Unlocking Hidden Savings: How Economizers in Boilers Pay for Themselves

In the world of boilers, maximizing efficiency is a top priority. The ability to recover waste heat and transform it into useful energy can significantly enhance the performance of these systems. That’s where economizers come into play. Economizers are vital components that enable boilers to recover heat from flue gases and utilize it to preheat the boiler feedwater, leading to improved efficiency and substantial energy savings. In this article, we will delve into the workings of economizers and explore how they contribute to the overall efficiency of boilers.

Understanding the Role of Economizers in Boilers: An Introduction

What are economizers in boilers?

Economizers in boilers is a device installed in the lower part of the flue at the end of the boiler to recover the waste heat of the exhausted flue gas. The coal saver heats the boiler-feed water into the heating surface of saturated water under the pressure of a steam ladle. Because it absorbs the heat of high-temperature flue gas, it reduces the flue gas exhaust temperature, saves energy, and improves efficiency, so it is called economizer.

Economizers play a crucial role in enhancing the efficiency and cost-effectiveness of boilers. These remarkable devices are designed to recover waste heat from flue gases and utilize it to preheat the boiler’s feedwater. By harnessing this otherwise wasted heat energy, economizers help reduce the amount of fuel required to heat the water, resulting in significant energy savings.

One of the primary functions of an economizer is to increase the overall thermal efficiency of a boiler system. By preheating the feedwater before it enters the boiler, economizers can significantly lower the fuel consumption needed to achieve the desired temperature. This translates into substantial cost savings on fuel bills, making economizers a smart investment for businesses and homeowners alike.

Furthermore, economizers also contribute to reducing the environmental impact of boiler operations. By utilizing waste heat and optimizing fuel efficiency, they help to lower greenhouse gas emissions. This aligns with sustainability goals and promotes a greener approach to energy consumption.

The operation of an economizer involves transferring heat from the flue gases to the incoming feedwater. As the hot flue gases pass through the economizer’s tubes, they heat the water flowing around them. This heat transfer process efficiently utilizes the thermal energy that would otherwise be lost through the chimney.

Choosing the right type and size of economizer is essential to maximize its effectiveness. Factors such as the boiler’s capacity, flue gas characteristics, and specific application requirements need to be considered during the selection process. Consulting with a qualified professional or an experienced boiler technician can help ensure that you choose an economizer that is perfectly matched to your boiler system.

Economizers play a vital role in optimizing the performance and efficiency of boilers. By recovering waste heat and utilizing it to preheat the feedwater, these devices enable significant energy savings and cost reductions. Moreover, they contribute to environmental sustainability by reducing fuel consumption and emissions. Understanding the role of economizers in boilers is key to unlocking their hidden benefits and making informed decisions when it comes to upgrading or installing boiler systems.

DHB boiler has its own team of designers who will provide professional advice on coal saver configuration according to your boiler design.

Also DHB boiler has the certificate link below to meet the different specification requirements of each country.

How Economizers in Boilers Help Recover Waste Heat and Boost Efficiency

Economizers play a crucial role in boilers by helping to recover waste heat and boost overall efficiency. In industrial processes, boilers are widely used to generate steam or hot water for various applications. However, the combustion of fuel in boilers typically results in the production of hot flue gases that contain valuable heat energy. Economizers in boilers are designed to capture and utilize this waste heat, thereby improving the efficiency of the boiler system.

The function of an economizer is to preheat the feedwater entering the boiler using the residual heat from the flue gases. Typically, the economizer is positioned between the boiler’s combustion chamber and the chimney. As the flue gases pass through the economizer, they transfer heat to the feedwater tubes, which increases the temperature of the incoming water. This preheating process reduces the amount of fuel required to reach the desired steam or water temperature, resulting in fuel savings and improved efficiency.

By recovering waste heat, economizers in boilers offer several benefits to boiler systems. First and foremost, they enhance energy efficiency by utilizing heat that would otherwise be lost to the atmosphere. This not only reduces fuel consumption but also lowers greenhouse gas emissions, making the boiler system more environmentally friendly. Additionally, the use of economizers helps to decrease operating costs by reducing the need for additional fuel. This is especially important in industries with high energy demands, where even a slight improvement in efficiency can result in significant savings.

Economizers come in various designs and configurations, including tubular, finned, and spiral-wound. Tubular economizers consist of a bundle of water tubes through which the flue gases pass. Finned economizers have extended surface area in the form of fins attached to the tubes, which further enhances heat transfer. Spiral-wound economizers employ a spiral arrangement of tubes to achieve efficient heat recovery. The choice of economizer type depends on factors such as the boiler’s operating conditions, flue gas temperature, and available space.

