Shawna henderson_solarthermal_aci2008

getting into hot water

solar ready homesShawna Henderson

"

Copyright, 1996 © Dale Carnegie & Associates, Inc."

Abri Sustainable Design & Consulting"

April 2008

"

Approaching Net Zero Energy in Existing Housing ACI 2008, Pittsburgh"Abri Sustainable Design & Consulting"

Add-on Solar Technologies"•  Solar Domestic Hot Water"

•  40% to 60% energy savings potential"•  Market-ready technology " ""•  CSA standard for packaged systems"

•  Photovoltaics"•  2 to 5 kW system could create Net Zero Energy Home"

Both solar hot water and solar electricity generate far more value than their cost!


Why solar ready?"Canadian context: "

12 million existing homes"3.6 million major renovations/annually"

+110,000 new homes annually"

Houses built to last 50 - 100+ years"No consideration of future energy options"


Why Solar Ready Homes?"•  Similar to central

vacuum rough-in"– Minimal cost to builder/

homeowner at initial construction"

– What would market penetration of central vac industry be w/out builder buy-in to pre-installation?"


Why Solar?"•  Utilize ‘free’ energy from the sun"

–  Solar is preferred energy choice for 92 �% of Canadians surveyed"

–  Reliable equipment, minimal upkeep"–  Few parts to repair"–  Trouble-free energy

supply"–  Fixed operating costs"–  Provides 40 to 60%

of water heating requirements"

Solar Collectorcaptures light and traps heat

Hot Water

Hot Water Tankstores heat"


More Reasons Why..."

• Undeveloped market"–  ‘Green’ home market"– Anticipate homeowner needs"–  Increase customer satisfaction"

•  Build local solar thermal industry"– Address energy security issues"


Why Not Solar Now?"

•  Lack of Canadian market penetration"

• High initial costs (esp. PV)"• Misperceptions about Canadian

climate and solar energy"


Solar Thermal History 101"

•  1980s: BIG incentives available"– Boom, then bust"

•  Not technical failure"– No requirements for certification"– No training of installers"– No way to manage/encourage sustainable

growth in industry"


Current Canadian ST Market""

•  50% growth over 2002-2004"

•  1/3 market = DHW systems"–  67% DHW in residential sector"

•  2004: space and water heating"–  23% of residential market"– Strong growth in this sector"


Global ST Market"•  46 million homes worldwide"

•  Installed capacity, 2005 = 77 GWth"•  58% in China, 0.3% in Canada"

0

2

4

6

8

10

12

EU US Canada

World: 77 GWth "China: 45 GWth"EU: 9.8 GWth"US: 1.4 GWth"Canada: 0.26 GWth"Source: IEA "

!


07/08 Solar Ready Pilot ""

• NRCan Goals "– Demonstrate and monitor up to 100

Solar Ready Homes in small market with production builder"

– Integrate Solar Ready and Energy Star technologies and techniques"


NRCan study objectives"

•  Work with an established production builder to explore the "real" challenges of implementing Solar Ready in a typical subdivision setting"

•  Develop a comprehensive guide to Solar Ready in a subdivision setting which reflects the inherent challenges and limitations of this type of development"

•  Gauge consumer interest in Solar Ready and Solar Equipped Homes"


Other Solar Ready Incentives"•  New Mexico --Solar Ready legislated"

•  California -- Solar Ready focussed on PV"

•  Maine -- Builders Assoc. promoting Solar Ready"


Solar Domestic Hot Water ""

•  Typical residential DHW system:"– Proven, reliable technology"–  2 panels/30 tubes for 2 to 6 occupants"–  3 to 10 years payback investment"–  10 year Warranty"–  25 to 30 year life expectancy "


General information"–  footprint = 17 x 6 m (55 x 20 ft)"–  4/12 roof, no significant heel @ eave "–  framed w/2x4 walls"–  poured concrete basement"–  single pane windows (w/storms elsewhere)"

BEST OPPORTUNITY FOR NZEEH: Rancher/Bungalow in Vancouver"


Upgrades"•  Envelope "

