HomeMy WebLinkAboutSEA-AEE-JNU Riverbend Elementary 2012-E
Riverbend Elementary School
Juneau School District
Funded by:
Final Report
November 2011
Prepared by:
Energy Audit
Table of Contents
Section 1: Executive Summary 2
Section 2: Introduction 6
Section 3: Energy Efficiency Measures 8
Section 4: Description of Systems 14
Section 5: Methodology 17
Appendix A: Energy and Life Cycle Cost Analysis 20
Appendix B: Utility and Energy Data 29
Appendix C: Equipment Data 36
Appendix D: Abbreviations 40
Audit Team
The energy audit is performed by Alaska Energy Engineering LLC of Juneau, Alaska. The audit team
consists of:
Jim Rehfeldt, P.E., Energy Engineer
Jack Christiansen, Energy Consultant
Brad Campbell, Energy Auditor
Loras O’Toole P.E., Mechanical Engineer
Will Van Dyken P.E., Electrical Engineer
Curt Smit, P.E., Mechanical Engineer
Philip Iverson, Construction Estimator
Karla Hart, Technical Publications Specialist
Jill Carlile, Data Analyst
Grayson Carlile, Energy Modeler
Riverbend Elementary School 1 Energy Audit (November 2011)
Section 1
Executive Summary
An energy audit of the Riverbend Elementary School was performed by Alaska Energy Engineering
LLC. The investment grade audit was funded by Alaska Housing Finance Corporation (AHFC) to
identify opportunities to improve the energy performance of public buildings throughout Alaska.
Riverbend Elementary School is a 67,512 square foot building that contains commons, classrooms,
offices, a music room, a gym, a kitchen and cafeteria, a library, storage, and mechanical support
spaces. The following summarizes our assessment of the building:
Building Assessment
Envelope
The building envelope of Riverbend Elementary School appears to be providing good service and is
well maintained. Energy conscious selections of some exterior envelope materials included non-
aluminum framed windows and a judicious use of windows. Interior designs such as lower ceilings
and a sensible amount of lighting in interior spaces also support a reasonably energy efficient design.
Despite these selections and concepts, Riverbend Elementary School has the highest energy use index
of Juneau schools at 93 kBtu/sqft. This is just over 50% higher than the average Juneau school energy
use index of 60 kBtu/per sqft, which includes schools much older than Riverbend. There is great
incentive to improve the energy performance; if the building were at average performance, annual
energy costs would be approximately $75,000 less, saving about $2.3 million over a 25-year period.
The audit identified the following envelope design and performance problems:
Insufficient Insulation: The exterior walls consist of 2” x 6” metal studs without a thermal
break (such as a rigid exterior foam insulation panels) between the exterior siding and the
interior drywall surfaces. Although fiberglass batt insulation fills the voids between the wall
stud cavities, the metal studs themselves are acting as thermal conductors and are de-rating
the wall insulation performance. The overall wall assembly has an insulation value of only R-
9, well below the optimal R-26 value for modern efficient buildings.
Adding insulation to the walls will not provide a life cycle savings due to the cost to remove
and reinstall the siding. Future siding replacement projects at Riverbend Elementary
wibenefit from the installation of exterior foam insulation.
The ceilings are insulated with R-30 batts that are degraded, to a lesser extent than the walls,
by thermal bridging of the purlins and steel beams. The overall result is lower than the
optimum R-46 level currently used. Additional blown-in insulation is not recommended
because of access difficulties and the potential for restricting attic ventilation at the eves.
Riverbend Elementary School 2 Energy Audit (November 2011)
Complex Framing: The structural framework of the building made it difficult to install a
continuous, well-sealed vapor barrier and insulation package. The vapor barrier is installed on
the bottom of the roof trusses. However, it was cut and sealed at each roof beam because the
beams’ depth placed them below the bottom of the trusses. This sealing was ineffective.
To form a continuous vapor barrier, the wall vapor barrier must seal to the roof barrier at the
wall/roof junction. The structural frame places a large perimeter beam at this location,
making it extremely difficult to seal the two barriers together.
Smoke tests revealed that air is moving upward through the building and out leakage paths in
the poorly sealed vapor barrier. It is recommended that the vapor retarder be sealed in the
attic to reduce the leakage out the roof. In addition to increasing energy costs, this air leakage
has caused ice dam formation and large areas of melted snow on the cold roof. An exterior
insulation design will avoid these issues.
Exterior Doors: Exterior doors are not thermally broken. Future exterior door replacement
selection should include this feature. Weather stripping is in poor condition and should be
replaced.
Heating & Ventilation Systems
The school is heated by three fuel oil boilers that provide heat to seven air handling unit systems, fan
coil units, and perimeter hydronic systems. The air handling units deliver conditioned air to the spaces
through a hot deck system which mixes 62°F air with 140°F air to achieve the desired room
temperatures. The original design of the building was based on a hot deck system that never required
air to be heated above 110°F prior to mixing. It appears that the hot deck temperature was
significantly increased to compensate for building envelope heat loss. This fix causes additional
inefficiencies as the 140°F hot decks have higher heat loss, and that heat loss flows right out the roof.
The ventilation system is designed to develop a positive pressure within the building envelope. As
this pressure is increased, more warm air from conditioned spaces is pushed through the leaky
building envelope. Although the hot deck temperature was increased to help heat the building’s
conditioned spaces, the pressurization setpoint remained the same. It is likely that a lower hot deck
temperature can be successfully utilized if a lower building pressurization setpoint is established.
The heating and ventilating systems are in good condition; however, fairly simple improvements can
be made to improve its effectiveness and efficiency. These are outlined in Section 3, Energy
Efficiency Measures.
Lighting
Interior lighting consists primarily of T8 fluorescent fixtures. Exterior lighting consists primarily of
metal halide lighting. Because lighting operational hours are controlled by staff, operational costs for
lighting with existing infrastructure are kept to a minimum. Replacement of existing fixtures with
more efficient units and the addition of occupancy sensors are solutions for further reductions in
operational costs.
Summary
It was the assessment of the energy audit team that the majority of the building energy losses are due
to a poor thermal envelope, leakage paths in the vapor barrier, and building pressurization by the
HVAC systems. Additional opportunities to save energy include optimization of ventilation rates and
schedules in accordance with occupancy followed by a retro-commissioning of the ventilation
equipment.
Riverbend Elementary School 3 Energy Audit (November 2011)
Because the energy performance of Riverbend Elementary is so poor, it is strongly recommended that
school staff continue to focus on reducing all building heating loads as much as possible through
improvements to the efficiencies of the building envelope and heating and ventilating systems.
The AHFC audit process has provided a unique opportunity to not only develop a performance
database of individual buildings throughout Southeast Alaska, but, perhaps more importantly, to gain
a better perspective of the evolution of the design and construction process. The challenges of
creating a continuous vapor barrier and continuous thermal insulation plane are much greater in metal
frame buildings with metal framing components. This is primarily a design issue that must be
understood and corrected to ensure future buildings are energy efficient.
Energy Efficiency Measures (EEMs)
All buildings have opportunities to improve their energy efficiency. The energy audit revealed
numerous opportunities in which an efficiency investment will result in a net reduction in long-term
operating costs.
Behavioral and Operational EEMs
The following EEMs require behavioral and operational changes in the building use. The savings are
not readily quantifiable but these EEMs are highly recommended as low-cost opportunities that are a
standard of high performance buildings.
EEM-1: Weather-strip Doors
EEM-2: Replace Broken Window
EEM-3: De-Lamp Soft Drink Cooler
High and Medium Priority EEMs
The following EEMs are recommended for investment. They are ranked by life cycle savings to
investment ratio (SIR). This ranking method places a priority on low cost EEMs which can be
immediately funded, generating energy savings to fund higher cost EEMs in the following years.
Negative values, in parenthesis, represent savings.
