to variable volume through the installation of a Variable Frequency Drive. The single-zone supply fans SF-2, SF-3, and SF-4 which serve the Auditorium operate inefficiently. These systems should be converted from constant volume to variable volume to better meet the demand if the Auditorium space. The school should install a variable frequency drive to control the three (3) supply fans serving the space. The VFDs should be tied to the EMS. BT.05 Convert heating and ventilating unit HV-1 from constant volume to variable volume through the installation of a Variable Frequency Drive. 26
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION
Heating and ventilating unit HV-1 serves the entire Cafeteria area through constant volume supply, and also is configured as a single zone. This space should be converted to variable volume through the installation of a VFD. The VFDs should be controlled by the EMS. BT.06 Replace three fan coil units serving the radio station area with split system heating-only heat pumps. The radio station area creates a constant 24/7 demand on the heating system. Both the boiler serving this area and the three fan coils units receiving HHW from the boiler are therefore run 24/7 to meet the constant demand. The existing FCUs should be removed and replaced with split system heat pumps. The boiler's time-of-use schedule should likewise be reduced. BT.07 Install daylighting control and occupancy sensors. Lighting was observed to be turned on in numerous rooms with sufficient daylight. Daylighting control should be installed in conjunction with occupancy sensors to control lighting use during times of sufficient daylighting and periods of unoccupancy. BT.08 Install solenoid control valves for the four (4) fan coil units serving the first floor lab areas in the Science Building. The Fan Coil Units (FCU’s) do not have HHW control valves, resulting in a continuous flow through the FCU’s regardless of demand. Space heating is presently controlled through the ‘on-off’ operation of the FCU’s fans. The installation of solenoid valves is recommended in the HHW return piping to control the HHW flow through the FCUs. These valves should be wired in parallel with the operation of the FCU’s supply fans. Although the payback on this measure is significantly high, this measure is recommended because of the relatively low implementation cost.
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FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION Energy Analysis Results for Recommended Measures
ECM Number
kWh/yr Saved
BT.01
58,055
BT.02
13,558
BT.03
12,432
BT.04
7,944
BT.05
Greenhouse Natural Gas Annual Annual Annual Gas Saved Electrical Natural Gas Energy Cost Reduction* Project Cost (therms/yr) Cost Saved Cost Saved Saved (tons CO2) Estimate
kW Saved
22 -
7,622 15,459
Net Project Estimate
Simple Payback (years)
$8,460.42
$10,666.51
60.3
$344,519.12
$7,622.00
$336,897.12
31.6
$515.20 $17,159.49
$17,674.69
97.5
$286,470.00
$15,459.00
$271,011.00
15.3
1,251
$472.42
$1,388.61
$1,861.03
10.6
$47,946.93
$1,251.00
$46,695.93
25.1
-
3,601
$301.87
$3,997.11
$4,298.98
23.9
$75,279.71
$3,601.00
$71,678.71
16.7
1,724
-
2,046
$65.51
$2,271.06
$2,336.57
12.9
$18,458.51
$2,046.00
$16,412.51
7.0
BT.06
(13,002)
-
2,773
-$494.07
$3,078.03
$2,583.96
13.8
$27,960.00
$2,773.00
$25,187.00
9.7
BT.07
12,869
-
-
$489.03
$0.00
$489.03
3.1
$8,877.71
$0.00
$8,877.71
18.2
BT.08
-
-
$0.00
$34.97
$34.97
0.2
$3,660.00
$31.50
$3,628.50
103.8
$3,556.06 $36,389.69
$39,945.74
$813,171.96
$32,783.50
$780,388.46
19.5
TOTALS
93,581
4
$2,206.09
Potential Rebates
32 26
32,784
222
Non-Recommended Measures BT.09 Replace existing HHW pumps P-1, P-4, and P-5 with new high efficiency pumps. The HHW pumps P-1, serving the Gymnasium, P-4, serving the Classroom Building, and P-5, serving the Auditorium, are currently constant flow systems. Further, these pumps are beyond their useful life and are operating inefficiently. These three pumps should be removed and replaced with new high efficiency pumps with variable flow control. This measure also includes changing the existing 3-way control valves to 2-way control valves. BT.10 Install insulation on fan coil unit supply and return HHW piping. Install four (4) solenoid valves to the four fan coil units serving the Science Building. Approximately 400 ft of 1.5 inch piping providing heating hot water supply and return to the fan coil units on the 1st Floor of the Science Building was observed to be uninsulated. The fan coil units do not operate with control valves, resulting in a continuous flow through the units regardless of demand. The school should install 2 inch insulation to the exposed piping to prevent undue heat loss from the HHW system. The school should also install solenoid valves to control the HHW flow through the FCUs, and these valves should be wired in parallel to the operation of the supply fans. 28
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION
Image 13: Uninsulated Fan Coil Unit Piping
29