–  2.0 ACH"–  17.6 W/m2 (7Btu/ft2)"

•  Mechanicals: "–  4 kW electric bb"–  High-eff HRV"–  High-eff gas heater &

solar DHW"–  Drainwater HR"

–  Clg RSI 10.6 (R-60)"–  AGW RSI 7.0 (R-40)"–  BGW RSI 7.0 (R-40), "–  Slab RSI 1.8 (R-10)"

•  Est. Energy Usage"–  Space Heating: 5.1 GJ "

" " "(therms)"–  Water Heating: 3.9 GJ

" " "(therms)"–  Secondary Loads:

10 kWh/day, 3650 kWh/yr"


PV contribution"

•  To produce 3650 kWh/year"–  3 to 4.6 kWp capacity"–  With best south-facing slope

(±10° latitude)(not what every house offers!)"

–  24 to 30 m2 (260 to 325 ft2) roof face (not necessarily available!)"


Solar DHW contributions"

•  Best solution for DHW system (of those modelled)"

•  6m2 (65 ft2) flat-plate collector • 240L (60 gal) storage tank"

•  Water T = 55°C (130°F) " • Daily use = 150L (40 gal)"

•  Solar contribution ranged from 5.5 to 10.1 GJ (20,000 to 36,000 kWh-e)"

•  East or West facing systems: 48 to 65% solar contribution"

•  South facing systems: 59 to 83% solar contribution"


Results of upgrades"


Cost-effectiveness 1"

•  $30,000 investment (incl. SDHW)"»  25 yr mtg @ 4%"»  40 yr mtg $ �@ 6%"»  not accounting for fuel cost increases"

•  Increases mortgage payment by $125 to $165"

•  Decreases energy costs by $120 to $175"

•  7 out of 12 options see net savings"


Cost-effectiveness 2"

•  $50,000 investment (incl. SDHW & 2kW PV)"»  25 yr mtg @ 4%"»  40 yr mtg $ �@ 6%"»  not accounting for fuel cost increases"

•  Increases mortgage payment by $225 to $275"

•  Decreases energy costs by $130 to $195"

•  0 out of 12 options see net savings "–  (deficit = $35 to $140/mo)"


Climate Impacts on NZEEH"

•  Vancouver most likely"

•  Whitehorse/Prairies most difficult"

•  Coastal Regions : milder winters"–  better options for higher passive solar gain in retrofits,

flat plate SDHW good option"

•  Continental Regions: colder, more sun"–  higher kWh generated from PV,

colder winters -- look to evacuated tube SDHW?"


Energy Source Choices"•  Fuel choices based on big-picture:"

– GSHP with COP of 3"–  oil-fired generation o/all eff. = 25 to 30%"– GSHP efficiency = high-eff. oil-fired furnace "

•  GHG emissions & carbon footprint "– Hydroelectric better choice than fossil-fuel,

esp. where heating loads are minimal"


New Mexico, 2007"– New homes required by law to be

solar ready"•  New building standard unanimously passed by state

senate and house"•  ± 12,000 homes annually in state "

–  Standard includes requirements/guidelines for: "– Roof orientation"– Roof strength"– Obstructions to sunlight"–  Access to installation locations"–  Built-in conduit and wiring"–  Piping and brackets for attaching solar collectors"


California Solar Initiative, 2006"

•  Electricity mainly from natural gas"•  85% of natural gas imported = ‘double whammy’

Incentive in place for PV, but not SDHW"

–  $3k to $4k rebate for PV system"•  Will add 3000MW PV capacity in 10 years"•  ‘Glamorous’: lots of celebrity endorsement "•  Aim �: “electricity-neutral” homes"•  Many custom and production builders already offering"solar ready for both ST and PV"

– Equivalent Solar DHW initiative could save 971 million therms/1126 GigaWatt-hr"


California-based Study, 2004"

•  Study included over 13,000 grid-connected (PV) systems"

•  Benefits of Solar Ready Homes:"•  Shorter time on market"•  Increased property value"•  solar electric homes sell at a premium !

