How to calculate boiler efficiency by direct method?
Direct efficiency. This method calculates boiler efficiency by using the basic efficiency formula-. η= (Energy output)/ (Energy input) X 100. In order to calculate boiler efficiency by this method, we divide the total energy output of a boiler by total energy input given to the boiler, multiplied by hundred. Calculation of direct efficiency-.
Should I buy a high efficiency boiler?
The answer is yes — at least for some people. Since high-efficiency boilers are more expensive upfront, only consider buying one if you plan to be in your home for several years. Otherwise, you may never recoup your investment. Also consider what type of fuel is available (which is dictated by your local fuel supplier).
How to calculate the fuel consumption of the boiler?
The method of calculating 2 ton steam boiler fuel consumption
- Excess Air Effect on Industrial Boiler Efficiency.
- Flue Gas Temperature
- Convection and Radiation Losses
- Fuel Specification.
- Ambient Temperature.
How to increase boiler performance?
Tips to Increase Efficiency and Heat Recovery in a Boiler System
- Maintain, Maintain, Maintain. Keep up with annual boiler maintenance. ...
- Proper Water Treatment. Check that the boiler system water is treated properly. ...
- Install a High-Turndown Burner. ...
- Add Variable-Speed Drive Controls. ...
- Incorporate Parallel Positioning. ...
- Include O 2 Trim. ...
- Integrate Lead/Lag. ...
- Incorporate an Economizer. ...
- Recover and Repurpose Heat from Blowdown. ...
What is combustion efficiency in steam boiler?
Managing your boiler with the best amount of excess air will reduce heat loss up to the mass and enhance combustion efficiency. Combustion efficien...
What are the factors of combustion efficiency?
The thermal efficiency and combustion efficiency of a condensing device will be different. The only way to determine the exact thermal efficiency...
What are direct and indirect efficiencies in boiler?
The overall boiler efficiency relies on many parameters apart from combustion and thermal conductivity. These other parameters include ON-OFF damag...
How to calculate boiler efficiency?
Boiler efficiency can be calculated using ASME Performance Test Codes (PTC). PTC 34 is used for waste combustors with energy recovery using the boiler as a calorimeter. Using this method, the heat outputs, losses and credits must be calculated. Heat credits correct the efficiency to standard ambient conditions, such as air temperature. When comparing the efficiency of different systems, the heat credits do not matter, since they would be substantially the same for any system. Heat losses have the most significant impact on efficiency. Many parameters that contribute to heat loss, such as moisture and hydrogen in the fuel, are independent of the type of technology. Others, such as loss due to carbon monoxide in the flue gas, are small and can be ignored when comparing systems.
What is boiler efficiency?
Boiler efficiency is a measure of the goodness of the chosen process and equipment to transfer combustion heat to the heat in steam. Boiler efficiency can be defined as the ratio of the useful heat output to the total energy input.
What is the biggest loss in boiler efficiency?
The largest boiler efficiency loss is sensible heat lost as hot flue gases (and ash) exit the boiler. Unburned carbon losses equate to the fraction of combustible fuel which is not burned in the boiler. Other efficiency losses occur due to heat radiation and convection to the boiler surroundings.
What is boiler heat exchanger efficiency?
Boiler heat exchanger effectiveness is specific boiler thermal efficiency, which is converted to heat energy from the fire side to the water side. In addition, thermal efficiency is seriously affected by soot formation/scale formation on the boiler tubes.
How does low-rank coal affect boiler efficiency?
The high moisture content and resultant low heating value of low-rank coal affect boiler efficiency and transportation costs. Upgrading technologies increase the calorific value of a low-rank coal by removing water. Dewatering or drying are the processes used for this purpose. Moisture removal can be accomplished through the use of four different technologies – three are thermal and one is non-thermal:
What is a simplified boiler schematic?
