# Is it possible to build a jet engine that utilises all excess heat?

Is it possible to build a jet engine that utilises excess heat for thrust or does not produce any excess heat hence no need for cooling which is wasted energy

• You cannae change the laws of physics. – GdD Jan 11 '18 at 13:23

$$1-\frac{T_\text{C}}{T_\text{H}}$$