Generate All of Your Hot Water with Solar Power!
Solar Water Heater Overview
In addition to sitting on top of your roof, you can use
solar power to meet almost all of your home hot water needs. A solar thermal water system absorbs
heat from the sun and then channels that heat to produce hot water. Solar thermal water systems can potentially
replace all standard hot water heaters for your home. On average, if you
install a solar water heater, your water heating bills should drop 50%–80%.
There are two types of solar water heaters: direct and
indirect. A typical direct solar
water heater is made up of a solar collector (to collect heat from the sun) which
is connected via a series of pipes to a storage tank (to house heated water). As
the sun heats the water inside the pipes, the now hot water flows into the
storage tank. Direct systems require
more maintenance to ensure that the pipes heating the water are clear of
mineral deposits. Direct solar thermal systems are also much more effective in
warmer climates to avoid freezing of the pipes and system.
A standard indirect system does not heat water directly,
instead it runs a fluid (typically some type of antifreeze liquid found in cars
with a low-freezing point) through the pipes to absorb radiant energy from the
sun. As the temperature in the
pipes rise, the heat activates a pump that circulates the antifreeze through a
heat exchange coil in the water tank.
That coil then transfers its heat to the water tank which generates hot
water.
Solar Water Heaters - Operational Issues
Storage Volume
On average, a small (50 to 60 gallon) storage
tank is sufficient for one to two three people while a medium (80 gallon)
storage tank works well for three to four people. Also remember that the size
of the solar storage tank increases with the size of the collector—typically
1.5 gallons per square foot of collector. This helps prevent the system from
overheating when the demand for hot water is low. In very warm, sunny climates,
some experts suggest that the ratio should be increased to as much as 2 gallons
of storage to 1 square foot of collector area.
Storage Backup
Even if you live in a sunny climate, you will
still most likely need a backup water heating system for cloudy days and times
of increased demand. Many times, conventional and tankless water heaters are
included as a part of a package for a solar water heater.
Solar Water System Location
Solar water heating systems use both direct and
diffuse solar radiation so even if you do not live in a climate that has
abundant amounts of sunshine, you still might be able to buy a solar water
heater. Typically, if the building
has an unshaded area and faces south, a solar water heating will probably work. As far as a footprint for the system, contractors
usually follow a guideline of around 20 square feet (2 square meters) of
collector area for each of the first two family members. For every additional
person, add 8 square feet (0.7 square meters) if you live in a sunny area or
12–14 square feet if you live in the northern United States.
Solar Water Heaters and Cold Climates
Provided you have the proper amount of sunlight, a solar water heater can still work in cold climate regions. In these areas, however, you will want to invest only in a indirect system that uses antifreeze so that your pipes do not freeze or burst. Often times, the best applicator of a solar water heater in colder climates is as a pre-heater for your main water heater so that it does not have to work as hard to heat water for the house. In addition, if you do invest in a solar water heater, it is a good idea and advantageous for the systems efficiency to wrap the water storage tank with an insulation blanket to keep the water sufficiently warm and further minimize the need to rely on traditional power sources to heat water.
Installation & Maintenance
As with any system upgrade, make
sure you do your homework on your contractor. When in doubt, contact us for a free consultation and we’ll
have one of our trusted solar partners reach out to you.
*Once you do install your solar
water heater, you are going to need to maintain it. Always make sure you follow your installer’s advice and read
the manual. But here are some
other tips for you:
- Collector shading: visually check for shading of
the collectors during the day throughout the year as shading can greatly affect
the performance of solar collectors. Vegetation growth over time or new
construction on your house or your neighbor\'s property may produce shading that
wasn\'t there when the collectors were installed.
- Plumbing, ductwork, and
wiring connections: make sure there are no fluid leaks at pipe connections. If there are any leaks, seal them with a mastic compound. All
wiring connections should be tight.
- Piping, duct, and wiring
insulation: look for damage or degradation of insulation covering
pipes, ducts, and wiring.
- Support structures
Check
all nuts and bolts attaching the collectors to any support structures to ensure a secure fit.
- Pumps or blowers
Verify
that distribution pumps or blowers (fans) are operating. Listen to see if they
come on when the sun is shining on the collectors after mid-morning. If you
can\'t hear a pump or blower operating, then either the controller has
malfunctioned or the pump or blower has.
- Heat transfer fluids Antifreeze solutions in solar heating collectors need to be replaced periodically, however, this should always be performed by a qualified professional.
- Storage systems Check storage tanks, etc., for cracks, leaks, rust, or other signs of corrosion.
