Thermosiphon systems work on convective mode of heat transfer. The heating of water on large scale is the need of domestic as well as many industrial users. Different kinds of geyser and other devices are available in the market to accomplish this purpose. They use different kinds of energies like electrical, mechanical, chemical etc. and convert it in to thermal energy.
With the evolution of the concept of renewable energy and the development in solar technology, thermosiphon solar geysers are becoming common.
Modes of heat transfer
Generally, there are three modes of heat transfer.
Conduction takes place in metals and convection is the phenomenon occurring in fluids. Radiation has something to do with heat transfer through waves. This is the way through which heat of the sun reaches the earth.
Convection in thermosiphon systems
The main working principle of a thermosiphon water heating system is convection. Convection is responsible for uniformly heating any liquid. Here the fluid of our interest is water.
As you know, fluid when heated rises up. The same thing happens in thermosiphon water heating systems. Hot water rises up and the cold water comes down. In this way the whole water is heated uniformly.
The top layers of hot water are then passed to the places where they are desired to be used. The lower colder layers are further heated.
Gravity in thermosiphon systems
Gravity is the second most important factor that plays a vital role in the functioning of a thermosiphon solar water heating system.