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Home My WebLink AboutTTW Cantwell School 2012-EEManaging Office 2400 College Road 3105 Lakeshore Dr. Suite 106A 4402 Thane Road Fairbanks, Alaska 99709 Anchorage, Alaska 99517 Juneau, Alaska 99801 p. 907.452.5688 p. 907.222.2445 p: 907.586.6813 f. 907.452.5694 f. 907.222.0915 f: 907.586.6819 www.nortechengr.com ENERGY AUDIT – FINAL REPORT CANTWELL SCHOOL 29 Main Street Cantwell, AK Prepared for: Mr. Justin Mason Denali Borough School District Prepared by: David C Lanning PE, CEA Douglas Dusek CEA Stephanie Young EIT, CEAIT July 23, 2012 Acknowledgment: “This material is based upon work supported by the Department of Energy under Award Number DE-EE0000095” ENVIRONMENTAL ENGINEERING, HEALTH & SAFETY Anch: 3105 Lakeshore Dr. Ste 106A, 99517 907.222.2445 Fax: 222.0915 Fairbanks: 2400 College Road, 99709 907.452.5688 Fax: 452.5694 Juneau: 4402 Thane Road, 99801 907.586.6813 Fax: 586.6819 info@nortechengr.com www.nortechengr.com F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx i TABLE OF CONTENTS 1.0 EXECUTIVE SUMMARY ................................................................................................. 1 2.0 INTRODUCTION ............................................................................................................. 4 2.1 Building Use ......................................................................................................... 4 2.2 Building Occupancy and Schedules ..................................................................... 4 2.3 Building Description ............................................................................................. 5 3.0 BENCHMARKING 2010 UTILITY DATA ......................................................................... 7 3.1 Total Energy Use and Cost of 2010 ..................................................................... 8 3.2 Energy Utilization Index of 2010 ........................................................................... 9 3.3 Cost Utilization Index of 2010............................................................................. 10 3.4 Seasonal Energy Use Patterns .......................................................................... 11 3.5 Future Energy Monitoring ................................................................................... 12 4.0 MODELING ENERGY CONSUMPTION ........................................................................ 13 4.1 Understanding How AkWarm Models Energy Consumption ............................... 14 4.2 AkWarm Calculated Savings for the Cantwell School ........................................ 15 4.3 Additional Modeling Methods ............................................................................. 16 5.0 BUILDING OPERATION AND MAINTENANCE (O & M) .............................................. 17 5.1 Operations and Maintenance ............................................................................. 17 5.2 Commissioning .................................................................................................. 17 5.3 Building Specific Recommendations .................................................................. 17 Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx ii APPENDICES Appendix A Recommended Energy Efficiency Measures .......................................... 19 Appendix B Energy Efficiency Measures that are NOT Recommended ..................... 26 Appendix C Significant Equipment List ...................................................................... 27 Appendix D Local Utility Rate Structure ..................................................................... 28 Appendix E Analysis Methodology ............................................................................ 30 Appendix F Audit Limitations ..................................................................................... 31 Appendix G References ............................................................................................. 32 Appendix H Typical Energy Use and Cost – Fairbanks and Anchorage ..................... 33 Appendix I Typical Energy Use and Cost – Continental U.S. ................................... 34 Appendix J List of Conversion Factors and Energy Units .......................................... 35 Appendix K List of Acronyms, Abbreviations, and Definitions .................................... 36 Appendix L Building Floor Plan ................................................................................. 37 Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 1 1.0 EXECUTIVE SUMMARY NORTECH has completed an ASHRAE Level II Energy Audit of the Cantwell School, a 14,660 square foot facility. The audit began with benchmarking which resulted in a calculation of the energy consumption per square foot. A site inspection was completed on December 21, 2011 to obtain information about the lighting, heating, ventilation, cooling and other building energy uses. The existing usage data and current systems were then used to develop a building energy consumption model using AkWarm. Once the model was calibrated, a number of Energy Efficiency Measures (EEMs) were developed from review of the data and observations. EEMs were evaluated and ranked on the basis of both energy savings and cost using a Savings/Investment Ratio (SIR). While these modeling techniques were successful in verifying that many of the EEMs would save energy, not all of the identified EEMs were considered cost effective based on the hardware, installation, and energy costs at the time of this audit. While the need for a major retrofit can typically be identified by an energy audit, upgrading specific systems often requires collecting additional data and engineering and design efforts that are beyond the scope of the Level II energy audit. The necessity and amount of design effort and cost will vary depending on the scope of the specific EEMs planned and the sophistication and capability of the entire design team, including the building owners and operators. During the budgeting process for any major retrofit identified in this report, the building owner should add administrative and supplemental design costs to cover the individual needs of their own organization and the overall retrofit project. The following table, from AkWarm, is a summary of the recommended EEMs for the Cantwell School. Additional discussion of the modeling process can be found in Section 3. Details of each individual EEM can be found in Appendix A of this report. A summary of EEMs that were evaluated but are not currently recommended is located in Appendix B. PRIORITY LIST – ENERGY EFFICIENCY MEASURES (EEMs) Rank Feature/ Location Improvement Description Estimated Annual Energy Savings Estimated Installed Cost Savings to Investment Ratio, SIR Simple Payback (Years) 1 Lighting: Exterior Wall Pack Replace with 7 LED 17W Module StdElectronic $613 $2,500 3.2 4.1 2 Lighting: De- lamping Replace T8 32W bulbs with T8 25W energy saver bulbs $180 $531 2.4 3.0 3 Setback Thermostat: School Implement a Heating Temperature Unoccupied Setback to 60.0 deg F for the School space. Install DDC. $5,251 $35,000 2.0 6.7 4 Ceiling w/ Attic: Ceiling W/ Attic Add R-33 blown cellulose insulation to attic with Standard Truss. $936 $13,560 1.6 15 5 Lighting: Street Light Replace with 2 LED 17W Module StdElectronic $175 $1,500 1.5 8.6 Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 2 PRIORITY LIST – ENERGY EFFICIENCY MEASURES (EEMs) Rank Feature/ Location Improvement Description Estimated Annual Energy Savings Estimated Installed Cost Savings to Investment Ratio, SIR Simple Payback (Years) 6 HVAC And DHW Replace boiler and furnaces with high efficiency models, vent damper. $7,648 $100,000 1.1 13 7 Above-Grade Walls and Windows Install R-30 rigid foam board to exterior and cover with T1-11 siding and Replace existing metal framed windows with Low E/argon fiberglass or insulated vinyl windows $6,739 $138,049 1.0 20 TOTAL, cost-effective measures $22,296 $291,140 1.4 13 Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 3 Modeled Building Energy Cost Breakdown The above charts are a graphical representation of the modeled energy usage for the Cantwell School. The greatest portions of energy cost for the building are envelope air losses and wall/door losses. This indicates that the greatest savings can be found by reducing the amount of outside air provided to the building mechanically or through air leakage, and upgrading the envelope. Detailed improvements for ventilation, air leakage, envelope and other cost effective measures can be found in Appendix A. The energy cost by end use breakdown was provided by AkWarm based on the field inspection and does not indicate that all individual fixtures and appliances were