Calorific Value

The amount of heat energy present in food or fuel is calculated by full combustion of a defined quantity at constant pressure and under normal conditions. Calorific power is another name for it.

In the combustion process, water vapour is produced, and the heat should be recovered using specified ways.

It has a high calorific value if the heat contained in the water vapour can be retrieved. When the heat contained in water vapour cannot be retrieved due to its poor calorific value.

The calorific value of a fuel or meal determines its efficiency. If the value is high, then the efficiency will be high as well. If the value is low, the efficiency will suffer as well.

How to Work It Out ?

The quantity of heat or energy produced by a fuel during complete combustion is known as its calorific value. 

It is a variable that represents the amount of heat or energy released and is measured in Gross Calorific Value (GCV) or Net Calorific Value (NCV) (NCV). A bomb calorimeter can be used to determine the calorific value of a fuel. We may express the calorific value formula as follows using the preceding understanding of calorific value:

Formula for Calorific Value

Gross calorific value (GCV) – latent heat of water vapours = Net calorific value (NCV).

OR

Net calorific value + latent heat of water vapours = Gross calorific value.

Which of the following fuels has the highest calorie content? 

A higher calorific value is regarded to be a good fuel. For example, appropriate fuels with higher to lower calorific values in descending order, with LPG having the highest calorific value, include LPG, Petrol, Kerosene, and Biogas. It’s also crucial for determining the substance’s commercial value, and it’s the most essential factor in determining the price of solid biomass.

Food Calorie Content

The amount of energy required to raise the temperature of one litre of water by one degree is measured in kilocalories, which is defined as the amount of energy required to raise the temperature of one litre of water by one degree. 

Food’s energy value reflects its worth as a source of energy for the body.

Food’s energy value reflects its worth as a source of energy for the body. This could be lower than the heat value determined from tests in which food is burned outside the body using a bomb calorimeter. 

Because some of the food’s energy is ‘lost’ during digestion and metabolism within the body, this is the case. 

Because fibre is present in food, it is normally deducted from the total carbohydrate, fat, protein, or alcohol content. 

A sample weight is balanced in a Bomb Calorimeter, which is a metallic chamber surrounded by an amount of water whose temperature is determined when the meal is lit, to calculate the calorific value of various foodstuffs.

The average value:

Protein is 4Kcal/gram

Carbohydrate is 4Kcal/gram

Fat is 9Kcal/gm

Conclusion

Fuels and meals are important aspects of our lives that we use every hour and second of the day, thus keeping track of how much energy we consume or carry is critical. 

Knowing the calorific value of fuels and meals simplifies simple computations used by gas suppliers and transporters to bill gas consumers. 

Calculating the calorific value of food, on the other hand, contributes in guiding individuals toward a healthy calorie or food consumption.