Solar Hot Water Heating
As hot water is a constant daily requirement for our homes, it makes sense to consider the sun’s heat energy for our hot water needs, rather than to be dependent on fossil fuel energy, a source that is finite in supply and a well known cause of air pollution.
With current technology, solar hot water heaters have proven to be the second largest energy device found in today’s homes and offices, after heating and cooling devices. Every home should have a solar water heater, as it can cater to 70-80 percent of our hot water needs.
The process of capturing the sun’s heat for heating purposes is far easier than converting the sun’s energy into electrical power. Solar water heaters offer a 60 percent efficiency output, while photovoltaic systems for solar electricity offer only 15 percent efficiency output. Hence, solar electricity requires four times the number of panels to capture the same quantum of sun energy as solar water heaters.
Although the initial cost of installing a solar water heater may seem high at $3,000-9,000, the cost is considerably lessened when the possible 30 percent tax rebate and other utility incentives are taken into account. With an annual estimated cost of $300-600 for electrically sourced hot water, the cost for the solar water heater will be off-set in 5-10 years, with an expected lifespan of 25 years. Hence, solar water heater users enjoy an annual savings of 5-10 percent as part of the payback computation.
The lower cost of the solar water heater and its attractive investment are definite purchase considerations over PV considerations for solar electricity, but one has to consider certain crucial factors before installing a solar water heater, namely the location of the residence, as the climate may impact the delivery of the hot water that is required.
A solar water heater can be a direct-gain or batch collector system. The former uses a tank that stores the heated water from the sun via the solar panels, whereas the latter stores its heated water in a roof-top system. Besides considering the type of system you will be installing for use as a solar water heater, you may also need to consider the solar thermal collector, which is used to heat your water. You have a choice of flat-plate collectors and evacuated tube collectors. Flat-plate collectors have a good performance record and are less costly, while evacuated tube collector systems are best for cold climates.
One good application of the solar water heater is the heating of pools. As the pool contains a large amount of water, the cost of heating a pool using fossil fuel is quite high, whereas the cost is drastically reduced with a solar water heater. The latter’s installation is also easy and quick, giving rise to an efficient and durable system which allows the pool to be heated and enjoyed more frequently, despite cool weather conditions.
Solar pool heaters are especially effective and longer lasting when combined with a suitable pool cover to prevent evaporation and reduce heat lost to radiation.