What does an air preheater save on a Panipat thermic fluid heater running at 300 to 410 degrees at the stack?
The Panipat survey by The Energy and Resources Institute (TERI) prints a saving of 4 to 9% of fuel from an air preheater on a thermic fluid heater, paying back in up to 11 months. It found chimney gas at 300 to 410 degrees Celsius, hot enough to warm the incoming air.
The heater and the hot chimney
A thermic fluid heater is a furnace that heats oil instead of water. The oil carries heat to the stenter, the machine that stretches and heat-sets cloth, and to the printing section. TERI found heaters of 5 to 25 lakh (500,000 to 2,500,000) kilocalories an hour in the cluster, mostly fired with pet coke, and most with manual fuel charging.
TERI observed the flue gas, which is the hot gas leaving the chimney, at the stack end of these heaters at 300 to 410 degrees Celsius and called it quite high and recoverable. That gas is heat leaving for nothing.
What an air preheater does
An air preheater is a pre-warmer for the air that feeds the fire. Hot chimney gas passes beside the incoming air and hands over some heat, so the fuel starts burning in warm air and less fuel is needed. It works like a car heater, which uses the engine’s waste heat to warm the air going into the cabin.
What the survey table prints
- Existing: flue gas at 300 to 410 degrees Celsius, combustion air at 30 to 35 degrees Celsius.
- Proposed: an air preheater taking combustion air to 110 degrees Celsius.
- Energy saving potential: 4 to 9%. Simple payback: up to 11 months.
- The air rise is 110 − 35 = 75 up to 110 − 30 = 80 degrees Celsius, our arithmetic.
How it sits with our Pali page
Our Pali page reports a pet coke thermic fluid heater where an air preheater cools the flue gas from 250 to 180 degrees Celsius and saves 5.5% of fuel. That figure sits inside Panipat’s 4 to 9%. The two reports measure different heaters, so quote each with its own source.
Example: a heater burning 20 tonnes of pet coke a month
- Saving at 4%: 20 × 0.04 = 0.8 tonnes a month, 9.6 tonnes a year
- Saving at 9%: 20 × 0.09 = 1.8 tonnes a month, 21.6 tonnes a year
- Carbon dioxide (CO2) at 3.17 tonnes for each tonne of pet coke: 9.6 × 3.17 = 30.4 up to 21.6 × 3.17 = 68.5 tonnes a year
Example only. Pet coke is a hard black fuel left over from refining oil, counted here at defaults from the Intergovernmental Panel on Climate Change (IPCC). A before and after fuel record on your own heater gives your own figure.
What Senseible does here
Senseible reads your fuel invoices into monthly records, so the pet coke you buy each month is on file to compare before and after a preheater. It does not read a heater or its chimney, so the saving rests on your own invoices.
- Green loan readiness check
- Pali thermopac air preheater
- Panipat air to fuel controller
- Panipat fuels and carbon
Sources: TERI, Energy Profile: Panipat Textile Cluster, 2016 (SAMEEEKSHA), IPCC, 2006 Guidelines for National Greenhouse Gas Inventories, Volume 2, Energy
Last reviewed 2026-11-07. Figures are from the Panipat survey of 2014-15, published in 2016. The survey table prints each saving as a range with no boiler size, fuel tonnes or equipment cost. Check a current quote and your own fuel records before you rely on any payback.