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SOLAR POWER
When it comes to using a clean source of energy like solar power for homes, there are manyMost residential homes will require PV
systems that are usually attached to the roof as plating or shingle
type solar cells. Before considering solar power, the first decision should be
if the particular area provides
enough solar power for specific energy needs. Solar cells can provide enough
energy to power some but not
every appliance in most areas. Once the amount of energy desired from a PV
system is determined and the
size of the system is measured, checking state and local laws including
homeowners associations is necessary.
From there, a solar contractor will install a grid-connected solar
system that can take advantage of local utility
energy use as well. Those applications that require energy can be supplied from
the PV solar system when there
is enough energy and use the utility company when there is not enough solar
energy. Most of these applications
however require AC power that is produced from running the DC power produced
from PV systems through an
inverter. For homeowners, there can be several areas of solar cells for heating
pools, indoor systems, and other
areas as well.
Solar power use in homes can lead to lot of savings
from energy use as well as from tax incentives. Using solar
power in a grid connected system has very good benefits and consistent energy
use. Solar heating and power
generation in homes, no matter how slight, can lower energy consumption from
utility companies. Excessive solar
energy is sold back to the utility company through net metering and consumers
are given a credit for this energy.
Thus access solar energy is stored by the utility company like a battery.
Outdoor lighting can be virtually free using
solar lighting systems that power up during the daytime and light up at night.
There are federal, state, and local tax
incentives and even grants to help consumers get started. The www.dsireusa.org/
website can help locate these
incentives. All these savings can add up to become very significant over the
years. During energy crisis where electrical
costs nearly triple, these savings can help many families get by and the value
of solar power systems will be most
appreciated.
SOLAR WATER HEATERS
Solar water heaters—also called solar domestic hot
water systems—can be a cost-effective
way to generate hot water
for your home. They can be used in any climate, and the fuel they
use—sunshine—is free.
Solar water heating systems include storage tanks and
solar collectors. There are two types of solar water heating
systems: active, which have circulating pumps and controls, and passive, which
don't.
Most solar water heaters require a well-insulated
storage tank. Solar storage tanks have an additional outlet and inlet
connected to and from the collector. In two-tank systems, the solar water heater
preheats water before it enters the
conventional water heater. In one-tank systems, the back-up heater is combined
with the solar storage in one tank.
Three types of solar collectors are used for residential applications:
Glazed flat-plate collectors are insulated,
weatherproofed boxes that contain a dark absorber plate under one or
more glass or plastic (polymer) covers. Unglazed flat-plate
collectors—typically used for solar
pool heating—have a
dark absorber plate, made of metal or polymer, without a cover or enclosure.
Also known as ICS or batch systems, they
feature one or more black tanks or tubes in an insulated, glazed box.
Cold water first passes through the solar collector, which preheats the
water. The water then continues on to the
conventional backup water heater, providing a reliable source of hot water.
They should be installed only in mild-freeze
climates because the outdoor pipes could freeze in severe, cold weather.
They feature parallel rows of transparent glass
tubes. Each tube contains a glass outer tube and metal absorber
tube attached to a fin. The fin's coating absorbs solar energy but inhibits
radiative heat loss. These collectors are
used more frequently for U.S. commercial applications.
There are two types of active solar water heating systems:
Pumps circulate household water through the
collectors and into the home. They work well in climates where it
rarely freezes.
Pumps circulate a non-freezing, heat-transfer
fluid through the collectors and a heat
exchanger. This heats the water
that then flows into the home. They are popular in climates prone to
freezing temperatures.
Passive solar water heating systems are typically less
expensive than active systems, but they're usually not as efficient.
However, passive systems can be more reliable and may last longer. There are two
basic types of passive systems:
These work best in areas where temperatures rarely
fall below freezing. They also work well in households with significant
daytime and evening hot-water needs.
Water flows through the system when warm water
rises as cooler water sinks. The collector must be installed below
the storage tank so that warm water will rise into the tank. These systems
are reliable, but contractors must pay
careful attention to the roof design because of the heavy storage tank. They
are usually more expensive than integral collector-storage passive systems.
Solar water heating systems almost always require a
backup system for cloudy days and times of increased demand.
Conventional storage water heaters usually provide backup and may already be
part of the solar system package. A
backup system may also be part of the solar collector, such as rooftop tanks
with thermosyphon systems. Since an
integral-collector storage system already stores hot water in addition to
collecting solar heat, it may be packaged with
a demand
(tankless or instantaneous) water heater for backup.