Simplified boiler schematic. It is clear that the system boundaries can be drawn in many ways. For example, the boiler house might form a convenient system boundary. It has been pointed out that losses and heat input caused by fans, blowers, and pumps should not affect the boiler efficiency.
Why does a steam boiler need pumping energy?
A steam boiler needs pumping energy to be able to insert feedwater to produce pressurized steam. The higher the pressure, the higher the own power demand ( Table 3.3 ).
How to calculate boiler efficiency?
In order to calculate boiler efficiency by this method, we divide the total energy output of a boiler by total energy input given to the boiler, multiplied by hundred.
What is boiler efficiency?
Boiler efficiency is a combined result of efficiencies of different components of a boiler. A boiler has many sub systems whose efficiency affects the overall boiler efficiency. Couple of efficiencies which finally decide the boiler efficiency are-
What is combustion efficiency?
The combustion efficiency of a boiler is the indication of burner’s ability to burn fuel. The two parameters which determine the burner efficiency are unburnt fuel quantities in exhaust and excess oxygen levels in the exhaust. As the amount of excess air is increased, the quantity of unburnt fuel in the exhaust decreases.
Why is it important to have an efficient boiler?
In the operational life of a boiler, major costs arise out of the fuel costs. Ensuring efficient operation of boiler is critical to optimize the fuel costs. It is not always true that a boiler will work at its rated efficiency. Almost all the times, it has been found that the boilers operate at much lower than the rated efficiencies ...
Does boiler efficiency remain fixed?
Boiler efficiency does not remain fixed and large variations from ideal values take place during the course of operation. Shifting to real time efficiency monitoring can improve the boiler efficiency significantly depending upon the boiler type and actual conditions at site.
Is there a difference between direct and indirect efficiency?
There always exists some difference in the values of direct and indirect efficiencies. Indirect efficiency is measured at a particular time whereas direct efficiency is measured over a period of time and hence, losses on account of fluctuating loads, boiler on-off etc. are also taken into consideration.
What is boiler efficiency?
According to Wikipedia ” Boiler Efficiency is a relationship between energy supplied to the boiler and energy output received from the boiler.”. Boiler Efficiency usually expressed in (%) percentage.
What is the combustion efficiency of a boiler?
The combustion efficiency of a boiler signifies the burner’s capacity to burn fuel. It has two parameters that determine the burner efficiency: unburnt fuel supplies in the exhaust and excess oxygen levels in the exhaust. As the value of excess air is increased, the amount of unburnt fuel in the exhaust decreases.
How to increase boiler efficiency?
Here are the few boiler efficiencies boosting steps listed below: Complete combustion of fuel so that no unburnt is left behind is a good practice and will add to the boiler efficiency. Unburnt carbon coming out of the furnace can be re-injected again into the furnace so that complete combustion of fuel can take place.
How does a boiler reduce heat loss?
Managing your boiler with the best amount of excess air will reduce heat loss up to the mass and enhance combustion efficiency. Combustion efficiency is a measure of how efficiently the heat content of a fuel is transported into valuable heat.
What happens when the flue gases leave the boiler?
If the flue gases leaving the boiler is at a high temperature than the temperature for which it is designed, then most of the heat is getting wasted leading to reduced boiler efficiency.
How much can a boiler engineer increase efficiency?
After Analyzing heat losses in industrial boilers, boiler engineers or technicians can help you to increase your boiler efficiency by 6% – 10%.
Why is it important to make sure the boiler is working?
In the working life of a boiler, the major price comes out of the fuel costs. This is why making sure the effective operation of the boiler is crucial to optimize the fuel costs. It is a myth that a boiler will always operate at its estimated efficiency.
What is thermal efficiency?
Thermal efficiency of a boiler is defined as “the percentage of heat energy input that is effectively useful in to generated steam.”
How to calculate efficiency of indirect method?
