differentiate between Gross Calorific value(GCV) and Lower Calorific Value (LCV) of a fuel

Gross Calorific Value (GCV) and Lower Calorific Value (LCV) are both measures of the energy content of a fuel. However, they differ in the way they account for the energy associated with the water vapor produced during combustion.

1. Gross Calorific Value (GCV): Also known as the higher heating value (HHV), the GCV of a fuel is the amount of heat released by a specified quantity (initially at 25°C) once it is combusted and the products have returned to a temperature of 25°C. In other words, it measures the total energy content of the fuel. The GCV assumes that all the water vapor produced during combustion condenses and the heat contained in the water vapor is recovered.

2. Lower Calorific Value (LCV): Also known as the net heating value (NHV), the LCV of a fuel is the amount of heat released by combusting a specified quantity and returning the temperature of the combustion products to 150°C. It assumes that the water in the combustion products remains as vapor and the heat in the water vapor is not recovered. Therefore, the LCV is always less than the GCV.

In summary, the main difference between GCV and LCV is whether or not the heat contained in water vapor produced during combustion is considered. GCV includes this heat while LCV does not.