Phy...........

The solar panel is a device that generates electricity by absorbing and converting the sun light in to electricity. As the panel is shined by the sun light, it is heated up. In order to maintain the efficiency of the panel, it must be cooled. In the storage tank, water having higher temperature uses to stay in the upper layer of the liquid whereas the water having lower temperature uses to stay in the bottom of the storage tank.

In order to cool the solar panel, cold water must be tapped instead of hot water. When cold water travels through the solar panel, it cools the solar panel by absorbing the heat from the panel, i.e., the colder water is heated up. It returns to the storage tank where the hotter water remains in the top of the storage tank.

A radiator is a device to dissipate heat contained in the liquid. As explained in the above, the hotter water always stays in the top of the storage tank due to its lesser density, it travels into the radiator along the top slope of the tube of the radiator, whereas the cooled water travels in the lower slope of the tube of the radiator.

Both devices applies the basic physical property of water that hot water has a less density whereas colder water has a heavier density.