The indirect method is also called the heat loss method. The efficiency can be calculated by subtracting the heat loss fractions from 100 as follows:
What percentage of heat loss is due to evaporation of water formed due to H2 in fuel?
ii. Heat loss due to evaporation of water formed due to H2 in fuel : 7.10 percent
How much radiation is lost in a boiler?
In a relatively small boiler, with a capacity of 10 MW, the radiation and unaccounted losses could amount to between 1 percent and 2 percent of the gross calorific value of the fuel, while in a 500 MW boiler, values between 0.2 percent to 1 percent are typical. The loss may be assumed appropriately depending on the surface condition.
What is the evaporation ratio?
Evaporation Ratio = Heat utilized for steam generation/Heat addition to the steam
Is hydrogen fuel loss dependent on fuel?
Losses due to moisture in fuel and due to combustion of hydrogen are dependent on the fuel, and cannot be controlled by design.
What is combustion efficiency?
Combustion Efficiency - indicates a burners ability to burn fuel measured by unburned fuel and excess air in the exhaust. Thermal Efficiency - indicates the heat exchangers effectiveness to transfer heat from the combustion process to the water or steam in the boiler, exclusive radiation and convection losses.
Why is accurate control of the air supply important to boiler efficiency?
An accurate control of the air supply is essential to boilers efficiency. too little air and the combustion will be incomplete. Unburned fuel will be carried over and smoke produced.
What is the gross calorific value of a fuel?
The gross calorific value of the fuel includes the energy used for evaporating the water in the combustion process. The flue gases from boilers are in general not condensed. The actual amount of heat available to the boiler plant is therefore reduced.
What is fuel to fluid efficiency?
Fuel to Fluid Efficiency - indicates the overall efficiency of the boiler inclusive thermal efficiency of the heat exchanger, radiation and convection losses - output divided by input.
What is the net calorific value?
Net calorific value excludes the energy in the water vapor discharged to the stack in the combustion process. The combustion process can be expressed as:
Boiler Efficiency
Combustion Efficiency
Thermal Efficiency
- The thermal efficiency of a boiler specifies the effectiveness of the heat exchanger of the boiler which actually transfers the heat energy from fireside to water side. Thermal efficiency is badly affected by scale formation/soot formation on the boiler tubes.
Direct and Indirect Boiler Efficiency
- The overall boiler efficiency depends on many more parameters apart from combustion and thermal efficiencies. These other parameters include ON-OFF losses, radiation losses, convection losses, blow down losses etc. In actual practice, two methods are commonly used to find out boiler efficiency, namely direct method and indirect method of efficiency calculation.
Direct Efficiency
- This method calculates boiler efficiency by using the basic efficiency formula- η=(Energy output)/(Energy input) X 100 In order to calculate boiler efficiency by this method, we divide the total energy output of a boiler by total energy input given to the boiler, multiplied by hundred. Calculation of direct efficiency- E= [Q (H-h)/q*GCV]*100 Where,...
Indirect Efficiency
- The indirect efficiency of a boiler is calculated by finding out the individual losses taking place in a boiler and then subtracting the sum from 100%. This method involves finding out the magnitudes of all the measurable losses taking place in a boiler by separate measurements. All these losses are added and subtracted from 100% to find out the final efficiency. Blow down valve is kept clo…
Comparison of Direct and Indirect Efficiency-
- Both the methods of finding out boiler efficiency mentioned above have some advantages and some disadvantages associated with them. The greatest advantage of indirect method is that it also speaks about the sources of losses. By finding out indirect efficiency, one can come to know where the losses are increased and can be reduced. On the other hand, direct efficiency values a…
Real Time Efficiency Monitoring
- Boiler efficiency does not remain fixed and large variations from ideal values take place during the course of operation. Shifting to real time efficiency monitoring can improve the boiler efficiency significantly depending upon the boiler type and actual conditions at site. In nutshell, monitoring and maintaining the boiler efficiency for the overall operational life of the boiler is a must to cut f…