passive solar -types -features -costs -case studies david hammes: permanent student of solar and all...

Passive Solar-Types

-Features-Costs

-Case studies

David Hammes: permanent student of solar and all things renewable energy; sustainability, green building materials &

design

EnergyWithoutBorders: Comprehensive resource and global network for all things renewable energy, efficiency, sustainability

locally, worldwide

Types “Passive Solar” may pertain to various solar technologies• Most common usage associated with Passive:Using the sun to heat (or cool) a building through proper use of

Site / Building orientation- Glazing/ Glass

- Shading / Overhangs- Thermal Mass / Insulation

- Geographic climate conditions

Site / Building OrientationBegin with Energy Efficient design

strategies-South side to face 30 degrees +/- of

true south-Long axis runs east-west

-Not blocked by other structures, buildings, trees, hills, etc.

Peace ValleyNature Center bySunPower Builders

Peace ValleyNature Center

Sun Power Builders

Peace ValleyNature Center

Peace ValleyNature Center

Facing South and West- no glazing

???

South FacingLight shelf ShadingGlazing

Glass/ GlazingChoose the right type based on facings and climate conditions

orient the glazing based on optimizing winter sun heat gain and minimize summer heat gain

Factors to consider: Insulated, emissive coatings,types and functions, styles, colors, performance

Quantity facing north / westQuality day light

ambient, reflective, heat capture, stack effect

OrientationClimate

New Idea?

New idea

South face, stack effect, solar heat

gainNaturalday light

Sun space

Energy Loss:

Some of the greatest energy loss can be through glass-

70% of loss is heat, 46% air conditioning (government study HUD)

Special windows / technologyElectrochromic: A small electrical charge effecting

materials/ chemicals between glass layers change the light/ heat emissivity based on the desired amounts, time of year, etc. Solar Energy Industries Association claims that "smart" windows can save as much as 50 percent of a building's energy use

Types of Energy Loss

• Infiltration: LEAKS!

• Conductive: through materials

Radiation: air against materials

• More meaningful measurement beyond “R” and “U” values is the Energy Rating (ER) system

• Same amount of heat gain as loss = 0 ER• Net ER = amount in vs amount lost. • Average double pane glass window = negative 35 ER• Low “E” glass in insulated window = negative 11 ER• 6” fiberglass wall = negative 3 ER• Optimum heat gain and loss = +[ x] number of windows. Net gain in

energy• = net positive $ value• Low E coatings where needed, high emissivity where optimal, proper

shading = positive Energy Rating

Glass Efficiency:Single glass - “R”

(resistance) value of .87

Typical double-pane insulated * window is 2. to 3 “R” value, argon gas.

Super insulated can be near R-10

Other technologies: krypton gas,tripple-pane, automatic shading

It’s all about “U” btu/hr/sf/f

Infiltration= air leaks average about 20% of the energy loss Conduction=

transfer of heat/ cool through solid materials (glass, frame, etc.). This is 60% of the loss Radiation=

20% of loss- air touching glass: feels like breeze! Heat travels to cold.

• Infiltration on a typical 3’ x 5’ window is equivalent to a hole the size of a 3”x8” brick

• Conductivity on a typical 3’ x 5’ window = 3 – 3”x8” bricks

• Radiation on typical 3’ x 5’ window = 1- 3”x8” brick

• (normal condition window)

Copy rights EnviroView Corp.

Shading / Overhangs• Design strategy includes proper angles for sun

shading: optimize summer sun blockage and winter sun allowance for solar heat gain

For glazing: 40 degree angle winter roof overhang relation to wall, 80 degrees relation to wall summer (from bottom of glazing)

-

Thermal Mass + InsulationUsing proper efficient building materials and

techniques will save money, energy usage and offer a rapid ROI for Passive (or any) solar integration

Sealed, insulated building envelope such as SIPs, extra insulation, radiant barriers, attic ventilation make passive solar performance more effective….