25-Year Life Cycle Cost Analysis
Investment Operating Energy Total SIR
High Priority
EEM-4: Install Pipe Insulation $100 $0 ($8,200) ($8,100) 82.0
EEM-5: Isolate Lag Boiler $500 $2,000 ($38,400) ($35,900) 72.8
EEM-6: Replace Aerators $600 $0 ($21,200) ($20,600) 35.3
EEM-7: Seal Attic Vapor Retarder $16,100 $0 ($499,300) ($483,200) 31.0
EEM-8: Optimize Ventilation Systems $98,600 $17,000 ($508,000) ($392,400) 5.0
EEM-9: Electrical Room Heat Recovery $20,400 $7,700 ($79,400) ($51,300) 3.5
Medium Priority
EEM-10: Install Modulating Burner Controls $32,000 $0 ($58,900) ($26,900) 1.8
EEM-11: Replace Door Glazing $15,800 $0 ($23,900) ($8,100) 1.5
EEM-12: Replace Window Glazing $10,900 $0 ($16,500) ($5,600) 1.5
Totals* $195,000 $26,700 ($1,253,800) ($1,032,100) 6.3
Riverbend Elementary School 4 Energy Audit (November 2011)
*The analysis is based on each EEM being independent of the others. While it is likely that some
EEMs are interrelated, an isolated analysis is used to demonstrate the economics because the audit
team is not able to predict which EEMs an Owner may choose to implement. If several EEMs are
implemented, the resulting energy savings is likely to differ from the sum of each EEM projection.
Summary
The energy audit revealed numerous opportunities for improving the energy performance of the
building. It is recommended that the behavioral and high priority EEMs be implemented now to
generate energy savings from which to fund the medium priority EEMs.
Another avenue to consider is to borrow money from AHFCs revolving loan fund for public
buildings. AHFC will loan money for energy improvements under terms that allow for paying back
the money from the energy savings. More information on this option can be found online at
http://www.ahfc.us/loans/akeerlf_loan.cfm.
Riverbend Elementary School 5 Energy Audit (November 2011)
Section 2
Introduction
This report presents the findings of an energy audit of the Riverbend Elementary School located in
Juneau, Alaska. The purpose of this investment grade energy audit is to evaluate the infrastructure
and its subsequent energy performance to identify applicable energy efficiencies measures (EEMs).
The energy audit report contains the following sections:
Introduction: Building use and energy consumption.
Energy Efficiency Measures: Priority ranking of the EEMs with a description, energy
analysis, and life cycle cost analysis.
Description of Systems: Background description of the building energy systems.
Methodology: Basis for how construction and maintenance cost estimates are derived and the
economic and energy factors used for the analysis.
BUILDING USE
Riverbend Elementary School is a 67,512 square foot building that contains commons, classrooms,
offices, a music room, a gym, a kitchen and cafeteria, a library, storage, and mechanical support
spaces. The following summarizes our assessment of the building:
The elementary school is operated by 60 staff and attended by 318 students.
Teachers 6:00 am – 5:00 pm (M-F)
Students 7:45 am – 3:30 pm (M-F) School
3:30 pm – 6:00 pm (M-F) Rally
Community Use As Needed
History
History of the building includes:
1997 – Original Construction
1998 – Electric Room Exhaust System
Riverbend Elementary School 6 Energy Audit (November 2011)
Energy Consumption
The building energy sources include an electric service and a fuel oil tank. Fuel oil is used for the
majority of the heating loads and domestic hot water while electricity serves all other loads. The
following table shows annual energy use and cost.
Annual Energy Consumption and Cost
Source Consumption Cost Energy, MMBtu
Electricity 528,620 kWh $58,100 1,800 32%
Fuel Oil 27,826 Gallons $105,700 3,780 68%
Totals - $163,800 5,580 100%
Electricity
This chart shows electrical energy use
from 2007 to 2010. The effective cost—
energy costs plus demand charges—is
11.0¢ per kWh.
Fuel Oil
This chart shows heating energy use from
2007 to 2010. The chart compares annual use
with the heating degree days which is a
measurement of the demand for energy to
heat a building. A year with a higher number
of degree days reflects colder outside
temperatures and a higher heating
requirement.
Currently, fuel oil costs $3.80 per gallon and
electricity costs $0.113 per kWh. The cost of
heat, assuming a fuel oil conversion efficiency of
70% and an electric boiler conversion efficiency
of 95%, is $39.20 per MMBtu of fuel oil heat and
$35.01 per MMBtu for electric heat. Electric heat
is less expensive than fuel oil heat.
Riverbend Elementary School 7 Energy Audit (November 2011)
Section 3
Energy Efficiency Measures
The following energy efficiency measures (EEMs) were identified during the energy audit. The
EEMs are priority ranked and, where applicable, subjected to energy and life cycle cost analysis.
Appendix A contains the energy and life cycle cost analysis spreadsheets.
The EEMs are grouped into the following prioritized categories:
Behavioral or Operational: EEMs that require minimal capital investment but require
operational or behavioral changes. The EEMs provide a life cycle savings but an analysis is
not performed because the guaranteed energy savings is difficult quantify.
High Priority: EEMs that require a small capital investment and offer a life cycle savings.
Also included in this category are higher-cost EEMs that offer significant life cycle savings.
Medium Priority: EEMs that require a significant capital investment to provide a life cycle
savings. Many medium priority EEMs provide a high life cycle savings and offer substantial
incentive to increase investment in building energy efficiency.
Low Priority: EEMs that will save energy but do not provide a life cycle savings.
BEHAVIORAL OR OPERATIONAL
The following EEMs are recommended for implementation. They require behavioral or operational
changes that can occur with minimal investment to achieve immediate savings. These EEMs are not
easily quantified by analysis because they cannot be accurately predicted. They are recommended
because they offer a life cycle savings, represent good practice, and are accepted features of high
performance buildings.
EEM-1: Weather-strip Doors
Purpose: The exterior steel doors do not seal and are missing weather stripping. Energy will be
saved if doors are properly weather-stripped to reduce infiltration.
Scope: Replace weather stripping on exterior doors.
EEM-2: Replace Broken Window
Purpose: A 4’ x 5’ window in the commons area is broken and covered only with a single plexi-
glass sheet. Energy will be saved if the broken window is repaired.
Scope: Repair broken window with energy efficient double glazing.
EEM-3: De-Lamp Soft Drink Cooler
Purpose: Lighting in the soft drink vending machine in the staff lounge area is on continuously and
is not necessary. Energy will be saved if this lamp is removed.
Scope: Remove lamp from soft drink cooler in the staff lounge
Riverbend Elementary School 8 Energy Audit (November 2011)
HIGH PRIORITY
The following EEMs are recommended for implementation because they are low cost measures that
have a high savings to investment ratio. The EEMs are listed from highest to lowest priority. Negative
values, in parenthesis, represent savings.
EEM-4: Install Pipe Insulation
Purpose: A 6’ section of 2 ½” boiler loop circulation pipe is uninsulated in Area B fan room.
Energy will be saved if this section of piping is optimally insulated.
Scope: Install pipe insulation
Annual Costs Life Cycle Costs
Operating Energy Total Investment Operating Energy Total SIR
$0 ($290) ($290) $100 $0 ($8,200) ($8,100) 82.0
EEM-5: Isolate Lag Boiler
Purpose: During moderate weather when only one boiler is needed to supply the heating load,
keeping circulation through the lag boiler results in a 1% efficiency loss as it acts as a
heat sink. Energy will be saved if only a single boiler is on line during moderate weather.
Scope: Disable the lag boiler during moderate weather when only a single boiler is needed to
heat the building.
Annual Costs Life Cycle Costs
Operating Energy Total Investment Operating Energy Total SIR
$120 ($1,350) ($1,230) $500 $2,000 ($38,400) ($35,900) 72.8
EEM-6: Replace Aerators
Purpose: Energy and water will be saved by replacing the lavatory aerators with low-flow models.
Scope: Replace lavatory aerators with water-conserving fixtures.
Annual Costs Life Cycle Costs
Operating Energy Total Investment Operating Energy Total SIR
$0 ($1,080) ($1,080) $600 $0 ($21,200) ($20,600) 35.3
Riverbend Elementary School 9 Energy Audit (November 2011)
EEM-7: Seal Attic Vapor Retarder
Purpose: An investigation revealed that there is considerable air leakage occurring through the
roof. The primary leakage path occurs where the vapor retarder was not adequately sealed
at each structural beam. The audit team was unable to schedule a blower door test to
measure the leakage, but estimates from previous experience that the roof is leaking at
0.3 air changes per hour.
Energy will be saved if the vapor retarder is properly sealed to the structural beams.
