Net-Zero, Net-Zero Ready, Carbon Neutral Buildings: What are they? Why build one? And how? Bennington Superior Court and State Office Building NRG Systems Dartt House and Maclay Architects Office
Global Challenges, Our Built Environment & Survival Economy, Energy, Environment, Equity & Population
Workplace in Transition
Energy At the Core ENERGY Ecosystem Population Degredation Climate Lifestyle Change
Peak Oil – The Energy Transition Historical Fuel Oil price / barrel (in 2012 dollars)
The Energy Transition – Renewable Energy Solar Plateau Cost per unit of fuel when the cost of heat from a heat pump powered by PV is equivalent – (in New England) with efficiencies of heat sources incorporated Natural Electric Propane gas (kWh) (gal) Oil (gal) (therm) $/MMBtu $0.14 $3.76 $5.58 $4.10 $41.02 *Current cost of electricity from PV $0.12 $3.84 $5.71 $4.20 $35.67 *Plateau for heating sources $0.06 $1.92 $2.85 $2.10 $17.83 *Current cost of heat from Heat Pump and PV $0.04 $1.26 $1.88 $1.38 $11.72 *Current Cost including 30% federal tax credit
Net-Zero: The New / Rediscovered Paradigm
Key Questions “The world we have created today as a result of our thinking thus far has problems that cannot be solved by thinking the way we thought when we created them.” -Albert Einstein
Evolution of Energy & Lifestyle Farming/Renewable Coal Oil Renewable Coal Oil Renewable & Other 1800 1900 2000
What are Net-Zero Buildings? Net-Zero Buildings produce more energy than they consume on an annual basis • Building • Site • Source NREL’s Research Support Facility Golden, CO • Net-metered 220,000 sf - 35.4 EUI • Equivalent 100% renewable from on site PV • Offsets
Is this a Net-Zero Building?
The Three Elements of a Net-Zero Building • Low Energy Consumption • Efficient Simplified Systems • Renewable Energy
How do we get low energy consumption? • Integrated Building Design • Massing • E-W orientation • Daylight • Healthy Workplace
How do we get low energy consumption? • Energy Conserving Building Envelope • Walls, Roof, Foundation, air movement
How do we get low energy consumption? • Energy Modeling/Metrics (10-25 kBtu/sf-yr for offices) • Programming • Design • Commissioning • Construction
What are simplified systems? • Right Size Equipment • Minimize Distribution • High Performance Mechanical Systems (ASHP) • Controls
What are Renewables? • Usually Solar Photovoltaics • Own • Lease • Power Purchase Agreement
What is a Net-Zero Ready Building? • A Net-Zero building without Renewables Bennington Superior Court and State Office Building
What is a Carbon Neutral Building? • A Net-Zero Building with biomass for renewable energy Private Residence, Putney, VT NRG Systems, Hinesburg, VT Aldo Leopold Legacy Center, Baraboo, WI
NRG Systems OWNER Wind NRG Partners, LLC DESIGN TEAM Architects – Maclay Architects Mechanical , Electrical & Fire Protection – Salem Engineering / LN Consulting Structural & Civil – Engineering Ventures Preconstruction Services – Erickson Consulting Energy Consultant – Energy Balance Landscape - TJ Boyle and Associates Lighting Design – Naomi Miller Lighting Design Fire Protection - Chase Engineering, PC CONSTRUCTION TEAM General Contractor – Breadloaf Construction / HP Cummings Construction
NRG Systems BUILDING TYPE: Model Renewable-Powered Workplace SCOPE: Two new buildings and masterplan PROJECT SIZE: Phase 46,500 SF, 31,000 SF PROJECT COST: $5,000,000, $6,500,00 COST/SQFT: $107/SF, $212/SF ENERGY INTENSITY: 23 kBtu/SF-yr, 19 kBtu/SF-yr PERCENT RENEWABLE: 89%, 95% AIR INFILTRATION: 0.18 cfm50/SF, 0.092 cfm50/SF NATURAL: 0.08 ACH, winter, 0.05 ACH, winter LEED RATING: LEED-NB Gold both buildings
