The Sun: it was, it is
and it will be the solution for our energy problems.
Our first goal is to develop the research in
the solar thermal and photovoltaic sector.
But... where is the Sun now?
Look at the picture below and find out what part of the world could be
powered by the sun just now!
Photovoltaic Systems
Green Energy Solution has
developped a number of photovoltaic systems, which are suitable to
power a variety of applications and particularly:
RURAL ELECTRIFICATION Remote houses,
mountain shelters, holiday resorts.
VILLAGE POWER Remote villages, islands,
social centres, schools.
LIGHTING Streetlights, illumination of
remote cross roads, rural villages and military zones.
MEDICAL Hospitals, medical equipment, health
care centres and mobile medical units.
WATER PUMPING Drinkable water for villages,
irrigation systems, purification and desolation of water.
CATHODIC PROTECTION Oil, gas and water
pipeline.
REFRIGERATION Domestic use, foods, vaccine
conservation.
DATA RECORDING Metereological stations,
pollution recording units, water level metering, avalanches warning,
earthquake and fire alarm systems.
SIGNALLING AND WARNING Off-shore platform,
lighthouses, sea buoys, railroad crossing, highway call boxes, fire
alarm systems, airport and heliport traffic lights.
TELECOMMUNICATION Radio and TV repeaters,
radio telephones, satellite receivers, radar stations, educational TV,
mobile radio stations.
Solar Water Heating Systems
Today, most western homes and businesses use
natural gas, electricity, or oil to provide them with hot water. The
amount of energy required to meet our hot water needs is not
insignificant. According to the U.S. Department of Energy (DOE),
heating water today accounts for up to 14 percent of the average
household’s energy use, and nearly four percent of total U.S.
energy consumption. With electricity and natural gas prices continuing
to rise, the costs of having a constant supply of hot water can really
add up.
Solar water heating (SWH) technologies are a
simple, reliable, and cost-effective method of harnessing the
sun’s energy to provide for the energy needs of homes and
businesses. Simply stated, SWH systems collect the energy from the sun
to heat air or a fluid. The air or fluid then transfers solar heat
directly or indirectly to your water supply.
Though these systems have been in use for
centuries, with today’s technological advances, SWH
technologies can be operated efficiently and affordably in any climate.
Systems are specifically designed for various climatic and geographical
areas of the country. Regions with temperatures that fall below
freezing require the use of an indirect or drain-back system, while
warmer, sunnier climates can use a direct system, which directly heats
the water to be used.
SWH systems also provide an important
opportunity to reduce our nation’s growing demand for energy
from fossil fuels. By installing a SWH system, a typical household can
meet 50 to 80 percent of their hot water needs. In warm and sunny
climates like Hawaii, a SWH unit can meet 100 percent of a
household’s hot water needs. Reduced demand for fossil fuels
will improve the environment by reducing air and water pollution as
well as the heat-trapping gases that cause global warming. And though
they cost a little bit more up front to install, a SWH system will save
consumers money in the long run as the fuel source (the sun’s
energy) will always be free.
Currently there are more than 300,000 SWH
units installed across the United States (excluding swimming pool
applications). While the number of installations continues to grow by
the thousands every year, there still exists an enormous untapped
market with great potential for reducing a significant portion of our
nation’s energy use.
Basics of Solar Water Heating
The most popular type of solar collector for
water heating is the flat panel design (other types include
evacuated-tube, concentrating, and integral collector storage). A flat
panel collector is an insulated weatherproof enclosure with an absorber
plate, flow tubes, and a transparent cover. The transparent cover
allows solar energy to pass through and be absorbed by the absorber and
flow tubes. The heat generated is then transferred to the fluid
circulating through the flow tubes.
Once the solar energy is collected, it is
commonly employed with the pumped indirect SWH system. Best suited for
colder climates, an indirect system pumps heat-transfer fluids (usually
a non-toxic propylene glycol-water antifreeze mixture) through
collectors, and then transfers the heated fluid from the collectors to
a storage tank. Heat exchangers transfer the heat from the fluid to the
household water stored in the tanks.
Water stored within the tank is then heated
when the fluid passes through a heat exchanger located inside the
storage tank. Antifreeze fluid is used to prevent collector piping from
freezing and allow for the maximum transfer of heat from the solar
collector to the storage tank. Many indirect system designs also
incorporate an external heat exchanger.
The drain-back system is another common cold
climate system. With this system, the water in the collectors and
exposed piping drains into an insulated drain-back reservoir tank each
time the pump shuts off. Removing all water from the collectors and
piping when the system is not collecting heat provides a fail-safe
method of ensuring that collectors and the collector loop piping never
freeze.
In warmer climates, direct systems are more
commonly used. The direct system circulates potable water directly
through the solar collector into the storage tank. In other words, the
water that is used in the house is the same water that has circulated
through the solar collector. These systems incorporate various
strategies to control the operation of the circulating pump, which can
include photovoltaic or differential controllers.
Passive direct systems are also used in
warmer climates. The unique characteristic of these systems is that
they do not use pumps or other electrical components, thereby providing
a simple and reliable system. The most common passive systems are the
thermosiphon (see diagram below) and integral collector storage
systems. Indirect thermosiphon systems could also be used in colder
climates.
Solar water heating systems typically cost
between $2,000 and $5,000 installed, depending on the type and size of
system. Some state governments and local utilities may offer rebates or
other financial incentives to help reduce the costs. With regular
inspection, the system will operate for 20 to 30 years with minimal
maintenance and costs.
Solar Water Heating for Swimming
Pools
In order to maintain swimming pool
temperatures during different seasons, homeowners and businesses may
want to invest in solar water heating systems. Conventional natural gas
and electric heaters are available for heating swimming pools, but they
can be costly and inefficient. By comparison, SWH systems for swimming
pools are cost competitive, primarily because the fuel source is free
and the operating costs are low.
A typical solar pool heating system can
range from $2,000 to $4,000, depending on variable factors such as ease
of installation, state codes and safety requirements, and access to
financing. The investment, however, is well worth the effort as a SWH
system for a pool can pay for itself in just 2 to 4 years when you
account for the energy bill savings. Solar pool heating systems are
also highly reliable and generally maintenance free.
Solar heating systems are available for both
in-ground and aboveground pools. They are effective because swimming
pools require a low temperature heat source, which a relatively small
solar collector can easily provide. Most SWH systems for pools include
a solar collector, filter, pump, and flow control valve. Pool water is
first pumped through the filter. Then it flows through the solar
collector where it is heated before returning to the pool.
Some systems offer manual automatic sensor
valves that can send water through the collector when the collector
temperature is greater than the pool temperature, or bypass the
collector when its temperature is similar to the pool water. In
particularly hot climates, passing pool water through the solar
collectors during the evening hours can serve as a cooling mechanism.
|
