Presentation on theme: "Finding Residential Energy Solutions through Energy Modeling"— Presentation transcript:
1Finding Residential Energy Solutions through Energy Modeling A Case Study of Fort Belknap IHS Staff Quarters, Ft. Belknap MTI have been studying residential energy modeling for some time nowFocus: Staff Quarters Energy Use (how to save energy & bills)I will be presenting a lot of numbers, which can be hard to communicate effectively-Engineers are known for not being the best communicatorsIntroverted Engineer vs. Extroverted EngineerMichael R. Young, P.E.Civil EngineerDivision of Engineering Services - SeattleIndian Health Service
2ObjectivesTo 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.Emphasis: to identify the most cost-effective ways to save energy in existing staff quarters
3Overview Federal Regulations Case Study: Fort Belknap, MT Results: Energy ConsumptionAnnual Utility BillsLife Cycle Cost AnalysisRecommendations: DesignHere is an overview of my presentation:
4Emerging Energy Regulations EPAct 2005 (Public Law )Federal Leadership in High Performance and Sustainable Buildings MOUEISA 2007Executive Order 13423Strengthening Federal Environmental, Energy, and Transportation Management10 CFR 433, 434, 435Executive Order 13514Federal Leadership in Environmental, Energy, and Economic PerformanceEPAct: 2% Reduction in energy consumption in federal buildings every year (20% improvement by 2015) + metering requirements + 30% over ASHRAE 90.1 in new buildingsMOU: Sustainability became a requirement (Green Buildings; “Guiding Principles”)EISA: Energy Independence and Security Act of 2007; more stringent energy performance goals: Fossil Fuel reduction to 55% by FY 2010, 100% by 2030EO 13423: Each agency must reduce energy consumption in federal 3% annually, or 30% by FY 2015CFR: Energy standards for Federal Residential Buildings (topic of this study)EO 13514: Net-zero energy by 2030.
5Requirements of 10 CFR 435Meet ICC International Energy Conservation Code, 2004 Supplement Edition, andIf Life-Cycle Cost-Effective, exceed the standard by 30% (Btu Consumption, not Cost)Space HeatingSpace CoolingDomestic Hot Water HeatingIf not LCC-effective, achieve maximum level of energy efficiency that is LCC-effective10 CFR 435 has the most specific application to staff quarters
6Limitations in 10 CFR 435/IECC Neglects Lighting & Appliance LoadsSimulated Performance: Must use same fuel type in baseline as designHeating Oil: 140,000 Btu/galPropane: 91,800 Btu/galDifferent Efficiencies Available in NG, Propane, & Heating Oil FurnacesL&A: ~25-30% of all energy consumed
7Evaluation of IHS Staff Quarters Simulated the energy performance for a 3-bedroom staff quarters unit at Fort BelknapModified the design to meet the IECC Baseline (Standard Reference Design)Compared design to BaselineSimulated Design Alternatives to Seek 30% ImprovementThe effort to comply with these regulations has led to this study.We chose Ft. Belknap because the design is complete, and current.
8Applicability throughout IHS Ft. Belknap – Climate Zone 6BSimilar IECC Requirements also in Regions 7 & 8Long Heating SeasonShort Cooling SeasonDry Climate (Cold, Sunny Winter Days)Does not compare well with Marine Climates, the Southwest, Southeast, or East CoastBefore I go on, first I need to point out the limited applicability nationwide:Heating Degree Days/Cooling Degree Hours for Ft. Belknap: 8952/4762Page: 4349/6405Phoenix: 1444/54404Ponca City: 4285/24265Seattle: 5122/1050
10Energy Costs Recent Post-Occupancy Evaluation (Southwest) Findings: Primary concern of Occupants: Energy CostIn some cases, monthly heating bills reached a significant percentage of the rental rateQuestions regarding unit sizing, placement of heating registers, design & construction qualityHow does energy savings translate to cost savings?Virtually nobody is happy about the utility bills they pay, so we have to take complaints with a grain of salt.However, there may be some real issues out there. For example, a recent POE showed-
11Life Cycle Cost Analysis Examines energy cost savings versus first costs.25-year analysis, comparing all proposed design modifications.Follows federal standards for LCCAOMB discount ratesCalculates Savings-to-Investment RatioCalculates Discounted Payback PeriodEvaluates Internal Rate of ReturnAnother aspect of this study is the LCC (condition given in the CFR)
12Case Study Fort Belknap, MT 8952 Heating Degree Days 198 Cooling Degree DaysHere is a quick background to our case study-
14Design of Ft. Belknap Unit (3 BR) 1525 SF (Gross)12,200 CF (Conditioned Space)Crawlspace Foundation (Conditioned), with ICF WallsUninsulated Floor2 x 6 Frame Walls with R-19 Cavity InsulationWindows: Aluminum Frame, Double-Paned, 10% of Conditioned Floor Area; (U = 0.46, SHGC = 0.45)Here are the relevant design features of our new staff quarters in Ft. Belknap(here is an actual photograph of our first unit at the final inspection)
15Design of Ft. Belknap Unit (3 BR) Doors: Steel, Urethane Core with Thermal Break (R = 4.4)Ceiling: R-49 Blanket InsulationHeating: Natural Gas Furnace, AFUE = 0.92Air Conditioning: Conventional, SEER = 13Hot Water: 50-gallon tank, NG heatedDucting: In conditioned crawlspace, return ducting in conditioned space, no insulationInfiltration: SLA = ft2/ft2SEER: Season Energy Efficiency Ratio
