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Home My WebLink AboutB11-0496 ENERGY CODE COMPLIANCE approvedStrata Vail Vail, Colorado IECC 2012 COMPLIANCE REPORT December 20, 2013 Prepared by: Group14 Engineering, Inc 1325 E. 16th Avenue Denver, CO 80218 (303) 861-2070 www.group14eng.com Received By Lynne Campbell at 11:03 am, Jan 13, 2014 B11-0701 Reviewed for Code Compliance Code: 2012 International Building Code (IBC) Contents 1 Introduction ........................................................................................................................................ 2 Project Summary ..................................................................................................................................... 2 2 Building Energy Models ...................................................................................................................... 3 2.1 Overview ...................................................................................................................................... 3 Utility Rates ............................................................................................................................................ 4 Climate .................................................................................................................................................... 4 2.2 CODE Baseline Model Description ............................................................................................... 5 2.3 Proposed Design Model Description ............................................................................................ 5 Appendix A: Modeling Inputs and Assumptions ......................................................................................... 7 Appendix B: Simulation Outputs ............................................................................................................... 10 1 Introduction This report documents IECC 2012 energy code compliance per section C401.2.1 using ASHRAE 90.1- 2010, section 11 Energy Cost Budget Method for Strata Vail, Vail, CO. The analysis includes heating, cooling and service water heating energy only to demonstrate code compliance. The project demonstrates the proposed design has annual energy costs less than or equal to the annual energy costs of the standard reference design (budget building design). Project Summary Strata Vail is a 310,818SF 10-story new construction multifamily building in Vail, Colorado. It has 78 residential condo units with an indoor swimming pool. TABLE 1: PROJECT DETAILS Location 705 W Lionshead Cir, Vail, CO 81657 Building Type Multifamily Conditioned Floor Area 310,818 SF (124,468SF parking garage) Unconditioned Floor Area N/A Above-Grade Stories 7 Below-Grade Stories 3 (parking garage) Electric Utility Holy Cross Energy Natural Gas Utility Xcel Energy Strata Vail 2 Building Energy Models 2.1 Overview The EQuest 3.6 interface for DOE-2.2 hourly building energy simulation program was used for the building energy analysis. The figures below are renderings from the eQuest model for the various building envelope geometries and zoning. The geometry is typically simplified for modeling purposes to accurately simulate energy transfer through all surfaces in the building. Windows on the same orientation and zone are often grouped together to decrease simulation time; this does not affect results of the model. The buildings were zoned for perimeter versus core spaces, and for differing space uses. FIGURE 1: EQUEST SKETCH OF ENERGY MODEL FIGURE 2: TYPICAL FLOOR THERMAL ZONING GROUP14 ENGINEERING, INC. Strata Vail Utility Rates Electricity and gas costs are based on Xcel Energy’s current rate information: Table 1: COMMERCIAL UTILITY RATES Electricity (Holy Cross Energy*) Customer Charge Per Month $12.5 Off-Peak Energy Charge per kWh $0.05583 On-Peak Energy Charge per kWh (1pm-9pm, Mon-Fri excluding holidays) $0.18250 *Electric rates used are those effective November 1, 2012. Natural Gas (Xcel Energy Small Commercial Gas*) Customer Charge Per Month $33.30 Cost per Therm $0.57105 *Gas rates are effective January 1, 2013. TABLE 2: RESIDENTIAL UTILITY