How many kiln batches a year do the Bureau of Energy Efficiency Godavari heat recovery reports assume, and do their batch lengths fit?
The three Bureau of Energy Efficiency (BEE) Godavari heat recovery reports use 30, 20 and 15 batches a year. For the 50 tonne kiln it fits the 6 day basis but not the 8 day batch the same report prints. The 100 tonne kiln prints fewer batches than its text implies; the 200 tonne kiln more than its days allow.
What each report prints
- 50 tonnes: 2 to 3 batches a month; 6 days of continuous firing a batch (section 1.3.1); batch of 8 days in the operating parameters in section 1.4.1 (slow firing 2, rapid 4, held 1, cooling 1); 30 batches a year in the annexure.
- 100 tonnes: the same text, 2 to 3 batches a month, 6 days, an 8 day batch; but 20 batches a year in the annexure.
- 200 tonnes: 1 to 2 batches a month; 15 to 18 days of continuous firing; a batch of slow firing 5, rapid 8, held 2 and cooling 1, which is 16 days; 15 batches a year.
- All three say the kiln is operated 15 days a month, which is 180 days a year, and all three describe the same 72 hour slow fire, 48 hour rapid fire, 24 hour hold and 24 hour natural cooling in section 1.1.1, which add to 168 hours or 7 days.
Do the days fit
- 50 tonnes: 30 batches x 6 days = 180 days, exactly 15 days a month. At the 8 day batch it would be 240. The annexure count fits the 6 day basis.
- 100 tonnes: 20 batches x 6 days = 120 days, or x 8 = 160. Below 180, and below the 24 to 36 batches that 2 to 3 a month would give.
- 200 tonnes: 15 batches x 16 days = 240 days, above 180. A single 16 day batch is longer than the 15 days a month the report says the kiln runs.
- 200 tonnes, hold: section 1.4.1 prints heat maintained 2 days, but section 2.1.1 says 3 days is the soaking period. At 3 days the batch is 17 days, so the fit is worse. That is my sum.
What that does to the savings
- 100 tonnes: at 24 to 36 batches the saving is 38,439.5 x 24 = 922.5 to x 36 = 1,383.8 tonnes of coal, against the printed 768.79. The printed figure is the cautious one.
- 200 tonnes: if the kiln runs only 180 days a year, a 16 day batch gives 180 / 16 = 11.25 batches, so 86,826 x 11.25 = 976.8 tonnes, against 1,302.39. At rupees (Rs) 4,500 a tonne that is Rs 43.96 lakh, less Rs 2.42 lakh of electricity, so Rs 41.54 lakh. Payback 25.00 / 41.54 = 0.60 years, not 0.44.
- Both calculations are mine, built on the reports' own batch figures. They hold the blower electricity at the printed amount.
What to do before you rely on a payback
- Count the batches your kiln fired in the last 12 months from your firing book.
- Take the coal per batch from your own invoices and stock records.
- Multiply the report's saving per batch share (27.5% to 31%) by your coal, not by the report's batches.
The 200 tonne report on a 180 day year
- Printed: 86,826 kilograms a batch x 15 = 1,302.39 tonnes
- Days: 15 batches x 16 days = 240, against 15 days a month x 12 = 180
- Batches that fit: 180 / 16 = 11.25; 86,826 x 11.25 = 976.8 tonnes
- Saving at Rs 4,500 a tonne: 976.8 x 4,500 = Rs 43.96 lakh; less Rs 2.42 lakh = Rs 41.54 lakh; payback 25.00 / 41.54 = 0.60 years
A 16 day batch is the sum of the report's own phases, and 15 days a month is the report's statement. Whether that statement means days of firing is my reading.
What Senseible does here
Senseible reads fuel invoices and electricity bills into monthly records, so once you upload your coal and power bills, coal bought each month sits on record, and tonnes of coal over the report's tonnes a batch is a rough check on batches fired. In the self-serve product it does not read kiln logs; custom integrations are available on request.
- Godavari heat recovery reports compared
- Downdraft kiln heat recovery on a 100 tonne kiln
- Refractory kiln coal to biomass gasifier
- Green loan readiness check
Sources: BEE, Detailed project report: waste heat recovery for preheating refractories, up to 50 tonnes a batch, Godavari refractories cluster (SAMEEEKSHA), BEE, Detailed project report: waste heat recovery, 100 tonne kiln, Godavari refractories cluster (SAMEEEKSHA), BEE, Detailed project report: waste heat recovery, 200 tonne kiln, Godavari refractories cluster (SAMEEEKSHA)
Last reviewed 2026-11-06. Figures are from the Bureau of Energy Efficiency (BEE) Small and Medium Enterprises (SME) programme reports, at the report year's prices, coal at Rs 4,500 a tonne. Check today's coal price and a current quote before relying on any payback. Where a report disagrees with itself this page says so.