A Virtual Tour ofSolar Harvest

Presented by:Eric Doub, Ecofutures Building, Inc.1025 Rosewood Ave. Suite #204

Boulder, CO 80304www.ecofuturesbuilding.com

Mom & Dad’s house 1982:Designed & Built Attached Solar GreenhouseStanford University, A.B. 1987:“Sustainable U.S Resource and Security Policies”

Boulder, CO 1993: birth of Ecofutures Building, Inc.

1887 Orchard Ave 2005: Designed & built Solar Harvest, Boulder’s first net-zero energy home

1982 Greenhouse, North Boulder –

tomatoes in February!

First, a brief timeline

New Home Construction

Additions and Remodeling

Kitchen design & remodel

Home Performance with Energy Star Audits & Retrofits

Solar & Renewables Consulting

Whole-systems analysis

Zero Energy Home pioneering

Ecofutures Today

Ecofutures Success

38% growth per year since 1993

After 5 years, 95% remodeling businesses will have disappeared. Ecofutures is in its 12th year

Winner of 2001 P.A.C.E (Partners in Action for a Clean Environment) Award for Environmental Leadership

What is Solar Harvest?The city of Boulder’s first Net-Zero Energy HomeThe highest rated Colorado home by Energy Star for energy efficiency

Earned 97.7 out of 100 possible points!A showcase home for green buildingA home that asks: How far can we go with solar? The answer: 100% & even more!

Full Details and Specs on Solar Harvest

26-page booklet

Solar homes tour article

Solar Harvest in the Daily Camera, Denver Post and elsewhere

Radio interview with Eric Doub on Colorado Public Radio aired December 5, 2005

Photographic tour on Ecofutures’ website

What is Zero-Net Energy?Zero-Net-Annual Site Energy

Homes that offset any imported energy by exporting an equal amount of site-derived energy

Zero-Net-Annual Source EnergyHomes that offset any imported energy by exporting a relative amount of site-derived energy at a ratio of:1 unit electricity = ~3 units fossil fuels

Zero-Net-Annual Energy CostHomes that “sell” equal or more energy to the grid than they purchase from the energy utility, measured in common market valuation ($$)

Zero-Net-Annual EmissionsHomes that offsets emissions equal to the amount emitted through the source energy that powers the building

Source: Environmental Building News Oct. 2005

Solar Harvest

X

What’s Missing from these Definitions?Transportation Impacts

Measuring the building’s impact on energy use to bring occupants to/from the building

Energy cost fluctuation over timeVariations in energy production

Such as when utilities fire up inefficient generators to meet high demand

Differences between forms of energyBurning fossil fuels for energy vs. clean natural gas or grid-supplied wind power through RECs

2005 U.S. Energy Use by Sector

Residential22%

Commercial18%

Industrial32%

Transportation 28%

Source: Monthly Energy Review March 2006

Residential Energy Use

Heating and cooling account for almost half of the energy use in new homes!

Why Should We Aim for Zero?

Climate Change

Satellite picture of the US at night

Resource depletion

Water pollution

Human health Ecosystems health

Dependency on foreign resources

Air pollution

Biodiversity

But don’t forget the positive side!

Zero Energy Homes can also:

Increase personal satisfaction in home ownership

Provide financial incentives for research and development

of new technologies

Support local industries

Increase the home’s value

Support cutting-edge technologies to increase chances for widespread adoption

Increase local awareness of energy issues

Enough lecture, let’s start the tour!

Solar Thermal Panels

Solar Harvest: Exterior Features

Photovoltaic Panels

Sunroom

High performance windows

Porous Pavement

Geothermal preheat

Textbook passive solar overhangs (2’ for 40º N.Latitude)

“If you want to fill a bathtub with hot water,

first put in the drain plug.”– Amory Lovins

Super-insulating

walls, windows, ceilings

(Another Ecofutures home!)

Sample of roofing used made from 100% post-consumer recycled carpet

Geothermal Fresh Air Pre-Heating & Pre-Cooling

These pipes provide fresh air to the home with air warmed in winter and cooled in summer,

courtesy of the ground

Photovoltaic Electricity

The 6.48 kW PV array mounted in two sets collect solar energy and convert it into DC power

Inverters

Inverters convert DC power into regular AC power for household use and to send to the grid

“Net Meter”

Set at different angles & of different sizes, the arrays collect different amounts of solar energy

Any sunny day, the net meter’s wheel runs BACKWARD!

It’s going backwards!!

6.84 kW grid-tied PV panels

mounted in two arrays:One array set at 40º

Inverters

Household electric useEnergy needs during cloudy days or nighttime “purchased”from the grid

Regular AC Power

One array set at 20º

20

Xcel Energy GridDuring sunny days when panels produce more

energy than the home consumes, energy is “sold” to the grid at a wholesale price

DC Power

Now let’s go inside!

The Building Envelope

The Key: “BUILD TIGHT, VENTILATE RIGHT” using commonly available materials & standard building practices

A little thicker than a standard 2x6 wall

SUNSPACE:Passive solar heating

with active distribution

On a 2º F day in February, sunspace was at 92º F

“Sunspace” allows max solar input while avoiding “sundrenching” and glare – common mistakes in solar home design

Air warmed in the sunroom is pumped by fans through ducts to rooms inside the

house, controlled by normal thermostats

Underfloor heat set at 40º F –unused winter 2005-2006

Low limit

Heat rejection thermostat

Almost 100 on a winter day!

