Popular Branches
MBA
B.Tech
BBA
BSc
Home > Articles > Calorific Value: Fuels, Definitions, Measurement, Formula, Importance, Efficiency, Applications, and Sample Questions
Updated on 19th May, 2023 , 5 min read
The quantity of heat produced by a unit volume of a substance upon full combustion is referred to as its calorific value. It is measured in kilojoules per kilogram. Calorific Power is another name for it. The heat contained in fuels or food is determined by the full combustion of specified quantities at constant pressure and normal circumstances.
"Calorific value refers to the amount of heat produced by a substance per unit volume by complete combustion."
The calorific value of a substance specifies its energy content; it is the quantity of heat produced following full combustion. It is also known as the gross calorific value (GCV) or high heating value. In addition, a substance's calorific value (usually, solid biofuel or food) is the specific energy of burning per unit mass. KJ/kg is the SI unit for calorific value.
The following are some of the importance of calorific value-
Calorific value is the amount of heat produced per unit volume of a material when completely burned. Kilojoules per kilogram, or kJ/kg, is the unit of measurement.
For Example: If we state that kerosene has a calorific value of 45000 kJ/kg, it indicates that if 1 kilogram of kerosene is totally combusted, it would create 45000 kilojoules of heat energy.
The following is the formula for determining calorific value-
There are two sorts of Calorific value, and their relationship is as follows-
The heat created by burning 1 kg of the material and then cooling it to room temperature is referred to as the Gross Calorific Value, as the water vapor formed during the combustion process also produces heat that should be recovered. The more heat recovered from water vapor, the higher the Gross Calorific Value.
Calorific Value is mostly used to determine fuel economy. The higher the calorific value, the more efficient the gasoline and the better the fuel. The quantity of heat created by various types of fuels varies based on the element's nature and the percentage of elements contained in them. When fuels are burned, they have the potential to generate energy in thermal power plants. The optimum fuel for generating power is mostly determined by its calorific value. The following fuels and their calorific values are listed-
Fuel |
Calorific Values (approx.) |
Biogas |
35000 - 40000 |
CNG |
50000 |
Coal |
25000 - 33000 |
Cow Dung |
6000 - 8000 |
Diesel |
45000 |
Hydrogen |
1500000 |
Kerosene |
45000 |
LPG |
55000 |
Methane |
50000 |
Petrol |
45000 |
Wood |
17000 - 22000 |
LPG has a higher calorific value than diesel, petrol, and kerosene.
The heat energy produced in the human body during metabolism is referred to as the Calorific Value of food. When food is digested, the energy in the meal breaks down to provide fuel for the body to carry out everyday operations. It is usually expressed in Kilocalories. It is the amount of energy needed to raise the temperature of one liter of water by one degree Celsius. The following table lists numerous food products and their calorie counts-
Categories |
Calorific Value (in approx.) |
||
Category of Food |
Quantity (in grams) |
Kilojoules (KJ) |
Kilocalories (Kcal) |
Alcohols |
1 |
29 |
7 |
Carbohydrates |
17 |
4 |
|
Dietary fiber |
8 |
2 |
|
Fats |
37 |
9 |
|
Polyhydric Alcohols |
10 |
2.4 |
|
Protein |
17 |
4 |
The widely held assumption that fat should be avoided while dieting stems from the fact that fat has the highest calorific value when compared to other macronutrients.
The calorific value of a food fuel determines its efficiency; the higher the value, the higher the efficiency, and vice versa. Hydrogen fuel, for example, has the highest calorific value, 150 KJ/kg. Therefore, it is easy to realize that the efficiency of the substance is related to the calorific value. Furthermore, water vapor formed during the combustion process includes heat, and if it is recovered using various procedures, the substance will have a greater calorific value (GCV), and vice versa if it results in a lower or net calorific value (NCV). NCV is the consequence of allowing the products of combustion to escape.
The following are some of the applications of calorific value-
Solution: The calorific value of a fuel is determined by its composition and the relative quantities of the components present. It rises as the quantity of hydrogen in the fuel grows and falls as the moisture content drops.
Solution: Kilojoules per kilogram (kJ/kg) is the calorific value.
Solution: Hydrogen, as it contains 150000 kJ/kg of calorific value. The energy contained in a fuel or food is estimated by measuring the heat produced by the full combustion of a particular quantity of it. This is currently commonly represented in terms of joules per kilogram. As a result, hydrogen has the greatest calorific value.
Pilot Salary in India 2024: Starting Salary, Requirements, Qualifications, Per Month Salary
By - Nikita Parmar 2024-09-06 10:59:22 , 6 min readAns. Calorific value is the quantity of heat produced by the complete combustion of a unit volume of a material.
Ans. Calorific value is a critical criterion for determining the energy content of fuels and foods. It is used to calculate the fuel efficiency and heat generated by the human body during metabolism. Food’s energy content breaks down during digestion, releasing energy into the body. A kilocalorie is a unit of measurement for this energy.
Ans. It is significant because it provides the value of fuel or food in figures that may be determined using a formula. Because people consume energy and food on a regular basis, tracking their consumption is vital in both financial and health terms.
Ans. A higher calorific value (HCV) is the absolute amount of heat emitted by a specific fuel per unit mass or volume following burning. When side products are permitted to escape, a lower calorific value (LCV) is the absolute amount of heat released after burning a unit mass or volume of fuel. One of the primary contrasts between greater and lower calorific values is that there is no heat loss when side products escape in the latter, whereas higher losses occur.
Ans. The calorific value of the fuel is calculated under ordinary circumstances. The words "gross calorific value (GCV) and net calorific value (NCV) are used in the calculation to determine the calorific value of the fuel. To calculate the net calorific value, subtract the latent heat escape (in the form of water vapor) from the gross calorific value.