Summer Solstice

It’s officially summer here in the northern hemisphere. That means street festivals and backyard barbeques, but more importantly warmer, longer days. Well, relatively longer, for now. In addition to Father’s Day, last Sunday, June 21 was Summer Solstice, the longest day of the year. Days will become incrementally shorter by seconds and minutes as the sun slowly falls lower in the sky, until it reaches its lowest point at Winter Solstice on December 21. But let’s not think of that dreary time. Instead, let’s think about what Summer Solstice means beyond its festive significance.

Generally speaking, solstices are the two instances each year where each of the earth’s axes are tilted at their peak distance toward or away from the sun. In the northern hemisphere, these occur on June 21 and December 21, the Summer and Winter Solstices, respectively the longest and shortest days of the year. The axis of the earth is tilted at a constant 23.5 degrees, and depending on the point at which the earth is found on its revolution around the sun, this tilt determines the seasons. For example, summer is characterized by more perpendicular rays of solar energy that hit the surface of the earth, and the Summer Solstice is the time of year where solar rays are at their most direct angle. These angles are called solar incidence, and they determine the amount of solar energy a place will receive. In contrast, the northern hemisphere receives more acute angles of solar incidence in the winter, hence the sun’s lower position in the sky and shorter days.

While the sun is positioned higher in the sky and we receive more direct solar energy down here on earth, how does this affect our daily habits? More than the outdoor activities and short-sleeved shirts, the acuity of solar rays and received solar energy is evident in our living spaces. My apartment in Chicago lacks central air-conditioning and is at the top of a six flat building. It can get unbearably hot and muggy inside if it weren’t for my building’s location off of Lake Michigan, where the usual cool breezes coming off the water keep the apartment’s interior temperature mostly livable. However, the structure’s design is made not for the permeability of interior temperature; rather it was made to keep the heat in, with a brick exterior and solarium in the central stairwell. This typical residential architecture in Chicago pervades the city and many of the residential structures in the suburbs. Our reliance on heating and cooling devices, which themselves rely on unsustainable energy sources, is climatologically and ecologically insufficient. That is to say, for the lack of an HVAC system and the sun’s most direct rays of the year, it was quite warm in my apartment this past Sunday.

Complaints aside, there are architectural solutions that can replace those with which my 100 year old building was designed. Elements that take into consideration the solstices, Spring and Fall Equinoxes, climate zone and topology of the landscape in which structures are to be erected can affect the interior functionality and livability of a building. Twenty-five such designs will be offered in our upcoming Fall exhibition Lessons From Modernism: Environmental Design Strategies in Architecture, 1925-1970. Several modern architects, from Le Corbusier to Marcel Breuer, designed ecologically and climatologically sustainable structures planned for various locations throughout the globe that seriously considered topographical characteristics and, perhaps most importantly, solar incidence. So, while the sun is still high in the sky, take a minute to think about the functionality and habitability of the structures you frequent or live in, then mark your calendar for Lessons From Modernism this coming September to see how sustainable design can effectively create more comfortable living and working spaces.

PG

The Karuizawa Summer House, designed by Antonin Raymond, is one example of the 25 projects studied in Lessons From Modernism: Environmental Design Strategies in Architecture, 1925-1970. Raymond was one of the many modern architects who deliberately considered the site at which the building would be built, including the topology of the landscape, airflow, and solar incidence. In its aerial and cross-section views, this chart exemplifies the angles of solar incidence: overall in the larger graphic on the left, Summer Solstice in the top right, Spring and Fall Equinoxes in the middle, and Winter Solstice in the bottom right.