Capturing Solar Energy
Three Approaches
Three different solar energy approaches are currently available for residential use: photovoltaic systems, passive solar heating, and active solar heating. Each type has a role to play in the smart home world.
Photovoltaic systems use photovoltaic (solar) panels to convert solar energy directly into electric power, which can then be used for any purpose, anywhere in the home—including heating and cooling.
Passive solar heating systems involve the careful design of the home itself—using windows to admit significant amounts of light (when the weather is cold outside), then use a concrete floor, wall, or other high-mass material to capture that solar energy, in order to heat the area. Alternatively, when it is hot outside, window shades are used to block the light from entering the home. This is done without the use of electrical or mechanical systems to move the heat from one place to another.
Active systems use water pumps or fans to move heat captured by a passive solar system from one place to another within the home.
Photovoltaic Energy
The most exciting news in solar energy today is the lowered cost and higher efficiency of photovoltaic (solar) panels that directly convert the sun’s rays into electricity. This concept has been around for decades—but the efficiency of the technology has improved greatly, and it may be possible to use it in new situations.
Recent advances in this technology have increased the electrical output of solar panels, and lowered manufacturing costs, making this form of solar energy increasingly affordable for many homeowners—especially when combined with government-sponsored rebate programs in some locations that encourage homeowners to convert to solar power. See Photo-Voltaic Solar Energy.
Photovoltaic panels are by far the most flexible way to capture solar energy. You can use the electricity they generate to heat, cool, pump, illuminate, cook, and virtually any of the other things around the home that require electrical power.
When a photovoltaic power generation system is integrated with energy control and conservation technologies, homeowners can substantially enhance their personal comfort and convenience. They may be able to reduce the long-term cost of electric power and significantly reducing their carbon footprint. It can be like winning the trifecta in some places!
Passive Solar Heating
The passive solar approach takes advantage of two basic facts: 1) that light is converted to heat as it passes through glass (the greenhouse effect), and 2) that high-mass objects such as concrete or stone (when properly positioned relative to the light), can collect this heat, then gradually re-radiate it back into the home environment—as the outside ambient temperature drops. Primitive versions of this passive solar arrangement have kept humans warm for many centuries.
Smart home integration technologies improve on this basic concept by using automated window coverings to admit (or block) solar energy as appropriate, thus increasing the efficiency and convenience of passive solar systems. A simplified version of this approach is described in the automated Window Coverings section.
Remotely (or thermostatically) controlled shades open to allow the sun in when you want to warm the room, then automatically close them—to block the sun when you don’t want to capture heat, and when you don’t want the heat you’ve captured inside your home to escape back through the glass.
Active Solar Heating
The addition of fans or pumps to a solar collection system can actively move passively collected solar heat from one place in the home to another. For example, hot water solar collectors located on roofs or near the ground can capture the sun’s heat in water. Then the heated water can be pumped elsewhere, and used to heat a swimming pool, hot tub, or even a hot water heating system within the home.
Adding home automation technologies like remote temperature monitoring and shade control can allow active solar collection systems to operate more efficiently (and conveniently).