March 13, 2018 David Houghton PE Zero Net Energy for Commercial Buildings
We’ll talk about: ❖ Commercial ZNE Concepts ❖ Los Osos Middle School ZNE project ❖ Bellevue Santa Fe Charter ZNE project ❖ Pomona Valley Indoor Swap Meet
ZNE Concepts ❖ Energy efficiency first ❖ Target: Energy Use Intensity (EUI) 20–30 kBtu/ft2-y ❖ Solar PV to offset annual energy ❖ Gas use can be handled by over-producing electricity ❖ California uses Time-Dependent Valuation (TDV)
Time-Dependent Valuation ❖ Not all kWh are created equal! ❖ TDV stands in for source energy (vs site energy) Sample 24-hour TDV Mul3pliers Source: Integral LOMS Energy Modeling Report
CA Electricity Mix Average hourly genera3on by month and fuel type in 2016 Source: CAISO Annual Report 2016
Solar roof above vs energy use below 335W PV Panel Deployed on roof Annual energy Annual “EPI” 18.0 W/ft2 (DC) 6.3 W/ft2 (DC) 10.4 kWh/ft2-y 35.6 kBtu/ft2-y ✔ Taller Buildings— Pre-retrofit Post-retrofit Lower EUI and/or 50 kBtu/ft2-y 30 kBtu/ft2-y PV over parking, etc.
Energy Use Intensity Averages K-12 School 58 All Values in kBtu/ft2-y College/University 131 Convenience Store 193 Fast Food Rest 384 Hospital 197 Hotel 73 Senior Care 126 Office 67 Retail-Strip Mall 94 Warehouse—non-refr 20 Warehouse—refr 126 Source: US DOE Commercial Building Energy Consumption Survey (CBECS) 2016
Demand & Storage ❖ Demand charges ≈ $20/kW, peak electric rates >$1/kWh ❖ Peak Shaving depends on load shape ❖ Batteries can shift load and trim peaks ❖ Demand response can be manual or automatic (OpenADR 2.0) 2MWh Battery System at CSU Long Beach ISO Dispatch Center—Folsom CA CA Electric Load—March 11 2018
California Climate & HVAC Trends ❖ Our climate is very mild (Zone 5) ❖ Yet, more cooling is being installed ❖ Yet, runtime is relatively low ❖ More refrigerant-based systems (VRF, VRV) You are here ❖ Heat pumps for heating, cooling, and water heating ❖ Passive strategies work great in coastal climate zones
Los Osos Middle School
LOMS Overview Solar PV 200kW Installed 2012 Relocatables 9,000 ft2 Main School 63,500 ft2 Built 1978 Library Addition Built 1998
Design, Modeling, Meetings ❖ Two on-site meetings, several phone Principal PG&E meetings Gas Co ❖ Consultants: utility co, modeling, Measurement & Verification (M&V) ❖ School District: Principal, VP, electricians, maintenance staff +Consultants Light meter VP Carl Blum
LOMS ZNE Recipe ❖ Reduce EUI from 35 kBtu/ft2-y to 27 kBtu/ft2-y ❖ Existing 200KW Solar PV offsets remaining energy use (on a TDV Basis) ❖ Proposition 39 funded soft costs, capital buy-down Source: Integral LOMS Energy Modeling Report
LOMS Electricity Los Osos Middle School Electric Production & Consumption 50000 45000 40000 Monthly Electricity (kWh) 35000 30000 25000 20000 15000 10000 5000 0 Jan Feb Mar Apr May Jun July Aug Sept Oct Nov Dec (Pre-retrofit) Solar production (2012-2013) Electric Consumption (2011-2012) Source: SLCUSD Billing Data
LOMS Baseline Energy Use Gas Impact Source: Integral LOMS Energy Modeling Report
Energy Efficiency Measures ❖ Indoor Lighting ❖ Outdoor Lighting ❖ New Relo Heat Pumps ❖ Condensing water heaters ❖ Asstd controls
Measures not selected ❖ Envelope upgrades (insulation, glazing, etc.) payback way too long—mild climate ❖ AHU retrofits existing units in great shape ❖ Daylighting requires roof penetration, heavy construction, downtime ❖ DDC controls District developing standards for controls ❖ Plug load improvements/controls Prop 39 won’t buy computers, copiers, etc. ❖ Kitchen equipment upgrades Low runtime, costly upgrades, long payback
Rooftop HVAC Units ❖ Custom units in great shape ❖ Economizers, heating, no a/c ❖ Low efficiency, but better-built than most new equipment ❖ Decision: Keep ‘em! RTUs Zone dampers Controls OA dampers
Furnaces ❖ Residential-scale units ❖ Non-condensing (low effcy) ❖ Mix of vintages ❖ Low runtime = long payback ❖ Decision: Keep ‘em!
