Happy Summer Solstice to everyone living in the northern hemisphere! Today we celebrate the longest day of the year and the beginning of summer. Seems like a good day to discuss how we use solar energy.
We were disappointed, but not surprised, to learn from a Solarize Amherst site visit that our house and yard are too shaded and are oriented incorrectly to be good candidates for the installation of costly solar PV panels. But we have found many ways to use solar energy that are less expensive and have reduced our need for other more polluting sources of energy.
Cooking with sun energy:
Sipping iced tea yesterday with my friend Vicki, reminded me that it is time to start brewing some sun tea. So today I filled two glass jars with water. To one jar I added tea bags and into the other I put some freshly gathered leaves of mint and lemon balm. After they brew in the sun for half a day, I will strain the tea and place it in the refrigerator for a cool refreshing drink this evening!
One of the most enjoyable ways we use solar energy is to cook dinner in our Sun Oven. This week I made Khichri, an Indian dish. Starting on the electric stove, I briefly sauteed chopped onions, frozen green pepper slices and cinnamon stick, cardamom pods and cloves. Then I added uncooked rice and lentils and stir fried briefly. Finally I put in chopped kohlrabi (since I was out of potatoes), chopped kale (since I was out of cabbage) and a quart of canned tomatoes, salt and water. After bringing it all to a boil I transferred the covered pot into the preheated sun oven. I left it in the sun for about 4 hours and it was cooked and warm for dinner!
Heating with solar:
Back in 1998, we added windows to our south-facing living room, and it is amazing how the winter sun shining through those windows warms the room. At the same time we added the windows, weatherization teacher and energy efficiency builder Bick Corsa constructed a low-tech Thermal Air Panel (TAP) on the same south-facing wall. This shallow, glass covered box contains black painted metal roofing and is connected by high and low vents to the adjoining room. Air heats and rises when the sun shines on the TAP panel and enters the living space at 70 – 80 degrees F on a sunny day in late winter. This keeps the room comfortable even after the morning wood fire dies down. We later added a second panel on the second floor, although we cover it in the summer to avoid adding heat when we don’t need it!
Solar hot water:
According to the US Department of Energy, water heating accounts for about 15% of household energy use. We saved our pennies and in 2002 added a solar hot water system, which uses the sun shining on glazed panels on our roof to heat pipes full of an anti-freeze-like liquid. A little PV panel powers a thermostatically controlled pump and a large insulated tank holds a heat exchanger and the warmed water. Today I will switch off the backup electric hot water tank for the summer to save on our electric bill.
The energy from the sun, falling on earth, powers the weather cycles and the growth of plants, and is thus the foundation of life for us animals as well. Now we’ve burned so much of the ancient sunlight embedded in fossil fuels that its gaseous byproducts have altered our whole planetary climate system.
I read that more sun energy hits the surface of the earth every hour than the amount of energy used by entire global population in a year! So, fellow earth creatures, on this summer solstice, what are some ways you use energy from the sun?