Environmental Engineering Reference
In-Depth Information
energy is utilized to accelerate the biological processes and thus reduce the waiting
time or increase the production cycle. In endothermic biological processes, application
of solar energy directly or indirectly is possible using different solar energy collectors.
Production of bio-fuels with the support of solar energy enhances the processes.
Hydrogen production from water and other sources has been demonstrated as an
alternative clean energy source. However, production of hydrogen through thermo-
chemical or molecular breaking or through electro-chemical processes are the main
methods and require external energy input. Hydrogen production or any thermo-
chemical processes can be done with the support of solar energy either as direct thermal
energy or using electricity generated from solar energy. There are several large scale
research facilities for the production of hydrogen through thermal energy. It has also
been demonstrated that the production of hydrogen through electrochemical processes
is feasible.
In agricultural industries, application of thermal energy for drying is most impor-
tant to increase the shelf life of the products. Solar energy can also be used for
the bio-chemical processes in agricultural production. There are many existing and
under-demonstration technologies for agricultural applications. The most common
and typical application is the solar dryer which has been demonstrated to be feasible
and practical using simple design, local materials and unskilled workers. In addi-
tion, solar cookers and other food processing applications of solar energy have been
demonstrated.
Machines minimize human effort with increase of production and operations in
many different applications. There are many thermally operated mechanical processes
including heating, ventilating and air-conditioning systems, heat engines, pumps and
fans. Application of solar energy to support the thermal requirements of these machines
and equipment is feasible. Thermally operated air-conditioning systems, pumps and
fans have been shown and demonstrated to be feasible and practical. There are many
concepts, designs and technologies readily available and being conceptualized for
applications.
The occupants of buildings always demand thermal comfort conditions during
summer time and winter time, both daytime and nighttime. The maintenance of indoor
thermal comfort conditions in buildings consumes large amounts of energy. Also, the
reduction of humidity in buildings consumes large amounts of energy in tropical cli-
mates. Indoor cooling and heating both in tropical and temperate climates consumes
considerable amounts of energy. Furthermore, the lighting for buildings is another main
consumer of energy particular for office buildings. Solar energy which is readily avail-
able can be utilized to support the day-to-day operation of buildings and to support
the indoor comfort conditions for occupants. For instance, solar energy can be utilized
to support the air flow rate requirement through natural ventilation. Solar energy can
be used to support the thermal energy requirement of buildings through solar thermal
collection. Solar energy can be used to support the electricity requirements of build-
ings through photovoltaic installations. Solar energy can be collected through thermal
storage to support the nighttime thermal energy requirement of buildings.
The effect of a heat island is felt in big cities because of the increased utilization of
air-conditioning systems and application of urban materials which absorb solar energy.
Proper design through urban planning can minimize the effect of solar radiation includ-
ing sun shading, alternative materials, air movement for natural ventilation and the
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