Power Plant Engineering

2.16.4 RECENT DEVELOPMENTS IN SOLAR POWER PLANTS
Solar Thermal Applications. The applications include water heating for domestic, commer-
cial and industrial use, space heating and drying, solar distillation, solar cooling through absorption &
adsorption cycles, solar water pumping and solar power generation.
Solar Photovoltaics. Photovoltaic (PV) or solar cells refers to the creation of voltage from
light. A solar cell is a converter; it changes the light energy into electrical energy. A cell does not store
any energy, so when the source of light (typically the sun) is removed, there is no electrical current from
the cell. If electricity is needed in the night, a battery must be included in the circuit. There are many
materials that can be used to make solar cells, but the most common is the element silicon. A typical
solar cell is 3-6 inches in diameter and are now available in various shapes like circular, square, etc.
The conversion processes occurs instantly whenever there is light falling on the surface of a cell. And
the output of the cell is proportional to the input light.

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NON-CONVENTIONAL ENERGY RESOURCES AND UTILISATION
73
2.17 ELECTROCHEMICAL EFFECTS AND FUEL CELLS
Fuel cells produce electricity from an electrochemical reaction between hydrogen and oxygen.
Fuel cells are efficient, environmentally benign and reliable for power production. The use of fuel cells
has been demonstrated for stationary/portable power generation and other applications.
Fuel cell is device that converts the chemical energy stored in a fuel directly to electrical energy.
Fuel cell is an open system.
–
+
H
2
O
2
H O
2
Fuel
Cell
Fig. 2.16
Some similarity to a battery except that energy must be stored or built into a battery. Batteries
are closed systems.
Battery
–
+
Fig. 2.17
There are two Principles of the fuel cell
1. Chemo electricity
— Chemistry must occur before energy flows
— F/C system like an entire chemical plant
2. Match Energy Source to Application
— Stationary/Vehicle/Portable
— Sometimes F/Cs won’t work.