Thermosiphon Solar Water Heating System

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
  • Convection
  • Radiation

 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.

These systems generally consist of vertical closed loops through which water circulate. Gravity pulls cold water down. Thus, it forces the hot water up.

Location of storage tank

Another important thing to consider during the construction of a thermosiphon solar water heating system is the location of the storage tank. The hot water storage reservoir should be at the top of the system since the heated water goes up.

Methods of heating in thermosiphon system

Generally, there are two methods for heating water in a thermosiphon solar water heating system.

  • Direct heating
  • Indirect heating

Direct heating

In this type of heating water passes directly through the collector. There is no heat transfer medium between the collector which is absorbing solar energy and the water which needs to be heated.

Indirect heating

In this mode of heating a heat transfer medium is used for the transfer of heat between the collector and the water. The medium can be an antifreeze or any other substance that can suffice for the purpose.

Pumping mechanism

There is no separate or external pumping mechanism needed in thermosiphon systems. The passage of water in closed vertical loops creates natural pumping system. Moreover the convection and gravity constantly exchange heat and energy and a continuous pumping mechanism is obtained.

One Response to “Thermosiphon Solar Water Heating System”

  1. Ags Solar says:

    Great explanation here thanks

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