Today’s solar power systems offer a bundle of energy advantages for the home. They reduces the home’s impact on the environment, enable individual energy independence and guarantee savings on energy bills. Fortunately for you, home solar power systems have never been more subsidized. While usually requiring a decent sum of cash up front, within a few tax years, many homeowners can expect to recoup at least half of that initial investment. As diverse as the benefits and financial incentives for home solar power are, equally so are the different types of systems.
Photo Credit: Alternative-Heating
Let’s start with the basics. All home solar applications are either active or passive systems. Active systems have mechanical parts (fans, motors, pumps, etc.), while passive systems have none and are usually built into the design of the home (i.e. south-facing windows, thermal walls and floors, solar chimneys, etc.) The most common variety are active systems.
Home solar power systems can be divided into two categories: solar photovoltaic (PV) systems, which convert sunlight directly into usable electricity, and solar thermal systems, which use solar radiation to heat water, heat or cool the living space, or both.
Home Solar PV Systems
The solar PV system is the poster child of the solar energy movement, as well as the most initially expensive solar power application for the home (check out your local subsidies). All home solar electric systems provide the same service: creating clean, grid-free electricity. They consist of solar panels installed on a rooftop or ground-mount system, which are wired through an inverter to the home’s electric infrastructure.
PV systems are either grid-tied or off-grid, the latter requiring a battery bank to store power for use at night and on cloudy days. Grid-tied systems are by far the most popular because they are also connected to the local utility grid. When producing at peak potential, these systems feed electricity unused at home into that grid, where it offsets energy you might need from the grid at night, and in some cases, can actually make money or energy credits for the homeowners.
Aside from grid-tied versus off-grid, home solar electric systems are differentiated by the type of solar panels used to collect and convert sunlight into electricity. The majority in use today are made up of conventional silicon-based panels. These modules can be a bit bulky and expensive to produce, but are the most efficient at converting sunlight. Quickly gaining on silicon PV panels are thin-film panels, which are much smaller, can be building-integrated and are cheaper to make, albeit less efficient than their predecessors.
Home Solar Thermal Systems
Solar thermal systems, especially hot water systems, are much less expensive than their electric-producing cousins. Considering that space and water heating are the top two energy consuming systems in the average American household, a solar thermal system can have a significant effect on home energy costs.
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Solar hot water systems are the most cost-effective solar application of all. There are various types of solar collectors (the thermal version of a solar panel), which differentiate one type of home solar water heater from another. All serve the same purpose: to absorb solar heat. That heat is then transferred to water or an anti-freeze solution (for climates likely to reach freezing temperatures), which then transfers that heat to the home water supply. Note that in open-loop water heaters, the water heated within the collector is the same water used within the home.
Solar thermal space heaters are very similar to hot water heaters and in fact, are often hybrid systems used to heat both (water when space heating is not required). Home solar space heating systems are either liquid- or air-based, depending on what exactly is used to transfer heat from the collectors to the living space.
Solar thermal cooling systems are a bit more complex, as they actually use collected solar heat to air-condition the home. Active cooling systems are either absorption or desiccant systems. Other cooling systems include solar chimneys and solar ventilation. There are also evaporative coolers that are not inherently solar-powered, but because of their low energy demand, can easily be powered by a small photovoltaic solar panel.
Solar pool heaters are yet another type of home solar power system. These systems typically tie into the existing pool pump, circulating pool water up onto the roof in black pipes to be solar heated before returning to the pool. Solar pool heaters can be very effective and save a good deal in energy costs. Of course, solar pool heating also has its passive arm in the form of the solar pool cover.
The Solar Home of the Future
Home solar power is gaining momentum. Government and utility incentives are as lucrative as ever, equipment prices are continually dropping, and the desire to make a difference in our climate and neighborhood is going viral. Above are very simple descriptions of the different types of home solar power systems. Throughout CalFinder Solar, you will find a wealth of detailed information on the future of solar power in the American home and its many promising permutations. On top of that, when you’re ready to go solar, CalFinder will connect you with qualified solar installers in your area.