物理學中研究熱與其他能量形式之間關系的分支叫做熱力學。在此基礎上，描述了熱能是如何轉化為各種其他形式的能量，以及物質是如何受此影響的(Rosen, Marc, 2002)。它基本上是一種能量，由於它的溫度，它有運動或振動的分子。這種能量的測量可能非常復雜。
The branch of physics that works for the kind of relationships heat and other forms of energy have is known as thermodynamics. Under this it is described that how thermal energy gets converted into various other forms of energy and how the matter is affected due to this (Rosen, Marc, 2002). It is basically an energy that has the moving or vibrating molecules because of its temperature. The measurement of this kind of energy can be extensively complicated.
A renewable energy sources is a source of fuels with which man can get energy forever if these sources are properly taken care of. The various energy sources with which humans can take advantages are solar power, biomass, geothermal and wind power etc. Human beings are utilizing the power of natural sources such as sun, wind and earth etc and the efficiency of each source varies.
The topic of discussion here is “The application of thermodynamics principles in the renewable energies.”
It is stated by the second law of thermodynamics that there are spontaneous changes in all sorts of energies such as light, kinetic and chemical etc. in a form that are less organized, random but more dispersed. The second law is also known as “entropy increases”. Entropy is that form of energy which is unavailable and random. There has been a progressive increase in entropy over a long period of time and the rest of the universe has suffered energy’s net loss from the earth. The time scales that are relevant to humans do not have any significance for this natural process of energies. The fundamental potential of carrying the age of sustainable prosperity in the present civilization is on various sources of renewable energy such as solar, wind and bio-matter.