# Calculating Boiler Efficiency for Year-Round Use

• TSN79
In summary, the speaker is asking how to find the overall efficiency for a boiler that has different efficiencies during different periods of the year. They suggest using a simple average calculation or integrating the efficiencies over the corresponding times. They also mention the concept of availability and capacity in relation to efficiency. Another person suggests considering part load and standby type efficiencies for a more accurate estimation.
TSN79
I have a boiler which for a certain period of the year has a spesific boiler efficiency, let's call it A. For another period of the year the boiler isn't used that much, and so it now has a different boiler efficiency B for this period. How do I find the overall efficiency for the whole year?

Hope someone can help me...

Thermodynamic efficiency is pretty much independent of time, unless it degrades due to changes in the system which are time dependent, e.g. build up of deposits.

If one has two time periods T1 and T2, and two rates A and B during those periods, then a simple average is (A*T1 + B*T2)/(T1+T2), otherwise one has to integrate A(t), B(t) over the corresponding times and use the appropriate averaging technique.

Now as for efficiency, are you sure the problem is not calling for 'availability'. Some plants can be operable, but are not needed, and therefore will have a low capacity factor.

Availablity is the time that a plant can operate, and capacity is based on the actual time of operation.

A plant down for repairs has no availability.

Astronuc said:
If one has two time periods T1 and T2, and two rates A and B during those periods, then a simple average is (A*T1 + B*T2)/(T1+T2), otherwise one has to integrate A(t), B(t) over the corresponding times and use the appropriate averaging technique.
I think he is talking about part load and standby type efficiencies. Using the correct values for these efficiencies and using Astronu's average calculation should give a pretty good overall efficiency estimation.

## 1. What is boiler efficiency?

Boiler efficiency is a measure of how well a boiler is able to convert fuel into usable heat. It is typically expressed as a percentage and indicates how much of the fuel's energy is being converted into heat for use in a building or process.

## 2. How is boiler efficiency calculated?

Boiler efficiency is calculated by dividing the heat output of the boiler by the heat input, and then multiplying by 100. This ratio is known as the combustion efficiency and is typically measured using instruments such as a flue gas analyzer.

## 3. What factors affect boiler efficiency?

There are several factors that can affect boiler efficiency, including the type and condition of the boiler, the fuel type and quality, the operating conditions, and the maintenance and cleaning of the boiler.

## 4. Why is it important to calculate boiler efficiency for year-round use?

Calculating boiler efficiency for year-round use is important because it allows for proper maintenance and optimization of the boiler, leading to cost savings and improved energy efficiency. It also ensures that the boiler is operating at its maximum potential, providing consistent and reliable heat for the building or process.

## 5. Is there a standard for boiler efficiency?

Yes, there is a standard for boiler efficiency known as the Annual Fuel Utilization Efficiency (AFUE). This is a measure of the average efficiency of a boiler over the course of a heating season, and is used to compare the efficiency of different boilers. The higher the AFUE rating, the more efficient the boiler is.

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