Energy flow describes the process of transferring physical energy between different technical or natural systems (also energy transfer). The energy flow is measured as physical power energy per time. As a result, it has different units depending on the field of application:
- Watt (W)
- Joules per second (J/s)
- Joules per day (J/d)
- Horsepower (hp)
- Kilowatt hours per day (kWh/d)
- Hard coal units per year (tSKE/a)
In the explanations that follow, we mostly address the technical flow of energy.
Physical energy
The term energy, which comes from the Greek and translates as “acting force,” is understood in physics to mean the ability to perform work, emit heat, or radiate light. If we apply this definition to everyday situations, it means that we need energy to move objects from A to B, to warm up our home in winter, or to produce light in our headlights when we drive our car at night.
Primary energies
Primary energies are energies that occur in our nature and do not have to be produced or converted through work steps. These energy sources are solar radiation, wind, hydroelectric power, hard coal, lignite, crude oil, natural gas, etc.. In our energy economy, they serve as the basis for the technical flow of energy in industry, services, transport and for end consumers.
Secondary energies
When primary energy is converted into a new form of energy, it is referred to as secondary energy. Examples of the conversion of primary to secondary energy:
- Solar radiation, wind and hydroelectric power are converted into electricity
- Hard coal and lignite become briquettes, coke and town gas
- Petroleum becomes gasoline, diesel fuel and heating oil
- Coal, oil and natural gas become electricity
Electrical energy (electricity) has established itself as the most important secondary energy. Due to the worldwide electricity network, this energy is available very quickly at the necessary location.
What other energy flows are there?
Besides the technical energy flow, we also have the natural energy flow. This refers to the ecological energy flow. It deals with the whole process of energy production of plants by sunlight and the resulting food chain.
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