The sun is the center of our solar system. The energy it releases warms our planet and powers all life on earth. Through photosynthesis, solar energy is transformed into organic matter; the food that makes our life possible. The fossil fuels we use are actually stored energy. Solar energy is also incredibly abundant. Half a day's sunlight falling on the US provides enough energy to run 300 million people for one year.
We often think that modern society were the first to use solar energy. We've been using since the beginning. Early cave dwellers preferred caves that had openings facing south-east. This allowed the morning sun to warm them up without overheating in the warm months. Native Americans in the southwest oriented their pueblo style houses so the low winter sun would heat the buildings by direct solar radiation. Cliffs and overhangs blocked the sun during the summer months, helping to keep the dwellings cooler when the sun was high in the sky.
The ancient Greeks, with a climate that was sunny almost year-round, built their houses to take advantage of the sun's rays during moderately cool winters, and to avoid the sun's heat during the summer. Modern excavations of many classic Greek cities show that individual homes were oriented towards the south and entire cities were planned to allow equal access to the winter sun. It is interesting to note that by 500 B.C., when the Greeks had almost completely deforested their whole country and needed to find a reliable alternative fuel source, they chose solar energy.
The Roman Empire advanced solar technology by adapting home building design to different climates, using clear window coverings to enhance the effectiveness of solar heating, and expanding solar architecture to include greenhouses and large public bath houses. Solar architecture became so much a part of Roman life that sun-rights guarantees were eventually enacted into Roman law. This society depleted its forest resource as well.
After the fall of the Roman Empire, the use of glass to enhance solar gain in buildings was mostly forgotten. Interest in passive solar architecture and greenhouses was rekindled during the Renaissance. As technologies advanced, glass manufacturing was revived, resulting in an increased use of glass windows. This also made large greenhouses possible for agricultural purposes as well as for recreation.
In the 1700s, a leading naturalist named Horace de Saussure began to experiment with solar hot boxes. These precursors to today's active solar collectors were simple insulated boxes painted black on the inside and with one side covered with glass. They were very similar to today's solar cookers and in fact, many early experimenters used their hot boxes to cook. Many of the solar principles we use today were identified during those early experiments. Unfortunately, these experiments resulted in few successful applications.
During the late 1800s domestic water piped directly into homes became more common. Like today, this water supply was cold. People soon wanted running hot water. At first, all water heaters were either coal or wood fired. In 1891 Clarence Kemp patented the world's first commercial solar water heater, called the "Climax". It was a black painted water tank mounted in an insulated box with glass on one side.
The Climax was instantly popular in California, where it could be used year-round. Thousands of Climaxes and similar systems were installed in a short time. They all fall into what we now call "batch-type" solar water heaters: the sun heats the water directly in the tank and the hot water is stored in the collector tank.
In 1909 a California engineer named William J. Bailey began selling a system called the "Day and Night" solar water heater. It consisted of a solar collector and a separate storage tank mounted above the collector. His tanks were among the first to be insulated for better heat retention and his collectors consisted of a pipe grid attached to a flat plate and enclosed in a compact glazed and insulated enclosure. Cold water dropped down into the sun. As the water was heated, it rose up into the insulated storage tank for later use. Today, we call these heaters "flat plate" collectors.
In 1913 a freak cold snap hit southern California and many Day and Night collectors froze and burst. To eliminate future freezing problems, Bailey installed a coil of pipe within the storage tank to act as a heat exchanger. Then he used an alcohol and water mixture as the antifreeze solution for his heat exchange medium. As the sun warmed the solar fluid, it rose up to the storage tank heat exchanger. As the heat from the solar fluid was transferred to the water in the storage tank, the solar fluid collected and dropped to the collectors for further heating. This system is described today as a "closed-loop" solar water heating system.
Between 1920 and 1930, huge deposits of natural gas were found in the Los Angeles area. To capitalize on this new, cheap fuel source, Bailey began to manufacture a thermostatically controlled gas water heater. Sales of his gas heater took off and sales of solar heaters plummeted. Gas companies offered generous incentives to hookup to their new gas heaters. Bailey made his last batch of solar water heaters in 1941.
During this same time period, entrepreneurs took the California solar water heater designs to Florida and were met with great success. In a building boom between 1935 and 1941, up to 60,000 systems were installed. More than half the population of Miami used solar water heaters by 1941, and 80 percent of the homes built between 1937 and 1941 were solar equipped.