Increase in appraisal value for house with PV system ±20 times the annual reduction in operating costs due to PV system!


Maine Home Builders, 2006"•  Program to Promote Solar Ready "

•  Focus of promotion on cost savings""– Electricity savings in Maine"

•  2.0 kW PV saves about $644 per year. Over 20 years, total savings could exceed $19,000"

– Hot water savings in Maine "•  A solar hot water system for a family of 4 would

replace over 3,400 kWh of electric-heated hot water each year. Over 20 years, savings could be over $22,000 in electricity"


Maine Home Builders"

•  Least-cost solar financing "•  Build into the mortgage"•  Works because solar systems last so long!

–  Buy it with your new home – !–  Monthly energy savings outweigh increased payment. !–  Include it when you refinance —!–  Add the capital cost of retrofit to mortgage balance. !

•  Return on Investment (ROI) for PV!•  Under conservative assumptions (output and eq. Life)"•  2.0 kW system represents (after state and federal

rebates) an annual return on investment (ROI) of ± 9%"


Europe"

•  Austria has same climate as Minnesota"–  40x more SDHW installed than California"–  1/4 population base"


Solar Thermal Collectors"

•  Glazed Flat Plate"

•  Evacuated Tube"


Flat Plate Collector"

Outflow"

Inflow"

Enclosure"

Glazing frame"Glazing"

Absorber plate"

Flow Tubes"

Insulation"


Evacuated Tube Collector"

Inflow"

Outflow"

Evacuated tube"Cover glazing"

Outer glass tube"Absorbing coating"

Cross Section"Inner glass tube"

Fluid Tubes"Cooper Sheet"Evacuated space"

Reflective surface"


Solar Hot Water Systems"

•  Closed Loop"–  Antifreeze in

collector loop"

–  Year-round operation"


Solar Hot Water Systems"

•  Open Loop"–  Direct feed

to storage tank"

–  Seasonal operation in cold climates"

–  Pools"


Solar Hot Water Storage"

•  Storage Tank with Internal Heat Exchanger"

•  Storage Tank with External Heat Exchanger"


PV Systems"• Grid-Tied"

•  inverter, one or more meters, utility access"


PV Arrays"•  Building Integrated"

Shingles "

or Metal"

Panels"

•  Roof-mounted"

Can be flush mounted or mounted on racks on flat or low-slope roofs"


Balance of System (BOS)"

•  Exterior Controls"

"Utilities can require access for control of system"

Interior Controls - where allowable by utility"


Solar Ready Design Issues"•  Orientation of roof face to solar"

•  Slope of roof face to solar"

•  Unobstructed/unshaded area on roof face for collectors"

•  Roof loading"

•  Floor space for additional equipment"

•  Wall space for additional controls"


Solar Ready Service Issues"

•  Install Conduit (straight run only)"

•  Pre-plumb from attic to utility room"

•  Pre-wire from attic to utility room"


Orientation of Roof Face"

•  SE to SW quadrant optimal"– SE = more morning sun"– SW = more evening sun"

•  E and W orientations are less efficient but still give benefit"


Roof Slope"

•  Roof slope = latitude of site ± 10° for year-round performance"– Summer performance latitude minus 15°"– Winter performance latitude plus 15°"

•  Lat. 45°N year-round = 8:12 to 16:12 slope"•  Lat. 45°N summer = 7:12 slope"•  Lat. 45°N winter = 20:12 slope (Vertical)"


Unobstructed Roof"

•  Route all roof penetrations away from south-face roof, or move to the ridge area. "

•  Dormers and satellite dishes adjacent to the collector site will cause shading.!


Roof Area"

•  Allow ± 1500mm x 1500 (10x10 ft)"– Flat plate collectors are 1200mm x 2400mm

(4 x 8 ft) each, with 2 panels for typical DHW system"

– Vacuum tubes are 1800 to 2400 mm (6 to 8 ft) long, in banks 900 to 1200 mm (3 to 4 ft) wide)"

•  For aesthetic reasons, a larger space may be required!