Scope: Seal the vapor barrier in the attic at each structural beam.
Annual Costs Life Cycle Costs
Operating Energy Total Investment Operating Energy Total SIR
$0 ($17,620) ($17,620) $16,100 $0 ($499,300) ($483,200) 31.0
EEM-8: Optimize Ventilation Systems
Purpose: The HVAC systems are constant volume systems that supply ventilation and thermal
control to interior spaces during occupied and unoccupied hours. There are opportunities
to modify the systems and reduce energy consumption.
Scope: Optimize the operation of the HVAC systems and retro-commission all air handling units
to perform as a properly integrated system when completed:
SF-2 (Gymnasium)
- Convert to variable air flow by installing a VFD for the supply fan.
- Optimize night setback control so the system operates when the gym temperature
drops to 60°F and fully heats until reaching 64°F.
- Verify CO2 control of the outside air dampers. The system is currently bringing in
outside air when CO2 levels are low, and then heating it.
- Verify relief air damper control from room pressure sensor. The relief damper was
driven open further than expected for a leaky envelope and the system is bringing in
more outside air than needed for daytime classroom occupancy.
SF-3 (Area E), SF-4 (Area D), SF-5 (Area C), SF-6 (Area B), SF-7 (Area A)
- Reduce minimum outside air flow to maintain a neutral building pressure.
Recommend revising the mixed air temperature control to one that maintains
minimum outside air flow and resets the mixed air temperature between 60°F and
68°F to cool the critical cooling zone.
- Modify relief air damper controls. Install a pressure sensor(s) in the building and
modulate the EAD independently to maintain the building at neutral pressure.
- Optimize night setback control so the system operates when 20% of the rooms drop
to 60°F, or any room drops to 57°F and operates until all rooms reach 64°F.
Annual Costs Life Cycle Costs
Operating Energy Total Investment Operating Energy Total SIR
$1,000 ($18,150) ($17,150) $98,600 $17,000 ($508,000) ($392,400) 5.0
Riverbend Elementary School 10 Energy Audit (November 2011)
EEM-9: Electrical Room Heat Recovery
Purpose: Heat is generated by computer equipment and transformers in the two electrical rooms.
This heat is removed by an exhaust fan in each room and discharge outdoors. Energy will
be saved if the heated air is supplied to the entry and commons.
Scope: Install an exhaust air system that draws air from each electrical room and supplies it to
the entry and commons.
Annual Costs Life Cycle Costs
Operating Energy Total Investment Operating Energy Total SIR
$450 ($2,780) ($2,330) $20,400 $7,700 ($79,400) ($51,300) 3.5
MEDIUM PRIORITY
Medium priority EEMs will require planning and a higher level of investment. They are
recommended because they offer a life cycle savings. The EEMs are listed from highest to lowest
priority. Negative values, in parenthesis, represent savings.
EEM-10: Install Modulating Burner Controls
Purpose: The boilers have modulating burners. They were observed to not be modulating and are
operating as on-off burners. The burners were originally controlled from a boiler control
panel that has been disconnected Energy will be saved if modulating control is
reestablished.
Scope: Reestablish modulating control by replacing the boiler control panel or through the DDC
system.
Annual Costs Life Cycle Costs
Operating Energy Total Investment Operating Energy Total SIR
$0 ($2,080) ($2,080) $32,000 $0 ($58,900) ($26,900) 1.8
EEM-11: Replace Door Glazing
Purpose: Single pane Plexiglas glazing is installed in the aluminum entry doors. Energy will be
saved if the Plexiglas is replaced with double pane energy efficient glazing.
Scope: Replace single pane Plexiglas with energy efficient double pane glazing units.
Annual Costs Life Cycle Costs
Operating Energy Total Investment Operating Energy Total SIR
$0 ($840) ($840) $15,800 $0 ($23,900) ($8,100) 1.5
EEM-12: Replace Window Glazing
Purpose: Single pane Plexiglas glazing is installed in some of the window frames. Energy will be
saved if the Plexiglas is replaced with double pane energy efficient glazing.
Scope: Replace single pane Plexiglas with energy efficient double pane glazing units.
Annual Costs Life Cycle Costs
Operating Energy Total Investment Operating Energy Total SIR
$0 ($580) ($580) $10,900 $0 ($16,500) ($5,600) 1.5
Riverbend Elementary School 11 Energy Audit (November 2011)
LOW PRIORITY
Low priority EEMs do not offer a life cycle energy savings and are not recommended.
EEM-13: Upgrade Gym Lighting
Purpose: The gym lighting utilizes 20 pendant-mounted 400-watt metal halide fixtures. Similar
light levels could be achieved with multi-lamp T5 lighting. Energy will be saved if the
metal halide light fixtures are replaced with 6-bulb T5 fixtures.
Scope: Replace metal halide lighting with fluorescent T5 lighting.
Annual Costs Life Cycle Costs
Operating Energy Total Investment Operating Energy Total SIR
($50) ($570) ($620) $16,200 ($800) ($11,200) $4,200 0.7
EEM-14: Upgrade Exterior Lighting to LED
Purpose: The existing perimeter parking lot lighting consists of metal halide fixtures. These fixture
styles are less efficient than LED lighting and the lamp life is much shorter.
Scope: Replace existing exterior lights with LED lights.
Annual Costs Life Cycle Costs
Operating Energy Total Investment Operating Energy Total SIR
($500) ($1,050) ($1,550) $60,200 ($15,500) ($20,700) $24,000 0.6
EEM-15: Upgrade Motors to Premium Efficiency
Purpose: The equipment inspection identified nine motors that could be upgraded with premium
efficiency models to save energy. They are:
SF-2 10 HP from 89.5% efficiency to 91.7% efficiency
SF-3 15 HP from 90.2% efficiency to 93.0% efficiency
SF-4 15 HP from 90.2% efficiency to 93.0% efficiency
SF-5 15 HP from 90.2% efficiency to 93.0% efficiency
SF-6 15 HP from 90.2% efficiency to 93.0% efficiency
SF-7 15 HP from 90.2% efficiency to 93.0% efficiency
RF-3 5 HP from 86.5% efficiency to 89.5% efficiency
RF-5 7 ½ HP from 88.5% efficiency to 91.0% efficiency
RF-7 7 ½ HP from 88.5% efficiency to 91.0% efficiency
Scope: Replace identified motors with premium efficiency motors.
Annual Costs Life Cycle Costs
Operating Energy Total Investment Operating Energy Total SIR
$0 ($540) ($540) $19,800 $0 ($10,600) $9,200 0.5
Riverbend Elementary School 12 Energy Audit (November 2011)
EEM-16: Increase Wall Insulation
Purpose: The exterior walls have an insulating value of R-9 due to thermal bridging of the metal
studs through the insulated wall cavity. An optimal R-value by current construction
standards is R-26. Energy will be saved if the insulation level of the walls is increased.
Installing exterior rigid insulation with new siding and cladding is an effective approach.
Scope: Install a minimum of 4” of exterior foam insulation with new siding and brick veneer
around the perimeter of building. The energy savings is unable to offset the high cost of
adding the insulation to the existing wall.
Annual Costs Life Cycle Costs
Operating Energy Total Investment Operating Energy Total SIR
$0 ($24,120) ($24,120) $2,223,700 $0 ($683,700) $1,540,000 0.3
Riverbend Elementary School 13 Energy Audit (November 2011)
Section 4
Description of Systems
ENERGY SYSTEMS
This section provides a general description of the building systems. Energy conservation
opportunities are addressed in the Energy Efficiency Measure section of the report.
Building Envelope
R-value
Component Description (inside to outside) Existing Optimal
Exterior Wall 5/8” Gyp. bd, 2”x6” metal stud, R-19 batt, ½” plywood, siding R-9 R-26
Roof 24” o.c. trusses w/ R-30 batt, 5/8” gyp. bd. (2 layers) R-30 R-46
Floor Slab 4” Concrete slab-on-grade R-10 R-10
Foundation 8” concrete w/ 2” perimeter insulation board R-10 R-20
Windows Vinyl double pane windows w/ plexi glass shield R-1.5 R-5
Doors Steel doors w/ non-thermally broken frames R-1.5 R-5
Heating System
The building is heated by two fuel oil boilers that provide heat to five air handling unit systems, fan
coil units, and perimeter hydronic systems. The heating system has the following pumps:
P-1A & P-1B are heating supply pumps.