World War II all but halted solar water heater installations. Copper was a major component of solar water heaters and the use of copper was frozen for all non-military use. When the war was over, solar companies came back, but other factors soon led to their decline. Existing solar water heaters were too small to meet the new, increased demand for automatic washing machines and dishwashers. In a final blow , electrical rates fell to half their cost before the end of the war, making electric water heating much more affordable. In an aggressive campaign to increase electrical consumption, Florida Power and Light even offered free water heater installations. By this time, many of the original, ageing solar water heaters were experiencing leaky tanks and plugged pipes. Many homeowners found it cheaper to install an inexpensive electric water heater than fix their solar water heating system.
In the United States,the 1950s and 60s were years of unbridled energy consumption. For all but a few, solar energy was a non-issue. This changed with the first Arab oil embargo in 1973, when Americans experienced long lines at gas stations, limited supplies of other oil products like heating fuel, and energy prices that doubled and tripled. President Jimmy Carter helped make energy efficiency and the use of renewable energy a national priority, symbolized by his donning a sweater and installing a solar water heater on the White House roof.
The oil embargo profoundly changed the United States. Coming at the end of the Vietnam War, it added to America's realization of its vulnerability. For the first time since World War II, Americans looked at how they used energy. Consumers began to demand higher energy efficiency standards in everything from homes to automobiles. People also looked to renewable energy sources to replace some of the fossil fuels they were using.
The whole nation took on the challenge of reducing its dependence on oil from the Middle East. Renewable energy sources were rediscovered and new companies sprouted everywhere to fill the growing demand. Government spending on renewable energy research and development increased from around $1 million to over $400 million. While this was a small fraction of the attention and money given to the nuclear industry, it was a dramatic change nonetheless.
During the 70s and early 80s, installing solar energy systems was seen as patriotic. The federal government, as well as many states, passed legislation encouraging the use of solar energy systems through tax credits. Federal incentives combined with state incentives (where available) often offset over 50 percent of the cost of many renewable energy systems. A new solar boom began. People looked to wind-powered electric systems, advanced passive solar heating systems, the newly emerging solar electric systems, and advances in energy saving technologies, a swell as the old reliable solar water heaters.
Most of the solar energy companies that sprung up in the 1980s were reliable firms that installed quality systems. Unfortunately, with the headlong plunge into the use of renewable resources by the general public, a few companies selling inferior products and doing inferior work joined the fray. Some brought products to the market without proper testing. Others just wanted to make a quick buck and didn't care if they were taking advantage of well-intentioned consumers. while most renewable energy systems were of good quality, the minority that weren't gave solar a bad name.
The young solar industry was experiencing the typical growth pains that come with most emerging technologies and took steps to correct the problems. The federal government as well as many state governments also stepped in to ensure higher quality.
This move towards renewable energy did not sit well with those who profited from selling fossil fuels. After the most expensive presidential campaign ever, financed in part by oil interested, Ronald Reagan became president of the United States. His presidency heralded a return to fossil fuels. One of his first acts as president was to remove the solar water heater on the White house that President Cater had installed. Between 1981 and 1986, Reagan effectively gutted the US solar industry. He negotiated a repeal of the tax credit legislation for renewable energy by 90 percent. He also spearheaded a massive campaign to discredit renewable energy. The result was a 91 percent drop in the sales of solar hot water collectors between 1984 and 1986. The solar market in north America from the 1980s through the 1990s was primarily supported by customers who wanted to invest in renewable energy for environmental reasons. For an in-depth analysis of this subject, read Who Owns the Sun: People, Politics, and the Struggle for a Solar Economy by Daniel Berman and John O'Connor. Their very thorough and thought-provoking book will change the way you look at energy and politics forever.
While North America abandoned it's use of renewable energy, virtually all other developed nations in the world continued to embrace renewable resources and energy efficiency. As a result, of this continued effort, our European and Asian trading partners reduced their energy consumption as related to gross national product up to one half that of North America. They also reduced the energy they need to support a similar lifestyle to half that of the United States. Some countries, like Israel, require solar water heaters be installed on all new dwellings and businesses. Developing nations and Third World countries are also embracing renewable energy technologies over traditional fossil fuel energy sources. While their track record is not perfect, their attitude towards renewable energy is significantly better than that of North America.
Tags: History of Solar Energy, History of Solar Heating.