Roof Loading"•  Collector ‘filled’ weight = 20kg/m2"

–  Most likely no extra support required, BUT..."•  If system has storage on roof, size accordingly"•  Racked systems have higher wind loading"•  Low slope roofs = special loading considerations"

•  Include bracing between trusses or rafters. "•  2x8 @ 600mm (24 in) o.c. will cover most mounting systems."•  Spacing dependent on type of system "!

•  Install small access catwalk"•  Ensure enough height to work in space"


Rough-in Conduit"

•  Feeds from collectors are insulated 12.5mm (1/2”) to 19mm (3/4)�”copper pipes "

•  Require 75mm (3”) or 100mm (4”) ABS or PVC conduit from utility space to attic, straight run"–  Or 2 - 50mm (2”) conduit"

•  May require floor plan changes to get straight-run for 3” or 4” pipe"–  1-storey do-able"–  2-storey: challenging"


Pre-Plumbed and Wired"

•  Two insulated 12.5mm (1/2”) to 19mm (3/4)�”copper pipes "–  Install from attic to utility space"–  Pressure test"–  Cap and seal"–  Label!"

•  2 - 24V, 14-gauge shielded wires"–  Label!"


Pre-Plumbed Solar Bypass"

•  Install solar plumbing connections "– Solar bypass valve installed on cold water

feed to hot water tank"– Cap and seal"

• may require backflow preventer and pressure tank as well"

–  Label!"


CanSIA Solar Ready"

•  Program focussed on Marketing Support to Builders"–  Include SR tag for

labelling of conduit, plumbing and/or wiring visit: www.cansia.ca"


Floor and Wall Space"

•  Allow utility space for storage tank, plus additional square footage to allow access to tank for service/replacement "

•  600 x 1200 mm (2x4 ft) floor space "•  600 x 900 mm (2x3 ft) wall space for controls"•  No windows or electrical panels behind utility

space"


Floor Loading"

•  200 to 300L storage tanks weigh about 270kg to 400kg filled"– Basement/concrete floors no problem"

•  If water heater is installed in other area, ensure that storage tank location will stand extra loading"


Range of Costs"

•  Variable, depending on house design"–  Redesign of roof"–  Redesign of floor plan/mechanical vis a vis roof"–  2- 2” conduit"

•  ± $300 for installation"

Plumbing " " "$60.00"Electrical Outlet " "$40.00"2-2” C-Vac conduits " "$150.00"Design Time (per plan-set) "$50.00"Stickers " " "$2.00""Total " " "$302.00"


Solar Ready Pilot Project"

• Two basic issues:"1. How to build it "2. How to sell it "

• What’s different?"•  Roof: pitch, orientation, obstructions"•  Subdivision planning"•  2 - 2” conduit, straight run built into design"•  Mechanical Room"


Project Current Status"

•  18 houses built"– 3 have solar DHW installed"

– European clients accustomed to seeing collectors on homes"

– Promoting as a premium entity"


The Tarry Residence (completed December 2006)

The solar panels are just visible on the roof behind the porch. "

The First Solar Thermal Installation


The Ivystone Model Home

•  Solar Thermal Hot Water System displayed in Model"

•  Demonstrates the system to customers"

•  Installation allowed builder to gain experience with the system."

•  (Home was a 2007 OHBA Awards of Distinction Winner)"


The Lambert Model Home

•  Solar Thermal Hot Water System displayed in Model."

•  (Home was a 2007 OHBA Awards of Distinction Winner)"


• Solar Panels on roof to left of the upper balcony.

The Ivystone Rear Elevation


Demonstration Homes

•  Each of these homes are equipped with Solar Thermal Heating Systems for the Domestic Hot Water Needs."

•  All three homes are production homes, built within a traditional subdivision. The lots are typical in design, with no Solar Orientation changes on the part of the Developer."

•  In Addition all Three Homes are finalists in their categories for the 2007 National SAM Awards."

•  These homes show that Solar Thermal Homes can be well designed with Award Winning Curb appeal."