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION 5. CONCLUSION The SFUSD stands to realize substantial energy and cost savings through the mechanical system retrofit projects described in this audit report. Although the low electrical energy rates charged to the SFUSD by the SFPUC substantially lengthens the simple payback on a majority of the identified measures, by considering the cost of service rate offered by the SFPUC and the market rate for electricity, the public benefit of implementing energy efficiency projects within the SFUSD becomes apparent. As stated previously, the results of this report will be used to extrapolate the potential impact of the district-wide implementation of EEMs similar to those described in this report. Though the extrapolation methodology remains to be determined, Cogent Energy has presented the results of the EEM analysis as the results of singular retrofit projects per the request and scope provided by the SFUSD. Where necessary, the results of the measures were cascaded to avoid the double-counting of savings where one measure would affect the results of another, yet the results of this report largely view energy efficiency on a measure by measure approach. The SFUSD may realize a significantly greater energy and cost savings impact through a comprehensive energy efficiency program compared to the impact available through the pursuit of individual retrofit measures. As previously described, a comprehensive program would include three key components. First, retrocommissioning (RCx) would be performed to identify low cost and no cost EEMs, capital equipment replacement opportunities, maintenance and repair, necessary improvements for code compliance of ventilation and life-safety systems, and opportunities to optimize existing energy management systems. Following RCx, a mechanical contractor would be tasked with implementing the measures identified through RCx. The third component entails commissioning (Cx) of new systems to optimize system performance, verify equipment operation and integration of new equipment into the EMS, verify new systems function in compliance with ventilation and life safety codes, and to perform quality assurance that all systems meet the SFUSD’s operational requirements. A comprehensive energy efficiency program may be undertaken through a number of approaches. The following are four recommended approaches: The SFUSD may choose to identify selected EEMs that meet an acceptable payback threshold and pursue these measures district-wide. This approach would include highly tailored RCx to identify the sites where the preferred measures apply, rank the sites through quantifying the selected measures’ impact, and identify additional low cost/no cost measures for implementation. Additionally, this approach may allow the district the flexibility to contract directly with an equipment vendor instead of a general contractor, if for example the preferred measure was to install VFDs on constant volume fan systems. Cx in this approach would likewise be tailored to the chosen measures and systems. 30
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION The SFUSD may choose to identify selected school buildings that are known to use large amounts of energy as compared to buildings of similar size and student population and focus on a more holistic and comprehensive approach to these particular sites. This approach would entail detailed RCx, wherein all components and systems would be evaluated for functional performance, and recommendations would be made as to what retrofits would best optimize the site’s energy performance. After the contractor implemented the recommended measures, which would range from low cost/no cost measures up to capital equipment replacement measures, Cx would be performed to verify the functional performance of the new systems and their integration into the EMS. The SFUSD has identified a number of schools scheduled to receive capital improvement funds through the 2010 bond cycle. These schools may be leveraged with a comprehensive energy efficiency program to maximize the impact of the available bond money. Specifically, prior to the allocation of bond funds, RCx may be performed on the schools selected to receive bond money. The results of the RCx projects would then be used to determine how to best allocate the funds to have a maximum impact on energy and cost savings. The role of the mechanical contractor under this third option would be similar to the second, in that the contractor would be expected to implement the full array of retrofit and optimization measures. Cx would likewise verify the functional performance of the new systems. If funding permits, a fourth opportunity exists that would offer the most aggressive approach to energy and cost savings. Under this fourth approach, RCx would be performed district-wide at all SFUSD facilities in order to identify and implement all low cost and no cost measures available. Beyond low cost and no cost measures, this option would also allow the SFUSD to identify higher cost measures. Some capital intensive measures would be expected to offer attractive short-term paybacks and could be implemented immediately, while those with less attractive paybacks would be identified for future planning. This approach may rely more heavily on a controls contractor than a mechanical contractor as it would focus on providing new and optimizing existing control systems and sequences of operation. Further, a district-wide effort would provide an economy of scale that would allow for reduced administration costs for both the commissioning agent as well as the contractor. The RCx and Cx costs of a program similar to those described above would be largely dependent on the type of program pursued, the overall project scope, as well the overall scale of the program. However, the impact of an energy efficiency program will not only provide immediate and substantial energy and cost savings and a reduction of greenhouse gas emissions, but it will ensure the continuance of the realized savings for years going forward and an improvement to the district’s infrastructure.
