Question

Define solar energy and explain the working of solar water heater

Answer 1

Energy derived from the sun's radiation is called solar energy.
Solar energy is used on Earth in various ways. It is used as a passive source of energy, for example, in the form of sunlight that comes through a window and heats up a room, or as an active source, as in the conversion of sunlight to electrical energy in solar cells.

Parts of the Solar Water Heating System

A solar water heating system consists of a flat plate solar collector, a storage tank kept at a height behind the collector, and connecting pipes.

The collector usually comprises copper tubes welded to copper sheets (both coated with a highly absorbing black coating) with a toughened glass sheet on top and insulating material at the back. The entire assembly is placed in a flat box.

In certain models, evacuated glass tubes are used instead of copper; a separate cover sheet and insulating box are not required in this case.

Working of a solar water heater

The system is generally installed on the roof or open ground, with the collector facing the sun and connected to a continuous water supply.

Water flows through the tubes, absorbs solar heat and becomes hot.

The heated water is stored in a tank for further use.

The water stored in the tank remains hot overnight as the storage tank is insulated and heat losses are small.

Answer 2

Solar energy is radiant light and heat from the Sun that is harnessed using a range of ever-evolving technologies such as solar heating, photovoltaics, solar thermal energy, solar architecture, molten salt power plants and artificial photosynthesis.