Recently I walked into a Home Depot and was greeted by a sales person who was selling photovoltaic systems. Finally, I said to myself, this technology is mainstream. The technology this person was selling is at least thirty years old. As a proponent of alternative energy technologies, it has been frustrating to see solar technologies be historically considered “alternative”, “fringe” or something those “hippies” used. Had this technology become mainstream sooner, and the rate of technological change propelled earlier, imagine what we could potentially have today.
What about solar? is a question I often hear from clients and I find myself giving a mini lesson explaining the different ways in which the sun’s rays can be used to illuminate, heat and generate electricity for buildings. This is a brief overview of how our building designs can take advantage of this wonderful, renewable energy source which can both benefit the owner’s financial well-being and our planet.
Passive Solar
Passive solar does not involve any mechanical systems. It is how a building receives the sun’s rays and subsequently heats up and stores the energy. I also like to include day-lighting strategies as passive solar. The placement of a building on a site, the micro climate, the building’s shape, materials and glazing placement all impact how a building will receive and store the sun’s energy. I think it is essential that architects pay close attention to all of these factors or risk having some spaces in the building overheating on sunny days. Also, a carefully planned building can make use of the sunlight to illuminate and heat spaces, which in turn helps reduce the amount of non-renewable energy consumed to operate the building. A poorly planned building can have the exact opposite effect as it can become over dependent on its mechanical and lighting systems, consuming more energy than it should.
For more information regarding Passive Solar Design, please see this article published by the Department of Energy:
http://energy.gov/energysaver/articles/passive-solar-home-design
Active Solar
Active solar technologies use various panels and collectors to capture the sun’s energy and store it in liquid antifreeze. The heated liquid can be piped throughout a building and used to heat spaces. In most cases an active solar heating system cannot stand alone and is integrated with a conventional heating system. Most buildings have a boiler that burns oil or gas to heat water and the heated water is piped through the building to radiators or air handlers which distribute the heat to the spaces. The water the boiler heats, whether it comes from a municipal supply or a well, is usually around 55 degrees Fahrenheit. The boilers heat the water to 180 degrees before it is distributed through the building. It is easy and relatively inexpensive to setup a solar preheat system. In this type of system the heated liquid from the solar collector is sent to a heat exchanger that transfers the heat to the incoming water from the municipality or well before it reaches the boiler. The boiler doesn’t have to work as hard to heat the water it distributes to the building because it is warmer than 55 degrees. The solar preheat system reduces the amount of non-renewable energy needed to heat the building.
For more information regarding Active Solar Heating, please see this article published by the Department of Energy:
http://energy.gov/energysaver/articles/active-solar-heating
Solar Electric
Photovoltaic systems are what most people think of when it comes to making use of solar energy. These systems are comprised of a series of interconnected panels that convert the sun’s light to an electrical current. These systems can be very large, as in the form of a massive solar farm, or as small as a battery charger. They can often be integrated with buildings and in essence become mini power plants. More often than not, when photovoltaic cells are integrated with a building, the electricity they generate does not go directly into the building but is rather fed back into the power lines and distributed throughout the power grid. The owner of the building gets paid back by the utility company, as law requires the utilities to purchase the electricity. Often on the residential scale, if a house is situated properly and has adequate roof space, it can easily generate equal to fifty percent of the electricity it consumes. There are great tax incentives to be gained from installing photovoltaic systems and there are a variety of purchasing and leasing options as well.
Listening to the radio I fairly regularly hear commercials from companies advertising solar electric systems. As I look around Beacon, the small city I live in, I see more and more roof tops with photovoltaic arrays. I am encouraged and hopeful that as we move into the future, we are getting closer to the ideal of creating buildings capable of generating the power they need to operate themselves.
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