What is the difference between HCV and LCV?

The main difference between HCV and LCV is that with HCV the by-products of the reaction can cool to room temperature, while with LCV by-products can escape. Therefore, a certain amount of heat that is lost with the by-products can be recovered in HCV, while a certain amount of heat is removed by the steam in LCV. In addition, LCV is equal to the value obtained by subtracting the heat removed by the steam from HCV.

HCV (higher heating value) and LCV (lower heating value) are two measurements of the heat generated in the combustion is released fuel of a unit mass. In addition, HCV is also known as the upper calorific value , while LCV is known as the calorific value .

Key areas covered

1. What is HCV - definition, facts, meaning 2. What is LCV - definition, facts, meaning 3. What are the similarities between HCV and LCV - overview of the common characteristics 4. What is the difference between HCV and LCV - comparison of main differences

key terms

Combustion of fuel, condensation, HCV, latent heat of vaporization, LCV, net calorific value, water vapor

Difference Between HCV and LCV - Comparative Summary

What is HCV

HCV (higher calorific value) or HHV (higher calorific value) is the amount of heat or energy released during the combustion of a particular fuel when its by-products condense . Here, when some hydrogen fuels are burned, water vapor is released, which then evaporates from the system. The process of water evaporation is supposed to absorb part of the heat released during the combustion reaction. And this heat is called latent heat of vaporization . However, it does not add to the work done by the energy produced by the system. That means; the formation and release of water vapor reduce the amount of thermal energy available in the system.

Difference between HCV and LCV

Figure 1: Combustion of methane

Therefore, some systems can go through a secondary condensation process in which water vapor is condensed. Thus, this method helps to recover a certain amount of heat that has been released from the system, whereby it can use the latent heat for certain work. Therefore, the value of HCV is equal to the sum of the amount of energy retained in the system; in other words, on the LCV and the amount of heat recovered through the secondary condensation process. For this reason, the HCV is also referred to as the calorific value.

What is LCV

The LCV (lower calorific value) or LHV (lower calorific value) is the amount of heat or energy that is released during the combustion of a particular fuel when the by-products escape freely from the system. Therefore, the value of LCV is equal to the value obtained by subtracting the heat removed by the steam from the system's HCV. This is why the LCV is also referred to as the net calorific value.

Key difference - HCV vs. LCV

Figure 2: Relationship between HCV and LCV

In addition, the LCV value becomes the calorific value for the fuel if the combustion unit does not have a secondary condensation process. However, this reduces the efficiency or productivity of the fuel.

Similarities Between HCV and LCV

  • HCV and LCV are two measurements of the heat released when a unit mass of fuel is burned.
  • Therefore, both represent the amount of heat or energy in a certain mass or volume of fuel.
  • Also, the units of measurement of both are MJ / kg for solid fuels and MJ / nm3 for gases.
  • In addition, the LCV value is equal to the value obtained by subtracting the heat removed from the stem from the HCV value.

Difference between HCV and LCV

definition

HCV (higher calorific value) refers to the amount of heat developed when a unit weight (or in the case of gaseous fuels, volume) of the fuel is completely burned and the combustion products are cooled to normal conditions (with condensed water vapor as a result). LCV (lower calorific value) refers to the amount of heat developed when a unit weight (or volume in the case of gaseous fuels) of the fuel is completely burned and water vapor escapes with the combustion products without being condensed. These definitions explain the main difference between HCV and LCV.

other names

HCV is also known as higher calorific value (HHV) or gross calorific value, while LCV is also known as lower calorific value (HHV) or net calorific value.

Correspondence

Another difference between HCV and LCV is that HCV is the total energy released when products are cooled to room temperature and water condenses out, while LCV is the energy released when products are hot.

Byproducts

The by-products are allowed to condense in HCV while the by-products are allowed to escape in LCV. This is another difference between HCV and LCV.

Heat or energy in by-products

In addition, some of the heat or energy in by-products in HCV can be recovered through condensation, while the heat or energy in by-products escapes the system.

value

The value is another difference between HCV and LCV. HCV is high while LCV is low.

diploma

HCV is the amount of heat or energy released when a fuel burns when its by-products are condensed to reclaim some of the energy released during combustion. In comparison, LCV is the amount of energy that is released when a fuel burns when its by-products freely escape the system. Therefore, the main difference between HCV and LCV is the type of heat that is accounted for in each system.

References:

1. “What is a lower calorific value and a higher calorific value?” Maschinenbau , May 24, 2016, available here

About the author: Lakna

Lakna, a graduate in molecular biology and biochemistry, is a molecular biologist and has a broad and strong interest in discovering things related to nature