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It is crucial to implement conservation and efficiency measures before installing a solar hot water solar system. These measures can reduce hot water need by a half. Thus, a smaller, more inexpensive solar hot water system can meet your family’s needs.. In Florida it is common to size the solar hot water system to produce three-quarters of annual demand.
Florida is an especially strategic place to install hot water solar panels. The climate is warm and sunny year-round. Most Florida hot waters heaters run on expensive electricity from coal fired power plants, which emit huge amounts of carbon dioxide.
The Florida Solar Energy Center FSEC estimates a family of four could save $200 to $300 per year by installing a solar household hot water system http://www.fsec.ucf.edu/en/consumer/solar_hot_water/homes/q_and_a/index.htm .
A solar hot water system would also reduce carbon dioxide emissions by 2.5 tons annually. (Note: If state-of-the art conservation and efficiency measures reduced your family hot water needs by half, these solar savings would be approximate $100 to $150 per year.)
Solar pool heating could save homeowners $2,500 to $3,500 dollars per year in utility costs http://www.fsec.ucf.edu/en/consumer/solar_hot_water/pools/sizing.htm! This would cover the solar pool heater cost in one year.
Solar generated hot water is mainly used to heat swimming pools and household water. In cool climates it is sometimes used for home heating. Typically solar hot water systems are paired with a gas or electricity backup.
Many have first experienced solar hot water while running their garden hose. Sunlight striking the hose surface is transformed into heat. The heat travels through the hose wall and heats the water inside.
In a similar way, solar hot water collectors transmit the sun’s energy to tubes, pipes or tanks of water. Some hot water collectors are made of plastic; others are metal. Some are open to the air; others are enclosed in insulated boxes or evacuated glass tubes. All collector surfaces are dark to absorb maximum solar heat.
“Passive” systems require no pumps. “Active” systems pump water or anti-freeze heat exchange fluid back and forth between a solar collector and a storage tank. Active systems use thermostatic controls to operate pumps and valves. The Florida Solar Energy center website has a good description of the types of household solar heaters http://www.fsec.ucf.edu/en/consumer/solar_hot_water/homes/system_types.htm .
On very simple “passive” system consists of blackened water tanks, enclosed in a insulated box. Cold water enters in one end and hot water exits the other. When you turn on your hot water faucet, the ordinary line pressure pushes the sun-heated water to your faucet. Thus, no pumps or electricity are needed. The advantage here is simplicity and reliability
An active system, used for pool heating consists of a flexible black plastic sheet open to the air. The sheet is inlaid with a continuous loop of water tubes. Cool pool water is pumped in at one end of the system. Sun-warmed water is pumped out the other end to heat the pool. This type of collector can be also adapted for household water heating in warm climates.
More complex active solar water systems include include: flat plate collectors or evacuated glass tubes; hot water storage tanks; pumps; and. thermostatic controls. Their collecting surface consists of a loop of blackened metal water pipes, augmented with dark fins or metal sheets for extra heat absorption.
These active collectors take advantage of the greenhouse effect to heat water to a higher temperature than their “naked” cousins. These more efficient collectors are used in cool climates for household water and space heating applications. The evacuated tube collectors are the most efficient of all, and are used in cold, cloudy climates. These higher efficiency active systems have the trade-off of higher installation and maintenance costs.
It is necessary to guard solar collectors against freezing temperatures. One method is to drain the water circulating in the solar collector back into the hot water storage tank. The other method, used extensively in cold climates, is to use anti-freeze as a heat-exchange fluid. The anti-freeze circulates in a closed loop between the solar collector and a heat exchanger located within a hot water storage tank.
On a hot day, a household solar hot water system may harvest 8 kWh (0.3 therms) of energy, equivalent to a quart of gasoline. This is enough to heat 75 gallons, enough for a family of four. A typical Florida solar system may be sized to supply three quarters of a home’s hot water.
The Solar Rating and Certifying Corporation (SRCC) rates the performance of hundreds of household solar water systems for all parts of the country. They provide estimates of the annual gas or electric savings of household hot water solar systems at the following link http://www.solar-rating.org/ratings/annuals/annuals.htm.
The performance of a solar hot water heater is measured by SEF (solar energy fraction). The SEF equals: The hot water energy supplied by solar collector divided by the energy supplied by backup gas or electricity (including any electricity needed to run the collector). The SEF is used by state governments to qualify solar collectors for state rebates and tax credits.
The SEF values for a given solar hot water system are not fixed. They are higher in warm sunny areas and lower in cold cloudy areas. The SEF values are also higher for solar collectors paired with 90-95% efficient backup electric heaters, as compared to 60-80% efficiency gas heaters. Often, the back systems are on-demand gas or electric hot water heaters.
The Florida Solar Energy Center (FSEC) provides FEF (Florida Energy Factor) ratings for solar systems assuming an electric backup. A FEF is actually a SEF, modified for three climate zones in Florida–north, south and central http://www.fsec.ucf.edu/en/industry/testing/STsystems/ratings/#DHWRatings.
FSEC estimates a family of four could save $200 to $300 per year by installing a solar household hot water system http://www.fsec.ucf.edu/en/consumer/solar_hot_water/homes/q_and_a/index.htm
A solar hot water system can save 2,500 kW of electricity or 130 therms of gas annually and reduce carbon dioxide emissions by 2.5 tons.
Solar pool heating could save homeowners $2,500 to $3,500 dollars per year in utility costs http://www.fsec.ucf.edu/en/consumer/solar_hot_water/pools/sizing.htm! This would cover the solar pool heater cost in one year. A typical solar pool installation saves an astonishing 25,000 kWh of electricity or 8.700 therms and 25 tons of carbon dioxide each year. If you wish to heat your pool, solar heaters are truly are a no-brainer.
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