31
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION APPENDIX A: NON-CASCADED RECOMMENDED ENERGY EFFICIENCY MEASURES ($0.038/KWH) EEM Number
ECM Title
kWh/yr Saved kW Saved
Natural Gas Saved (therms/yr)
Annual Electrical Cost Saved
Annual Natural Gas Cost Saved
Annual Energy Cost Saved
Greenhouse Gas Reduction* (tons CO2)
Project Cost Estimate
Simple Potential Net Project Cost Payback Rebates Estimate (years)
Robert Louis Stevenson Elementary
9,811
-
ST.01
Convert HV-1 variable volume flow
ST.02
Upgrade EMS
ST.03
Install demand control ventilation
-
-
ST.04
Install lighting occupancy control
9,361
-
12,869
-
26,221
2
2,547 $
373 $
2,827 $
3,200
17.9 $
22,866 $
2,547 $
20,320
6.4
1,305 $
996 $
1,449 $
2,445
14.2 $
30,675 $
1,305 $
29,370
12.0
1,412
-
1,567 $
1,567
8.6 $
1,200 $
960 $
240
0.2
$
356
2.2
$4,181 $
- $
4,181
11.8
- $
489
3.1
$7,990 $
-
$7,990
16.3
$
$
356
$
489 $
Everett Middle School EV.01
Install daylighting control in classrooms and offices.
-
Burton High School
109,263
BT.01
Convert SF-1 to variable volume flow
BT.02
Upgrade the EMS
69,887
BT.03
Convert the air systems serving the Gymnasium to variable volume
15,061
BT.04
Convert SF-2, SF-3, and SF-4 to variable volume
16,417
BT.05
Convert HV-1 to variable volume
BT.06
27 3
22,633 $
4,152
25,122 $
29,274
164.0 $
344,519 $ 22,633 $
321,886
11.0
26,325 $
2,656
29,221 $
31,877
177.2 $
286,470 $ 26,325 $
260,145
8.2
1,661 $
572 $
1,843 $
2,416
13.7 $
47,947 $
1,661 $
46,286
19.2
-
4,906 $
624 $
5,446 $
6,070
33.8 $
75,280 $
4,906 $
70,373
11.6
1,864
-
2,053 $
2,053 $
2,279 $
4,332
13.0 $
18,459 $
2,053 $
16,405
3.8
Replace the fan coil units with split system heat pumps .
