Energy

A primary energy is an energy that is not transformed. However, it would need to be converted in another type to suit with equipment’s design and industrial processes.

Often, several cycles are required for a primary source of energy to be suitable by appliances. However, each of these transformations, depreciate the full energy potential.

The below figure shows the conversion scheme that is required to transform an energy into another form and it highlights as well, the number of cycles that is required to reach its final energy form.

To clarify these transformation cycles, let's take the example of a standard refrigerator keeping food fresh.

It all starts at the powerstation, where the primary source of energy is often coal, nuclear or gas that will be transformed into heat energy, which will be further transformed into mechanical energy, which will be further transform into electrical energy.

The electricity from the powerplant will be then further converted few times into different electrical level and distributed to the household. There, the electricity will be transformed into mechanical energy, which will be eventually transformed into cold by the compressor. Therefore;

- 1. The fossil fuel energy is transformed into heat by the boiler.

- 2. The heat energy is transformed into mechanical by the turbine.

- 3. The mechanical energy is transformed into electricity by the generator.

- 4. The electrical energy is transported and converted by the transformers to the level required by the appliances.

- 5. The electrical energy is transformed into mechanical by a motor.

- 6. The mechanical energy is transformed into thermal energy by a compressor.

Therefore, in this case, to refrigerate fresh food, there are six conversion cycles each with its own efficiency and energy degradation. A first estimation, shows that 90% of the energy has been lost in these transformation.

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The below table shows the energy conversion path, its process and the associated application and efficiency.