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Finding Residential Energy Solutions through Energy Modeling A Case Study of Fort Belknap IHS Staff Quarters, Ft. Belknap MT Michael R. Young, P.E. Civil.

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Presentation on theme: "Finding Residential Energy Solutions through Energy Modeling A Case Study of Fort Belknap IHS Staff Quarters, Ft. Belknap MT Michael R. Young, P.E. Civil."— Presentation transcript:

1 Finding Residential Energy Solutions through Energy Modeling A Case Study of Fort Belknap IHS Staff Quarters, Ft. Belknap MT Michael R. Young, P.E. Civil Engineer Division of Engineering Services - Seattle Indian Health Service

2 Objectives To illustrate methods to achieve energy efficiency in low-rise residential buildings. To demonstrate most effective measures to save energy over the life cycle of the system. To help save money to the occupants.

3 Overview Federal Regulations Case Study: Fort Belknap, MT Results: Energy Consumption Annual Utility Bills Life Cycle Cost Analysis Recommendations: Design

4 Emerging Energy Regulations EPAct 2005 (Public Law 109-58) Federal Leadership in High Performance and Sustainable Buildings MOU EISA 2007 Executive Order 13423 Strengthening Federal Environmental, Energy, and Transportation Management 10 CFR 433, 434, 435 Executive Order 13514 Federal Leadership in Environmental, Energy, and Economic Performance

5 Requirements of 10 CFR 435 Meet ICC International Energy Conservation Code, 2004 Supplement Edition, and If Life-Cycle Cost-Effective, exceed the standard by 30% (Btu Consumption, not Cost) Space Heating Space Cooling Domestic Hot Water Heating If not LCC-effective, achieve maximum level of energy efficiency that is LCC-effective

6 Limitations in 10 CFR 435/IECC Neglects Lighting & Appliance Loads Simulated Performance: Must use same fuel type in baseline as design Heating Oil: 140,000 Btu/gal Propane: 91,800 Btu/gal Different Efficiencies Available in NG, Propane, & Heating Oil Furnaces

7 Evaluation of IHS Staff Quarters Simulated the energy performance for a 3- bedroom staff quarters unit at Fort Belknap Modified the design to meet the IECC Baseline (Standard Reference Design) Compared design to Baseline Simulated Design Alternatives to Seek 30% Improvement

8 Applicability throughout IHS Ft. Belknap – Climate Zone 6B Similar IECC Requirements also in Regions 7 & 8 Long Heating Season Short Cooling Season Dry Climate (Cold, Sunny Winter Days) Does not compare well with Marine Climates, the Southwest, Southeast, or East Coast

9 U.S. Climate Zones

10 Energy Costs Recent Post-Occupancy Evaluation (Southwest) Findings: Primary concern of Occupants: Energy Cost In some cases, monthly heating bills reached a significant percentage of the rental rate Questions regarding unit sizing, placement of heating registers, design & construction quality How does energy savings translate to cost savings?

11 Life Cycle Cost Analysis Examines energy cost savings versus first costs. 25-year analysis, comparing all proposed design modifications. Follows federal standards for LCCA OMB discount rates Calculates Savings-to-Investment Ratio Calculates Discounted Payback Period Evaluates Internal Rate of Return

12 Case Study Fort Belknap, MT 8952 Heating Degree Days 198 Cooling Degree Days

13 Case Study

14 1525 SF (Gross) 12,200 CF (Conditioned Space) Crawlspace Foundation (Conditioned), with ICF Walls Uninsulated Floor 2 x 6 Frame Walls with R-19 Cavity Insulation Windows: Aluminum Frame, Double-Paned, 10% of Conditioned Floor Area; (U = 0.46, SHGC = 0.45) Design of Ft. Belknap Unit (3 BR)