P-2 is the boiler header circulation pump.
P-3 is the primary domestic hot water circulation pump.
P-4 is the glycol pump.
HWMP-1 is the domestic hot water boiler loop circulation pump for area E.
HWMRP-1 is the domestic hot water circulation pump for area E.
HWMP-2 is the domestic hot water boiler loop circulation pump for area D.
HWMRP-2 is the domestic hot water circulation pump for area D.
HWMP-3 is the domestic hot water boiler loop circulation pump for area C.
HWMRP-3 is the domestic hot water circulation pump for area C.
HWMP-4 is the domestic hot water boiler loop circulation pump for area B.
HWMRP-4 is the domestic hot water circulation pump for area B.
HWMP-5 is the domestic hot water boiler loop circulation pump for area A.
HWMRP-5 is the domestic hot water circulation pump for area A.
Riverbend Elementary School 14 Energy Audit (November 2011)
Ventilation Systems
Area Fan System Description
Mechanical SF-1 2,000 cfm ½ hp constant volume air handling unit consisting of an outside air
damper and supply fan
Gym SF-2 12,540 cfm 10 hp constant volume air handling unit consisting of a heating coil,
mixing box, filter section, and supply fan
Area E SF-3 11,775 cfm 15 hp constant volume air handling unit consisting of a mixing box,
filter section ,supply fan, hot deck with heating coil, and cold deck
Area D SF-4 12,090 cfm 15 hp constant volume air handling unit consisting of a mixing box,
filter section ,supply fan, hot deck with heating coil, and cold deck
Area C SF-5 11,570 cfm 15 hp constant volume air handling unit consisting of a mixing box,
filter section , primary heating coil, supply fan, hot deck with heating coil, and cold
deck
Area B SF-6 11,275 cfm 15 hp constant volume air handling unit consisting of a mixing box,
filter section , primary heating coil, supply fan, hot deck with heating coil, and cold
deck
Area A SF-7 11,570 cfm 15 hp constant volume air handling unit consisting of a mixing box,
filter section , primary heating coil, supply fan, hot deck with heating coil, and cold
deck
Area E RF-3 8,615 cfm 5 hp constant volume fan supplying return air to SF-3
Area D RF-4 9,535 cfm 5 hp constant volume fan supplying return air to SF-3
Area C RF-5 9,940 cfm 7 1/2 hp constant volume fan supplying return air to SF-3
Area B RF-6 9,970 cfm 5 hp constant volume fan supplying return air to SF-3
Area A RF-7 9,940 cfm 7 1/2 hp constant volume fan supplying return air to SF-3
Area E EF-3 2,595 cfm 1 ½ hp constant volume exhaust air fan
Area D EF-4 1,030 cfm ½ hp constant volume exhaust air fan
Area C EF-5 590 cfm constant volume exhaust air fan
Area B EF-6 590 cfm constant volume exhaust air fan
Area A EF-7 590 cfm constant volume exhaust air fan
Domestic Hot Water System
A direct hot water heater system consisting of one 51-gallon Vanguard 4500-watt direct hot water
heater that is used to serve Area E when the boilers are off, and five Amtrol 41-gallon indirect hot
water heaters – one located above each wing of the building.
Automatic Control System
The building has a DDC system to control the operation of the heating and ventilation systems.
Energy can be saved through further optimization of fan system scheduling combined with a retro-
commissioning of the air handler systems.
Riverbend Elementary School 15 Energy Audit (November 2011)
Lighting
Interior lighting consists primarily of T8 fluorescent fixtures. Exterior lighting consists primarily of
metal halide lighting. Because lighting operational hours are controlled by staff, operational costs for
lighting with existing infrastructure are kept to a minimum. Replacement of existing exterior metal
halide fixtures with more efficient units would save energy and labor; however, a life cycle analysis
showed the upgrade is not cost-effective.
Electric Equipment
Commercial equipment for food preparation was located in the kitchen and surrounding spaces.
Riverbend Elementary School 16 Energy Audit (November 2011)
Section 5
Methodology
Information for the energy audit was gathered through on-site observations, review of construction
documents, and interviews with operation and maintenance personnel. The EEMs are evaluated using
energy and life cycle cost analyses and are priority ranked for implementation.
Energy Efficiency Measures
Energy efficiency measures are identified by evaluating the building’s energy systems and comparing
them to systems in modern, high performance buildings. The process for identifying the EEMs
acknowledges the realities of an existing building that was constructed when energy costs were much
lower. Many of the opportunities used in modern high performance buildings—highly insulated
envelopes, variable capacity mechanical systems, heat pumps, daylighting, lighting controls, etc.—
simply cannot be economically incorporated into an existing building.
The EEMs represent practical measures to improve the energy efficiency of the buildings, taking into
account the realities of limited budgets. If a future major renovation project occurs, additional EEMs
common to high performance buildings should be incorporated.
Life Cycle Cost Analysis
The EEMs are evaluated using life cycle cost analysis which determines if an energy efficiency
investment will provide a savings over a 25-year life. The analysis incorporates construction,
replacement, maintenance, repair, and energy costs to determine the total cost over the life of the
EEM. Future maintenance and energy cash flows are discounted to present worth using escalation
factors for general inflation, energy inflation, and the value of money. The methodology is based on
the National Institute of Standards and Technology (NIST) Handbook 135 – Life Cycle Cost
Analysis.
Life cycle cost analysis is preferred to simple payback for facilities that have long—often perpetual—
service lives. Simple payback, which compares construction cost and present energy cost, is
reasonable for short time periods of 2-4 years, but yields below optimal results over longer periods
because it does not properly account for the time value of money or inflationary effects on operating
budgets. Accounting for energy inflation and the time value of money properly sums the true cost of
facility ownership and seeks to minimize the life cycle cost.
Construction Costs
The cost estimates are derived based on a preliminary understanding of the scope of each EEM as
gathered during the walk-through audit. The construction costs for in-house labor are $60 per hour for
work typically performed by maintenance staff and $110 per hour for contract labor.
The cost estimate assumes the work will be performed as part of a larger renovation or energy
efficiency upgrade project. When implementing EEMs, the cost estimate should be revisited once the
scope and preferred method of performing the work has been determined. It is possible some EEMs
will not provide a life cycle savings when the scope is finalized.
Riverbend Elementary School 17 Energy Audit (November 2011)
Maintenance Costs
Maintenance costs are based on in-house or contract labor using historical maintenance efforts and
industry standards. Maintenance costs over the 25-year life of each EEM are included in the life cycle
cost calculation spreadsheets and represent the level of effort to maintain the systems.
Energy Analysis
The energy performance of an EEM is evaluated within the operating parameters of the building. A
comprehensive energy audit would rely on a computer model of the building to integrate building
energy systems and evaluate the energy savings of each EEM. This investment grade audit does not
utilize a computer model, so energy savings are calculated with factors that account for the dynamic
operation of the building. Energy savings and costs are estimated for the 25-year life of the EEM
using appropriate factors for energy inflation.
Prioritization
Each EEM is prioritized based on the life cycle savings to investment ratio (SIR) using the following
formula:
Prioritization Factor = Life Cycle Savings / Capital Costs
This approach factor puts significant weight on the capital cost of an EEM, making lower cost EEMs
more favorable.
Economic Factors
The following economic factors are significant to the findings.
Nominal Interest Rate: This is the nominal rate of return on an investment without regard to inflation.
The analysis uses a rate of 5%.
Inflation Rate: This is the average inflationary change in prices over time. The analysis uses an
inflation rate of 2%.
Economic Period: The analysis is based on a 25-year economic period with construction beginning in
2010.
Fuel Oil
Fuel oil currently costs $3.80 per gallon for a seasonally adjusted blend of #1 and #2 fuel oils. The
analysis is based on 6% fuel oil inflation which has been the average for the past 20 years.
