Which of the four Bureau of Energy Efficiency fixes for a Jamnagar brass billet reheating furnace pays back first?

In the Bureau of Energy Efficiency (BEE) Jamnagar manual, controllers pay back first, in about four months. On a 500 tonne a year oil-fired billet furnace, controllers save 3,000 litres for rupees (Rs) 0.30 lakh and gauges 900 for Rs 0.20 lakh. Insulation saves 1,850, and a new furnace 6,885 litres for Rs 4 lakh.

The four fixes as the manual prints them

• New energy efficient reheating furnace: efficiency 17.59% to 28.00%, furnace oil 37.03 to 23.26 litres a tonne, so 13.77 litres a tonne less. On 500 tonnes that is 6,885 litres, Rs 1.93 lakh a year at Rs 28 a litre. Cost Rs 4.00 lakh, payback 2.07 years.
• Air-fuel controllers on the existing furnace: excess air in the flue gas 9.41%, efficiency 17.59% to 20.99%, 37.03 to 31.03 litres a tonne. Saves 6 litres a tonne, 3,000 litres, Rs 0.84 lakh. Cost Rs 0.30 lakh, payback printed as 0.34 years.
• Better insulation: furnace skin temperature 112 down to 55 degrees Celsius, 39 to 35.3 litres a tonne. Saves 1,850 litres, Rs 0.52 lakh. Cost Rs 0.75 lakh, payback 1.4 years.
• Temperature gauges: billets leave at 795 degrees against the 750 the pressing needs, 39 to 37.20 litres a tonne. Saves 900 litres, Rs 0.25 lakh. Cost Rs 0.20 lakh, payback 0.80 years.

Checks on the printed arithmetic

• The furnace row ties: 13.77 x 500 = 6,885 litres, x Rs 28 = Rs 1,92,780, which is Rs 1.93 lakh.
• The controller payback does not quite tie. Rs 0.30 lakh divided by Rs 0.84 lakh is 0.36 years, about four months, not 0.34.
• In all three efficiency rows, efficiency times litres a tonne comes to about 651 (17.59 x 37.03, 20.99 x 31.03, 28 x 23.26). That is my check, not the report's statement: it shows the report holds the useful heat per tonne fixed and moves only the efficiency.
• The summary table (Table 5.1) prints the new furnace as 7,000 litres, Rs 1.96 lakh and 2.04 years, where the body table gives 6,885, Rs 1.93 lakh and 2.07. Use the body figures; the gap is small.

Do not add the four together

The manual prices each fix alone. The manual's section 3.4.1 lists only quality, reheating time, environment and productivity as benefits, so it does not say what the new furnace includes. BEE's detailed project report for a 1.2 tonnes an hour version of this furnace does include a controlled burner, insulation and gauges, so it is likely to overlap with the other three and should not be stacked on them. The baselines also differ: 37.03 litres a tonne for the furnace and controller rows, 39 for the insulation and gauge rows. My sum of the three retrofits is 5,750 litres a year (11.5 litres a tonne, about 31% of 37.03) for Rs 1.25 lakh, which would pay back in about 0.78 years. Treat that as an upper bound: the fixes share the same flue gas and the same fuel.

The same 37.03 to 23.26 litres a tonne appears in BEE's detailed project report for a larger 1.2 tonnes an hour furnace on 2,400 tonnes a year, where it costs Rs 9.35 lakh (8.50 plus 0.85) with a 1.08 year payback. That 1.08 years is after deducting 11,800 kWh of blower power; the manual's 2.07 years is not. Scale changes the rupees, not the litres a tonne.

How many units BEE thought could take each fix

Table 5.1 lists 120 units for the new furnace (840,000 litres across the cluster), 90 for controllers (270,000), 80 for insulation (148,000) and 100 for gauges (90,000). Each is the per-unit saving times the unit count, using Table 5.1's 7,000 litres for the new furnace (7,000 x 120 = 840,000), not the body's 6,885 (x 120 = 826,200).

The gauge fix, line by line (carbon dioxide is an estimate)

• Billet temperature 795 degrees against 750 needed. Furnace oil 39 litres a tonne falls to 37.20.
• Saving 1.80 litres x 500 tonnes = 900 litres; x Rs 28 = Rs 25,200, printed as Rs 0.25 lakh
• Payback Rs 0.20 lakh / Rs 0.25 lakh = 0.80 years
• Carbon dioxide (CO2): 900 litres x 2.97 kilograms = about 2.7 tonnes a year. The new furnace: 6,885 x 2.97 = about 20.4 tonnes

Prices are the manual's Rs 28 a litre. 2.97 kilograms of CO2 a litre is furnace oil at about 0.95 kilograms a litre and the Intergovernmental Panel on Climate Change (IPCC) default for residual fuel oil, an estimate; use the density on your own invoice.

What Senseible does here

Self-serve, Senseible reads fuel invoices and electricity bills into monthly records; furnace temperature and flue gas are custom, on request. The furnace oil you buy each month can sit beside the tonnes you pressed, which come from your own records. Compare litres a tonne before and after a fix.

• Green loan readiness check
• Efficient oil fired reheating furnace, 1.2 tonnes an hour
• Reheating furnace on gas instead of oil
• Furnace oil litres to kilograms

Sources: BEE, Manual on energy conservation measures in brass cluster Jamnagar (Winrock International India), BEE, Detailed project report: energy efficient oil fired reheating furnace, 1,200 kg/hr, Jamnagar brass cluster (2010, SAMEEEKSHA), IPCC 2006 Guidelines, Volume 2 Energy

Last reviewed 2026-11-06. Figures are from BEE's Jamnagar cluster manual, which prints no year on the pages used; costs and the Rs 28 a litre oil price are that report's. The 1.2 tonnes an hour comparison uses BEE's detailed project report. Re-run the payback at today's oil price and a current quote.