Solar Energy: Save Money & Reduce Your Footprint
Three different kinds of solar energy systems are currently available for residential use: passive solar heating, active solar heating, and photovoltaic systems. Each type can play a valuable role in smart home automation. Passive systems rely on the careful design of a home to admit, trap, and store solar energy in the form of heat (when it is cold) or to block solar energy from entering and heating a home (when it is warm), without the use of electrical or mechanical systems to move the heat from one place to another. Active systems use pumps or fans to move heat derived from solar energy from one place to another. Photovoltaic systems use photovoltaic cells to convert solar energy directly into electric power that can be used for any purpose, anywhere in the home.
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 can temporarily store this heat, and then gradually re-radiate it back into the home environment—useful when the outside ambient temperature drops at night. Variations on this passive arrangement have kept humans warm for many centuries.
Smart home integration improves on this basic concept by using automating window coverings to admit (or block) solar energy, thus increasing the efficiency and convenience of passive solar systems. A simplified version of this approach is illustrated in the automated Window Coverings section: remotely (or thermostatically) controlled shades allow the sun to penetrate through windows when you want to warm the room, then automatically close the shade to block the sun when you don’t want to capture heat, or when you don’t want the heat you’ve already 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 to another. Solar hot water collectors on roofs or near the ground can capture heat and transfer it to the water inside, which then can be pumped for use in swimming pools, hot tubs, or even domestic hot water systems. Adding home automation technologies allow active solar collection systems to operate efficiently (and conveniently), through the use of remote temperature monitoring and shade control.
The most exciting news in solar energy today is the rapidly declining cost of photovoltaic panels that directly convert the sun’s rays into electricity. Although this concept has been around for decades, recent advances in the technology have increased output and lowered manufacturing costs, making this form of solar energy cost-effective for many homeowners, especially when combined with government-sponsored rebate programs to encourage homeowners to convert to solar power. See Go Solar and Save BIG.
Photovoltaic panels are by far the most flexible way to capture solar energy: you can use the electricity they generate to heat, cool, pump, light, and do so many other things around the house. When a photovoltaic power generation system is integrated with energy control and conservation technologies, homeowners can substantially enhance personal comfort and convenience, while at the same time reducing the long term cost of electric power, and significantly reducing their carbon footprint. See Power Management; and Real-life Energy Savings.