15 Doors: Steel, Urethane Core with Thermal Break (R = 4.4) Ceiling: R-49 Blanket Insulation Heating: Natural Gas Furnace, AFUE = 0.92 Air Conditioning: Conventional, SEER = 13 Hot Water: 50-gallon tank, NG heated Ducting: In conditioned crawlspace, return ducting in conditioned space, no insulation Infiltration: SLA = 0.00048 ft 2 /ft 2 Design of Ft. Belknap Unit (3 BR)

16 Results—Energy Consumption Using Conventional Furnace

17 Results—Energy Consumption Using Ground Source Heat Pump

18 Comparison of Heating/Cooling Systems

19 Evaluation of Energy Costs Prices Vary Significantly By Region Fort Belknap Block Charges – Electricity: $0.0955/kWh Natural Gas: $10.1187/MMBtu ($101.187/Therm)

20 Summary of Energy Costs Using Conventional Furnace Savings = $200-$400/year Not Addressed by 10 CFR 435 (~30%)

21 Lighting & Appliances Not addressed by 10 CFR 435 Constitutes ~25% of the total energy cost A 40% savings in L&A = 10% savings in total energy cost Energy Star Appliances: ~$75/yr savings (based on a $2000/yr energy budget)

22 Summary of Energy Costs Using Ground Source Heat Pump Savings = $400-$550/year

23 Furnace vs. Ground Source Heat Pump

24 Energy Savings vs. Life Cycle Cost Savings

25 Life Cycle Cost Analysis – Conventional Furnace First Costs 3 Bedroom Unit: $275,000 Vinyl Windows: $(1,600) Tankless Hot Water Heater: $1,700

26 Life Cycle Cost Analysis – Ground Source Heat Pump

27 Each has a point of diminishing returns Conventional Furnace System: Difficult to exceed 30% over IECC More pronounced for LCC Savings Vinyl Windows have a significant LCC benefit Remaining Iterations: Energy Savings essentially “offset” first costs Energy Savings vs. LCC Savings

28 LCCA – Conventional vs. GSHP Energy Savings does not translate equally to cost savings GSHP Swaps Natural Gas ($10/MMBtu) for Electricity ($28/MMBtu) Higher First Cost for a GSHP

29 Infiltration

30 Baseline Model: 39% of total Heating Load Final Model: 55% of total Heating Load Diminishing Returns

31 A Closer Look at Infiltration IECC Baseline (SLA=0.00048) 0.5 ACH (Structural Insulated Panels)Δ% Heating43.442.80.61.4% Cooling2. DHW16.2 00% Total62.361.60.71.1% A Comparison of Conventional Infiltration versus SIP Infiltration

32 Recommended Prescriptive Design Requirements: ParameterValue Basement TypeConditioned Crawl Space or Basement Foundation WallsInsulated Concrete Forms, R-44 or greater Above-Grade Walls2x6 wood frame with R-19 cavity insulation; Investigate Feasibility of SIPs Windows Vinyl Frame with Double-Pane (U=0.30 or below) Solar Heat Gain Coefficient = 0.60 or above DoorsSteel-urethane core with break (R=4.4 or greater) CeilingR-49 Continuous HeatingNatural Gas Furnace, AFUE=92% or greater Air ConditioningSEER=13 or greater Hot Water Heating Require tankless or solar as an option (emerging federal standards require that a minimum of 30% of hot water be heated with solar heat) Ducting In conditioned crawlspace, Return ducting in conditioned space, Insulation not necessary. InfiltrationTested in accordance with ASHRAE 119, Section 5.1.

33 What Can Users Do? Thermostat Settings Every °F = ~$30 savings/yr Turn off Lights Turn down heat or A/C while away Choose a smaller unit (if available) Solar Shading (summer) Solar Gains (winter)

34 Recap Federal Regulations Energy Savings in IHS Staff Quarters Computer Modeling of “Typical” Unit Best Measures for Saving Energy Impact on Utility Bills Life Cycle Cost Implications Recommended Design Modifications Energy Saving Practices (Occupants)

35 Conclusion Identify Greatest Energy Sinks Which Ones Can We Address? Regional Impacts Energy Studies will be posted on DES website (

36 Questions

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