directly measured. The current energy costs are shown above on the left hand pie graph and the projected energy costs, assuming use of the recommended EEMs, are shown on the right. The chart breaks down energy usage by cost into the following categories: • Envelope Air Losses—the cost to provide heated fresh air to occupants, air leakage, heat lost in air through the chimneys and exhaust fans, heat lost to wind and other similar losses. • Envelope o Ceiling—quantified heat loss transferred through the ceiling portion of the envelope. o Window—quantified heat loss through the window portion of the envelope. o Wall/Door—quantified heat loss through the wall and door portions of the envelope. o Floor—quantified heat loss through the floor portion of the envelope. • Water Heating—energy cost to provide domestic hot water. • Fans—energy cost to run ventilation, and exhaust fans. • Lighting—energy cost to light the building. • Refrigeration—energy costs to provide refrigerated goods for the occupants. • Other Electrical—includes energy costs not listed above including cooking loads, laundry loads, other plug loads and electronics. Envelope Air Losses $9,745 15% Ceiling $3,898 6% Window $731 1% Wall/Door $3,411 5% Floor $4,385 7% Water Heating $5,643 9% Fans $22 0% Lighting $5,789 9% Refriger- ation $1,737 3% Other Electrical $5,011 8% EEM Savings $23,272 37% Retrofit Building Energy Cost Breakdown $41,587 Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 4 2.0 INTRODUCTION NORTECH contracted with the Alaska Housing Finance Corporation to perform ASHRAE Level II Energy Audits for publically owned buildings in Alaska. This report presents the findings of the utility benchmarking, modeling analysis, and the recommended building modifications, and building use changes that are expected to save energy and money. The report is organized into sections covering: • description of the facility, • the building’s historic energy usage (benchmarking), • estimating energy use through energy use modeling, • evaluation of potential energy efficiency or efficiency improvements, and • recommendations for energy efficiency with estimates of the costs and savings. 2.1 Building Use The building serves as the K-12 education facility for the Cantwell community. 2.2 Building Occupancy and Schedules Approximately 30 students and 10 staff members occupy the school Monday through Friday, from 7:00 am to 5:00 pm. The annual schedule is from mid-May through Mid-August with closure of the school during the summer Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 5 2.3 Building Description The building was originally constructed in 1955 and has undergone several remodels and additions: one in 1976, another in 1994 and a new roof in 2004. During the planning phase for the 1994 addition, demolishing the original building was considered but discarded due to community concerns. Plans for the school were unavailable before the audit; therefore construction types and dates are based on interviews with district personnel and field observations. The school is a single story structure with an on-grade slab foundation. There is a small mezzanine in the shop and a small upstairs ventilation room associated with the gym. Building Envelope Building Envelope: Walls Wall Type Description Insulation Notes Above-grade walls: Oldest Portion 2x4 wood framed walls R-11 fiberglass batts + 2-inches of rigid foam insulation Structure is aging therefore insulation damage is likely. Above-grade walls: Newer Portions 2x8 wood framed walls Estimated R-20 insulation Seem to be in good condition Building Envelope: Floors Floor Type Description Insulation Notes Floor Un-insulated slab None None Floor Perimeter Insulated CMU wall 1-inch spray foam No visible vapor barrier, no visible water damage Building Envelope: Roof Roof Type Description Insulation Notes Library Roof Cold roofs framed with wood trusses. R-30 Fiberglass batt insulation Major Icing issues, suspect ventilation failure Roofs Flat, built-up, hot roof 5-inches rigid foam insulation New as of 2004 Building Envelope: Doors and Windows Door and Window Type Description Estimated R-Value Notes All Man Doors 2-inch, commercial grade, insulated metal doors 4.2 some with half-lite windows Garage Door 2-inch, sectional metal door with insulated core 7 Aging but in good condition Old Windows Metal-framed, double and single- paned windows 1 Need replacement New Windows Insulated, vinyl-framed, double and triple paned windows 2.0 Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 6 Heating and Ventilation Systems Two large, identical furnaces provide heat and ventilation for the gym and library portions of the school. Heat to these areas is controlled by simple electric thermostats. These furnaces have outside air supplies, but the dampers have been manually closed due to declining enrollment. No outside air is currently provided. Two small furnaces supply the administrative area and hallways with heat. The same simple electric thermostats regulate heat in this area. No outside air supplies these furnaces. The one boiler has five zones that serve the classrooms and storage areas in the oldest section of the building. Heat is only circulated when one of the five non-programmable, electric thermostats calls for heat. No mechanized ventilation is provided in this portion of the building. Air Conditioning System No air conditioning system is installed in the building. Energy Management No energy management system is installed in the building. Lighting Systems The building is in the midst of a lighting upgrade. Once the upgrade is complete the lighting will consist of fluorescent, high-bay fixtures with T5 (5/8-inch, 4-foot) bulbs in the gym and ceiling- mounted fixtures with T8 (1-inch, 4-foot) bulbs in the rest of the building. An estimate of the savings for this upgrade is approximately $ 2,000 per year. Savings from completing the upgrade is not included in the total savings presented later in this report. Domestic Hot Water A single 120 gallon hot water heater serves the entire building. Hot water re-circulates 24 hours per day. Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 7 3.0 BENCHMARKING 2010 UTILITY DATA Benchmarking building energy use consists of obtaining and then analyzing two years of energy bills. The original utility bills are necessary to determine the raw usage, and charges as well as to evaluate the utility’s rate structure. The metered usage of electrical and natural gas consumption is measured monthly, but heating oil, propane, wood, and other energy sources are normally billed upon delivery and provide similar information. During benchmarking, information is compiled in a way that standardizes the units of energy and creates energy use and billing rate information statistics for the building on a square foot basis. The objectives of benchmarking are: • to understand patterns of use, • to understand building operational characteristics, • for comparison with other similar facilities in Alaska and across the country, and • to offer insight in to potential energy savings. The results of the benchmarking, including the energy use statistics and comparisons to other areas, are discussed in the following sections. Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 8 3.1 Total Energy Use and Cost of 2010 The energy use profiles below show the energy and cost breakdowns for the Cantwell School. The total annual energy use is 1,560 mmBTUs and the total cost for the building in 2010 is $44,636. These charts show the portion of use for a fuel type and the portion of its cost. The above charts indicate that the highest portion of energy use is for fuel oil and the highest portion of cost is for electricity. Fuel oil consumption correlates directly to space heating and domestic hot water while electrical use can correlate to lighting systems, plug loads, and HVAC equipment. The energy type with the highest cost often provides the most opportunity for savings. Electric 500 32% Oil 1,060 68% Energy Use Total (mmBTU) Electric 24,091 54% Oil 20,545 46% Energy Cost Total ($) Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 9 3.2 Energy Utilization Index of 2010 The primary benchmarking statistic is the Energy Utilization Index (EUI). The EUI is calculated from the utility bills and provides a simple snapshot of the quantity of energy actually used by the building on a square foot and annual basis. The calculation converts the total energy use for the year from all sources in the building, such as heating fuel and electrical usage, into British Thermal Units (BTUs). This total annual usage is then divided by the number of square feet of the building. The EUI units are BTUs per square foot per year. The benchmark analysis found that the Cantwell