RATES Electricity (Holy Cross Energy*) Customer Charge Per Month $6.5 Winter Charge per kWh $0.09531 *Electric rates used are those effective November 1, 2012. Climate Weather data for Eagle Country, Colorado (TMY3) was used for the energy simulations. Table 2 summarizes the climatic information. Table 2. Climatic Conditions Climatic Conditions Location Vail CO Weather File TMY3 from Eagle County, CO Latitude 39.64° N Longitude 106.36° W Elevation (feet) 8,150 Heating Deg Days (base 65° F) 8,749 Cooling Deg Days (base 50° F) 1,374 Heating Design Temp -13° F Cooling Design Dry Bulb 88° F Cooling Design Coinc. Wet Bulb 58° F ASHRAE Climate Zone 6B This building energy analysis has two building models. These are defined as follows.  CODE Base: This is the ASHRAE 90.1-2010 -compliant baseline building energy model.  Proposed: This model reflects the proposed design. The following sections describe the two models and the results of the hourly building simulation analysis. GROUP14 ENGINEERING, INC. Strata Vail 2.2 CODE Baseline Model Description The CODE Baseline Model was developed using ASHRAE 90.1-2010 Energy Cost Budget Method (per IECC 2012 section C401.2.1). The baseline model has Energy Cost Budget Method (ECB) System 7 for residences and common areas. All efficiencies comply with the standard. 2.3 Proposed Design Model Description The proposed design energy model reflects the building as it has been designed. The proposed design incorporates the following energy efficiency measures: Envelope • Exterior wall with R19 batt in steel stud with 1.5” Roxul mineral wool (R4.2/inch) (U=0.065) • Combination of R-36 insulation, R38 fiberglass in metal stud, and R33 rigid on high sloping roof • Underground concrete parking garage walls with R7.5 rigid insulation • Windows: o Low-e low SHGC Cardinal LoE366 glazing in thermally-broken aluminum frames (center of glazing U=0.29, SHGC=0.27) Lighting and Equipment • Condo unit lighting with switched outlets (LPD 1.25W/sf), corridor (1.08 W/sf), parking garage (0.18W/SF) HVAC • 4-pipe fan coil units serving residential units and common spaces • Helical rotary chiller with VFD control rated at 0.575kW/ton (100% capacity) with 2 closed- circuit cooling towers • 83% efficient boiler plant with boiler stack economizer • Corridor MUA with chilled water and 80% natural gas • Hydronic unit heaters for all levels parking garage, with direct-fired gas make up air unit for level 1 parking garage entry Domestic Water Heating • Side-arm domestic hot water storage tank • Standard flow showers (2.5GPM) and low flow Lavs (0.5GPM) used in bathrooms Pool • DesertAire with cooling/heating/dehumidification with DX cooling and water cooled condenser and hydronic heating Snowmelt • Snowmelt heat exchanger served by the boiler plant and heating approximately 24,000SF. GROUP14 ENGINEERING, INC. Strata Vail Table 3 shows the annual energy consumption and costs for the two models. Per ASHRAE 90.1-2010 Energy Cost Budget Method, the proposed design must have annual energy costs less than or equal to the standard reference design. The proposed design of the Strata Vail has annual energy costs that are 11.3% less than the ASHRAE 90.1-2010 Energy Cost Budget Method reference model. TABLE 3: ENERGY MODEL RESULTS Strategy Annual Energy Cost Annual Savings Relative to Cost Base % Energy Cost Savings Total Electricity Use (kWh) Electricity Savings Relative to Base (kWh) Total Natural Gas Use (Dtherms) Natural Gas Savings Relative to Base (Dtherms) Code IECC 2012 Code Baseline $221,776 - - 1,197,553 0 14,203 0 Design Proposed $196,754 $25,022 11.3% 1,062,873 134,680 12,099 2,104 This Simulated Performance analysis was performed in compliance with IECC 2012 C401.2.1, Total Building Performance. Signed, ___________________________ Xia Fang, P.E. GROUP14 ENGINEERING, INC. Strata Vail Appendix A: Modeling Inputs and Assumptions TABLE 9: BUILDING ENVELOPE MODEL INPUTS Element Code Baseline (IECC 2012/ASHRAE 90.1- 2010) Proposed Design Conditioned Floor Area 186,350 SF residential, 124,468SF parking garage Above Grade Stories 7 Below Grade Stories 3 Avg. Floor-to-Floor Height 12’ % Window