Economizers In Boilers

Advantages of Tubular Economizers

Efficient Heat Transfer:

Tubular economizers are designed with a series of small-diameter tubes arranged in a staggered pattern. This configuration promotes efficient heat transfer between the flue gases and the boiler feedwater. The compact size of the tubes allows for a larger surface area, enabling better heat exchange and maximizing the recovery of waste heat. This efficient heat transfer capability ensures that a significant amount of thermal energy is harnessed and utilized effectively, leading to improved overall boiler efficiency.

Versatility and Adaptability:

One notable advantage of tubular economizers is their versatility and adaptability to various boiler types and sizes. They can be customized and tailored to fit specific boiler systems, making them suitable for a wide range of applications. Tubular economizers can be seamlessly integrated into new boiler installations or retrofitted into existing systems, allowing for easy and cost-effective implementation. This versatility makes them an attractive choice for boiler operators looking to enhance efficiency without the need for major system modifications.

Durability and Low Maintenance:

Tubular economizers are built to withstand high temperatures and harsh operating conditions commonly encountered in boiler systems. They are constructed using robust materials such as carbon steel or stainless steel, ensuring durability and longevity. The design of tubular economizers minimizes the risk of fouling or corrosion, reducing the need for frequent maintenance and cleaning. This characteristic translates into lower maintenance costs and minimal downtime for the boiler system, resulting in increased operational efficiency and productivity.


From a financial standpoint, tubular economizers offer significant cost savings over the long term. By recovering waste heat and preheating the boiler feedwater, these economizers reduce the amount of fuel required to achieve the desired operating temperature. The decreased fuel consumption leads to substantial energy savings and lower fuel bills. Additionally, the adaptability of tubular economizers allows for easy installation and integration, eliminating the need for extensive system modifications or downtime. This cost-effectiveness makes tubular economizers a practical investment for both new and existing boiler installations.

Environmental Benefits:

In addition to the economic advantages, tubular economizers also contribute to environmental sustainability. By recovering waste heat and optimizing boiler efficiency, they reduce the overall energy consumption and carbon footprint of the system. The decreased fuel consumption results in lower greenhouse gas emissions, promoting eco-friendly practices and compliance with environmental regulations. Incorporating tubular economizers into boiler systems aligns with the growing emphasis on energy efficiency and sustainable operations, making them an attractive choice for environmentally conscious organizations.

Tubular economizers offer a range of advantages that make them a preferred option for optimizing boiler efficiency. Their efficient heat transfer capabilities, versatility, and adaptability to different boiler systems, durability, low maintenance requirements, cost-effectiveness, and environmental benefits all contribute to their popularity. By harnessing waste heat and maximizing energy recovery, tubular economizers enable significant fuel savings, reduced operating costs, and a smaller carbon footprint. Consider implementing tubular economizers to enhance the performance and sustainability of your boiler system, while reaping the financial and environmental rewards they offer.

1-Dhb Boiler

The DHB boiler has Tubular Economizers, which would be an excellent choice for improving the efficiency of your boiler.

It is worth noting that economizers have limitations and considerations to ensure optimal performance. The temperature difference between the flue gases and the feedwater, known as the approach temperature, plays a significant role in determining the amount of heat that can be recovered. A lower approach temperature indicates better heat transfer and higher efficiency. However, excessively low temperatures may result in the condensation of corrosive elements from the flue gases, potentially damaging the economizer. Proper design, material selection, and regular maintenance are essential to mitigate these risks and ensure long-term performance.

In conclusion, economizers are crucial components in boiler systems, enabling the recovery of waste heat from flue gases. By preheating the feedwater, economizers contribute to improved efficiency, reduced fuel consumption, and lower operating costs. Their installation offers both economic and environmental benefits, making them a valuable addition to industrial processes that rely on boilers. With the right design and maintenance practices, economizers can play a significant role in enhancing energy sustainability and overall system performance.

Economizers In Boilers

Calculating Cost Savings: The Financial Benefits of Economizers in Boilers

The amount of energy that can be saved by a coal saver, or economizer, in a boiler system can vary depending on several factors such as boiler size, operating conditions, and the efficiency of the economizer itself. However, it is important to note that economizers typically offer significant energy savings and fuel consumption reduction. 


Let’s consider a medium-sized industrial boiler with a capacity of 10,000 pounds of steam per hour. Without an economizer, the boiler consumes 1,000,000 British thermal units (BTUs) of fuel per hour. By installing an economizer, the boiler’s fuel consumption can be reduced by approximately 5-10%. Assuming a conservative estimate of 5% fuel savings, the economizer would save 50,000 BTUs of fuel per hour. Over a year of continuous operation (8,760 hours), this would result in savings of approximately 438 million BTUs.

