What causes high flue temperature?
Table of Contents
What causes high flue temperature?
The boiler water is being pushed through the fairly small coil at a flow rate high enough to accommodate the boiler flow rates and the tank loss. The tank can’t absorb all of the BTUs the boiler is pushing out. The remaining BTUs exit through the flue, causing the rise in temperature.
How does the Net stack temperature affect the efficiency?
Ambient Temperature. Net stack temperature is the difference between the flue gas temp and the ambient temperature. Although it’s tempting to minimize ambient temperature with hopes of lowering flue gas temp, a 40 degree alteration in ambient temperature can affect industrial boiler efficiency by one percent or more.
How do you reduce stack temperature?
Stack losses can be minimized by reducing excess air‚ which reduces the quantity of flue gas that is heated to exhaust temperature (FGT)‚ and by reducing the exhaust temperature.
What is stack temperature?
The “net stack temperature” is the difference between the flue gas inside the chimney and the room temperature outside the burner.
Why do flue gases leave the stack at high temperature?
The combustion flue gases inside the flue gas stacks are much hotter than the ambient outside air and therefore less dense than the ambient air. That causes the bottom of the vertical column of hot flue gas to have a lower pressure than the pressure at the bottom of a corresponding column of outside air.
What is the recommended stack temperature of boiler?
around 350 to 450 degrees Fahrenheit
Normally, you should expect stack temperatures around 350 to 450 degrees Fahrenheit. Every 100 degrees above that equates to a 2.5\% efficiency loss. Most buildings schedule boiler cleanings at regular intervals throughout the year, but if you notice those numbers jump above that range, it’s time for a cleaning.
Why is combustion not efficient?
Combustion efficiency decreases with increasing superficial gas velocity. Combustion efficiency initially increases with increasing excess air level and then decreases. This is believed to be due to an increase in CO and hydrocarbon emissions as the excess air level increases to higher levels [23].
What is the effect of excess air in combustion?
Too much excess air leads to lower flame temperature. That means less heat gets into the system. Also, excess air must heat up to flue gas temperature, which consumes extra energy.
What does stack loss mean?
Stack losses typically are the largest single energy loss in boiler operations and involve both excess air and stack temperatures. The amount of heat lost will depend on the temperature and volume of gas leaving the boiler.
How can we improve efficiency using boiler’s?
15 Ways To Increase Boiler Efficiency
- Increase Boiler Efficiency: Lower the Stack Temperature.
- Install an Economizer.
- Tune the Burner Regularly.
- Install a Variable Frequency Drive.
- Increase Boiler Efficiency: Insulate your Valves.
- Clean the Fireside.
- Preheat Combustion Air.
- Clean the Water Side.
What causes stack effect?
Stack effect is a pressure difference that causes uncontrolled air flow. It occurs when the temperature differs from outside to inside a building. The direction of air flow depends on whether the building is being heated or cooled.
What is high stack?
Read on to learn what stack height is and exactly how we measure it at Running Warehouse. Stack height is the term used to refer to the amount of shoe material between your foot and the ground. A shoe with more cushioning will have a higher stack height while a shoe will less cushioning will have a lower stack height.