(13,002)
-
13,217 $
(494) $
14,671 $
14,176
77.5 $
27,960 $ 13,217 $
14,743
1.0
BT.07
Install daylighting control and occupancy sensors
12,869
-
$
489 $
- $
489
BT.08
Install solenoid control valves * (kWh * 0.524 lbs per kWh + Therms * 13.446 lbs per therm) / (2204.6 lbs per Tonne) http://www.pge.com/myhome/environment/calculator/assumptions.shtml ** Project costs do not include markups for Engineering, Project Management, Project Administration and Contingencies
32 $
- $
35 $
35
-
3.1 0.2 $
$8,878 $
- $
8,878
18.2
3,660 $
32 $
3,629
103.8
32
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION APPENDIX B: CASCADED RECOMMENDED AND NON-RECOMMENDED ENERGY EFFICIENCY MEASURES ($0.038/KWH) ECM Number
kWh/yr Saved
ECM Title
Annual Greenhous Natural Gas Annual Natural Annual e Gas Saved Electrical Gas Cost Energy Reduction* (therms/yr) Cost Saved Saved Cost Saved (tons CO2)
kW Saved
Project Cost Estimate
Potential Rebates
Simple Net Project Payback Estimate (years)
Robert Louis Stevenson Elementary ST.01
Convert HV-1 from constant volume to variable volume through the installation of a Variable Frequency Drive.
ST.04
Upgrade EMS to include control of AC units to prevent loss of scheduling. Upgrade EMS to include control of heating & ventilating unit HV-1. Install a CO2 sensor in the Auditorium to control HV-1 based on space occupancy. Install lighting occupancy control to turn off lights in rooms that are not in use.
ST.05
Replace existing windows with new windows and insulation.
ST.06
Install a new Domestic Hot Water Heater.
ST.02 ST.03
TOTALS
7,475
-
26,221
2
-
-
9,361
-
-
-
43,057
1,960
$284.05
$2,175.60
$2,459.65
13.7
$22,866.42
$1,960.00
$20,906.42
8.5
1,305
$996.40
$1,448.97
$2,445.37
14.2
$30,675.00
$1,305.38
$29,369.62
12.0
1,412
$0.00
$1,566.86
$1,566.86
8.6
$1,200.00
$960.00
$240.00
0.2
$355.70
$0.00
$355.70
2.2
$4,181.24
$0.00
$4,181.24
11.8
296
1.6
-
92 $ $ 102 $ 102 5,036 $1,636.16 $5,589.92 $7,226.08
0.6 41
267 $
2
-
$
296 $
-
-
-
$33,123 $ 92 $92,045.66 $4,317.38
$33,031 $87,728.29
323.5 12.1
$7,989.72
16.3
Everett Middle School EV.01 EV.02 EV.03
Install daylighting control in classrooms and offices. Replace the existing windows in the Gymnasium with operable windows with access to open/close mechanisms. Replace manual control valves and broken automatic valves serving the steam radiators with new automatically controlled valves. TOTALS
12,869
-
-
-
-
-130 $
0 0
0 0
181 181
$489.03 0 $0.00
$0.00 $
(144) $ 201 $200.91
$489.03
3.1
$7,989.72
(144)
-
-
201 $200.91
1.1 1
$0.00 -
22,800 $ 181.00 $22,800.00 $181.00
22,619 $22,619.00
113 112.6
33
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION APPENDIX B: CASCADED RECOMMENDED AND NON-RECOMMENDED ENERGY EFFICIENCY MEASURES ($0.038/KWH) CONTINUED ECM Number
kWh/yr Saved
ECM Title
Annual Greenhous Natural Gas Annual Natural Annual e Gas Saved Electrical Gas Cost Energy Reduction* (therms/yr) Cost Saved Saved Cost Saved (tons CO2)
kW Saved
Project Cost Estimate
Potential Rebates
Simple Net Project Payback Estimate (years)
Burton High School
BT.01
Convert the main building supply fan SF-1 from constant volume to variable volume through the installation of a Variable Frequency Drive. Install VAV boxes in ducts connected to SF-1.
58,055
BT.02
Upgrade the EMS to include control of all building equipment and systems.
13,558
BT.03
Convert the air systems serving the Gymnasium from constant volume to variable volume through the installation of Variable Frequency Drive control.
12,432
BT.04
Convert supply fans SF-2, SF-3, and SF-4 from constant volume to variable volume through the installation of a Variable frequency Drive.
7,944
BT.05
Convert heating & ventilating unit HV-1 from constant volume to variable volume through the installation of a Variable Frequency Drive.
BT.06
Replace the three (3) fan coil units serving the radio station area with split system heat pumps .
BT.07
Install daylighting control and occupancy sensors
BT.08
Install solenoid control valves for the four (4) fan coil units serving the first floor lab areas in the Science Building.
