The first law of thermodynamics has been validated experimentally several times in many places. It`s really a law of physics. It always transforms energy from one form to another, but never allows energy to be produced or destroyed in the process of transformation. But this is not a complete description of the processes of thermal energy conversion. The first law would transfer heat from a cold body to a warm body as long as the amount of heat transmitted reduced the inner energy of the cold body by the amount that increased the inner energy of the hot body. But that never happens. Heat can only be transmitted from a warm body to a cold body. There is therefore a requirement for a law that explicitly expresses the direction of thermal energy transmission in addition to energy savings in the first act. This is the second law of thermodynamics. A simple statement of the second law would be that “heat cannot be transmitted spontaneously from a cold body to a hot body.” Below are more elegant statements. The potential energy can be exchanged with the system environment if the environment imposes a force field on the system, such as gravel or electromagnetic.
On the basis of the experimental results, the existence of two new properties, temperature and internal energy, are therefore invoked, which are not born in ordinary mechanics. Similarly, another remarkable relationship between heat and temperature is established and a new property, entropy, is defined. Although it is a much less familiar property, it should be noted that the general approach is quite the same as it was used for the implementation of The Zeroth and First Laws. A general principle and a property related to each system are extracted from the experimental results. From this point of view, entropy should not appear more mystical than inner energy. The increase in entropy in a natural process is no less real than energy saving. The third law of thermodynamics can be referred to as: Equation (2) as the basic thermodynamic relationship for a closed system in energy representation, for which the defined state variables are S and V, of which T and P are partial derivatives of U.    It is only in the reversible fictitious case if isochoric work is excluded. the work done and the heat transmitted are provided by the E/P dV and T dS. Soil geothermal or thermal air conditioning systems and heat pump systems use long U-shaped tubes in deep wells or a series of horizontal pipes buried in a large area through which working fluid circulates, and heat is transmitted in or from the earth. Other systems use rivers or seawater to heat or cool working liquid. Mitra continued: “The variation in the internal energy of a system is the sum of all energy inputs and outputs to and from the system, much like all the deposits and withdrawals you make that determine changes in your bank account.” This is expressed in mathematical terms such as: “U-Q – W,” where the “U” is the change in internal energy, Q the heat added to the system and W the system work.