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Solar Thermal
Japanese Solar Thermal Facts
The use of solar heat soared in the 1980's, shortly
after the second oil crisis.
The decrease in new installation comes from the high costs.
Most of the systems are installed in hospitals and
public institutions.
Now the solar thermal industry is developing new
technologies, such as integrated into roofs and other
building materials, and hybrid system combining solar
thermal technology and photovoltaics technology.
(NEF -Renewable energy in Japan http://www.nef.or.jp/english/act06PU01pdf/part01-03.pdf)
7/30/03
Japanese Solar Thermal Systems
The Japanese solar thermal program is focused on
active solar thermal processes (e.g., systems to provide
heat and hot water for industrial processes). Relatively
little attention appears to be paid to passive building
design research because the Japanese government believes
that this is a fairly mature technology that requires
little further research. The active solar thermal
program is focused on the development of systems that
are capable of using solar energy to provide either
heating or cooling applications for use in areas of
high insulation (e.g., work is underway on a solar
freezing/refrigerating system that would provide cooling
to -10 °C for use in desert areas). The program
is also attempting to transfer solar heat energy utilization
technologies formerly developed under this program
to industry and to developing nations (e.g., an industrial
dehydration system for wood products utilizing an
air heating collector is being developed and deployed
for use in Indonesia).
(Energy Research and Development
http://energytrends.pnl.gov/japan/ja005.htm)
7/29/03
Solar Thermal Utilization
The solar heat equipment has higher energy exchange
ratio and has better cost-effectiveness with relatively
lower price among other new Energy sources.
We have various types in solar heat system, such
as room heater/cooler with water heater system, industrial
solar system, solar heat power generation system,
combined heat and electric power solar system. All
in all, in order to expand solar heat application,
we have developed many kinds of technologies that
enable us to use the collected solar heat in various
fields, and we expect further dissemination because
of the increasing awareness of global environmental
issues in recent years.
A: Water Heater System
B: Room Heater/Water Heater System
(Floor Heater)
C: Room Heater, Water Heater System
(Air Heater)
D: Room Heat/Cool-Water Heater System
(Agency for Natural
Resources and Energy http://www.enecho.meti.go.jp/english/energy/new_energy/solar.html)
8/20/03
Mechanisms
These systems use the sun to heat either
water or a heat-transfer fluid, such as a water-glycol
antifreeze mixture, in collectors generally mounted
on a roof. The heated water is then stored in a tank
similar to a conventional gas or electric water tank.
Some systems use an electric pump to circulate the
fluid through the collectors.
Solar water heaters can operate in any
climate. Performance varies depending, in part, on
how much solar energy is available at the site, but
also on how cold the water coming into the system
is. The colder the water, the more efficiently the
system operates. In almost all climates, you will
need a conventional backup system. In fact, many building
codes require you to have a conventional water heater
as the backup.
(Energy Efficiency and Renewable
Energy http://www.eere.energy.gov/erec/factsheets/solrwatr.html)
7/29/03
Benefits
There are many benefits to owning a solar water heater,
and number one is economics. Solar water heater economics
compare quite favorably with those of electric water
heaters, while the economics aren't quite so attractive
when compared with those of gas water heaters. Heating
water with the sun also means long-term benefits,
such as being cushioned from future fuel shortages
and price increases, and environmental benefits.
Solar water heaters do not pollute. By investing
in one, you will be avoiding carbon dioxide, nitrogen
oxides, sulfur dioxide, and the other air pollution
and wastes created when your utility generates power
or you burn fuel to heat your household water. When
a solar water heater replaces an electric water heater,
the electricity displaced over 20 years represents
more than 50 tons of avoided carbon dioxide emissions
alone. Carbon dioxide traps heat in the upper atmosphere,
thus contributing to the "greenhouse effect"
Solar water heaters offer long-term benefits that
go beyond simple economics. In addition to having
free hot water after the system has paid for itself
in reduced utility bills, you and your family will
be cushioned from future fuel shortages and price
increases.
(Energy Efficiency and Renewable
Energy http://www.eere.energy.gov/erec/factsheets/solrwatr.html)
7/29/03
The Average Water Temperature of Solar Thermal Systems
Blue bar- tap water
Orange bar- solar assisted temperature
Using solar thermal system, the water
temperature goes about 60 °C (140 °F).
This water temperature can provide warm
air and hot water in one household.
(New Energy Foundation
http://www.nef.or.jp/what/whats02.html)
8/20/03
Existing Organizations and Associations
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