Diverse types of energy can be converted into other forms, but that only occurs under the constraints of the First and the Second Laws of Thermodynamics.
The First Law of Thermodynamics is a principle of conservation of energy that J. Joule systemized.
It teaches that a total amount of energy in an isolated system does not change and that the amounts lost and generated when a form of energy is converted into another form are equivalent.
In other words, energy can change its form but doesn’t get created or destroyed.
Also by the theory of relativity, it was discovered that the mass of an object is equivalent to energy, and energy and mass can be converted into each other.
For this, we follow the formula E=mc2.
The Second Law of Thermodynamics is based on the study of Carnot. This law defines the direction of movement of thermal energy.
In other words, it clarifies that heat always moves from an object of higher temperature to one of lower temperature and its inversion is impossible unless work is involved.
Therefore, power must be exerted in order to move thermal energy from a colder object to a hotter object.
According to the Second Law of Thermodynamics, mechanical energy can be converted into thermal energy of the same quantity.
However, inversely, thermal energy cannot be completely converted into mechanical energy.
Therefore, a heat engine wastes a large quantity of infused thermal energy because it cannot convert all thermal energy into mechanical energy.
For example, an internal combustion engine such as an automobile converts only about 25% of used combustion energy into mechanical energy, that is, the type of energy that makes an automobile move, and the rest 75% is released into the air as thermal energy.
Efficiency in a heat engine indicates the proportion of work generated by infused thermal energy, and according to the Second Law of Thermodynamics, no heat engine is 100%