School has an EUI of 106,000 BTUs per square foot per year. The EUI is useful in comparing this building’s energy use to that of other similar buildings in Alaska and in the Continental United States. The EUI can be compared to average energy use in 2003 found in a study by the U.S. Energy Information Administration of commercial buildings (abbreviated CBECS, 2006). That report found an overall average energy use of about 90,000 BTUs per square foot per year while studying about 6,000 commercial buildings of all sizes, types, and uses that were located all over the Continental U.S. (see Table C3 in Appendix I). In a recent and unpublished state-wide benchmarking study sponsored by the Alaska Housing Finance Corporation, schools in Fairbanks averaged 62,000 BTUs per square foot and schools in Anchorage averaged 123,000 BTUs per square foot annual energy use. The chart below shows the Cantwell School relative to these values. These findings are discussed further in Appendix H. 102,000 62,000 123,000 0 20000 40000 60000 80000 100000 120000 140000 Btu/ Sq. Ft Annual Energy Use Index (Total Energy/ SF) Cantwell School Fairbanks Schools Anchorage Schools Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 10 3.3 Cost Utilization Index of 2010 Another benchmarking statistic that is useful is the Cost Utilization Index (CUI), which is the cost for energy used in the building on a square foot basis per year. The CUI is calculated from the cost for utilities for a year period. The CUI permits comparison of buildings on total energy cost even though they may be located in areas with differing energy costs and differing heating and/or cooling climates. The cost of energy, including heating oil, natural gas, and electricity, can vary greatly over time and geographic location and can be higher in Alaska than other parts of the country. The CUI for Cantwell School is about $3.04 per square foot per year. This is based on utility costs from 2010 and the following rates: Electricity at $ 0.17 / kWh ($ 4.98 / Therm) # 1 Fuel Oil at $ 2.74 / gallon ($ 1.96 / Therm) The Department of Energy Administration study, mentioned in the previous section (CBECS, 2006) found an average cost of $2.52 per square foot in 2003 for 4,400 buildings in the Continental U.S (Tables C4 and C13 of CBDES, 2006). Schools in Fairbanks have an average cost for energy of $2.42 per square foot while Anchorage schools average $2.11 per square foot. The chart below shows the Cantwell School relative to these values. More details are included in Appendix H. $3.04 $2.42 $2.11 $0.00 $0.50 $1.00 $1.50 $2.00 $2.50 $3.00 $3.50 Annual Energy Cost Index (Total Cost/ SF) Cantwell School Fairbanks Schools Anchorage Schools Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 11 3.4 Seasonal Energy Use Patterns Energy consumption is often highly correlated with seasonal climate and usage variations. The graphs below show the electric and fuel consumption of this building over the course of two years. The lowest monthly use is called the baseline use. The electric baseline often reflects year round lighting consumption while the heating fuel baseline often reflects year round hot water usage. The clear relation of increased energy usage during periods of cold weather can be seen in the months with higher usage. Fuel data was unavailable for the periods before July 2009 and after September 2010. 0 2000 4000 6000 8000 10000 12000 14000 16000 Apr-09Jun-09Aug-09Oct-09Dec-09Feb-10Apr-10Jun-10Aug-10Oct-10Dec-10Feb-11KWH Electrical Consumption 0 500 1,000 1,500 2,000 2,500 3,000 Apr-09Jun-09Aug-09Oct-09Dec-09Feb-10Apr-10Jun-10Aug-10Oct-10Dec-10Feb-11Gallons Fuel Oil Deliveries Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 12 3.5 Future Energy Monitoring Energy accounting is the process of tracking energy consumption and costs. It is important for the building owner or manager to monitor and record both the energy usage and cost each month. Comparing trends over time can assist in pinpointing major sources of energy usage and aid in finding effective energy efficiency measures. There are two basic methods of energy accounting: manual and automatic. Manual tracking of energy usage may already be performed by an administrative assistant: however if the records are not scrutinized for energy use, then the data is merely a financial accounting. Digital energy tracking systems can be installed. They display and record real-time energy usage and accumulated energy use and cost. There are several types which have all of the information accessible via Ethernet browser. Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 13 4.0 MODELING ENERGY CONSUMPTION After benchmarking of a building is complete and the site visit has identified the specific systems in the building, a number of different methods are available for quantifying the overall energy consumption and to model the energy use. These range from relatively simple spreadsheets to commercially available modeling software capable of handling complex building systems. NORTECH has used several of these programs and uses the worksheets and software that best matches the complexity of the building and specific energy use that is being evaluated. Modeling of an energy efficiency measure (EEM) requires an estimate of the current energy used by the specific feature, the estimated energy use of the proposed EEM and its installed cost. EEMs can range from a single simple upgrade, such as light bulb type or type of motor, to reprogramming of the controls on more complex systems. While the need for a major retrofit can typically be identified by an energy audit, the specific system upgrades often require collecting additional data and engineering and design efforts that are beyond the scope of the Level II energy audit. Based on the field inspection results and discussions with the building owners/operators, auditors developed potential EEMs for the facility. Common EEMs that could apply to almost every older building include: • Reduce the envelope heat losses through: o increased building insulation, and o better windows and doors • Reduce temperature difference between inside and outside using setback thermostats • Upgrade inefficient: o lights, o motors, o refrigeration units, and o other appliances • Reduce running time of lights/appliances through: o motion sensors, o on/off timers, o light sensors, and o other automatic/programmable systems The objective of the following sections is to describe how the overall energy use of the building was modeled and the potential for energy savings. The specific EEMs that provide these overall energy savings are detailed in Appendix A of this report. While the energy savings of an EEM is unlikely to change significantly over time, the cost savings of an EEM is highly dependent on the current energy price and can vary significantly over time. An EEM that is not currently recommended based on price may be more attractive at a later date or with higher energy prices. Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 14 4.1 Understanding How AkWarm Models Energy Consumption NORTECH used the AkWarm model for evaluating the overall energy consumption at Cantwell School. The AkWarm program was developed by the Alaska Housing Finance Corporation (AHFC) to model residential energy use. The original AkWarm is the modeling engine behind the successful residential energy upgrade program that AHFC has operated for a number of years. In the past few years, AHFC has developed a version of this model for commercial buildings. Energy use in buildings is modeled by calculating energy losses and consumption, such as: • Heat lost through the building envelope components, including windows, doors, walls, ceilings, crawlspaces, and foundations. These heat losses are computed for each component based on the area, heat resistance (R-value), and the difference between the inside temperature and the outside temperature. AkWarm has a library of temperature profiles for villages and cities in Alaska. • Window orientation, such as the fact that south facing windows can add heat in the winter but north-facing windows do not. • Inefficiencies of the heating system, including the imperfect conversion of fuel oil or natural gas due to heat loss in exhaust gases, incomplete combustion, excess air, etc. Some electricity is also consumed in moving the heat around a building through pumping. • Inefficiencies of the cooling system, if one exists, due to various imperfections in a mechanical system and the required energy to move the heat around. • Lighting requirements and inefficiencies in the conversion of electricity to light; ultimately all of the power used for lighting is converted to heat. While the heat may be useful in the winter, it often isn’t useful in the summer when cooling may be required to remove the excess heat. Lights are modeled by wattage and operational hours. • Use and inefficiencies in refrigeration, compressor cooling, and heat pumps. Some units are more efficient than others. Electricity is required to move the heat from inside a compartment to outside it. Again, this is a function of the R-Value and the temperature difference between the inside and outside of the unit. • Plug loads such as computers, printers, mini-fridges, microwaves, portable heaters, monitors, etc. These can be a significant part of the overall electricity consumption of the building, as well as contributing to heat production. • The schedule of operation for lights, plug loads, motors, etc. is a critical component of how much energy is used. AkWarm adds up these heat losses and the internal heat gains based on individual unit usage schedules. These estimated heat and electrical usages are compared to actual use on both a yearly and seasonal basis. If the AkWarm model is within 5 % to 10% of the most recent 12 months usage identified during benchmarking, the model is considered accurate enough to make predictions of energy savings for possible EEMs. Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 15 4.2 AkWarm Calculated Savings for the Cantwell School Based on the field inspection results and discussions with the building owners/operators, auditors developed potential EEMs for the facility. These EEMs are then entered into AkWarm to determine if the EEM saves energy and is cost effective (i.e. will pay for itself). AkWarm calculates the energy and money saved by each EEM and calculates the length of time for the savings in reduced energy consumption to pay for the installation of the EEM. AkWarm makes recommendations based on the Savings/Investment Ratio (SIR), which is defined as ratio of the savings generated over the life of the EEM divided by the installed cost. Higher SIR values are better and any SIR above one is considered acceptable. If the SIR of an EEM is below one, the energy savings will not pay for the cost of the EEM and the EEM is not recommended. Preferred EEMs are listed by AkWarm in order of the highest SIR. A summary of the savings from the recommended EEMs are listed in this table. Description Space Heating Water Heating Lighting Refrigeration Other Electrical Cooking Ventilation Fans Service Fees Total Cost Existing Building $45,145 $5,643 $6,085 $1,737 $3,005 $2,006 $22 $240 $63,883 With All Proposed Retrofits $23,933 $5,643 $5,001 $1,737 $3,005 $2,006 $22 $240 $41,587 Savings $21,211 $0 $1,085 $0 $0 $0 $0 $0 $22,296 Savings in these categories do not reflect interaction with other categories. So, for example, the savings in lighting does not affect the added space heating cost to make up for the heat saved in replacing less-efficient lights with more-efficient lights that waste less heat. Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 16 4.3 Additional Modeling Methods The AkWarm program effectively models wood-framed and other buildings with standard heating systems and relatively simple HVAC systems. AkWarm models of more complicated mechanical systems are sometimes poor due to a number of simplifying assumptions and limited input of some variables. Furthermore, AKWarm is unable to model complex HVAC systems such as variable frequency motors, variable air volume (VAV) systems, those with significant digital or pneumatic controls or significant heat recovery capacity. In addition, some other building methods and occupancies are outside AkWarm capabilities. This report section is included in order to identify benefits from modifications to those more complex systems or changes in occupant behavior that cannot be addressed in AkWarm. Then wood-framed Cantwell School could be modeled well in AKWarm. Retrofits for the HVAC system were adequately modeled in AkWarm and did not require additional calculations. The model and subsequent EEM savings were calculated based upon current 2012 utility and fuel prices of $0.21 per KWH and $4.50 per gallon of fuel oil. As the price of fuel and electricity increase the economy of the EEM also increases. Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 17 5.0 BUILDING OPERATION AND MAINTENANCE (O & M) 5.1 Operations and Maintenance A well-implemented operation and maintenance (O & M) plan is often the driving force behind energy savings. Such a plan includes preserving institutional knowledge, directing preventative maintenance, and scheduling regular inspections of each piece of HVAC equipment within the building. Routine maintenance includes the timely replacement of filters, belts and pulleys, the proper greasing of bearings and other details such as topping off the glycol tanks. Additional benefits to a maintenance plan are decreased down time for malfunctioning equipment, early indications of problems, prevention of exacerbated maintenance issues, and early detection of overloading/overheating issues. A good maintenance person knows the building’s equipment well enough to spot and repair minor malfunctions before they become major retrofits. Operations and Maintenance staff implementing a properly designed O & M plan will: • Track and document o Renovations and repairs, o Utility bills and fuel consumption, and o System performance. • Keep available for reference o A current Building Operating Plan including an inventory of installed systems, o The most recent available as-built drawings, o Reference manuals for all installed parts and systems, and o An up-to-date inventory of on-hand replacement parts. • Provide training and continuing education for maintenance personnel. • Plan for commissioning and re-commissioning at appropriate intervals. 5.2 Commissioning Commissioning of a building is the verification that the HVAC systems perform within the design or usage ranges of the Building Operating Plan. This process ideally, though seldom, occurs as the last phase in construction. HVAC system operation parameters degrade from ideal over time due to incorrect maintenance, improper replacement pumps, changes in facility tenants or usage, changes in schedules, and changes in energy costs or loads. Ideally, re-commissioning of a building should occur every five to ten years. This ensures that the HVAC system meets the potentially variable use with the most efficient means. 5.3 Building Specific Recommendations The Cantwell School is aging and subsequently requires more maintenance than a new school of its size. Special care should be taken to ensure that equipment is inspected regularly, and repairs are conducted immediately. In addition the following tests should be conducted: • A simple indoor air quality test for CO2 to determine if additional ventilation is required. • An infra-red camera photography, done during the winter to help determine if roof ventilation is adequately provided. Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 18 APPENDICES Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 19 Appendix A Recommended Energy Efficiency Measures A number of Energy Efficiency Measures (EEMs) are available to reduce the energy use and overall operating cost for the facility. The EEMs listed below are those recommended by AkWarm based on the calculated savings/investment ration (SIR) as described in Appendix E. AkWarm also provides a breakeven cost, which is the maximum initial cost of the EEM that will still return a SIR of one or greater. This section describes each recommended EEM and identifies the potential energy savings and installation costs. This also details the calculation of breakeven costs, simple payback, and the SIR for each recommendation. The recommended EEMs are grouped together generally by the overall end use that will be impacted. A.1 Temperature Control Programmable thermostats should be installed and programmed in the entire school. Programmable thermostats allow for automatic temperature setback, which reduce usage more reliably than manual setbacks. Reduction of the nighttime temperature set points will decrease the energy usage. Due to multiple retrofits the onsite maintenance person is unsure which of the existing thermostats work. The installation of a small Direct Digital Control (DDC) system will allow for easy management of energy usage and facility monitoring. Since ventilation is not currently provided and indoor air quality check should be performed to ensure that the school meets current ASHRAE standards. An indoor air quality check could provide knowledge about ventilation needs and CO2 demand-based controls could ensure that adequate air is being supplied. Another option is to replace the simple thermostats with programmable thermostats. This option is much less expensive, but it does not allow for automatic