The article discusses how thermodynamic cycles and efficiencies are important in understanding energy systems. It explains that the 2nd Law of Thermodynamics is about the limitations of energy exchanges, and introduces the concept of entropy as a property that is not conserved. By combining energy and entropy balance equations, the article shows how energy is dissipated as thermal energy. The study demonstrates that using an on-site heat engine to power a heat pump for home heating is the most efficient option.