Sample Passive Solar Components• Glazing, glass with proper orientation• Thermal mass: Trombe walls to collect sun’s heat • Dark floors (slate, masonry) absorb heat• Light floors strategically placed reflect light where

needed• Solar Light Tube- reflecting/ refractory light/ skylight• Stone Heater (10’x10’x10’ stone-filled bin heated with

passive solar heated air to release warmth at night)• Solar air heaters- black corrugated metal sheets

encapsulated (or not) with perforation and venting controls

Atas™ Solar Wall

Hot AirFresh Air

Ventilation

Atas Inspire Passive Solar

Wall

SolaTube™

Climate conditionsSun blockage from trees is good – in the sunbeltEvergreens can be good on the north and west face

in the North/ Northeast US. Extra glass & glazing, even with less R value – is fine

in areas where there is a moderate temperatureExtra U value and energy rating values are

important for glazing in extreme weather conditions

“World’s greenest building”

Hearst Tower

20% less Steel than typical sky-scraper

Considerations: Approximate range of $2 per square foot for

energy costs in a typical commercial building.And $20 per square foot for real estate value.But $200 per square foot for employee costs;

…what does this mean?....

Case studies: Proper comfort levels, heating, cooling, Indoor Air Quality, Day Lighting, reduced glare, natural day light harvesting; employees are happier, more productive,

absent less frequently, (health costs go down).10% increase in employee satisfaction and

performance through Passive Solar (and other clean technologies) you offset (a portion of) your building’s energy costs.

• Glass: melting silica and lime and sodium carbonate. Add metallic properties through “sputtering” resulting in a wide variety of performance, each designed for specific results.

• Titanium and silver reflect specific long (heat) wave lengths of the spectrum. Copper, iron, etc. reflect other wave lengths determining performance and appearance.

Glass with the least amount of additives or coatings gains the most long (heat) as well as short (visible) waves of the spectrum.

This is evident in “solar glass” for PV where you want maximum waves.

SyntheticCoatingsFilmsFilter heat& light

But use the right ones!

• Metallic Oxide layers create low “E”. • Grey, Green, Blue, Bronze, Copper colors allow for

varying light transmittance: Grey is approx. equal visible and infrared. Bronze is less visible but more infrared.

• If you are trying to gain heat but create a look, then you must weigh characteristics carefully. A wrong choice results in an opposite desired effect and a huge cost and wasted energy over the life a building.

OxidesColoring

Red BIPVruthenium

Some Features of Passive Solar• Significant savings in building operational costs-

especially over the life of the building• Fewer light fixtures, less energy used to manufacture,

install, service, replace and maintain• Greater health, performance and occupant comfort

levels ($avings)• Smaller HVAC demands, less equipment, less energy

costs, less labor, less fossil fuels usage• Initial cost savings and/ or minimal cost to commission

Commercial glass

building

2 houses, $800,000 ea. Total of 60 sf of glazing on true south.

Case StudiesCapistrano Unified School District (California) and

the Seattle Public School District (Washington) answer questions from the peer review panel. The [] findings are as follows: (1) overall, students in classrooms with the most daylight showed a 21 percent improvement in learning rates compared to students in classrooms with the least daylight; (continued)

Case Study continued (2) a teacher survey and teacher bias analysis found no

assignment bias that might have skewed the original results; more experienced or more educated teachers ("better" teachers) were not significantly more likely to be assigned to classrooms with more day lighting; (3) a grade level analysis found that the day lighting effect does not vary by grade…..[..]These results, which are consistent with the original findings, affirm that daylight has a positive and highly significant association with improved student performance. These findings may have important implications for the design of schools and other buildings. Report NO: P500-03-082A3

Grande Palais

Passive old

greenhouse

Grande Palais

Thank you!http://energywithoutborders.com/solar-power/

David Hammesdavid@energywithoutborders.com

215 534 3889Solar and all things Renewable Energy, Sustainability

Energy Efficiency locally, globally