Efficiency (sometimes also degree of efficiency) is a measure of how effectively a technical process, system, or machine converts input energy into usable energy. It is commonly expressed as the ratio of useful energy (or output power) to the supplied energy, indicating what proportion of the energy input is successfully converted into the desired output.

Calculating the degree of efficiency

Efficiency (η) is typically calculated using the formula:

An efficiency of 100% would mean that all the supplied energy is converted into useful energy. However, in real-world applications, energy losses always occur due to factors like heat dissipation or friction.

A high degree of efficiency is essential for the energy performance and sustainability of technical systems. In industrial processes, optimizing efficiency helps reduce energy consumption, lower operating costs, and minimize CO₂ emissions—a critical factor in sustainable process heat applications.

Efficiency in high-temperature heat pumps

The efficiency of a high-temperature heat pump measures how well it converts supplied energy into usable process heat. To avoid confusion, technical literature typically expresses the thermal efficiency of heat pumps and refrigeration systems using the Coefficient of Performance (COP). The COP represents the ratio of heat output to electrical energy input. Another key performance metric is the Seasonal Performance Factor (SPF).

Conclusion

The efficiency or degree of efficiency is a key indicator of the performance and sustainability of technical systems. By continuously improving efficiency, businesses can achieve both economic benefits and environmental sustainability. In the case of high-temperature heat pumps, efficiency is commonly expressed using the COP.