Meanwhile, in the basement, geothermally pre-warmed fresh air is

pumped through the ERV into the house

From buried pipes

This winter, when exterior temperatures were 4° F, incoming air to ERV was measured at 38° F; this keeps ERV from freezing and assists maximum heat recovery efficiency.

The Ultimate Air RecoupAerator can cycle air at 50 - 200 cfm and is rated at 93-96% heat recovery with outdoor temperatures of 32° F and 70° F indoors.

Incoming fresh air

Fresh, filtered

air to house

Stale exhaust air

Exhaust air to

outdoors

Indoor Air Quality• Minimize emissions from cabinets, floors, & all building materials

• Provide adequate ventilation

These systems help to maintain comfortable interior temperatures & humidity levels

ERV

EconoCool mode for cool air delivery

In summer

96% heat recovery

6” PVC pipe buried 6-8 feet for seasonal thermal pre-warming & pre-cooling of incoming fresh air

Fresh air supply

Thermostats in high-use zones enhance temperature control

and prevent wasted heat

Fans and ducts carrywarm air to interior

spaces

230 square feet of south glazing on sun space for

optimum solar gain

Fresh air warms to comfortable temperatures to be delivered

to living spaces

Motorized dampersprevent backdrafts

Stale air exhaust

Hot water pumped from the solar tank runs in plastic tubes beneath flooring to

warm from the bottom - up

6000 gallon super insulated solar hot water storage tank

Maintains 120º - 170º temperatureallowing for household use of

8-10 gallons per minute!

12 salvaged Novan thermal flat-plate collectors

Mounted at 55º in drainback system

to staple-up radiant floor space heating

hot water for sinks,showers and other

household use

360 gallon hot tubkept at 103º

Coils of copper tube act as heat

exchangers to pass heat to domestic

water

So warm!

Hot Water and the Solar Tank

Plastic tubes with hot water run throughout the house for underfloor radiant heat – barely used winter 2005-2006

Temperature inside the radiant floor system

The Mechanical RoomCopper pipes that run through the solar cistern carry hot water to showers and sinks throughout the house for all hot water needs

Also known as the “gauge of marital sustainability”

Instant hot water dispenser for tea, soup & coffee – 100% solar, any way you count it

Solar Tank Luxuries

Did I forget to mention the hot tub?!

The solar tank is capable of keeping the hot tub at a relaxing 103 degrees F

throughout the entire winter.

ERV

EconoCool mode for cool air delivery

96% heat recovery

6” PVC pipe buried 6-8 feet for seasonal thermal pre-cooling of

incoming fresh air

Fresh air supply

Stale air exhaust

Whole-house fan pulls 1600 cfmof warm air out of the house forcooling and fresh air exchange

Warm, exhaust air leaves house through attic vents

High skylight for passive“chimney stack effect” allowshot air to rise and exit building

pulling in cooler outdoor air below

Whole house fan with insulated operable doors – NOT a “hole in the envelope” High skylight (electric with remote)

Interior windows allow great summer nighttime airflow

“From our analysis, we conclude that the heating system will maintain 68°F at 36°F above the floor for approximately eight cold, cloudy days… This represents a conservative, worst-case scenario with no curtailment of space heating set point or domestic water use.”

..English, please?

Solar Harvest was approved by engineers and by Boulder’s chief building official for construction without fossil-fuel burning back-up heating system. It can be heated completely with renewable energy! – the sun!

Critiques, Challenges & Next Frontiers

TOOLS FOR ASSESSMENT:Life Cycle Costing vs. Life Cycle Assessment

TOTAL HOUSEHOLD / FAMILY ENERGY USEWhat about transportation?What about food?

Low Energy Communal Housing by Larry Kinney

CRADLE TO CRADLE, or CRADLE TO GRAVE?Durability & reusability questions Will today’s beautiful countertops be the avocado green of tomorrow?

For example

Critiques, Challenges & Next Frontiers

MARKET FAIRNESS:Conventional fuels are subsidized; renewables should compete on level playing fieldCurrent tax credits are a start, more policy changes and programs are needed

THE “BIG GUYS” – PRODUCTION BUILDERS“Extra costs of energy efficient housing aren’t worth it”Yet: 3% increase in initial costs can save 30-50% of lifetime energy use in an average houseInstitutional and information barriers

EXISTING HOUSING – RENTAL AND OWNEDRetrofitting and replacing Home Performance with Energy Star

Critiques, Challenges & Next Frontiers

SOCIAL NORMS AND SOLAR COLLECTORSBuilding codes and covenants need to be more encouraging “A house without collectors will be like a house without windows” – what year will this become the norm?On Payback by Seth Portner

STANDBY LOSSES, AKA PHANTOM OR VAMPIRE LOSSES5-7% of U.S. electricity is lost in these waysThat’s about 23 nuclear plants’ worthAt Solar Harvest, Comcast box uses 50 Watts, 24/7

Average Boulder Household Greenhouse Gas Emissions Sources

The house42%

Transportation58%

Source: City of Boulder Office of Environmental Affairs

Life Cycle of Building Products

Resource Extraction Manufacturing

On-Site Construction

Demolition Occupancy/Maintenance

Disposal/Recycling/Reuse

READ THIS BOOK!