Riverbend Elementary School 18 Energy Audit (November 2011)
Electricity
Electricity is supplied by Alaska Electric Light & Power Company (AEL&P). The building is billed
for electricity under AEL&P’s Rate 24. This rate charges for both electrical consumption (kWh) and
peak electric demand (kW). Electrical consumption is the amount of energy consumed and electric
demand is the rate of consumption. AEL&P determines the electric demand by averaging demand
over a continuously sliding fifteen minute window. The highest fifteen minute average during the
billing period determines the peak demand. The following table lists the electric charges, which
includes a 24% rate hike that was recently approved:
AEL&P Small Government Rate with Demand
Charge 1 On-peak (Nov-May) Off-peak (June-Oct)
Energy Charge per kWh 6.11¢ 5.92¢
Demand Charge per kW $14.30 $9.11
Service Charge per month $99.24 $99.24
Over recent history, electricity inflation has been less than 1% per year, which has lagged general
inflation. An exception is the recent 24% rate hike that was primarily due to construction of additional
hydroelectric generation at Lake Dorothy. This project affords the community a surplus of power
which should bring electric inflation back to the historic rate of 1% per year. Load growth from
electric heat conversions is likely to increase generating and distribution costs, especially if diesel
supplementation is needed. Combining these two factors contribute to an assumed electricity inflation
rate of 3%.
Summary
The following table summarizes the energy and economic factors used in the analysis.
Summary of Economic and Energy Factors
Factor Rate or Cost Factor Rate or Cost
Nominal Discount Rate 5% Electricity $0.113/kWh
General Inflation Rate 2% Electricity Inflation 3%
Fuel Oil Cost (2012) $3.80/gal Fuel Oil Inflation 6%
Riverbend Elementary School 19 Energy Audit (November 2011)
Appendix A
Energy and Life Cycle Cost Analysis
Riverbend Elementary School 20 Energy Audit (November 2011)
Alaska Energy Engineering LLC Energy and Life Cycle Cost Analysis
25200 Amalga Harbor Road Tel/Fax: 907.789.1226
Juneau, Alaska 99801 jim@alaskaenergy.us
Riverbend Elementary School
Basis
Economic
Study Period (years) 25 Nominal Discount Rate 5%General Inflation 2%
Energy
2011 $/gal Fuel Inflation 2012 $/gal
Fuel Oil $3.52 6% $3.73
Electricity $/kWh (2011)$/kW (2011)Inflation $/kWh (2012)$/kW (2012)
w/ Demand Charges $0.061 $12.14 3% $0.063 $12.50
w/o Demand Charges $0.113 -3% $0.116 -
EEM-4: Install Pipe Insulation
Energy Analysis
Service Size Length Bare BTUH Insul BTUH Factor kBtu η boiler Gallons
Heating 2.50 6 154 15 100% -7,306 68%-78
-78
Life Cycle Cost Analysis Year Qty Unit Base Cost Year 0 Cost
Construction Costs
2-1/2"0 6 lnft $10 $60
Estimating contingency 0 15%$9
Project management 0 8%$6
Energy Costs
Fuel Oil 1 - 25 -78 gal $3.73 ($8,204)
Net Present Worth ($8,100)
EEM-5: Isolate Lag Boiler
Energy Analysis
Boiler Input MBH Loss %Loss MBH Hours, exist Hours, new kBtu η boiler Gallons
Lag 2,533 0.75% 19 3,600 1,800 -34,196 68%-363
GPH Head η pump BHP η motor kW Hours kWh
-125 16 60% -1.1 85% -1.0 3,600 -3,563
Life Cycle Cost Analysis Year Qty Unit Base Cost Year 0 Cost
Construction Costs
Change operating procedure 0 1 ea $500 $500
Annual Costs
Enable lag boiler in Nove,ber;Disable in March 1 - 25 2 hrs $60.00 $2,043
Energy Costs
Electric Energy 1 - 25 -3,563 kWh $0.063 ($4,400)
Fuel Oil 1 - 25 -363 gal $3.73 ($38,400)
Net Present Worth ($40,300)
Riverbend Elementary School 21 Energy Audit (November 2011)
Alaska Energy Engineering LLC Energy and Life Cycle Cost Analysis
25200 Amalga Harbor Road Tel/Fax: 907.789.1226
Juneau, Alaska 99801 jim@alaskaenergy.us
Riverbend Elementary School
EEM-6: Replace Aerators
Energy Analysis
Fixture Existing Proposed Uses/day Days Water,Gals % HW kBTU kWh
Lavatories 0.3 0.2 1,140 180 -36,936 80% -19,715 -5,778
-36,936 -5,778
Life Cycle Cost Analysis Year Qty Unit Base Cost Year 0 Cost
Construction Costs
Replace lavatory aerators 0 17 ea $35 $595
Energy Costs
Water 1 - 25 -37 kgals $10.960 ($7,958)
Electric Energy (Effective Cost)1 - 25 -5,778 kWh $0.116 ($13,220)
Net Present Worth ($20,600)
EEM-7: Seal Attic Vapor Retarder
Energy Analysis
Exhaust Air Savings
sqft height Volume Leakage, ACH CFM Winter CFM,winter
67,512 14 945,168 -0.5 -7,876 60% -4,726
Tave Trm Hours MBH kBtu Factor η boiler Gallons
40 62 6,480 -114 -741,087 60% 68% -4,721
Life Cycle Cost Analysis Year Qty Unit Base Cost Year 0 Cost
Construction Costs
Seal vapor retarder 0 200 hrs $60 $12,000
Materials 0 1 LS $1,000 $1,000
Estimating contingency 0 15%$1,950
Project management 0 8%$1,196
Energy Costs
Fuel Oil 1 - 25 -4,721 gal $3.73 ($499,321)
Net Present Worth ($483,200)
Gallons per Use
Riverbend Elementary School 22 Energy Audit (November 2011)
Alaska Energy Engineering LLC Energy and Life Cycle Cost Analysis
25200 Amalga Harbor Road Tel/Fax: 907.789.1226
Juneau, Alaska 99801 jim@alaskaenergy.us
Riverbend Elementary School
EEM-8: Optimize Ventilation Systems
Energy Analysis
Fan Case CFM ΔP η, fan BHP η, motor kW Hours kWh
SF-2 Existing -12,540 2.38 55%-9 91%-7 1,683 -11,754
Ventilation SA CFM MAT T,room MBH Hours kBtu η boiler Gallons
SF-3 Existing -11,775 62 70 -102 1,400 -142,430 68%-1,512
# Optimized 11,775 61 70 114 1,400 160,234 68%1,701
SF-4 Existing -12,090 58 70 -157 1,400 -219,361 68%-2,329
Optimized 12,090 65 70 65 1,400 91,400 68%970
SF-5 Existing -11,570 60 70 -125 1,400 -174,938 68%-1,857
# Optimized 11,570 65 70 62 1,400 87,469 68%929
SF-6 Existing -11,275 58 70 -146 1,400 -204,574 68%-2,172
