Zero Net Energy for Commercial Buildings Well talk about: - - PowerPoint PPT Presentation

David Houghton PE

Zero Net Energy for Commercial Buildings

March 13, 2018

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

Sample 24-hour TDV Mul3pliers

Source: Integral LOMS Energy Modeling Report

❖ Not all kWh are created equal! ❖ TDV stands in for source energy (vs site energy)

CA Electricity Mix

Source: CAISO Annual Report 2016

Average hourly genera3on by month and fuel type in 2016

Solar roof above vs energy use below

335W PV Panel 18.0 W/ft2 (DC) Deployed on roof 6.3 W/ft2 (DC) Annual energy 10.4 kWh/ft2-y Annual “EPI” 35.6 kBtu/ft2-y Pre-retrofit 50 kBtu/ft2-y Post-retrofit 30 kBtu/ft2-y Taller Buildings— Lower EUI and/or PV over parking, etc.

✔

Energy Use Intensity Averages

K-12 School 58 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

All Values in kBtu/ft2-y

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)

ISO Dispatch Center—Folsom CA CA Electric Load—March 11 2018 2MWh Battery System at CSU Long Beach

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)

❖ Heat pumps for heating, cooling,

and water heating

❖ Passive strategies work great in

coastal climate zones

You are here

Los Osos Middle School

LOMS Overview

Main School 63,500 ft2 Built 1978 Relocatables 9,000 ft2 Solar PV 200kW Installed 2012 Library Addition Built 1998

Design, Modeling, Meetings

❖ Two on-site meetings, several phone

meetings

❖ Consultants: utility co, modeling,

Measurement & Verification (M&V)

❖ School District: Principal, VP,

electricians, maintenance staff

PG&E Principal Gas Co +Consultants VP Carl Blum Light meter

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

5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 Jan Feb Mar Apr May Jun July Aug Sept Oct Nov Dec

Monthly Electricity (kWh)

Los Osos Middle School Electric Production & Consumption

Solar production (2012-2013) Electric Consumption (2011-2012)

Source: SLCUSD Billing Data

(Pre-retrofit)

LOMS Baseline Energy Use

Source: Integral LOMS Energy Modeling Report

Gas Impact

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 OA dampers Controls

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

Propane Boiler T12 Fluorescent Lighting 1960’s CMU Construction Cabinet-Style hydronic heaters

BVSF Upgrades

VRF Heating/Cooling Outdoor Condensing Unit Indoor Ceiling Cassettes Dimmable LED Lighting

BVSF Energy Use

10000 20000 30000 40000 50000 60000 70000 80000 90000 2013 2014 2015 2016 2017

Annual Electric Energy (kWh)

Annual Electric Use vs Projected Solar

Electric Use Projected Solar

Energy Efficiency Measures 30kW Solar PV

Source: Billing data, PVWatts estimated production

BVSF Monthly Electric Use/Production

1000 2000 3000 4000 5000 6000 7000 8000 9000 May-16 Jun-16 Jul-16 Aug-16 Sep-16 Oct-16 Nov-16 Dec-16 Jan-17 Feb-17 Mar-17 Apr-17

Monthly Electric Energy (kWh)

Monthly Electric Use vs Projected Solar

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.

60kW Overnite Load 480kW Peak 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

Source: SCE Meter Data, Baker Electric Calculations

20000 40000 60000 80000 100000 120000 140000 Feb-17 Mar-17 Apr-17 May-17 Jun-17 Jul-17 Aug-17 Sep-17 Oct-17 Nov-17 Dec-17 Jan-18

Monthly Use or Production (kWh/m)

VISM Electric Use & Production

Electric Use (2017) Solar Production (Projected)

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