"


Issues: Site and Orientation"

•  Perfect Solar Aspect:"– Custom solar homes often

on 1Acre lots"

•  Production builder, few site options:"

– 36 ft wide lots"– less than optimum

orientations"– obstructions and shading"

– East/West running street"– Lose 50% of homes

automatically if cannot use front (South) elevation on North side of street"

– Vaulted great rooms @ back of South side of street w/complex rooflines limits potential further"


Issues: Sites and Roofs"

•  Two cases, similar loss of efficiency:"– Unobstructed west-facing roof"– Bungalow in shadow of 2 storey"

•  South roof shaded for some months"

•  West facing roof is out of range of CanSIA guidelines for Solar Ready"

•  However, could provide normal range of solar gain Mar through Oct"


In the field 3: west-facing panels"

•  Lambert model, installation day. "

•  Because of street alignment, this system is on a primarily West facing roof. "

•  Note the use of roof jacks and a 2” x 10” working platform during installation. "


Issues: Rooflines"

•  Modify and redesign?"– No roofline repetition:"

•  Orientation issues"•  Streetscape"•  Unlikely to have clients OK with design

restrictions based on solar aspect"

•  Cannot pass cost of roof redesign for solar onto client"


In the field: rooflines 1"•  Gable End Roof Designs are a

problem when the front of the home faces South or West."

•  Vaulted Roof Designs can also create problems both for placing the panels and for attic access space"

•  This is an actual client home that was not changed before agreement & there was no orientation that worked for the panels."


In the field: rooflines 2"•  In this case the roof was redesigned

to be a Cottage Style. The client then signed off on the re-design.

•  This change was slightly more expensive than the original design, but since it was discovered after the agreement, the builder could not recover the added cost.

•  In this market there is the added complication of restrictions on repetition of elevations within a certain number of units.


Issues: Framing"

•  100 mm (4”) conduit won’t fit in 2x4 wall. Options:"–  75mm (3”) "–  2 - 50mm (2”)"

•  Sticker on each end of conduit w/website link for reference"


Issues: Design and Plans"

•  Open concept, 2 storey homes difficult "•  No stacked walls "•  No direct vertical routes"•  50% of 2 storey designs needed reworking to

get conduit stack location"

•  Solutions"•  Set dimensions from mechanical room"

– Cross check on each floor: 30 minutes"


In the field: notes and symbols 1"

•  These are the Solar Panel Symbols used on roof elevation with a 9/12 pitch. "

•  Used for Roof Elevation Check and Future Location Note on Client Plans."

•  Note actual size of panel location on roof plan is 9’ x 9’ (for two panels)"

"


In the field: notes and symbols 2"

•  The Solar Panel Symbol indicates the future location on the elevation drawing. "

•  The corresponding vent stack note is visible above the roof."

"


In the field 5: floor plan symbols"


Issues: Attic Space"

•  No easy access"– Position conduit at least 2m (6 ft) away from

eave to allow trades room to work"


In the field 4: conduit stack"

•  These are the two principal mechanical symbols."•  Used to locate the installation on the plans. "•  These symbols will also be made available to NRCan

for builders that choose to participate."


In the field 4: conduit stack 2"

If the plumber puts a vent stack in your only viable spot for the panels, it’s no longer Solar Ready.


Issues: Specifications"

•  Energy Star Homes (Ontario)"– Fully weighted to PV, yet solar thermal is

paying dividends now"– Suggest a tiered system:"

•  South orientation gets 400kW credit"•  West is less, say 200 kW credit"


In the field: installation diagrams"

•  Installation Diagram from EnerWorks."

•  Provided to Plumbers for Installation Guidelines."

•  Plumbing Note on Basement Plan: “Provide Valves & T’s For Solar Ready Hot Water Tank.”"


Issues: Market Impacts"

•  West facing system has ± 13 year payback"– Better if payback were 7 to 8 years"– Need incentive in place"

•  Lack of ‘solar’ sites:"– Better to have 40,000 homes @ 70%

efficiency vs. 400 perfectly sited homes"

Business

Shawna henderson_solarthermal_aci2008