Solar water heaters are the most inexpensive and cost-effective way to go solar. These solar thermal systems may be used in any climate to great effect. While initially more expensive than conventional water heaters, solar hot water systems take advantage of free solar energy to save money over time. Federal, state and local incentives and rebates also cut down on those initial costs by at least 30 percent.

Types of solar water heaters

There are two general types of domestic solar hot water systems. Active systems have electronic controls and circulating pumps to move water throughout the system. Passive systems do not have any mechanical components and use convection, gravity or other natural forces to draw hot water through the system.

There are two types of active systems as well: indirect and direct flow systems. Direct systems circulate water through the collectors (described below) and into the home in a continuous cycle. Indirect systems utilize a medium, or heat transfer fluid, which runs through the collectors, absorbs solar heat, and then passes through a heat exchanger (typically within close proximity to the storage tank to prevent heat loss as the heated water travels), where that heat is transferred to the water supply.

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Water heater components

A solar water heater consists of two main components: the collector and the storage tank (add pumps and controls for active systems). There are three types of solar thermal collectors in residential use. The most popular of these is the flat plate collector, which are large, flat and contain a metal absorber plate that collects and transfers solar heat to water flowing through tubes attached to the absorber. (more…)

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Along with photovoltaics, solar thermal hot water heaters are growing more fashionable and marketable every year. Solar hot water heaters are more expensive than conventional models, although energy savings over time and increasing federal and state financial incentives narrow that gap considerably. After your new solar water heater is installed there is typically very little maintenance required — a big selling point for manufacturers and installers.

Very little, however, does not mean zero maintenance — just very rare maintenance. For active systems, pumps and other electrical components may need repair or replacement, but usually not for at least 10 years (quality solar thermal systems come with at least a 10-year warranty).

Yet another good maintenance question comes in regard to the water or fluid flowing through the system and/or solar thermal collectors.

Water

The water in solar thermal systems rarely needs to be replaced, even for systems with a storage tank. According to the federal government, the average person uses 15-20 gallons of water per day. That is why the average family of four’s water tank will be about 80 gallons in size. Remember that reducing your water usage will save even more money and reduce the size of your system, saving on initial costs as well.

Because the system is sized to provide enough water for daily use, the water within the system is not allowed to grow stagnant — the only real reason why the water would need to be replaced. Speak with your solar thermal installer about any further considerations that may arise based on your location, lifestyle, and type of system. (more…)

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The solar auto industry brings to mind sleek, futuristic cars humming silently down smooth highways, gleaming in the midday sun. Yet that idyllic picture of a green auto industry may have some viable competition. One struggling solar startup thinks it has discovered a cost-effective way to bring grid-independent solar thermal power to millions, all while boosting a desperate auto industry.

Infinia, a rather unique startup, has found a way to mix 21st Century ideals with 19th Century technology. Their innovation begins with a Stirling engine, one that runs on hot and cold air. So long as one end of the engine remains hotter than the other, the Stirling, which alternately compresses and expands a quantity of air or gas, will keep on pumping. It is so adaptable to today’s needs because the heat source does not matter.

That’s where Infinia’s design comes in. They’ve mounted the Stirling at the center of a large concentrating solar collector – a large satellite dish in appearance. This solar-powered Stirling uses solar heat to keep the engine pumping out electricity during the day. It folds up like a flower at night to conserve heat and is backed up by a small bio-fuel generator.

Photo Credit: infiniacorp.com

While Infinia has launched several failed Stirling-based technologies since 1985 when the company was formed, their latest innovation is their most positive. So far CEO J.D. Sitton has already garnered $70 million in funding and their first client: the U.S. Army. (more…)