BT.09
Replace existing HHW pumps P-1, P-4, and P-5 with new high efficiency pumps.
BT.10
Install insulation on fan coil unit supply and return HHW piping. Install four (4) solenoid valves to the four fan coil units serving the Science Building. TOTALS TOTALS
22
7,622
$2,206.09
$8,460.42
$10,666.51
60.3
$344,519.12
$7,622.00
$336,897.12
31.6
15,459
$515.20
$17,159.49
$17,674.69
97.5
$286,470.00
$15,459.00
$271,011.00
15.3
1,251
$472.42
$1,388.61
$1,861.03
10.6
$47,946.93
$1,251.00
$46,695.93
25.1
-
3,601
$301.87
$3,997.11
$4,298.98
23.9
$75,279.71
$3,601.00
$71,678.71
16.7
1,724
-
2,046
$65.51
$2,271.06
$2,336.57
12.9
$18,458.51
$2,046.00
$16,412.51
7.0
(13,002)
-
2,773
-$494.07
$3,078.03
$2,583.96
13.8
$27,960.00
$2,773.00
$25,187.00
9.7
12,869
-
-
$489.03
$0.00
$489.03
3.1
$8,877.71
$0.00
$8,877.71
18.2
-
-
$0.00
$34.97
$34.97
0.2
$3,660.00
$31.50
$3,628.50
103.8
8,210
-
-
4
32 -
13 101,790 144,847
26 28
32,796 38,013
$
312 $
- $
312
$
14 $
14
$3,868.04 $36,403.70 $40,271.74 $5,504.19 $42,194.53 $47,698.73
2.0 $
80,124
$
80,124
256.8
0.1 $
11,792
$
11,792
841.2
$905,087.64 $32,783.50 $872,304.14 $1,019,933.31 $37,281.88 $982,651.43
21.7 20.6
224 266
34
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION APPENDIX C: IDENTIFIED MAINTENANCE MEASURES EEM Number ECM Title Robert Louis Stevenson Elementary No Maintenance Measures were identified at Stevenson Everett Middle School
EV.MM.01
EV.MM.02
ECM Description
Repair boiler B-1 from its current non-operational condition.
Boiler B-1 was found to be non-operational. Facility personnel were unaware as to the cause of the boiler's failure. The school should repair the boiler to its operable condition and institute a scheduled maintenance program.
Verify that that the ignition sequences on boiler 2 are operating properly.
Boiler B-2 was found to be operating in fault mode. A district engineer reset the boiler and it fired properly. The fault indicates a possible problem with the ignition sequences. The school should verify that the boiler is operating properly and institute a scheduled maintenance program.
The boiler room is currently operating with restricted air supply. There are no Install low air supply to the boiler room to increase ventilation fans, and there is currently no low air supply. Per the CODE, the EV.MM.03 the outside air supply to the boiler room. school should install low air supply and ventilation fans. Burton High School No Maintenance Measures were identified at Burton
35
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION APPENDIX D: UTILITY CONSUMPTION PROFILES Figure B.1: Monthly Total Energy Consumption (MBtu) for Stevenson Elementary
Figure B.2: Monthly Demand (kW) and Electricity Consumption (kWh) for Stevenson Elementary School
36
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION Figure B.3: Monthly Natural Gas Consumption (therms) for Stevenson Elementary School
Figure B.4: Monthly Total Energy Consumption (MBtu) for Everett Middle School
37
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION
Figure B.5: Monthly Demand (kW) and Electricity Consumption (kWh) for Everett Middle School
Figure B.6: Monthly Natural Gas Consumption (therms) for Everett Middle School
38
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION
Figure B.7: Monthly Total Energy Consumption (MBtu) for Burton High School
Figure B.8: Monthly Demand (kW) and Electricity Consumption (kWh) for Burton High School
39
FINAL TACTICAL ENERGY AUDIT REPORT THE SAN FRANCISCO PUBLIC UTILITIES COMMISSION
Figure B.9: Monthly Natural Gas Consumption (therms) for Burton High School
40
