Rik DeGunther

The words “solar power” often bring to mind solar panels and photovoltaic (PV) solar systems, but you can harness the sun’s energy in a number of smaller ways. The practical and affordable solar projects listed here are ones anyone can build or take advantage of. They explain how to use solar energy to purify drinking water, enjoy a portable shower, and cool your house.

If you want to make alternative energy a part of your life, either through your car, home, or at work, you should understand some basic energy terminology and the various alternative energy sources being used and developed.

Radiant floor heat systems use solar power to heat water, which is then pumped through your home's floor. You can use solar-heated water to heat your home off-grid. Radiant heat, without solar, costs much less than forced-air heating for efficiency reasons. Installing a radiant heat floor system is almost surely not a do-it-yourself project, but it merits elaboration because it's such a complete and effective way to use solar energy water heating.

Solar water heaters can be either active or passive. Passive systems are cheaper because they're simpler and have fewer parts. But they're also less versatile. Active systems, on the other hand, can put out more energy and work under a wider range of weather conditions. In addition to choosing between active and passive systems, you have a couple of other decisions to make: Direct systems heat the water right in the collector.

Dozens of different types of systems that use solar energy to supplement your hot water heater are available, but only a few have stood the test of time. Sticking with proven entities is always a good idea, despite the extravagant claims you may hear regarding new technologies. In the real world, Murphy has a voracious appetite, and until something is tested thoroughly, the jury is still out.

Closed-loop, active, antifreeze systems are the most versatile and failsafe of all the solar supplemental water heating systems. Most new solar homes feature a variation of one kind or another. A special water-heater tank incorporating a heat exchanger works in conjunction with one or more flat-plate, roof-mounted collectors.

Installing a solar system to power your home is an involved process. Even though you'll be hiring a professional, it helps to understand what's going on. Expect the entire process of installing a full-scale photovoltaic (PV) system to take 90 days or more. The following list outlines all the things you need to do: Perform an energy audit.

In your solar power system, you need inverters to take the low-voltage, high-current signals from the PV panels and convert them into 120VAC or 240VAC, which is directly compatible with grid power. Inverters cost around $0.70 per watt, or around $2,600 for a typical application. From a reliability standpoint, they are generally the weak link in any PV system, so quality is a must.

Using the sun to purify drinking water is a great solar project for the do-it-yourselfer. A solar-powered purification system the size of a microwave oven can yield up to 3 gallons of purified drinking water on a sunny day. Here’s what you need for a basic solar powered water purifier like the one shown in the figure: Wooden or sheet metal enclosure Reflective material like aluminum foil Black paint, used for barbeque pits Sheet of glass Insulation (the white foam kind is fine) Glue (silicon sealant or similar weather-resistant material) Black tray that can absorb heat Catch trough and container for purified water A cross-section of a water purification system.