How much coke does heat recovery save on a Jagadhri brass pit furnace: 30%, 10% or 7.5%?

Not one figure. The Bureau of Energy Efficiency (BEE) Jagadhri manual says 30% of coke in its text, 10% in its table and 7.1 tonnes in its summary, for rupees (Rs) 0.30 lakh. The detailed project report says 7.2 tonnes, 7.5% and Rs 0.50 lakh. Each one's rupees fit only its 7.1 or 7.2 tonnes.

What each document prints

• Manual text: efficiency of the pit furnace "will be increased by atleast 5%", and the coke saving "is estimated as 30% of the present consumption".
• Manual table (Table 17): 600 kilograms melted a batch on 80 kilograms of coke at Rs 27 a kilogram (Rs 2,160 a batch), 96 tonnes a year. Saving printed as 10%, 10 tonnes, leaving 86. Rs 1.92 lakh a year, cost Rs 0.3 lakh, payback 2 months.
• Manual summary (Table 28): 7.1 tonnes of coke, Rs 1.92 lakh, cost Rs 0.3 lakh, payback 0.2 years.
• Detailed project report: 7.2 tonnes (7.5%) at Rs 22,000 a tonne is Rs 1.58 lakh. Cost Rs 0.50 lakh (0.45 equipment and 0.05 erection), payback 0.32 years, no downtime.

Which tonnes fit which rupees

• 10 tonnes at Rs 27 a kilogram would be Rs 2.70 lakh, and 9.6 tonnes (10% of 96) Rs 2.59 lakh. Neither is the Rs 1.92 lakh printed.
• 7.1 tonnes x Rs 27,000 = Rs 1.917 lakh. So the manual's rupees fit the 7.1 tonnes of Table 28, which is 7.4% of 96. That is my check; the manual does not say so.
• 7.2 x Rs 22,000 = Rs 1.584 lakh, and 7.2 / 96 = 7.5%. But the report's annexure computes the saving as 7.81% (heat exchanger 65%, flue gas 500 down to 200 degrees) and then uses 7.5% and 7.2 tonnes, so the 7.5% is a rounded figure under the 7.81% it works out.

Where 30% might come from

A gain of 5 percentage points on a furnace at about 11% efficiency cuts coke by roughly 31% (1 minus 11/16). So the text may be applying "5%" as points. That is my reading only. The detailed report says Jagadhri pit furnaces run at 8% to 15%, and the table then uses a third of that cut. Use the lower figures, 7.1 to 7.5%, until you have measured your own.

Two more differences to know

• Coke price: Rs 27 a kilogram in the manual, Rs 22 in the report. Use your own invoice price. The report half of this page is also set out under "Heat recovery on its own" on the linked pit furnace page.
• Life of the equipment: 20 years in the manual's Table 23, 5 years in the report. A payback of a few months does not depend on it, but a lender's cash flow will.
• Cluster: the manual's text counts 50 units, Rs 96 lakh a year for Rs 15 lakh. In Table 28 that is 25 coke fired units (178 tonnes of coke) and 25 oil fired (160 kilolitres of furnace oil).

The same furnace, three readings (96 tonnes of coke a year)

• 30% of 96 = 28.8 tonnes; at Rs 27 a kilogram that is Rs 7.78 lakh, which would repay Rs 0.30 lakh in about two weeks
• 10% = 9.6 tonnes = Rs 2.59 lakh at Rs 27
• 7.1 tonnes = Rs 1.92 lakh at Rs 27, as the manual prints. 7.2 tonnes = Rs 1.58 lakh at Rs 22, as the report prints
• Carbon dioxide (CO2) on 7.2 tonnes of coke: 7.2 x 3.02 = about 21.7 tonnes a year. The report's headline says 11; its own annexure line (60% of coke as carbon, 4.32 tonnes) would give 4.32 x 44/12 = 15.84

Coke at the Intergovernmental Panel on Climate Change (IPCC) default for coke oven coke, 107,000 kilograms of CO2 per terajoule at 28.2 gigajoules a tonne, about 3.02 kilograms a kilogram; an estimate.

What Senseible does here

Self-serve, Senseible reads fuel invoices and electricity bills into monthly records; flue gas measurement is custom, on request. The coke bought each month is on file; compare it with the brass melted, from your own records, before and after you fit heat recovery.

• Your carbon number for buyers and banks
• Efficient 600 kilogram pit furnace saving coke
• Jagadhri modified pit furnace, three CO2 figures
• Jagadhri brass and aluminium cluster footprint

Sources: BEE and Zenith Energy Services, Manual on energy conservation measures in brass and aluminium cluster, Jagadhri, BEE, Detailed project report: waste heat recovery for coke fired pit furnace, 600 kg, Jagadhri, IPCC 2006 Guidelines, Volume 2, Chapter 1 Introduction, IPCC 2006 Guidelines, Volume 2, Chapter 2 Stationary Combustion

Last reviewed 2026-11-06. Both documents are BEE publications for Jagadhri and print no year on the pages used. The reading of 30% as percentage points is the author's, and is labelled as one. The coke factor is an estimate.