# Optimized 11,275 65 70 61 1,400 85,239 68%905
SF-7 Existing -11,570 58 70 -150 1,400 -209,926 68%-2,229
Optimized 11,570 65 70 62 1,400 87,469 68%929
-439,417 -4,666
Life Cycle Cost Analysis Year Qty Unit Base Cost Year 0 Cost
Construction Costs
Optimize controls 0 6 ea $8,000 $48,000
Install VFD 0 1 LS $7,500 $7,500
Estimating contingency 0 15%$8,325
Overhead & profit 0 30% $19,148
Design fees 0 10%$8,297
Project management 0 8%$7,302
Annual Costs
DDC Maintenance 1 - 25 1 LS $1,000.00 $17,027
Energy Costs
Electric Energy 1 - 25 -11,754 kWh $0.063 ($14,518)
Fuel Oil 1 - 25 -4,666 gal $3.73 ($493,442)
Net Present Worth ($392,400)
Riverbend Elementary School 23 Energy Audit (November 2011)
Alaska Energy Engineering LLC Energy and Life Cycle Cost Analysis
25200 Amalga Harbor Road Tel/Fax: 907.789.1226
Juneau, Alaska 99801 jim@alaskaenergy.us
Riverbend Elementary School
EEM-9: Electrical Room Heat Recovery
Energy Analysis
Fuel Oil
Heat Gain
kW kVA η MBH Factor kBtu η boiler Gallons
-3 -10 40%-35,867 68% -381
-112.5 98.8% -5 40%-16,140 68% -171
-150 98.9% -6 40%-19,727 68% -209
-762
Electricity
Unit CFM ΔP η BHP kW Hours kWh
Fan 500 1 50% 0.16 0.12 6,000 704
Life Cycle Cost Analysis Year Qty Unit Base Cost Year 0 Cost
Construction Costs
Inline exhaust fan, 500 cfm 0 1 ea $2,500 $2,500
Inlet and supply grilles 0 4 ea $250 $1,000
Ductwork 0 1 ea $6,000 $6,000
Electrical and controls 0 1 ea $2,000 $2,000
Estimating contingency 0 15%$1,725
Overhead & profit 0 30%$3,968
Design fees 0 10%$1,719
Project management 0 8%$1,513
Annual Costs
Pump maintenance 1 - 25 1 LS $200.00 $3,405
Fan coil maintenance 1 - 25 1 LS $250.00 $4,257
Energy Costs
Electric Energy 1 - 25 704 kWh $0.063 $870
Electric Demand 1 - 25 1.06 kW $12.50 $260
Fuel Oil 1 - 25 -762 gal $3.73 ($80,553)
Net Present Worth ($51,300)
EEM-10: Install Modulating Burner Controls
Energy Analysis
Annual Gal % Savings Savings, Gal
27,826 -2.0% -557
Life Cycle Cost Analysis Year Qty Unit Base Cost Year 0 Cost
Construction Costs
Provide modulating burner control through the DDC system 0 3 LS $6,000 $18,000
Estimating contingency 0 15%$2,700
Overhead & profit 0 30%$6,210
Design fees 0 10%$2,691
Project management 0 8%$2,368
Energy Costs
Fuel Oil 1 - 25 -557 gal $3.73 ($58,857)
Net Present Worth ($26,900)
Riverbend Elementary School 24 Energy Audit (November 2011)
Alaska Energy Engineering LLC Energy and Life Cycle Cost Analysis
25200 Amalga Harbor Road Tel/Fax: 907.789.1226
Juneau, Alaska 99801 jim@alaskaenergy.us
Riverbend Elementary School
EEM-11: Replace Door Glazing
Energy Analysis
Component Area R,exist R,new ΔT MBH kBtu η boiler Gallons
Door 130 0.75 2.5 20 -2.4 -21,258 68%-226
-2.4 -21,258 -226
Life Cycle Cost Analysis Year Qty Unit Base Cost Year 0 Cost
Construction Costs
Replace door glazing unit 0 130 sqft $75 $9,750
Estimating contingency 0 5%$488
Overhead & profit 0 30%$3,071
Design fees 0 10%$1,331
Project management 0 8%$1,171
Energy Costs
Fuel Oil 1 - 25 -226 gal $3.73 ($23,871)
Net Present Worth ($8,100)
EEM-12: Replace Window Glazing
Energy Analysis
Component Area R,exist R,new ΔT MBH kBtu η boiler Gallons
Windows 90 0.75 2.5 20 -1.7 -14,717 68%-156
-1.7 -14,717 -156
Life Cycle Cost Analysis Year Qty Unit Base Cost Year 0 Cost
Construction Costs
Replace door glazing unit 0 90 sqft $75 $6,750
Estimating contingency 0 5%$338
Overhead & profit 0 30%$2,126
Design fees 0 10%$921
Project management 0 8%$811
Energy Costs
Fuel Oil 1 - 25 -156 gal $3.73 ($16,526)
Net Present Worth ($5,600)
Riverbend Elementary School 25 Energy Audit (November 2011)
Alaska Energy Engineering LLC Energy and Life Cycle Cost Analysis
25200 Amalga Harbor Road Tel/Fax: 907.789.1226
Juneau, Alaska 99801 jim@alaskaenergy.us
Riverbend Elementary School
EEM-13: Upgrade Gym Lighting
Energy Analysis
Lamp Lamp, watts Fixture Watts Lamp Lamp, watts Fixture Watts kW Hours kWh
MH 400 460 T5 310 357 -2.1 1,980 -4,099
Lamp Replacement
# Fixtures Lamp # Lamps Life, hrs Replace/yr $/lamp replace
20 MH -1 20,000 -1.98 $30
20 T5 6 30,000 1.32 $24
Life Cycle Cost Analysis Year Qty Unit Base Cost Year 0 Cost
Construction Costs
Replace 400 watt MH with T5 Fluorescent 0 20 LS $525 $10,500
Overhead & profit 0 30%$3,150
Design fees 0 10%$1,365
Project management 0 8%$1,201
Annual Costs
Existing lamp replacement, 400 watt MH 1 - 25 -1.98 replacements $60.00 ($2,023)
New lamp replacement, T5 1 - 25 1.32 replacements $54.00 $1,214
Energy Costs
Electric Energy 1 - 25 -4,099 kWh $0.063 ($5,062)
Electric Demand 1 - 25 -25 kW $12.50 ($6,106)
Net Present Worth $4,200
20
Existing Replacement
Fixtures
Savings
Riverbend Elementary School 26 Energy Audit (November 2011)
Alaska Energy Engineering LLC Energy and Life Cycle Cost Analysis
25200 Amalga Harbor Road Tel/Fax: 907.789.1226
Juneau, Alaska 99801 jim@alaskaenergy.us
Riverbend Elementary School
EEM-14: Upgrade Exterior Lighting
Energy Analysis
Type # Fixtures Lamp Lamp, watts Fixture Watts Lamp Lamp, watts Fixture Watts Savings, kWh
WallPak 36 MH 50 63 LED -35 -4,336
Cobra Head 15 HPS 250 295 LED -106 -12,417
-16,754
Lamp Replacement
Type # Fixtures Lamp # Lamps Life, hrs Lamps//yr $ / lamp $ / Replace
WallPak 36 MH -1 12,000 -13.14 $40 $60
Cobra Head 15 HPS -1 24,000 -2.74 $50 $100
WallPak 36 LED 1 60,000 2.63 $125 $60
Cobra Head 15 LED 1 60,000 1.10 $200 $100
Life Cycle Cost Analysis Year Qty Unit Base Cost Year 0 Cost
Construction Costs
Replace WallPak: 50 watt MH with LED 0 36 LS $625 $22,500
Replace Cobra Head: 250 watt HPS with LED 1 15 LS $900 $13,114