control of outside air dampers, or implementation of outside air temperature resets which are important ventilation and energy cost factors. Rank Building Space Recommendation 3 School Implement a Heating Temperature Unoccupied Setback to 60.0 deg F for the School space. Installation Cost $35,000 Estimated Life of Measure (yr.) 15 Energy Savings (/yr.) $5,251 Breakeven Cost $71,184 Savings-to-Investment Ratio 2.0 Simple Payback (yr.) 7 Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 20 A.2 Electrical Loads A.2.1 Lighting The electricity used by lighting eventually ends up as heat in the building. In areas where electricity is more expensive than other forms of energy, or in areas where the summer temperatures require cooling; this additional heat can be both wasteful and costly. Converting to more efficient lighting reduces cooling loads in the summer and allows the user to control heat input in the winter. The conversion from T12 (one and a half inch fluorescent bulbs) to T8 (one inch), T5 (5/8 inch), Compact Fluorescent Lights (CFL), or LED bulbs provides a significant increase in efficiency. LED bulbs can be directly placed in existing fixtures. The LED bulb bypasses the ballast altogether, which removes the often irritating, “buzzing” noise that magnetic ballasts tend to make. Rank Location Existing Condition Recommendation 1 Exterior Wall Pack 7 HPS 100 Watt StdElectronic with Manual Switching Replace with 7 LED 17W Module StdElectronic Installation Cost $2,500 Estimated Life of Measure (yr.) 17 Energy Savings (/yr.) $613 Breakeven Cost $7,940 Savings-to-Investment Ratio 3.2 Simple Payback (yr.) 4 Rank Location Existing Condition Recommendation 4 Street Light 2 HPS 100 Watt StdElectronic with Manual Switching Replace with 2 LED 17W Module StdElectronic Installation Cost $1,500 Estimated Life of Measure (yr.) 17 Energy Savings (/yr.) $175 Breakeven Cost $2,269 Savings-to-Investment Ratio 1.5 Simple Payback (yr.) 9 Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 21 The conversion to more efficient fluorescent T8 and T5 bulbs in progress should be completed immediately. Furthermore, some over lit areas could benefit from a lighting reduction through de-lamping or replacing the bulbs with 25-watt, T8 bulbs. Rank Location Existing Condition Recommendation 2 Janitorial Room, Girl's Bathroom, Boy's Bathroom, Janitor Office, Networking 6 INCAN A Lamp, Std 100W with Manual Switching Replace with 6 FLUOR CFL, Spiral 23 W Installation Cost $30 Estimated Life of Measure (yr.) 7 Energy Savings (/yr.) $10 Breakeven Cost $58 Savings-to-Investment Ratio 1.9 Simple Payback (yr.) 3 Rank Location Existing Condition Recommendation 2 Reading Room FLUOR (2) T12 4' F40T12 40W Standard Magnetic with Manual Switching Replace with FLUOR (2) T8 4' F32T8 25W Energy-Saver Instant StdElectronic Installation Cost $8 Estimated Life of Measure (yr.) 7 Energy Savings (/yr.) $23 Breakeven Cost $145 Savings-to-Investment Ratio 18 Simple Payback (yr.) 0 Rank Location Existing Condition Recommendation 2 Reading Room FLUOR (4) T8 4' F32T8 32W Standard (2) Instant StdElectronic with Manual Switching Replace with FLUOR (4) T8 4' F32T8 25W Energy-Saver (2) Instant StdElectronic Installation Cost $16 Estimated Life of Measure (yr.) 7 Energy Savings (/yr.) $11 Breakeven Cost $67 Savings-to-Investment Ratio 4.2 Simple Payback (yr.) 1 Rank Location Existing Condition Recommendation 2 Science Classroom 2 FLUOR (2) T8 4' F32T8 32W Standard Instant StdElectronic with Manual Switching Replace with 2 FLUOR (2) T8 4' F32T8 25W Energy-Saver Instant StdElectronic Installation Cost $16 Estimated Life of Measure (yr.) 7 Energy Savings (/yr.) $11 Breakeven Cost $67 Savings-to-Investment Ratio 4.2 Simple Payback (yr.) 1 Rank Location Existing Condition Recommendation 2 Special Ed FLUOR (2) T8 4' F32T8 32W Standard Instant StdElectronic with Manual Switching Replace with FLUOR (2) T8 4' F32T8 25W Energy-Saver Instant StdElectronic Installation Cost $8 Estimated Life of Measure (yr.) 7 Energy Savings (/yr.) $3 Breakeven Cost $15 Savings-to-Investment Ratio 1.9 Simple Payback (yr.) 3 Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 22 A.2.2 Other Electrical Loads Electrical loads at the Cantwell School are minimal and do not require retrofit. Rank Location Existing Condition Recommendation 2 Entry, Science Classroom 13 FLUOR (2) T8 4' F32T8 32W Standard Instant StdElectronic with Manual Switching Replace with 13 FLUOR (2) T8 4' F32T8 25W Energy-Saver Instant StdElectronic Installation Cost $104 Estimated Life of Measure (yr.) 7 Energy Savings (/yr.) $34 Breakeven Cost $195 Savings-to-Investment Ratio 1.9 Simple Payback (yr.) 3 Rank Location Existing Condition Recommendation 2 Laass Classroom, Main Hallway 22 FLUOR (2) T8 4' F32T8 32W Standard Instant StdElectronic with Manual Switching Replace with 22 FLUOR (2) T8 4' F32T8 25W Energy-Saver Instant StdElectronic Installation Cost $176 Estimated Life of Measure (yr.) 7 Energy Savings (/yr.) $57 Breakeven Cost $329 Savings-to-Investment Ratio 1.9 Simple Payback (yr.) 3 Rank Location Existing Condition Recommendation 2 Kitchen 5 FLUOR (2) T8 4' F32T8 32W Standard Instant StdElectronic with Manual Switching Replace with 5 FLUOR (2) T8 4' F32T8 25W Energy-Saver Instant StdElectronic Installation Cost $40 Estimated Life of Measure (yr.) 7 Energy Savings (/yr.) $8 Breakeven Cost $46 Savings-to-Investment Ratio 1.1 Simple Payback (yr.) 5 Rank Location Existing Condition Recommendation 2 Stairwell FLUOR (2) T12 4' F40T12 40W Standard Magnetic with Manual Switching Replace with FLUOR (2) T8 4' F32T8 25W Energy-Saver Instant StdElectronic Installation Cost $133 Estimated Life of Measure (yr.) 7 Energy Savings (/yr.) $23 Breakeven Cost $145 Savings-to-Investment Ratio 1.1 Simple Payback (yr.) 6 Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 23 A.3 Building Envelope: Recommendations for change A.3.1 Exterior Walls The existing walls have an R-value of 20 or lower. Adding R-30 rigid foam board to the exterior of the walls and replacing the siding in the old area of the school will significantly reduce heat loss through the walls. During this process the aluminum framed windows should be replaced with insulated vinyl windows with triple-panes. An infra-red camera investigation during cold weather would be needed in this design effort. Rank Location Existing Condition Recommendation 7 Above-Grade Wall: AG Wall 2 Wall Type: Single stud Siding Configuration: Just Siding Structural Wall: 2 x 8, 16 inches on center R-22 Batt: FG or RW, 7.5 inches Modeled R-Value: 19.8 Install R-30 rigid foam board to exterior and cover with T1-11 siding or equivalent. Installation Cost $37,861 Estimated Life of Measure (yr.) 30 Energy Savings (/yr.) $987 Breakeven Cost $23,376 Savings-to-Investment Ratio 0.6 Simple Payback (yr.) 38 Rank Location Existing Condition Recommendation 7 Above-Grade Wall: AG Wall 1 Wall Type: Single Stud Siding Configuration: Just Siding Structural Wall: 2 x 4, 16 inches on center R-11 Batt: FG or RW, 3.5 inches Modeled R-Value: 10.6 Install R-30 rigid foam board to exterior and cover with T1-11 siding or equivalent. Installation Cost $93,949 Estimated Life of Measure (yr.) 30 Energy Savings (/yr.) $6,201 Breakeven Cost $146,829 Savings-to-Investment Ratio 1.6 Simple Payback (yr.) 15 Rank Location Existing Condition Recommendation 7 Window/Skylight: Double Metal <3/8" Other Glass: Double, glass Frame: Aluminum, No Thermal Break Spacing Between Layers: Half Inch Modeled U-Value: 0.81 Solar Heat Gain Coefficient including Window Coverings: 0.46 Replace existing windows with Low E/argon fiberglass or insulated vinyl windows Installation Cost $4,287 Estimated Life of Measure (yr.) 20 Energy Savings (/yr.) $167 Breakeven Cost $2,909 Savings-to-Investment Ratio 0.7 Simple Payback (yr.) 26 Rank Location Existing Condition Recommendation 7 Window/Skylight: Single Metal Other Glass: Single, Glass Frame: Aluminum, No Thermal Break Spacing Between Layers: Half Inch Modeled U-Value: 1.30 Solar Heat Gain Coefficient including Window Coverings: 0.52 Replace existing windows with Low E/argon fiberglass or insulated vinyl windows Installation Cost $1,952 Estimated Life of Measure (yr.) 20 Energy Savings (/yr.) $137 Breakeven Cost $2,382 Savings-to-Investment Ratio 1.2 Simple Payback (yr.) 14 Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 24 A.3.2 Foundation and/or Crawlspace Adding insulation to the foundation is not economic at this time; however the benefits of adding insulation should be evaluated periodically. A.3.3 Roofing and Ceiling The roof over the library exhibits signs of an icing problem, indicating that proper ventilation to cool the roof is not available. Before the addition of cellulose insulation the existing insulation should be