We love the sun. I think we are solar powered, Steve and I. Even our dog seeks out a patch of sunshine beaming through the window for a snooze.
I don't know where you are, but it's been snowing here for 2 days. We're expecting 13" - 14" to dump on us. Steve's been shoveling the driveway literally all day long while the dog plays as if he were a seal sliding, hopping, and frolicking in the deep snow. No better time to talk about sunshine!
The Power of Sunshine
The radiant light and the heat we feel from the sun is called solar energy. Solar energy is the cleanest and most abundant renewable energy source on Earth.
Sunshine can be harnessed, directed, and converted into usable thermal or electrical energy.
Solar panels - Panels designed to absorb the sun's rays to generate heat or electricity.
Solar water heating - I found this great article recently about two sisters in Cairo who created a way of using the sun's heat to provide homes with warm water.
Solar architecture - Solar architecture is a design approach for building solar powered structures. A greenhouse is a great example of solar architecture.
Direct Sunshine
The first and foremost important factor necessary for passive solar power optimization is the location of the site. The site must have unobstructed southern sun exposure. Ideally a deep lot from north to south, with the house situated on the north end of the lot. As I've mentioned before, that's where Steve's expertise again shines forth.
Steve selected our land with solar design already in mind. The grand view of the mighty Hudson River, that's extra credit. He also considered the future use of the land to the south/southeast of our site. For our location, on top of a mountain, it is highly unlikely a future multi-story building will block our access to all day southern sunshine.
Steve is designing Bahay Namin with his bucket list of energy-efficient technology in mind, incorporating solar architectural design.
Update: There's an actual list of energy efficient technologies for residential home owners that have financial incentives and rebate programs for the state of New York. Steve is going to use that as a check list. Link: Energy Efficiency Program
Solar Architecture
Here is a cross section of the bahay namin. Image A shows the south-facing master bedroom (first floor level) and Steve's office below (basement level).
The yellow arrows illustrate the summer sun at an 80° angle.
The blue arrows illustrate the winter sun at a 29° angle.
Note the length of the overhangs that Steve designed; long enough to block out the strong overhead summer sun, yet short enough to welcome in the warm winter sun.
What's the difference between ACTIVE and PASSIVE solar technology?
Active solar technology converts sunlight into usable heat and causing air movement for ventilation to heat and cool living spaces with mechanical or electrical devices.
Passive solar technology uses no mechanical or electrical devices.
What exactly is solar ARCHITECTURE?
Solar Architecture is a home design with passive solar technologies that take advantage of the building's sun exposure, site, climate, and materials to control indoor temperatures year round.
The main strategy aims to reduce the amount of energy a house needs to warm up during winter and cool off during summer.
How does it work?
A passive solar home design collects heat as the sun shines through windows and retains it in materials that store heat within the building structure.
A successful design will have the following elements:
(A) South facing windows — The site must have unobstructed southern sun exposure.
(B) Control — Any device used to shade the aperture area during summer months: awnings, roof overhangs, even trees.
(C) Aperture — A large glass area through which sunlight enters the building. The aperture should face within 30° of true south; and should have full sun exposure for at least 6 "sun hours" between 9:00 am and 3:00 pm during the winter (heating season). Efficient glazing allows solar radiation inside, and slows heat loss at night.
(D) Thermal mass — Commonly concrete, brick, stone, and tile. These materials absorb heat from the sunlight during the day, then radiates the same heat at night through the floor and walls. The materials absorb heat from warm interior air during the summer (cooling season), and tempers extremes during autumn and spring.
(E) Distribution — A method by which solar heat is transferred from where it is collected and stored to different areas of the house by air circulation, conduction, convection, and radiation.
Image B illustrates the necessary elements for passive solar architecture. Steve designed the overhangs (B - control) to block out summer sunshine thereby controlling the shade on glass (C - aperture). The porcelain tile floor (D - thermal mass) will absorb the daytime sunlight and radiate the heat at night. A ventilation system will circulate the heat through the indoor space (E - distribution).
He's adding one more bonus step for passively optimizing the radiant heat at night: curtains. Curtains will create an air pocket between the glass and the curtain, effectively serving as a barrier to further insulate all that harvested heat, slowing radiant heat loss.
To make it more futuristic-techno-modern, the drawing of the curtains open and closed will be electric and automated. Our smart house will have smart curtains on a programmed smart schedule that responds the changing sunrise and sunset.
Just for fun: Here's a photo of our passive solar dog.
Steve just said, "Actually, this model is highly inefficient. It results in a negative output of energy." LOL!
Stay tuned for my next post on sustainability: Geothermal Heating and Cooling
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