Estimating contingency 0 15%$3,375
Overhead & profit 0 30% $11,697
Design fees 0 10%$5,069
Project management 0 8%$4,460
Annual Costs
Existing lamp replacement, 70 watt MH 1 - 25 -13.14 lamps $100.00 ($22,374)
Existing lamp replacement, 250 watt HPS 1 - 25 -2.74 lamps $150.00 ($6,992)
LED board replacement, 40 watts 1 - 25 2.63 LED board $185.00 $8,278
LED board replacement, 106 watts 1 - 25 1.10 LED board $300.00 $5,593
Energy Costs
Electric Energy 1 - 25 -16,754 kWh $0.063 ($20,692)
Net Present Worth $24,000
Existing Replacement
Riverbend Elementary School 27 Energy Audit (November 2011)
Alaska Energy Engineering LLC Energy and Life Cycle Cost Analysis
25200 Amalga Harbor Road Tel/Fax: 907.789.1226
Juneau, Alaska 99801 jim@alaskaenergy.us
Riverbend Elementary School
EEM-15: Upgrade Motors to Premium Efficiency
Energy Analysis
Equip Number HP ηold ηnew kW Hours kWh
RF-3 1 5 88.5% 89.5% -0.04 1,980 -74
RF-5 1 7.5 88.5% 91.7% -0.18 1,980 -354
RF-7 1 7.5 85.5% 91.7% -0.35 1,980 -687
SF-2 1 10 89.5% 91.7% -0.16 1,980 -325
SF-3 1 15 90.2% 92.4% -0.25 1,980 -487
SF-4 1 15 90.2% 92.4% -0.25 1,980 -487
SF-5 1 15 90.2% 92.4% -0.25 1,980 -487
SF-6 1 15 90.2% 92.4% -0.25 1,980 -487
SF-7 1 15 90.2% 92.4% -0.25 1,980 -487
-2.0 -3,877
Life Cycle Cost Analysis Year Qty Unit Base Cost Year 0 Cost
Construction Costs HP
Replace motor 5 0 1 LS 1,290 $1,290
Replace motor 7.5 0 2 LS 1,690 $3,380
Replace motor 10 0 1 LS 1,790 $1,790
Replace motor 15 0 5 LS 2,660 $13,300
Energy Costs
Electric Energy 1 - 25 -3,877 kWh $0.063 ($4,789)
Electric Demand 1 - 25 -23 kW $12.50 ($5,776)
Net Present Worth $9,200
EEM-16: Increase Wall Insulation
Energy Analysis
Component Area R,exist R,new ΔT MBH kBtu η boiler Gallons
Wall 32,948 9 29 30 -75.7 -663,505 68%-7,045
Life Cycle Cost Analysis Year Qty Unit Base Cost Year 0 Cost
Construction Costs
Install wall insulation 0 32,948 sqft $38 $1,252,024
Estimating contingency 0 15% $187,804
Overhead & profit 0 30% $431,948
Design fees 0 10% $187,178
Project management 0 8% $164,716
Energy Costs
Fuel Oil 1 - 25 -7,045 gal $3.42 ($683,696)
Net Present Worth $1,540,000
Riverbend Elementary School 28 Energy Audit (November 2011)
Appendix B
Energy and Utility Data
Riverbend Elementary School 29 Energy Audit (November 2011)
Alaska Energy Engineering LLC Billing Data
25200 Amalga Harbor Road Tel/Fax: 907-789-1226
Juneau, Alaska 99801 jim@alaskaenergy.us
Riverbend Elementary School
ELECTRIC RATE
Electricity ($ / kWh )0.0611 0.0592
Demand ( $ / kW )14.30 9.11
Customer Charge ( $ / mo )99.24 99.24
Sales Tax ( % )0.0% 0.0%
ELECTRICAL CONSUMPTION AND DEMAND
kWh kW kWh kW kWh kW kWh kW
Jan 61,090 184.8 45,630 186.4 49,020 181.8 47,920 188.9 50,915
Feb 61,550 179.4 53,760 186.6 49,490 181.0 48,990 193.0 53,448
Mar 60,680 179.4 45,090 185.4 50,910 186.0 49,860 188.0 51,635
Apr 52,620 177.0 47,380 183.2 44,000 187.8 45,810 186.4 47,453
May 55,270 176.4 38,310 159.7 42,550 186.1 45,520 186.7 45,413
Jun 32,250 172.9 24,060 153.1 37,600 183.4 32,250 177.5 31,540
Jul 24,680 77.5 22,320 132.1 34,000 160.3 30,300 158.4 27,825
Aug 24,550 160.0 25,120 110.1 30,180 141.0 37,100 157.6 29,238
Sep 44,950 175.6 36,840 176.9 41,550 183.4 46,000 188.1 42,335
Oct 48,560 184.6 45,810 181.8 46,800 186.1 46,890 187.1 47,015
Nov 53,060 193.7 46,040 185.7 49,610 184.1 48,090 188.5 49,200
Dec 54,130 191.8 48,120 184.8 52,890 201.6 55,280 188.5 52,605
Total 573,390 478,480 528,600 534,010 528,620
Average 47,783 171 39,873 169 44,050 180 44,501 182 44,052
Load Factor 38.3%32.4%33.5%33.4%176
ELECTRIC BILLING DETAILS
Month Energy Demand Cust & Tax Total Energy Demand Cust & Tax Total % Change
Jan $2,995 $2,600 $99 $5,694 $2,928 $2,701 $99 $5,728 0.6%
Feb $3,024 $2,588 $99 $5,711 $2,993 $2,760 $99 $5,852 2.5%
Mar $3,111 $2,660 $99 $5,870 $3,046 $2,688 $99 $5,834 -0.6%
Apr $2,688 $2,686 $99 $5,473 $2,799 $2,666 $99 $5,564 1.7%
May $2,600 $2,661 $99 $5,360 $2,781 $2,670 $99 $5,550 3.5%
Jun $2,297 $1,671 $99 $4,067 $1,970 $1,617 $99 $3,687 -9.4%
Jul $2,077 $1,460 $99 $3,637 $1,851 $1,443 $99 $3,394 -6.7%
Aug $1,844 $1,285 $99 $3,228 $2,267 $1,436 $99 $3,802 17.8%
Sep $2,539 $1,671 $99 $4,309 $2,811 $1,714 $99 $4,623 7.3%
Oct $2,859 $1,695 $99 $4,654 $2,865 $1,704 $99 $4,669 0.3%
Nov $3,031 $2,633 $99 $5,763 $2,938 $2,696 $99 $5,733 -0.5%
Dec $3,232 $2,883 $99 $6,214 $3,378 $2,696 $99 $6,172 -0.7%
Total $ 32,297 $ 26,492 $ 1,191 $ 59,980 $ 32,628 $ 26,790 $ 1,191 $ 60,609 1.0%
Average $ 2,691 $ 2,208 $ 99 $ 4,998 $ 2,719 $ 2,232 $ 99 $ 5,051 1.0%
Cost ($/kWh)$0.113 54% 44% 2% $0.113 0.0%
Electrical costs are based on the current electric rates.
2009 2010
2010
AEL&P Electric Rate 24 On-Peak
Nov-May
Off-peak
Jun-Oct
Month 2007 2008 2009 Average
Riverbend Elementary School 30 Energy Audit (November 2011)
Alaska Energy Engineering LLC Annual Electric Consumption
25200 Amalga Harbor Road Tel/Fax: 907-789-1226
Juneau, Alaska 99801 jim@alaskaenergy.us
Riverbend Elementary School
#DIV/0!
#DIV/0!
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0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecElectric Use (kWh)Month of the Year
Electric Use History
2007
2008
2009
2010
0.0
50.0
100.0
150.0
200.0
250.0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecElectric Demand (kW)Month of the Year
Electric Demand History
2007
2008
2009
2010
Riverbend Elementary School 31 Energy Audit (November 2011)
Alaska Energy Engineering LLC Electric Cost
25200 Amalga Harbor Road Tel/Fax: 907-789-1226
Juneau, Alaska 99801 jim@alaskaenergy.us
Riverbend Elementary School 2010
#DIV/0!