Chapter 2: “Why Being Less Bad is No Good”

Life Cycle ImpactsErosion

FragmentationSocial Displacement

Habitat Loss Greenhouse Gasses

Toxic Waste

Poor working conditions

Water pollution

Packaging WasteWater contamination

Toxic chemicalsEnergy consumption

Energy use

Ozone depletionToxic WasteWater pollution

Energy consumption Landfills

Energy UseEcosystem toxicity

Air pollution

Global warming

Acidification

Human health impacts

Cradle to Grave

Life Cycle AssessmentBegan in the 1960s when Coca-Cola wanted to determine the

environmental impact of switching from glass to plastic bottlesToday LCA is designed to support one of the following goals:

Documenting environmental performance for marketing purposesDeveloping policy and regulationsAssessing potential liabilityEvaluating environmental performance to document improvement for environmental management systemsGreen labelingPurchasing/procurement decisionsGuide green building towards materials with long life or construction from reusable materials

LCA vs. LCCLife Cycle Assessment

Quantifies and analyzes environmental burdens and impacts at each step in the entire life of a product Involves environmental accounting

Life Cycle CostingStrictly a financial tool for calculating the total cost of ownership over the useful life of an assetConsiders only economic value

Both tools give credit to items that are long-lived and durable

LCA Tools for Building ProfessionalsBEES (Building for Environmental & Economic Sustainability)

Easy-to-use free tool for product-to-product comparisons based on proprietary, unpublished data

Sample Performance Table: Carpet

www.bfrl.nist.gov/oae/sofware/bees.html

Athena Institute Environmental Impact EstimatorInventory data tool for product-to-product comparisons based

primarily on published Canadian data. www.athenasmi.ca

0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5

ManufacturingConstruction

O & MEnd-Of-Life

Total EmbodiedAnnual Op. En.

Air Pollution Index by Life Cycle StagesAir Pollution Index (times E+03 )

Material Transportation Annual Op. Energy

ENVEST U.K.-based LCA-based building design tool, only addresses whole building, and provides results in highly summarized “ecopoints”

www.bre.co.uk/sustainable/envest.html

Products used in Solar Harvest

CO

Greenblock

NyCore

Solar Panels

Icynene

GrailCoat

Fibertec

Alpen Windows

FSC LumberCountertops`Bamboo

Linseed Oil Varnish

Paint

AvoniteAppliances

ERV

Fans

Lyptus Sills

Cherry & Maple Wood

Carpets

Embedded energy -transportation

Korea

WHAT IS LEED?The LEED Green Building Rating System is a voluntary, consensus-based national standard for developing high-performance, sustainable buildings. LEED was created to:

•define “green building” & establish standards of measurement

•promote integrated, whole-building design practices

•recognize environmental leadership in the building industry

•stimulate green competition

•raise consumer awareness of green building benefits

•transform the building market

•provide a framework for assessing building performance emphasizing state of the art strategies for sustainable site development, water savings, energy efficiency, materials selection and indoor environmental quality.

7 points for Location and

Linkages

14 points for Sustainable

Sites

10 points for Water

Efficiency

13 Points for Indoor

Environmental Quality

9 points for Materials & Resources

33 points for “Energy and Atmosphere”

1 point for “Homeowner Awareness”

2 points for “Innovation and Design Process”

87

87 points = GOLD

designation

Room for ImprovementIncrease amount of bio-based productsReduce use of petroleum-based productsBuild with recyclability in mindInvest in products with longer life spansReduce energy used to import products

Bamboo (From China or Vietnam)Quartz Countertops (From South Korea)Recycled roofing (From Georgia)

Cradle to cradle

What is the next frontier of green building?

Rooftop gardens

South Burlington Living Machine

Cohousing

SummaryCommon materials, standard practices, easily replicableAdapted to local climateReasonable cost (+10% to get to 100% ZEH)New Horizons:

ZEH 60-home apartment under design in Arvada; affordable housing and zero energy costs per year!

In transition to efficiency and renewables,“Why not enjoy the inevitable?” – Amory Lovins

Resources and LinksPowerful nodes in the network

Boulder’s Green Building Guild www.bgbg.orgColorado’s leading renewable energy resource www.rmi.orgLeading national site on green building www.buildinggreen.comOur site www.ecofuturesbuilding.comComplex, yet amazingly useful government site www.doe.govBoulder’s Center for Resource Conservation

www.conservationcenter.orgNational Renewable Energy Laboratory www.nrel.govMcDonough Braungart Design Chemistry www.mbdc.com

Cradle to cradle design analysis

Resources and LinksPublications

Environmental Design and ConstructionEcostructureEnvironmental Building News (available through Buildinggreen.com)Home EnergyThe Last Straw (for developments in natural building)Mother Earth News