How much power does an efficient vertical agitator save on a 6,000 litre chemical reactor?
About 14,934 kWh a year in BEE's Ahmedabad report: a 5 HP direct drive vertical agitator replaces a 15 HP belt driven horizontal one drawing 8.5 kW for 12 hours a day. That is about 10 t CO2 on today's grid. Cost Rs 1.25 lakh, payback 1.56 years at 2010 power prices.
The agitator being replaced
- Horizontal agitator on a 7,000 litre vessel, 15 HP motor, belt drive and an old gear system, impeller at 100 rpm.
- It drew 8.5 kW; 7.04 kW reached the impeller and 3.73 kW did the mixing, so the drive was about 53% efficient.
- 12 hours a day: 102 kWh, or 0.0146 kWh per litre processed.
The replacement
- Vertical, top mounted, direct driven through a planetary gearbox, 5 HP at 84 rpm, two turbo foil impellers.
- Vessel 6,000 litres, 4,800 litres working volume, designed for liquor up to 1,700 kg per m3 and 700 cP.
- At full rating: 3.73 kW x 12 hours = 44.76 kWh a day, 0.0075 kWh per litre.
- Rs 1.12 lakh for the agitator, Rs 0.13 lakh to fit; about a week of downtime.
Two checks on the 14,934 kWh
- Days: the saving uses 2,100 kL a year, which is 6,000 litres a day for 350 days. The report's finance sheet assumes 300 days. At 300 days the saving is about 12,800 kWh, Rs 0.69 lakh at Rs 5.4 a kWh, payback about 1.8 years.
- Load: the new figure assumes the 5 HP motor at exactly its rating. Clamp a meter on it for a full batch before you claim the saving.
- Viscosity: if your batches are thicker than 700 cP or heavier than 1,700 kg per m3, ask the supplier to size the drive for them. An undersized agitator stretches the batch and eats the saving.
Where it sits in the unit's footprint
A typical unit in the report used 130,000 kWh and 350 t of wood a year: 1.2 kWh and 3 kg of wood per kg of product, with wood firing hot air generators for drying. One agitator saves about a tenth of the unit's power. Wood CO2 is biogenic and reported separately, so the grid is most of the unit's fossil figure.
One agitator, one year
- Old: 0.0146 kWh a litre; new: 0.0075; saved 0.0071 kWh a litre
- Report: 2,100,000 litres x 0.0071 = 14,934 kWh x 0.675 = 10.1 t CO2
- At 300 days: 1,800,000 litres, 12,800 kWh, 8.6 t CO2
- The report says 11 t in its summary and 12 t later
Grid at CEA's FY 2025-26 factor, an estimate.
What Senseible does here
Senseible reads your electricity bills into monthly records linked to each bill, with CO2 by the CEA factor for the bill's year, so the before and after months sit side by side. For a loan on the agitator, the green loan check lists the papers a lender will want.
Sources: BEE, Detailed project report: energy efficient vertical agitator (6000 litre), Ahmedabad chemical cluster (2010, SAMEEEKSHA), CEA CO2 Baseline Database, version 22.0
Last reviewed 2026-11-01. Report figures are from a BEE SME programme project report; costs and paybacks are at the report year's prices. Check today's tariff and a current quote.