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$ 0
$ 1,000
$ 2,000
$ 3,000
$ 4,000
$ 5,000
$ 6,000
$ 7,000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecElectric Cost (USD)Month of the Year
Electric Cost Breakdown
2010
Electric Use (kWh) Costs
Electric Demand (kW) Costs
Customer Charge and Taxes
0.0
50.0
100.0
150.0
200.0
250.0
0
10,000
20,000
30,000
40,000
50,000
60,000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Electric Demand (kW)Electric Use (kWh)Month of the Year
Electric Use and Demand Comparison
2010
Electric Use
Electric Demand
Riverbend Elementary School 32 Energy Audit (November 2011)
Alaska Energy Engineering LLC Annual Fuel Oil Consumption
25200 Amalga Harbor Road Tel/Fax: 907-789-1226
Juneau, Alaska 99801 jim@alaskaenergy.us
Riverbend Elementary School
Year Fuel Oil Degree Days
2,007 27,622 9,282
2,008 29,058 9,093
2,009 26,931 9,284
2,010 27,488 9,013
5,000
6,000
7,000
8,000
9,000
10,000
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
2007 2008 2009 2010 Degree DaysGallons of Fuel OilYear
Annual Fuel Oil Use
Fuel Oil
Degree Days
Riverbend Elementary School 33 Energy Audit (November 2011)
Alaska Energy Engineering LLC Annual Water Consumption
25200 Amalga Harbor Road Tel/Fax: 907-789-1226
Juneau, Alaska 99801 jim@alaskaenergy.us
Riverbend Elementary School
Year Water
2,007 480,000
2,008 492,000
2,009 504,000
2,010 420,000
340,000
360,000
380,000
400,000
420,000
440,000
460,000
480,000
500,000
520,000
540,000
2007 2008 2009 2010Gallons of WaterYear
Annual Water Use
Riverbend Elementary School 34 Energy Audit (November 2011)
Alaska Energy Engineering LLC Billing Data
25200 Amalga Harbor Road Tel/Fax: 907-789-1226
Juneau, Alaska 99801 jim@alaskaenergy.us
Annual Energy Consumption and Cost
Energy Cost $/MMBtu Area ECI EUI
Fuel Oil $3.80 $39.20 67,512 $2.45 83
Electricity $0.113 $35.01
Source Cost
Electricity 528,620 kWh $60,000 1,800 32%
Fuel Oil 27,826 Gallons $105,700 3,800 68%
Totals $165,700 5,600 100%
Annual Energy Consumption and Cost
Consumption Energy, MMBtu
$0
$5
$10
$15
$20
$25
$30
$35
$40
$45
Fuel Oil ElectricityCost $ / MMBtuCost of Heat Comparison
Riverbend Elementary School 35 Energy Audit (November 2011)
Appendix C
Equipment Data
Riverbend Elementary School 36 Energy Audit (November 2011)
MotorHP / Volts / RPM / EfficBoiler 1 Boiler Room Building HeatWeil-Mclain 988 2176 BTU/hr 480 V/ 3 PHModulation, Weishaupt BurnerBoiler 2 Boiler Room Building HeatWeil-Mclain 988 2176 BTU/hr 480 V/ 3 PHModulation, Weishaupt BurnerBoiler 3 Boiler Room Building HeatWeil-Mclain 988 2176 BTU/hr 480 V/ 3 PHModulation, Weishaupt BurnerHWMP 1 Area EDHW Boiler Circulation PumpTACO1/25 HP/ 120 V/ 1 PHHWMRP 1 Area E DHW Circulation Pump B+G0.8 A/ 120 VHWMAP 2 Area DDHW Boiler Circulation PumpTACO2176 BTU/hr 1/25 HP / 120 V/ 1 PHHWMRP 2 Area D DHW Circulation Pump B+G0.8 A/ 120 VHWMP 3 Area CDHW Boiler Circulation PumpTACO2176 BTU/hr 1/25 HP/ 120 V/ 1 PHHWMRP 3 Area C DHW Circulation Pump B+G0.8 A/ 120 VHWMP 4 Area BDHW Boiler Circulation PumpTACO2176 BTU/hr 1/25 HP/ 120 V/ 1 PHHWMRP 4 Area B DHW Circulation Pump Teel0.8 A/ 120 VHWMP 5 Area ADHW Boiler Circulation PumpTACO2176 BTU/hr 1/25HP / 120 V/ 1 PHHWMRP 5 Area A DHW Circulation Pump B+G1/8 HP/ 120 V/ 1720 RPMHW Tank Area E Electric Hot Water Tank Vanguard 3WA75 51 Gallon 208 V/ 3 PH4500 WP 1ABuilding HeatTACO 2508 250 GPM 7 1/2 HP/ 480 V/ 3 PH/ 91.7% 65' HeadP 1BBuilding HeatTACO 2508 250 GPM 7 1/2 HP/ 480 V/ 3 PH/ 91.7% 65' HeadP 2Boiler #1TACO 1632 125 GPM 3/4 HP/ 480 V/ 1720 RPM/ 82% 15' HeadP 3Boiler #2TACO 1632 125 GPM 3/4 HP/ 480 V/ 1720 RPM/ 82% 15' HeadRiverbend Elementary - Major Equipment InventoryCapacityNotesUnit ID Location Function Make Model
Riverbend Elementary School 37 Energy Audit (November 2011)
MotorHP / Volts / RPM / EfficRiverbend Elementary - Major Equipment InventoryCapacityNotesUnit ID Location Function Make ModelP 4Boiler #3TACO 1632 125 GPM 3/4 HP/ 480 V/ 1720 RPM/ 82% 15' HeadEDGGenerator RoomEmergency Generator ONAN 250 DFAC 250 KWHW Tank 1 Area E Area E DHWT Amtrol WH7C 41 Gallon Indirect HeatersHW Tank 2 Area D Area D DHW Amtrol WH7C 41 Gallon Indirect HeatersHW Tank 3 Area C Area C DHW Amtrol WH7C 41 Gallon Indirect HeatersHW Tank 4 Area B Area B DHW Amtrol WH7C 41 Gallon Indirect HeatersHW Tank 5 Area A Area A DHW Amtrol WH7C 41 Gallon Indirect HeatersSF 1 Mechanical PACE SCF-114 A 2000 CFM 1/2 HP/ 120 V/ 1 PH/ 78.5% 0.25" H2OSF 2 Gymnasium PACEPF-30 AFSWS112540 CFM 10 HP/ 480 V/ 1750 RPM/ 89.5% 2.375" H2OSF 3 Area E Supply Fan Area E PACEPF-30 AFSWS111775 CFM 15 HP/ 480 V/ 1750 RPM/ 90.2% 3.5" H2OSF 4 Area D Supply Fan Area D PACEPF-30 AFSWS112090 CFM 15 HP/ 480 V/ 1750 RPM/ 90.2% 3.25" H2OSF 5 Area C Supply Fan Area C PACEPF-30 AFSWS111570 CFM 15 HP/ 480 V/ 1750 RPM/ 90.2% 3.5" H2OSF 6 Area B Supply Fan Area B PACEPF-30 AFSWS111570 CFM 15 HP/ 480 V/ 1750 RPM/ 90.2% 3.5" H2OSF 7 Area A Supply Fan Area A PACEPF-30 AFSWS111570 CFM 15 HP/ 480 V/ 1750 RPM/ 90.2% 3.5" H2ORF 3 Area E Return Fan Area E PACE 8615 CFM 5 HP/ 480 V/ 1745 RPM/ 86.5% 2" H2ORF 4 Area D Return Fan Area D PACE 9535 CFM 5 HP/ 480 V/ 1745 RPM/ 88.5% 1.875" H2ORF 5 Area C Return Fan Area C PACE 9940 CFM 7 1/2 HP/ 480 V/ 1755 RPM/ 88.5% 1.875" H2ORF 6 Area B Return Fan Area B PACE 9970 CFM 5 HP/ 480 V/ 1745 RPM/ 88.5% 1.875" H2O
Riverbend Elementary School 38 Energy Audit (November 2011)
MotorHP / Volts / RPM / EfficRiverbend Elementary - Major Equipment InventoryCapacityNotesUnit ID Location Function Make ModelRF 7 Area A Return Fan Area A PACE9940 CFM 7 1/2 HP/ 480 V/ 1755 RPM/ 88.5% 1.875" H2OEF 3 Area E Exhaust Fan Area E Twin City2595 CFM 1 1/2 HP/ 208 V/ 3 PH/ 84% 3/4" H2OEF 4 Area D Exhaust Fan Area D Twin City1030 CFM 1/2 HP/ 208 V/ 3 PH3/4" H2OEF 5 Area C Exhaust Fan Area C Twin City590 CFM 1/3 HP/ 120 V/ 1 PH/ 77%1/2" H2OEF 6 Area B Exhaust Fan Area B Twin City590 CFM 1/2 HP/ 120 V/ 1 PH/ 78.5% 1/2" H2OEF 7 Area A Exhaust Fan Area A Twin City590 CFM 1/3 HP/ 120 V/ 1 PH/ 77%1/2" H2OT 1Transformer RoomTransformerSquare D 150T3HF 150 KVA 115 °C temperature riseNon TP RatedT 2Transformer RoomTransformerSquare D 112T3HP 112.5 KVA 115 °C temperature riseNon TP RatedRiverbend Elementary School 39 Energy Audit (November 2011)
Appendix D
Abbreviations
AHU Air handling unit
BTU British thermal unit
BTUH BTU per hour
CBJ City and Borough of Juneau
CMU Concrete masonry unit
CO2 Carbon dioxide
CUH Cabinet unit heater
DDC Direct digital controls
DHW Domestic hot water
EAD Exhaust air damper
EEM Energy efficiency measure
EF Exhaust fan
Gyp Bd Gypsum board
HVAC Heating, Ventilating, Air-
conditioning
HW Hot water
HWRP Hot water recirculating pump
KVA Kilovolt-amps
kW Kilowatt
kWh Kilowatt-hour
LED Light emitting diode
MBH 1,000 Btu per hour
MMBH 1,000,000 Btu per hour
OAD Outside air damper
PSI Per square inch
PSIG Per square inch gage
RAD Return air damper
RF Return fan
SIR Savings to investment ratio
SF Supply fan
UV Unit ventilator
VAV Variable air volume
VFD Variable frequency drive
Riverbend Elementary School 40 Energy Audit (November 2011)