16Results—Energy Consumption Using Conventional Furnace After simulating the energy performance “as designed”, I modified it for design iterations:
17Results—Energy Consumption Using Ground Source Heat Pump Since there has been a lot of talk about ground source heat pumps lately, I ran the same simulations, only replacing the furnace with a GSHP.9 100’ deep (model default)Loop flow: 9 gpmCOP: 3.1EER: 14.5
18Comparison of Heating/Cooling Systems This graph incorporates all the design iterations using both heating systems
19Evaluation of Energy Costs Prices Vary Significantly By RegionFort Belknap Block Charges –Electricity: $0.0955/kWhNatural Gas: $ /MMBtu ($ /Therm)Next, we looked at the impacts of these design modifications to the energy costsBut first, a qualifier-
20Summary of Energy Costs Using Conventional Furnace Savings = $200-$400/yearNot Addressed by10 CFR 435 (~30%)
21Lighting & Appliances Not addressed by 10 CFR 435 Constitutes ~25% of the total energy costA 40% savings in L&A = 10% savings in total energy costEnergy Star Appliances: ~$75/yr savings (based on a $2000/yr energy budget)On the topic of lighting & appliances, this is something a facility manager can bring to the occupant
22Summary of Energy Costs Using Ground Source Heat Pump Next, I’d like to talk about the potential cost savings with these design iterations combined with a ground source heat pumpSavings = $400-$550/year
23Furnace vs. Ground Source Heat Pump So now, how does the GSHP compare to a furnace in terms of cost?Although you are using much less energy, you are also swapping a cheaper fuel (NG) for a more expensive fuel (electricity)NG: $10/MMBtuElectricity: $28/MMBtu
24Energy Savings vs. Life Cycle Cost Savings Now, let’s compare the progression of each model run in terms of:Energy reductionLife Cycle Cost Savings
25Life Cycle Cost Analysis – Conventional Furnace Costs used in this analysis:Design (Higher Eff. Furnace, Less Glazing, add’l insulation, etc.): $1690Replace Al with Vinyl: ($1600)Tankless Hot Water: $1700Double Insulation on Crawlspace Walls: $1000Remove Low-e Coating: ($200)Re-Orient Building: $0Exterior Shading: $800First Costs3 Bedroom Unit: $275,000Vinyl Windows: $(1,600)Tankless Hot Water Heater: $1,700
27Energy Savings vs. LCC Savings Each has a point of diminishing returnsConventional Furnace System: Difficult to exceed 30% over IECCMore pronounced for LCC SavingsVinyl Windows have a significant LCC benefitRemaining Iterations: Energy Savings essentially “offset” first costsNow, a quick discussion about this graph-
28LCCA – Conventional vs. GSHP Energy Savings does not translate equally to cost savingsGSHP Swaps Natural Gas ($10/MMBtu) for Electricity ($28/MMBtu)Higher First Cost for a GSHPNow, a quick discussion about the LCC comparison between furnaces and GSHPs-
29InfiltrationI’d like to bring up infiltration to this discussion, because the study did not address it.However, the model gives us some very startling results-
30Infiltration Baseline Model: 39% of total Heating Load Final Model: 55% of total Heating LoadDiminishing ReturnsHere’s another statistic-
31A Closer Look at Infiltration A Comparison of Conventional Infiltration versus SIP InfiltrationIECC Baseline(SLA= )0.5 ACH(Structural Insulated Panels)Δ%Heating43.4126.96.36.199%Cooling188.8.131.52.7%DHW16.20%Total62.3184.108.40.206%Oak Ridge National Laboratories conducted a study in which SIPs outperformed conventional stick-built construction by a factor of 15 to 1.
32Recommended Prescriptive Design Requirements: ParameterValueBasement TypeConditioned Crawl Space or BasementFoundation WallsInsulated Concrete Forms, R-44 or greaterAbove-Grade Walls2x6 wood frame with R-19 cavity insulation; Investigate Feasibility of SIPsWindowsVinyl Frame with Double-Pane (U=0.30 or below)Solar Heat Gain Coefficient = 0.60 or aboveDoorsSteel-urethane core with break (R=4.4 or greater)CeilingR-49 ContinuousHeatingNatural Gas Furnace, AFUE=92% or greaterAir ConditioningSEER=13 or greaterHot Water HeatingRequire tankless or solar as an option (emerging federal standards require that a minimum of 30% of hot water be heated with solar heat)DuctingIn conditioned crawlspace, Return ducting in conditioned space, Insulation not necessary.InfiltrationTested in accordance with ASHRAE 119, Section 5.1.The product of this analysis is the following table of recommended prescriptive design requirements.
33What Can Users Do? Thermostat Settings Turn off Lights Every °F = ~$30 savings/yrTurn off LightsTurn down heat or A/C while awayChoose a smaller unit (if available)Solar Shading (summer)Solar Gains (winter)
34Recap Federal Regulations Energy Savings in IHS Staff Quarters Computer Modeling of “Typical” UnitBest Measures for Saving EnergyImpact on Utility BillsLife Cycle Cost ImplicationsRecommended Design ModificationsEnergy Saving Practices (Occupants)
35Conclusion Identify Greatest Energy Sinks Which Ones Can We Address? Regional ImpactsEnergy Studies will be posted on DES website (www.des.ihs.gov)In conclusion, I hope you can take away more information to enable you to-