inspected and re-placed to ensure that the soffits are clear, to allow air flow. A.3.4 Windows See Exterior Walls Section A3.1. A.3.5 Doors The doors in the building are in good condition, replacing them is not economic at this time. Care should be taken to ensure that weather stripping is properly maintained. Rank Location Existing Condition Recommendation 4 Ceiling w/ Attic: Ceiling W/ Attic Framing Type: Standard Framing Spacing: 24 inches Insulated Sheathing: None Insulation Layer: R-30 Batt: FG or RW, 9.5 inches Insulation Quality: Damaged Modeled R-Value: 29.3 Add R-33 blown cellulose insulation to attic with Standard Truss. Installation Cost $13,560 Estimated Life of Measure (yr.) 30 Energy Savings (/yr.) $936 Breakeven Cost $22,166 Savings-to-Investment Ratio 1.6 Simple Payback (yr.) 14 Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 25 A.4 Building Heating System / Air Conditioning A.4.1 Heating and Heat Distribution Currently manufacturers can produce furnaces and boilers with very high efficiencies. The existing furnaces and boiler are old and inefficient. Replacing all of the units with the best available replacement is recommended. In addition, it may be possible to simplify the heating system and eliminate the two small furnaces by extending the distribution ducts of the large furnaces or by extending the baseboard system from the boiler. This option should be evaluated as reducing the number of units will decrease idle losses and eliminate stack losses. A.4.2 Air Conditioning No air conditioning system is installed in the building A.4.3 Ventilation Ventilation is provided through the furnace heating system. As the school enrollment has declined, the outside air dampers are kept closed during the winter. Changes to the existing ventilation seem unlikely to result in energy savings. A.4.4 Air Changes and Air Tightening No specific EEMs are recommended in this area, however the addition of rigid foam insulation to the exterior will provide an additional vapor barrier that could provide unexpected savings. Rank Recommendations 6 Replace boiler and furnaces with high efficiency models, install vent damper. Investigate combining system. Installation Cost $100,000 Estimated Life of Measure (yr.) 20 Energy Savings (/yr.) $7,648 Breakeven Cost $113,834 Savings-to-Investment Ratio 1.1 Simple Payback (yr.) 13 Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 26 Appendix B Energy Efficiency Measures that are NOT Recommended As indicated in other sections of the report, a number of potential EEMs were identified that were determined to be NOT cost effective by the AkWarm model. These EEMs are not currently recommended on the basis of energy savings alone because each may only save a small amount of energy, have a high capital cost, or be expensive to install. While each of these EEMs is not cost effective at this time, future changes in building use such as longer operating hours, higher energy prices, new fixtures or hardware on the market, and decreases in installation effort may make any of these EEMs cost effective in the future. These potential EEMs should be reviewed periodically to identify any changes to these factors that would warrant re-evaluation. Although these upgrades are not currently cost effective on an energy cost basis, the fixtures, hardware, controls, or operational changes described in these EEMs should be considered when replacing an existing fixture or unit for other reasons. For example, replacing an existing window with a triple-pane window may not be cost effective based only on energy use, but if a window is going to be replaced for some other reason, then the basis for a decision is only the incremental cost of upgrading from a less efficient replacement window to a more efficient replacement window. That incremental cost difference will have a significantly shorter payback, especially since the installation costs are likely to be the same for both units. The following measures were not found to be cost-effective: Rank Feature/Location Improvement Description Annual Energy Savings Installed Cost Savings to Investment Ratio, SIR Simple Payback (Years) 15 Window/Skylight: Double Metal <3/8" Other Replace existing windows with Low E/argon fiberglass or insulated vinyl windows $167 $4,287 0.68 26 16 Above-Grade Wall: AG Wall 2 Install R-30 rigid foam board to exterior and cover with T1- 11 siding or equivalent. $988 $37,861 0.62 38 17 Window/Skylight: Double Wad <3/8" Other Replace existing windows with Low E/argon fiberglass or insulated vinyl windows $495 $21,840 0.39 44 18 Cathedral Ceiling: Cathedral Ceiling Install R-10 rigid board insulation. No cost included for covering insulation. $1,066 $66,564 0.38 63 19 Window/Skylight: Double Wd - Vn <3/8" South Replace existing windows with Low E/argon fiberglass or insulated vinyl windows $367 $16,973 0.38 46 Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 27 Appendix C Significant Equipment List HVAC Equipment Equipment Manufacturer Model No. Fuel Type Estimated Efficiency Notes Boiler Weil McLain BL576SW #1 Fuel Oil 76% Old Pumps Grundfos UP 15-42F Electric --- Single Unit for boiler distribution Large Furnaces Jackson & Church 50F-15-02FHRM #1 Fuel Oil 72% Two identical units Small Furnace Armstrong LG14-252127V40-ZA #1 Fuel Oil 74% Single Unit Small Furnace Olson --- #1 Fuel Oil 74% Single Unit Lighting Location Lighting Type Bulb Type Quantity KWH/YR Cost/YR Classrooms Fluorescent T8 103 11,095 $ 2,552 Gym Fluorescent T5 20 7,831 1,801 Exterior High Pressure Sodium 100W 9 4,467 1,027 Storage Areas, Mechanical Rooms, Bathrooms Fluorescent T8 39 1,746 401 Shop Fluorescent T8 14 1,659 381 Hallways Fluorescent T8 6 711 163 Kitchen Fluorescent T8 5 296 68 Hallways LED 4W 2 192 44 Energy Consumption calculated by AkWarm based on wattage schedule, and a $ 0.23 per KWH electric rate. Plug Loads Equipment Location Manufacturer KWH/YR Cost/YR Refrigerators and Freezer Kitchen Varies 6,000 $ 1,380 Server Server Room Varies 3,506 806 Head bolt Heaters Outdoors --- 3,088 710 Kitchen Appliances Kitchen Varies 2,062 474 Refrigerated Vending Machine Main Hall Dixie Narco 2,000 460 Computers Classrooms & Offices Varies 1,956 450 Classroom Electronics Classrooms Varies 1,280 294 Shop Equipment Shop Varies 340 78 Energy Consumption calculated by AkWarm based on wattage schedule, and a $ 0.23 per KWH electric rate. Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 28 Appendix D Local Utility Rate Structure The information in this section was provided directly from the local utility or gathered from the local utility’s publicly available information at the time of the audit. All language used in this section was provided by the local utility and believed to be current at the time of the audit. Energy use terms, specific fees, and other specific information are subject to change. Updated rate structure information should be gathered from the utility during future discussion of rates, rate structures and utility pricing agreements. Golden Valley Electric Association Rate Structure: GS-1 General Service Effective Rates*** Customer Charge $20.00 Utility Charge $0.08923 / kWh $0.21450 / kWh ***The effective rate is all of the charges totaled together and divided by the kilowatt hour used. GVEA offers five different rates to its members, depending on the classification of the service provided. The rates are divided into two categories: Residential and General Service (GS). Eighty-five percent of the electric services on GVEA's system are single-family dwellings, classified under the Residential rate. The four General Service rates apply to small and large power users that do not qualify for the Residential rate. The General Service rates break down as follows: GS-1 General Service Services under 50 kilowatts (kW) of demand per billing cycle GS-2(S) Large General Service Secondary Services 50 kW and higher of demand per billing cycle GS-2(P) Large General Service Primary Services at primary voltage GS-3 Industrial Service Services at transmission voltage Customer Charge A flat fee that covers costs for meter reading, billing and customer service. Utility Charge (kWh charge) This charge is multiplied by the number of kilowatt-hours (kWh) used in a monthly billing period. It covers the costs to maintain power plants and substations, interest on loans as well as wires, power poles and transformers. Fuel and Purchased Power This charge is based on a combination of forecasted and actual power costs. The monthly charge allows Golden Valley to pass on increases and decreases in fuel and energy purchases to our members. It is calculated quarterly and multiplied by the kilowatt-hours used each month. Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 29 Regulatory Charge This charge of .000492 per kWh is set by the Regulatory Commission of Alaska (RCA). Since November 1, 1992, the Regulatory Commission of Alaska has been funded by a Regulatory Charge to the utilities it regulates rather than through the State general fund. The charge, labeled "Regulatory Cost Charge." on your bill, is set by the RCA, and applies to all retail kilowatt-hours sold by regulated electric utilities in Alaska. Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 30 Appendix E Analysis Methodology Data collected was processed using AkWarm energy use software to estimate current energy consumption by end usage and calculate energy savings for each of the proposed energy efficiency measures (EEMs). In addition, separate analysis may have been conducted to evaluate EEMs that AkWarm cannot effectively model to evaluate potential reductions in annual energy consumption. Analyses were conducted under the direct supervision of a Certified Energy Auditor, Certified Energy Manager, or a Professional Engineer. EEMs are evaluated based on building use, maintenance and processes, local climate conditions, building construction type, function, operational schedule and existing conditions. Energy savings are calculated based on industry standard methods and engineering estimations. Each model created in AkWarm is carefully compared to existing utility usage obtained from utility bills. The AkWarm analysis provides a number of tools for assessing the cost effectiveness of various improvement options. The primary assessment value used in this audit report is the Savings/Investment Ratio (SIR). The SIR is a method of cost analysis that compares the total cost savings through reduced energy consumption to the total cost of a project over its assumed lifespan, including both the construction cost and ongoing maintenance and operating costs. Other measurement methods include Simple Payback, which is defined as the length of time it takes for the savings to equal the total installed cost and Breakeven Cost, which is defined as the highest cost that would yield a Savings/Investment Ratio of one. EEMs are recommended by AkWarm in order of cost-effectiveness. AkWarm first calculates individual SIRs for each EEM, and then ranks the EEMs by SIR, with higher SIRs at the top of the list. An individual EEM must have a SIR greater than or equal to one in order to be recommended by AkWarm . Next AkWarm modifies the building model to include the installation of the first EEM and then re-simulates the energy use. Then the remaining EEMs are re- evaluated and ranked again. AkWarm goes through this iterative process until all suggested EEMs have been evaluated. Under this iterative review process, the savings for each recommended EEM is calculated based on the implementation of the other, more cost effective EEMs first. Therefore, the implementation of one EEM affects the savings of other EEMs that are recommended later. The savings from any one individual EEM may be relatively higher if the individual EEM is implemented without the other recommended EEMs. For example, implementing a reduced operating schedule for inefficient lighting may result in relatively higher savings than implementing the same reduced operating schedule for newly installed lighting that is more efficient. If multiple EEMs are recommended, AkWarm calculates a combined savings. Inclusion of recommendations for energy savings outside the capability of AkWarm will impact the actual savings from the AkWarm projections. This will almost certainly result in lower energy savings and monetary savings from AkWarm recommendations. The reality is that only so much energy is consumed in a building. Energy savings from one EEM reduces the amount of energy that can be saved from additional EEMs. For example, installation of a lower wattage light bulb does not save energy or money if the bulb is never turned on because of a schedule or operational change at the facility. Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 31 Appendix F Audit Limitations The results of this audit are dependent on the input data provided and can only act as an approximation. In some instances, several EEMs or installation methods may achieve the identified potential savings. Actual savings will depend on the EEM selected, the price of energy, and the final installation and implementation methodology. Competent tradesmen and professional engineers may be required to design, install, or otherwise implement some of the recommended EEMs. This document is an energy use audit report and is not intended as a final design document, operation, and maintenance manual, or to take the place of any document provided by a manufacturer or installer of any device described in this report. Cost savings are calculated based on estimated initial costs for each EEM. Estimated costs include labor and equipment for the full up-front investment required to implement the EEM. The listed installation costs within the report are conceptual budgetary estimates and should not be used as design estimates. The estimated costs are derived from Means Cost Data, industry publications, local contractors and equipment suppliers, and the professional judgment of the CEA writing the report and based on the conditions at the time of the audit. Cost and energy savings are approximations and are not guaranteed. Additional significant energy savings can usually be found with more detailed auditing techniques that include actual measurements of electrical use, temperatures in the building and HVAC ductwork, intake and exhaust temperatures, motor runtime and scheduling, and infrared, air leakage to name just a few. Implementation of these techniques is the difference between a Level III Energy Audit and the Level II Audit that has been conducted. Disclaimer: "This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof." Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 32 Appendix G References Although not all documents listed below are specifically referenced in this report, each contains information and insights considered valuable to most buildings. Alaska Department of Education and Early Development; Education Support Services/Facilities. (1999). Alaska School Facilities Preventative Maintenance Handbook. Juneau, AK: Alaska Department of Education and Early Development. Alaska Housing Finance Corportation. (2010). Retrofit Energy Assessment for Loans. AHFC. ASHRAE. (1997). 1997 ASHRAE Handbook: Fundamentals. Atlanta, GA: ASHRAE. ASHRAE. (2007). ASHRAE Standard 105-2007 Expressing and Comparing Building Energy Performance. Retrieved from ASHRAE: www.ashrae.org ASHRAE. (2007). ASHRAE Standard 90.1-2007 Energy Standards for buildings Except Low- Rise Residential Buildings. Retrieved from ASHRAE: www.ashrae.org ASHRAE. (2010). ASHRAE Standard 62.1-2010 Ventilaton for Acceptable Indoor Air Quality. Retrieved from ASHRAE: www.ashrae.org ASHRAE. (2010). ASHRAE Standard 62.2-2010 Ventilation and Acceptable Indoor Air Quality in Low Rise Residential Buildings. Retrieved from ASHRAE: www.ashrae.org ASHRAE RP-669 and SP-56. (2004). Procedures for Commercial Building Energy Audits. Atlanta, GA: ASHRAE. Coad, W. J. (1982). Energy Engineering and Management for Building Systems. Scarborough, Ontario, Canada: Van Nostrand Reinhold Company. Daley, D. T. (2008). The Little Black Book of Reliability Management. New York, NY: Industrial Press, Inc. Federal Energy Management Program. (2004, March 3). Demand Controlled Ventilation Using CO2 Sensors. Retrieved 2011, from US DOE Energy Efficiency and Renewable Energy: http://www.eere.energy.gov/femp/pdfs/fta_co2.pdf Federal Energy Management Program. (2006, April 26). Low-Energy Building Design Guidelines. Retrieved 2011, from Department of Energy; Federal Energy Management Program: http://www.eren.doe.gov/femp/ Institute, E. a. (2004). Variable Speed Pumping: A Guide to Successful Applications. Oxford, UK: Elsevier Advanced Technology. International Code Council. (2009). International Energy Conservation Code. Country Club Hills, IL: International Code Council, Inc. Leach, M., Lobato, C., Hirsch, A., Pless, S., & Torcellini, P. (2010, September). Technical Support Document: Strategies for 50% Energy Savings in Large Office Buildings. Retrieved 2011, from National Renewable Energy Laboratory: http://www.nrel.gov/docs/fy10osti/49213.pdf Thumann, P.E., C.E.M., A., Younger, C.E.M., W. J., & Niehus, P.E., C.E.M., T. (2010). Handbook of Energy Audits Eighth Edition. Lilburn, GA: The Fairmont Press, Inc. U.S. Energy Information Administration. (2006). Commercial Building Energy Consumption Survey (CBECS). Retrieved 2011, from Energy Information Administration: http://www.eia.gov/emeu/cbecs/ Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 33 Appendix H Typical Energy