# In the Bureau of Energy Efficiency Kochi seafood reports, do variable speed drives on condenser water pumps or an evaporative condenser pay back faster?

Canonical: https://senseible.earth/answers/kochi-seafood-condenser-pump-drives-and-evaporative-condensers

In five Bureau of Energy Efficiency (BEE) Kochi reports, variable speed drives on condenser water pumps pay back in 1.16, 0.93 and 0.76 years, and evaporative condensers in 1.87 and 1.71. Two drive report files are named 55 and 75 kilowatts but cover 5.5 and 7.5 kilowatt pumps, four of each.

## The five reports side by side

- Drives on four 5.5 kilowatt (kW) pumps: cost rupees (Rs) 2.94 lakh, electricity 166,320 down to 120,120 kilowatt hours (kWh) a year, saving 46,200 kWh, benefit Rs 2.54 lakh, payback 1.16 years, internal rate of return 68.86 percent, printed carbon dioxide (CO2) cut 37 tonnes.
- Drives on four 7.5 kW pumps: Rs 3.21 lakh, 226,800 down to 163,800 kWh, 63,000 saved, Rs 3.47 lakh, 0.93 years, 85.18 percent, CO2 51 tonnes.
- Drives on three 11 kW pumps: Rs 3.50 lakh, 249,480 down to 166,320 kWh, 83,160 saved, Rs 4.57 lakh, 0.76 years, 101.81 percent, CO2 67 tonnes.
- Evaporative condenser in place of a cooling tower condenser, 243 kW of cooling: Rs 6.30 lakh, 105,840 down to 44,604 kWh, 61,236 saved, Rs 3.37 lakh, 1.87 years, 34.96 percent, CO2 49.6 tonnes.
- Evaporative condenser, 679 kW: Rs 12.97 lakh, 211,680 down to 73,332 kWh, 138,348 saved, Rs 7.61 lakh, 1.71 years, 39.98 percent, CO2 112.1 tonnes.
- All price power at Rs 5.50 a kWh and assume 24 hours on 350 days, which is 8,400 hours. The 11 kW drive report prints a payback of 0.76 years in its summary and 0.77 in Table 7.

## Two file names do not match the pumps

The first two drive files are named for 55 kW and 75 kW pumps. Inside, they are for 5.5 kW and 7.5 kW condenser water pumps, four of each. The third file, named 11 kW, does hold 11 kW pumps, three of them. 22, 30 and 33 kW of connected load at 90 percent loading over 8,400 hours gives the baselines of 166,320, 226,800 and 249,480 kWh. Read the pump size and number in the title page before you pick a report.

## Where the drive saving comes from

The saving is an assumed fall in loading, from 90 percent to 65 percent for the 5.5 kW and 7.5 kW pumps and to 60 percent for the 11 kW pumps. 166,320 x 65/90 is 120,120. The reports say a drive is fitted on 2 of the 4 pumps (2 of the 3 in the 11 kW report) but the whole system's consumption is counted, and that field trials showed 25 to 35 percent savings. The result is 27.8, 27.8 and 33.3 percent. Treat it as a target to confirm with before and after kW readings.

## The carbon lines

Every printed CO2 cut is the kWh saved times about 0.81 kilograms (37 tonnes for 46,200 kWh is 0.80, and the others 0.81), the same factor behind the Kochi absorption freezer reports. The factor used on this site now, 0.675 kilograms a kWh for 2025-26 (0.710 for 2024-25 bills), gives 31.2 tonnes for the first report, about 17 percent less. Recalculate with the current factor before you quote the printed figure.

## The four 5.5 kW pump report, rebuilt

- Connected load: 4 x 5.5 = 22 kW. At 90 percent over 8,400 hours: 22 x 0.9 x 8,400 = 166,320 kWh
- At 65 percent loading: 166,320 x 65 / 90 = 120,120 kWh. Saving 46,200 kWh
- Money: 46,200 x Rs 5.50 = Rs 2.54 lakh. Payback: 2.94 / 2.54 = 1.16 years
- CO2 at the report's 0.81: 46,200 x 0.81 = 37.4 tonnes. At 0.675: 31.2 tonnes

All inputs are the report's own figures except the 0.675 line, which is our arithmetic with the factor used on this site.

## What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records, so a year of site electricity before a change can be compared once uploaded. Bills show site electricity, not one pump's, so a pump saving needs its own kW readings.

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Sources: [BEE, Detailed project report: evaporative condenser, 243 kW, Kochi seafood cluster (SAMEEEKSHA)](https://sameeeksha.org/pdf/dpr/Kochi_sea_food_cluster/07_Evaporative_condenser_replacing_the_CT_based_condenser_system_243kW_Kochi.pdf), [BEE, Detailed project report: evaporative condenser, 679 kW, Kochi seafood cluster (SAMEEEKSHA)](https://sameeeksha.org/pdf/dpr/Kochi_sea_food_cluster/09_Evaporative_condenser_replacing_CT_based_condenser_system_679kW_Kochi.pdf), [BEE, Detailed project report: VFD on condenser water pumps (file named 55 kW), Kochi seafood cluster (SAMEEEKSHA)](https://sameeeksha.org/pdf/dpr/Kochi_sea_food_cluster/13_Installation_of_VFD_on_55_kW_centrifugal_pump_Kochi.pdf), [BEE, Detailed project report: VFD on condenser water pumps (file named 75 kW), Kochi seafood cluster (SAMEEEKSHA)](https://sameeeksha.org/pdf/dpr/Kochi_sea_food_cluster/14_Installation_of_VFD_on_75_KW_centrifugal_pump_Kochi.pdf), [BEE, Detailed project report: VFD on condenser water pumps (file named 11 kW), Kochi seafood cluster (SAMEEEKSHA)](https://sameeeksha.org/pdf/dpr/Kochi_sea_food_cluster/15_Installation_of_VFD_on_11_KW_centrifugal_pump_Kochi.pdf)

Last reviewed 2026-11-05. Report figures are from BEE's Small and Medium Enterprises (SME) programme project reports, at the report year's tariff. Check your tariff, measured pump kW and a current quote before you rely on the payback.