Relocatable Heat Pumps ❖ 2 of 8 units already retrofitted ❖ Higher-effcy units available, decent payback ❖ Decision: Upgrade!
Water Heating ❖ Low-efficiency NG tank-style water heaters (6) ❖ Large (1M+Btu/h) low-effcy boiler for locker room showers ❖ Decision: Upgrade!
Lighting—Classroom Fluorescents ❖ Biggest single category of retrofit ❖ All new LED fixtures with wireless zoning/dimming ❖ Lighting power density reduced from 1.05 to ≈ 0.40 W/ft2 Before After
Lighting—Outdoor ❖ Mix of metal halide & sodium lamps ❖ All retrofitted to LED ❖ Built-in photocells & occupancy sensors ❖ Saves energy, but not demand Before After
Odds & Ends ❖ Commercial Kitchen—most equipment not used Decision: Leave it ❖ Server room—split system a/c Decision: turn up T-stat ❖ Special light fixtures: shops, MPR Decision: custom retrofits
LOMS ZNE Project Credits ❖ California Energy Commission Proposition 39 (The Clean Energy Jobs Act) ❖ Pacific Gas & Electric Company—Electric Utility ❖ The Gas Company—Gas Utility ❖ Integral Group—Lead consultant/energy modeling ❖ Cadmus Group—Measurement & Verification ❖ Thoma Electric—Lighting retrofits ❖ All Systems Heating & Air—HVAC retrofits ❖ Avila Partners—Owner’s Rep
Bellevue-Santa Fe Charter School
BVSF Baseline T12 Fluorescent Lighting 1960’s CMU Construction Propane Boiler Cabinet-Style hydronic heaters
BVSF Upgrades VRF Heating/Cooling Indoor Ceiling Cassettes Outdoor Condensing Unit Dimmable LED Lighting
BVSF Energy Use Annual Electric Use vs Projected Solar 90000 80000 Energy Efficiency Measures 70000 Annual Electric Energy (kWh) 60000 50000 40000 30000 30kW Solar PV 20000 10000 0 2013 2014 2015 2016 2017 Electric Use Projected Solar Source: Billing data, PVWatts estimated production
BVSF Monthly Electric Use/Production Monthly Electric Use vs Projected Solar 9000 8000 7000 Monthly Electric Energy (kWh) 6000 5000 4000 3000 2000 1000 0 May-16 Jun-16 Jul-16 Aug-16 Sep-16 Oct-16 Nov-16 Dec-16 Jan-17 Feb-17 Mar-17 Apr-17 Historical Use (most recent year) Projected Solar Source: Billing data, PVWatts estimated production
Pomona VISM
Valley Indoor Swap Meet
VISM Load—One Week in Oct. 480kW Peak Load 60kW Overnite Load
VISM Panel Layout 685 kW of Solar PV $1.80/W Future Battery site
VISM Energy Values ❖ Electricity use 1,284,231 kWh/y (down 15%—efficiency measures) ❖ 108,000 ft2 gross area, EUI 40.6 kBtu/ft2-y, annual cost ≈ $250,000 ❖ 685 kW Solar PV system will generate ≈ 83% of annual electricity VISM Electric Use & Production 140000 120000 Monthly Use or Production (kWh/m) 100000 80000 60000 40000 20000 0 Feb-17 Mar-17 Apr-17 May-17 Jun-17 Jul-17 Aug-17 Sep-17 Oct-17 Nov-17 Dec-17 Jan-18 Electric Use (2017) Solar Production (Projected) Source: SCE Meter Data, Baker Electric Calculations
Key Points—New Construction ❖ Build to T24 for efficient envelope, systems, and controls (reduce loads) ❖ Use climate & natural advantages—daily temp swings, daylighting, breezes, solar access, pond HX, etc. ❖ Install efficient systems (high HSPF, lm/W, COP, etc.) ❖ Control effectively (scheduling, dimming, speed control) ❖ Include roof or site space for solar & storage electric ❖ Target EUI: <20–30kBtu/ft2-y
Key Points—Retrofits ❖ Efficiency first, then self-generation ❖ Align with deferred maintenance—what needs replaced? ❖ Group HVAC measures with lighting measures ❖ Solve multiple problems at once (i.e. new roof + PV) ❖ Involve operations staff ❖ Integrate controls and monitoring with regular oversight ❖ Target EUI: <20–30kBtu/ft2-y
Dave Houghton • 970-209-1216 • dave@avilapartners.com energy • buildings • research • consulting Applied Curiosity • Breakthrough Results
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