Integrated Environmental Design & Systems
Integrated Environmental Design & Systems Building 2 Energy conservation Daylighting Renewable energy usage Pond for cooling Storm water management
Pond – Cooling, Storm Water Retention, Recreation
Entrance, Cafe Terrace & Board Room Balcony
Building 1 – Central Heart Warehouse Connection View towards fireplace & hearth from café
Street & Office
Energy Conservation
Phase 2 Building Improvements Enhanced energy conservation Simplified mechanical systems Hybrid steel/wood structure
Building 2 – Central Heart Library and Floor Art on 2 nd Floor View into the café
Bennington Courthouse: Project Goals: Healthy Building Excellent Energy Performance
Bennington Courthouse: BUILDING TYPE: Healthy Building Renovation SCOPE: Renovation & Addition PROJECT SIZE: Phase 65,000 sf TOTAL CONSTURCTION COST: $13,500,000 (anticipated) COST/SQFT: $208/sq ft ENERGY INTENSITY (existing building): 110 kbtu/sf ENERGY INTENSITY (modeled): 23 kbtu/sf
Pre-Existing Conditions • Employee complaints • Unoccupied building • IAQ problems • Poor building envelope (moisture & energy)
Site Plan EXISTING BUILDING FOOTPRINT
Floor Slab Details NEW CONSTRUCTION EXISTING BUILDING
Bennington Court and Offices Actual Existing and Modeled Proposed 2,500,000 EUI =110 Electric other kBtu/sf-yr lighting 2,000,000 heating cooling 1,500,000 kWh 1,000,000 EUI = 25.6 kBtu/sf-yr 500,000 - Existing New TOTAL ENERGY USE ALL SOURCES, existing building fossil fuel converted to kWh Note: disaggregation of existing electric use very approximate
Building Performance July 2012-June 2013 = 459,052 kWh and 1,084 gallons of propane Total = 1,664,715 kBtu/year EUI = 25.6 kBtu/sf-yr
Financial Analysis Net-Zero Ready building -$370,000 additional capital cost -$49,000/yr projected energy savings Simple Payback: 7.6 years Net-Zero Ready 20 year cash flow ROI: 13% • capital cost (green) or financing option (red) Net Present Value*: $2,432,583 Internal Rate of Return*: 6.2% * with 3% annual fuel escalation rate 3 Building Options: 20 year capital and operation costs
Mixed Use, Historic, Net-Zero, Net-Metered Property: A Case Study from Waitsfield
Project Site Context Mad River Valley Historic Waitsfield Village Warren, VT residence
Waitsfield Context
Simplify / Minimize System Loads Open trusses, open office = daylighting Light guiding blinds Ceiling fans and efficient light fixtures Laptop computers Additionally: • ERV’s • Distribution – radiant and air Minisplits/heat pumps
Envelope Upgrades and Load Reduction
Install Renewables 2 kW PV NRG tracker Office purchased with tax credits 17.55 kW PV Alteris Carport Office financed plus GMP and USDA grants 20 kW PV All Earth Renewables tracker Power Purchase Agreement
Verification and Documentation Consumption: Office: 97,948 kBtu = 28,707 kWh Office EUI: Warren House: 59,021 kBtu = 17,298 kWh 38 kBtu/sf Apartments (1&2) 42,240 kBtu = 12,208 kWh Apartment building EUI: 199,209 kBtu = 58,213 kWh 19 kBtu/sf PV Production: Warren House EUI: Watisfield site: 63,712 kBtu =18,673 kWh 17 kBtu/sf Warren site: 83,966 kBtu = 24,609 kWh 147,678 kBtu = 43,282 kWh Net Energy used: 51,531 kBtu = 14,931 kWh (Oct 2012-September 2013 data)
Outcome • Rental income • From: 1 apartment - $1,200/month • To: 2 apartments -$1,900/ month • Net-Zero Architecture Office • Through on and off site renewables • Net-Metered mixed use complex • Off site additional renewables
Waitsfield and Moretown Town Offices
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