“Is my Heater operating at the full capacity? Or At what heat generation capacity – output, it is
running?”
This question lingers in the minds of many people. Though it is possible to measure output by a
flow meter, It is costly.
But there are certain empirical methods by which we can calculate the output of Thermic fluid
system. This may not be accurate but it fairly gives us an idea about “Where do we stand?”
- Fuel consumption per hour and at peak load.
Many plants have a record of per day fuel consumed. This helps us in finding per hour
average fuel consumption. Check data for 1 or 3 months and select the highest consumption.
A heater is designed for certain efficiency, say 75% in case of solid fuel like coal. So if a
heater is supplied to you for 10 lac kcal/hr heat generation capacity then it must deliver 10
lac kcal/hr after whatever losses are. Means, it’s heat output will not be 75% of 10 lac
kcal/hr but Heat input will be 100 /75 = 1.33 times more. Confirm this with heater supplier,
How much fuel/ hr the heater is capable of burning?
Find actual Fuel consumption and calorific value of the fuel. Heater manufacturer specifies
efficiency for which the heater is designed. As you know heat input ( kg of fuel and calorific
value) and efficiency, you can work out heat output if losses (Losses such as stack losses,
surface losses etc.) are under control. You will also need to check if fuel is burning
completely. In case of a solid fired heater, Gap in grate bars, Air supply, Fines carry– over
reduces actual fuel consumed. Similarly surface losses, stack losses also reduce actual heat
available at the outlet. This should be looked into carefully. - If heater fuel input is upto full capacity then look at on /off frequency of heater. The on-off
proportion will be the proportion at which heat is generated. If the fuel input is lesser then
reduce capacity assumed proportionately. - It is advisable to install hour meter (connect to Burner or ID fan) to find actual running of
heater (Fuel burning) - Another way is to find current drawn by pump motor, voltage, power factor, differential
pressure, Temp etc. With the help of the same, we can find actual pump flow. Then with
help of density, specific heat, we can calculate the heat flow thru the heater at particular
temperature and pressure at the particular moment.
The above methods give a fair idea on Heater output. There are additional methods to calculate
heater output but they are quite complicated and require more detailed calculations.