Whether we know it or not, solar energy applications are fairly pervasive in society, and essentially break down into simple conversions of solar irradiance to do some kind of work found useful or interesting to society. In looking back across history, technologies and common intergenerational traditions of solar use, called solar vernacular, that have been developing for millennia. These developments in solar adaptation often coincide with a specific fuel constraints, something that we call the energy constraint response. It is interesting that it only takes a few generations to lose traditional intergenerational knowledge, as access to inexpensive and accessible fuels opens up other avenues for societies.
A quick example drawn from my solar historian colleague and friend, John Perlin, in his book Let It Shine: The 6,000-Year Story of Solar Energy. During the fifth century BC., the Greeks faced severe shortages of wood fuel. If you run out of winter fuel from say, deforestation, that means that you still need warmth within the home, but the cost of heating your home is too high. Archaeological remains demonstrated that home designs of that age evolved such that all houses could provide high solar utility (preference for solar services) from the Sun’s warmth during the winter months.
It is interesting that famous Greek philosophers and artists commented on this solar design of homes. Aristotle has commented that home builders would shelter the north side of a home to keep out the cold winter winds. Socrates also lived in a home heated by the Sun, and observed,
“In houses that look toward the south, the sun penetrates the portico in winter”
And in doing so, the light from the Sun heats the floor and walls and keeps the space warm. And it works even better with the glass enclosure of windows (which came much later). An interesting translation is that a portico is essentially just an older term for a porch. And just for fun, I’m adding a familiar image of the South Portico from the White House in Washington DC. If you have one, does your porch look toward the south? Did you know that this was a core part of the solar vernacular for the home? Solar always seems to have a story in our lives!
The Greek playwright Aeschylus further made a negative commentary on unspecified ‘primitive’ cultures that:
“…lacked knowledge of houses turned to face the winter sun, dwelling beneath the ground like swarming ants in sunless caves.”
Huh. Seems to speak to our own culture now, having all these years with accessible and inexpensive fuel access permitting us to not need to have “knowledge of houses turned to face the winter sun”, to just slowly forget the story of solar, the solar vernacular of our spaces?
And yet our relatively new solar space that we associate with photovoltaic technology (solar PV is a mere 175+ years old) is only recently emerging as a bellwether to re-awaken our very long story of solar. It is time to start expanding more on the story of solar. Hope to post more on this topic soon.
More reading on the Energy Constraint and Response can be found in my own solar course from Penn State. This course is open content licensed under Creative Commons CC BY-NC-SA 3.0, as a part of the Open Educational Resources initiative of Penn State’s John A. Dutton e-Education Institute.
-JRSB