Presentation on theme: "Passive Solar Types Features Costs Case studies"— Presentation transcript:
1 Passive Solar Types Features Costs Case studies David Hammes: permanent student of solar and all things renewable energy; sustainability, green building materials & designEnergyWithoutBorders: Comprehensive resource and global network for all things renewable energy, efficiency, sustainabilitylocally, worldwide
2 “Passive Solar” may pertain to various solar technologies Types“Passive Solar” may pertain to various solar technologiesMost common usage associated with Passive:Using the sun to heat (or cool) a building through proper use ofSite / Building orientationGlazing/ GlassShading / OverhangsThermal Mass / InsulationGeographic climate conditions
3 Site / Building Orientation Begin 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.
10 Glass/ Glazing Choose 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 / west Quality day light ambient, reflective, heat capture, stack effect
16 Energy Loss: Some of the greatest energy loss can be through glass- 70% of loss is heat, 46% air conditioning (government study HUD)
17 Special windows / technology Electrochromic: 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
18 Types of Energy Loss Infiltration: LEAKS! Conductive: Radiation: through materialsRadiation:air against materialsTypes of Energy Loss
19 More meaningful measurement beyond “R” and “U” values is the Energy Rating (ER) system Same amount of heat gain as loss = 0 ERNet ER = amount in vs amount lost.Average double pane glass window = negative 35 ERLow “E” glass in insulated window = negative 11 ER6” fiberglass wall = negative 3 EROptimum heat gain and loss = +[ x] number of windows. Net gain in energy= net positive $ valueLow E coatings where needed, high emissivity where optimal, proper shading = positive Energy Rating
20 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-10Other technologies: krypton gas,tripple-pane, automatic shadingIt’s all about “U” btu/hr/sf/fInfiltration=air leaks average about 20% of the energy lossConduction=transfer of heat/ cool through solid materials (glass, frame, etc.). This is 60% of the lossRadiation=20% of loss- air touching glass: feels like breeze! Heat travels to cold.
21 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” bricksRadiation on typical 3’ x 5’ window = 1- 3”x8” brick(normal condition window)
23 Shading / OverhangsDesign strategy includes proper angles for sun shading: optimize summer sun blockage and winter sun allowance for solar heat gainFor glazing: 40 degree angle winter roof overhang relation to wall, 80 degrees relation to wall summer (from bottom of glazing)
25 -Thermal Mass + Insulation Using 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….
26 Sample Passive Solar Components Glazing, glass with proper orientationThermal mass: Trombe walls to collect sun’s heatDark floors (slate, masonry) absorb heatLight floors strategically placed reflect light where neededSolar Light Tube- reflecting/ refractory light/ skylightStone 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
30 Climate conditions Sun blockage from trees is good – in the sunbelt Evergreens 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 temperature Extra U value and energy rating values are important for glazing in extreme weather conditions
31 “World’s greenest building” Hearst Tower 20% less Steel than typical sky-scraper
32 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 $200 per square foot for employee costs; …what does this mean?....
33 Case studies: Proper comfort levels, heating, cooling, Indoor Air Quality, Day Lighting, reduced glare, natural day light harvesting; employees are happier, more productive, absent less frequently, (health costs go down). 10% increase in employee satisfaction and performance through Passive Solar (and other clean technologies) you offset (a portion of) your building’s energy costs.
34 Glass: melting silica and lime and sodium carbonate Glass: melting silica and lime and sodium carbonate. Add metallic properties through “sputtering” resulting in a wide variety of performance, each designed for specific results.Titanium and silver reflect specific long (heat) wave lengths of the spectrum. Copper, iron, etc. reflect other wave lengths determining performance and appearance.Glass with the least amount of additives or coatings gains the most long (heat) as well as short (visible) waves of the spectrum.This is evident in “solar glass” for PV where you want maximum waves.
35 SyntheticCoatingsFilmsFilter heat& lightBut use theright ones!
36 Metallic Oxide layers create low “E”. Grey, Green, Blue, Bronze, Copper colors allow for varying light transmittance: Grey is approx. equal visible and infrared. Bronze is less visible but more infrared.If you are trying to gain heat but create a look, then you must weigh characteristics carefully. A wrong choice results in an opposite desired effect and a huge cost and wasted energy over the life a building.
39 Some Features of Passive Solar Significant savings in building operational costs- especially over the life of the buildingFewer light fixtures, less energy used to manufacture, install, service, replace and maintainGreater health, performance and occupant comfort levels ($avings)Smaller HVAC demands, less equipment, less energy costs, less labor, less fossil fuels usageInitial cost savings and/ or minimal cost to commission
41 2 houses, $800,000 ea. Total of 60 sf of glazing on true south.
42 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)
43 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: P A3