It’s important to keep in mind that these examples are simplified and the actual energy savings achieved by an economizer can vary depending on specific factors such as boiler efficiency, flue gas temperatures, and operating conditions. Additionally, the type and design of the economizer will also influence the actual energy savings. Consulting with a qualified engineer or energy specialist can provide more accurate estimations based on the specific boiler system and its requirements.

Economizers In Boilers

Choosing the Right Economizer for Your Boiler: Factors to Consider

When it comes to optimizing the efficiency of your boiler system, selecting the right economizer is crucial. Economizers in boilers play a significant role in recovering waste heat and reducing fuel consumption, leading to substantial cost savings and improved energy efficiency. 

1. Boiler Type and Size:

The first factor to consider is the type and size of your boiler. Different boiler designs and sizes may have specific compatibility requirements for economizers. It is essential to ensure that the economizer you choose is suitable for your boiler system. Consider factors such as the heat transfer surface area, pressure and temperature ratings, and the flow dynamics of the flue gases and feedwater. Consulting with an engineer or manufacturer can help determine the most appropriate economizer for your specific boiler configuration.

2. Application and Operating Conditions:

Understanding the intended application and operating conditions of your boiler is vital when selecting an economizer. Consider whether your boiler operates primarily for steam generation, hot water production, or process heat. Additionally, factors such as the fuel type, combustion efficiency, flue gas temperature, and the potential for corrosive or fouling elements in the flue gases should be taken into account. These factors will influence the design and materials of the economizer to ensure optimal performance and durability in your specific operating environment.

3. Economizer Type and Design:

There are various types of economizers in boilers available, including tubular economizers, finned tube economizers, and plate economizers. Each type has its advantages and considerations. Tubular economizers, for example, offer efficient heat transfer and adaptability to different boiler sizes. Finned tube economizers provide increased surface area for heat exchange, while plate economizers in boilers offer compact designs suitable for space-constrained installations. Consider the specific benefits and limitations of each type and choose the one that best suits your requirements.

4. Energy Recovery Potential:

Assessing the energy recovery potential of an economizer is crucial for maximizing efficiency. Look for an economizer that can capture and utilize a significant amount of waste heat from the flue gases. Consider the efficiency ratings and heat transfer capabilities of different economizers to ensure they can recover and transfer heat effectively. Additionally, evaluate the potential for recovering latent heat from water vapor in the flue gases, as condensing economizers can provide even greater energy savings.

5. Maintenance and Accessibility:

Consider the maintenance requirements and accessibility of the chosen economizer. Look for features such as easy access for cleaning and inspection, removable tubes or plates, and options for online cleaning mechanisms. Choosing an economizer that is easy to maintain will ensure its long-term performance and minimize downtime for cleaning and maintenance activities.

6. Cost and Return on Investment (ROI):

While cost should not be the sole determining factor, it is important to consider the initial investment and potential return on investment (ROI) of the economizer. Evaluate the cost-effectiveness by comparing the estimated energy savings and operational benefits against the upfront costs. Consider the payback period for the investment and the long-term cost savings that the economizer can provide. It may be beneficial to consult with suppliers, engineers, or energy specialists to assess the potential ROI accurately.

When choosing the right economizer for your boiler, take into account factors such as boiler type and size, application and operating conditions, economizer type and design, energy recovery potential, maintenance requirements, and cost considerations. By carefully evaluating these factors and seeking expert advice, you can make an informed decision that maximizes energy efficiency, reduces operational costs, and contributes to a more sustainable future. Invest in the right economizer for your boiler and reap the benefits of improved efficiency and long-term cost savings.

Economizers In Boilers

DHB boiler economizer parameters:

Boiler Economizer Paramenters

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Research papers and publications from academic institutions or engineering organizations such as the American Society of Mechanical Engineers (ASME) or the International Society for Industrial Ecology (ISIE).

Technical journals and magazines that focus on energy efficiency, sustainable technologies, or HVAC systems.

Books or textbooks on energy management, thermodynamics, or boiler engineering written by reputable authors or experts in the field.

Government websites or publications from energy and environmental agencies that provide guidelines or case studies related to economizers and energy efficiency in industrial settings.

Manufacturer or supplier websites that specialize in boiler systems and energy-saving equipment, as they often provide technical specifications, case studies, and white papers.

When using information from external sources, it’s important to properly cite and attribute the information to maintain academic integrity and give credit to the original authors.

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