Details of energy, definition of energy,  unit of energy, relationship between them

Definition of energy: 

The ability or capability of a body for doing a work is known as energy. There are several kind of form of energy, but the most important ones are - 1. electrical energy, 2. mechanical energy and 3. thermal energy.

Now remember these energies are all interchangible.

Unit of energy:

Energy is a measurable quantity so we need to assign unit to energies, and as the energies are interchangeable so their unit should also have relation between them or same unit can be assigned because the energies are just in different forms.

1. Electrical Energy: The SI unit of electrical energy is watt-second also known as joule. Suppose there are two points which have a potential difference of 1 volt now a current of 1 ampere is flowing from one point to another. 

So Power is equal to 1 volt * 1 ampere =1 watt. 

Now if this continues for 1 second, then the energy consumed will be 1 watt * 1 second that is equal to 1 watt-second. 

In case the system is AC then another factor called power factor comes into picture, 

so, watt-second =1 volt * 1 ampere * power factor *1 second.

2. Mechanical Energy:

Unit of mechanical energy in SI system is Newton metre also known as joule. When a force of 1 Newton makes a body move by 1 metre distance then the work done on the body is 1 joule or 1 Newton metre.

3. Heat Energy:

Unit of heat energy in SI unit is joule. There are also other units that is calorie, British thermal unit or B. Th. U etc. Calories stands for the amount of heat energy that is required to increase the temperature of 1 gram water by 1 degree centigrade.

similarly British thermal unit can be expressed as the heat energy required to increase the temperature of one pound water by one degree fahrenheit.

Relationship between the unit of energy

All the three energies as mentioned above is convertible from one form to another, so their units are also have a relationship between them, and another thing is there to remember that all the three energies can do some work so they should have a common unit, and we can see that all the three energies have a common unit that is "Joule" now let us see the relationship between them.

Relationship between kWhr and Joule

1 kWhr (Unit)

= 1000 watt * 1 hr

=1*10^3 watt*3.6*10^3 sec.

=3.6*10^6 watt- sec= 3.6*10^6 Joule

Relationship between kWhr and N-m

1 N-m = 1 Joule

1 kWhr= 3.6*10^6 Joule

= 3.6*10^6 N-m

Relationship between Calorie and kWhr

1 kWhr=3.6*10^6 Joule

Again,

1 Calorie=4.18 Joule (Experimental value)

So, 

1 Joule= 1/4.18 Cal

So,

1 kWhr= 3.6*10^6/4.18 Cal

Basic of electrical energy|Electrical Energy Fundamentals

Energy means everything. Just imagine yourself with lots of energy. How many thing you can do. Similarly if you are without energy you won't be able to do anything. The backbone of development is energy. Our modern world is building continuously with the help of energy.

There are many variants of energy such as kinetic energy, static energy, thermal energy, e mechanical energy etc. But the most useful one is the electrical energy. Also as electrical Engineer we will focus on electrical energy. However please remember all energies are convertible from one form to another.

What are the major advantages of electrical energy?

Why electrical energy is so important?

We need energy in different forms some time for cooling, some time for heating, as light, as motion. Now I just rewind your basic and you can find that electrical energy can be converted to all of them. This is the main advantage of electrical energy. So let us list down the advantages of electrical energy.

1. Environment-friendly: Electrical energy clean and environment friendly. Pollutes the atmosphere very less. It does not produce toxic gases.

2.Ease of transmission distribution and control: You can transfer electrical energy over several thousand kilometres with the help of conductor. You can distribute it as you want also you can control the energy by only switching on or off a circuit.

3. Easily convertible: Electrical energy can be converted to rotational energy (motor), photoenergy (light), heat energy (heater or air conditioner), sound energy (speaker) etc. with ease. No other form of energy is such easily convertible.

Source of electrical energy!!!! No no we should say conversion of other energy into electrical energy.

We know that energy cannot be created or destroyed. It can only transform from one form to another.

So there are many kind of preliminary source of energies from where electrical energy can be obtained.

The major sources and form of energies are

1. Fuel (solid/liquid/gas): Solid or coal, liquid or oil, or fuel gas have calorific values which releases heat when burnt. Now this heat is used to convert water into steam. This steam is thrown on steam turbine, so heat energy is converted to kinetic energy. The steam turbine is coupled with alternator. The alternator when rotates generates electrical energy. Liquid fuel is used in internal combustion engine which rotates and generator connected with it generate electrical energy. Gas is often used in gas turbine which generates electrical energy as generator connected with it.

2. Water: Water when stored at high level or its flow is restricted by dam, it stored static energy. So if it is released through a pipe the energy is released as kinetic energy. Now this water is fall on water turbine. The Kinetic linear energy is then converted into rotational energy. So the water turbine rotates and as alternator is coupled with the turbine so the alternator also starts rotating and generates electrical energy.

3. The Sun: The Sun gives us heat energy and photo or light energy. Both can be converted to electrical energy. From light energy emitted by sun, electrical energy can be obtained by using solar photovoltaic cell commonly known as solar panel, which converts light energy to electrical energy. Also the heat energy is collected via reflector and used to heat up the water which eventually converts into steam and operates the steam turbo generator.

4. Wind: At coastal area wind has high kinetic energy so the wind turbines are installed at coastal areas. With these wind turbine often known as wind mill a generator is coupled inside it. So when wind blows the turbine it starts rotating and the generator located inside also starts rotating and it generates electricity.

4. Nuclear: Nuclear energy is another kind of source from where we can extract electrical energy. There are sevaral radioactive material which participate in fission reaction and generates heat. This heat, coming out of the nuclear energy can converts water into steam. This steam is thrown to the turbine, the turbine rotates, and the alternator coupled with the turbine also rotates. So electricity is generated.

5. Chemical energy: Inside battery due to chemical reaction energy is generated.

These are the major source of energy. Apart from the above geo thermal energy, tidal energy etc. are also used for electrical energy generation.

Hope you have enjoyed this article.

Thank you very much....