Use and Cost – Fairbanks and Anchorage This report provides data on typical energy costs and use on selected building in Fairbanks and Anchorage, Alaska for comparative purposes only. The values provided by the US Energy Information Administration CBECS study included a broader range of building types for the Continental U.S. are not necessarily good comparatives for buildings and conditions in Alaska. An assortment of values from CBECS may be found in Appendix I. The Alaska data described in this report came from a benchmarking study NORTECH and other Technical Services Providers (TSPs) completed on publicly owned buildings in Alaska under contract with AHFC. This study acquired actual utility data for municipal buildings and schools in Alaska for the two recent full years. The utility data included costs and quantities including fuel oil, electricity, propane, wood, steam, and all other energy source usage. This resulted in a database of approximately 900 buildings. During the course of the benchmarking study, the comparisons made to the CBECS data appeared to be inappropriate for various reasons. Therefore, this energy use audit report references the average energy use and energy cost of Anchorage and Fairbanks buildings as described below. The Alaska benchmarking data was evaluated in order to find valid comparison data. Buildings with major energy use information missing were eliminated from the data pool. After detailed scrutiny of the data, the most complete information was provided to NORTECH by the Fairbanks North Star Borough School District (FNSBSD) and the Anchorage School District (ASD). The data sets from these two sources included both the actual educational facilities as well as the district administrative buildings and these are grouped together in this report as Fairbanks and Anchorage schools. These two sources of information, being the most complete and reasonable in-state information, have been used to identify an average annual energy usage for Fairbanks and for Anchorage in order to provide a comparison for other facilities in Alaska. Several factors may limit the comparison of a specific facility to these regional indicators. In Fairbanks, the FNSBSD generally uses number two fuel oil for heating needs and electricity is provided by Golden Valley Electric Association (GVEA). GVEA produces electricity from a coal fired generation plant with additional oil generation upon demand. A few of the FNSBSD buildings in this selection utilize district steam and hot water. The FNSBSD has recently (the last ten years) invested significantly in envelope and other efficiency upgrades to reduce their operating costs. Therefore a reader should be aware that this selection of Fairbanks buildings has energy use at or below average for the entire Alaska benchmarking database. Heating in Anchorage is through natural gas from the nearby natural gas fields. Electricity is also provided using natural gas. As the source is nearby and the infrastructure for delivery is in place, energy costs are relatively low in the area. As a result, the ASD buildings have lower energy costs, but higher energy use, than the average for the entire benchmarking database. These special circumstances should be considered when comparing the typical annual energy use for particular buildings. Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 34 Appendix I Typical Energy Use and Cost – Continental U.S. Released: Dec 2006 Next CBECS will be conducted in 2007 Table C3. Consumption and Gross Energy Intensity for Sum of Major Fuels for Non-Mall Buildings, 2003 All Buildings* Sum of Major Fuel Consumption Number of Buildings (thousand) Floor space (million square feet) Floor space per Building (thousand square feet) Total (trillion BTU) per Building (million BTU) per Square Foot (thousand BTU) per Worker (million BTU) All Buildings* 4,645 64,783 13.9 5,820 1,253 89.8 79.9 Building Floor space (Square Feet) 1,001 to 5,000 2,552 6,789 2.7 672 263 98.9 67.6 5,001 to 10,000 889 6,585 7.4 516 580 78.3 68.7 10,001 to 25,000 738 11,535 15.6 776 1,052 67.3 72.0 25,001 to 50,000 241 8,668 35.9 673 2,790 77.6 75.8 50,001 to 100,000 129 9,057 70.4 759 5,901 83.8 90.0 100,001 to 200,000 65 9,064 138.8 934 14,300 103.0 80.3 200,001 to 500,000 25 7,176 289.0 725 29,189 101.0 105.3 Over 500,000 7 5,908 896.1 766 116,216 129.7 87.6 Principal Building Activity Education 386 9,874 25.6 820 2,125 83.1 65.7 Food Sales 226 1,255 5.6 251 1,110 199.7 175.2 Food Service 297 1,654 5.6 427 1,436 258.3 136.5 Health Care 129 3,163 24.6 594 4,612 187.7 94.0 Inpatient 8 1,905 241.4 475 60,152 249.2 127.7 Outpatient 121 1,258 10.4 119 985 94.6 45.8 Lodging 142 5,096 35.8 510 3,578 100.0 207.5 Retail (Other Than Mall) 443 4,317 9.7 319 720 73.9 92.1 Office 824 12,208 14.8 1,134 1,376 92.9 40.3 Public Assembly 277 3,939 14.2 370 1,338 93.9 154.5 Public Order and Safety 71 1,090 15.5 126 1,791 115.8 93.7 Religious Worship 370 3,754 10.1 163 440 43.5 95.6 Service 622 4,050 6.5 312 501 77.0 85.0 Warehouse and Storage 597 10,078 16.9 456 764 45.2 104.3 Other 79 1,738 21.9 286 3,600 164.4 157.1 Vacant 182 2,567 14.1 54 294 20.9 832.1 This report references the Commercial Buildings Energy Consumption Survey (CBECS), published by the U.S. Energy Information Administration in 2006. Initially this report was expected to compare the annual energy consumption of the building to average national energy usage as documented below. However, a direct comparison between one specific building and the groups of buildings outlined below yielded confusing results. Instead, this report uses a comparative analysis on Fairbanks and Anchorage data as described in Appendix F. An abbreviated excerpt from CBECS on commercial buildings in the Continental U.S. is below. Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 35 Appendix J List of Conversion Factors and Energy Units 1 British Thermal Unit is the energy required to raise one pound of water one degree F° 1 Watt is approximately 3.412 BTU/hr. 1 horsepower is approximately 2,544 BTU/hr. 1 horsepower is approximately 746 Watts 1 "ton of cooling” is approximately 12,000 BTU/hr., the amount of power required to melt one short ton of ice in 24 hours 1 Therm = 100,000 BTU 1 KBTU = 1,000 BTU 1 KWH = 3413 BTU 1 KW = 3413 BTU/Hr. 1 Boiler HP = 33,400 BTU/Hr. 1 Pound Steam = approximately 1000 BTU 1 CCF of natural gas = approximately 1 Therm 1 inch H2O = 250 Pascal (Pa) = 0.443 pounds/square inch (psi) 1 atmosphere (atm) = 10,1000 Pascal (Pa) BTU British Thermal Unit CCF 100 Cubic Feet CFM Cubic Feet per Minute GPM Gallons per minute HP Horsepower Hz Hertz kg Kilogram (1,000 grams) kV Kilovolt (1,000 volts) kVA Kilovolt-Amp kVAR Kilovolt-Amp Reactive KW Kilowatt (1,000 watts) KWH Kilowatt Hour V Volt W Watt Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 36 Appendix K List of Acronyms, Abbreviations, and Definitions ACH Air Changes per Hour AFUE Annual Fuel Utilization Efficiency Air Economizer A duct, damper, and automatic control system that allows a cooling system to supply outside air to reduce or eliminate the need for mechanical cooling. Ambient Temperature Average temperature of the surrounding air Ballast A device used with an electric discharge lamp to cause the lamp to start and operate under the proper circuit conditions of voltage, current, electrode heat, etc. CO2 Carbon Dioxide CUI Cost Utilization Index CDD Cooling Degree Days DDC Direct Digital Control EEM Energy Efficiency Measure EER Energy Efficient Ratio EUI Energy Utilization Index FLUOR Fluorescent Grade The finished ground level adjoining a building at the exterior walls HDD Heating Degree Days HVAC Heating, Ventilation, and Air-Conditioning INCAN Incandescent NPV Net Present Value R-value Thermal resistance measured in BTU/Hr.-SF-̊F (Higher value means better insulation) SCFM Standard Cubic Feet per Minute Savings to Investment Ratio (SIR) Savings over the life of the EEM divided by Investment capital cost. Savings includes the total discounted dollar savings considered over the life of the improvement. Investment in the SIR calculation includes the labor and materials required to install the measure. Set Point Target temperature that a control system operates the heating and cooling system Simple payback A cost analysis method whereby the investment cost of an EEM is divided by the first year’s savings of the EEM to give the number of years required to recover the cost of the investment. Energy Audit – Final Report Cantwell School Cantwell, Alaska F:\00-Jobs\2011\2602 F - AHFC Grade Audits\50-300 Doyon Other Region\50-360 Denali Borough SD\50-362 Cantwell School\Reports\Final\2012.07.12 Final AHFC Final Report TTW Cantwell School.Docx 37 Appendix L Building Floor Plan Floor plan drawn by NORTECH field team. North