Area % Window Area Building Average 19.5% 19.5% Roof Construction Type Insulation entirely above deck Insulation entirely above deck and vented attic Insulation R-20 c.i. R-33 average Total U-Factor U-0.048 U-0.031 Exterior Walls Construction Type Steel-Framed Steel-Framed Insulation R-13.0 + R-7.5 continuous R-19 + R6.3 c.i. (1.5” Roxul mineral wool) Total U-Factor U-0.064 U-0.065 Floors Construction Type Mass Mass Insulation R-14.6 c.i. NA Underground Walls Construction Type Mass Mass Insulation R-7.5 R-7.5 Fenestration Fenestration Type Double-pane low-e Double-pane low-e, low SHGC (Cardinal loE 366) Fenestration Assembly U-Factor U-0.55 U-0.32 Fenestration SHGC SHGC-0.40 SHGC-0.25 Center-of-Glass Properties U-0.41, SHGC-0.42 U-0.29, SHGC-0.27 Frame Type Metal framing Aluminum with thermally broken frame Shading Devices None Balconies GROUP14 ENGINEERING, INC. Strata Vail TABLE 10: HVAC MODEL INPUTS Element Code Baseline (IECC 2012/ASHRAE 90.1-2010) Proposed Design Primary System Type System 7: constant volume 4-pipe fan coil units with chilled water and hot water boiler plant 4-pipe fan coil units with water cooled chiller plant and hot water boiler plant, corridor/kitchen make up air units with chilled water and gas fired heating, pool dehumidification/cooling/heating unit with DX cooling/water cooled condenser and hot water heating Secondary System Type Hydronic unit heaters and gas fired garage make up air units Hydronic unit heaters and gas fired garage make up air units Air-Side Supply Fan Control Constant volume Two speed Supply Fan Energy 0.835W/CFM (average) on FCUs, 0.3W/CFM unit heaters 0.6W/CFM (average) Fan coil units, 0.55W/CFM Corridor MUA, 0.53W/CFM Kitchen MUA, 0.3W/CFM unit heaters Return Air Path Direct Direct Design Outdoor Air Same as proposed Common areas: 5cfm/person + 0.06cfm/sf, corridor: 0.75cfm/sf, all ducted from corridor MUAs, building total OSA 50,900cfm Economizer Control 75F DB (on common area equip) NA Demand Control Ventilation NA NA Energy Recovery none none Heating Space Setpoints 70°F, 50°F parking garage, 80°F pool 70°F, 50°F parking garage, 80°F pool Heating Equipment Hydronic heating for corridors, units, common areas and parking garages, gas fired heating for garage entry. Boiler plant with primary VFD pumping 180°F HWST, 130°F HWRT, pump at 19W/gpm Gas heating for corridors, hydronic heating for units (FCU), common spaces (FCU) and parking garage (unit heaters. Direct gas fired MUA for P3 parking Heating Efficiency 80% eff. 83% eff. boiler (with stack economizer additional 5% eff. improvement), 80% gas fired heating on makeup air units Cooling Space Setpoints 76° F 76°F Minimum Supply Air Temp 55° F 55°F Cooling Equipment Open circuit cooling tower with chillers, condenser water temperature design 75°F (10°F approach), VFD pumping on chilled water 44°F CHWST, 56°F CHWRT, 22w/gpm pump. Closed circuit cooling towers with chiller (VFD compressor linear unloading), condenser water temperature 80°F (15°F approach), VFD pumping Cooling Efficiency 0.680 kW/ton 0.575kW/ton Lighting Lighting Power (peak W/ft2) 1.25 W/SF residential units 0.66W/SF corridor, 0.19W/SF parking garage, 0.72W/SF fitness, 0.64W/SF 1.25W/SF residential units 1.08 W/SF corridor, 0.18W/SF parking garage, 0.96W/SF fitness, 0.96W/SF GROUP14 ENGINEERING, INC. Strata Vail lobby, 0.65W/SF future restaurant Lobby 0.65W/SF future restaurant Exterior Lighting (peak kW) 20.064 kW 6.432 kW Domestic Hot Water/ Equipment/ Process Loads Domestic Hot Water Equipment 80% efficient natural gas water heater Side-arm from boiler plant (83% with stack economizer) Water Use Reduction (low flow fixtures) None 2.5 gpm showerheads, 0.5 gpm lav Plug Loads (peak W/ft2) 0.65 W/SF 0.65 W/SF Snowmelt 24,000SF 80% boiler 24,000SF with snowmelt heat exchanger served by boiler plant Pool Dehumidification/cooling, 31,591 Btuh latent load Dehumidification/cooling, 31,591 Btuh latent load GROUP14 ENGINEERING, INC. Appendix B: Simulation Outputs Code Baseline Strata Vail GROUP14 ENGINEERING, INC. Strata Vail Proposed GROUP14 ENGINEERING, INC. Strata Vail GROUP14 ENGINEERING, INC. Strata Vail GROUP14 ENGINEERING, INC.