Hot water for washing, CIP, laundry or process tanks is often the biggest fuel bill nobody looks at. Here is a worked example using the same method as our hot water calculator.
The duty
10,000 litres a day, heated from 25 °C to 70 °C, over an 8-hour shift. That is a heat load of about 56,250 kcal/hr (65 kW).
Running cost per day
| Option | Consumption | Cost per day* |
|---|---|---|
| Diesel hot water generator | 7.4 L/hr | ₹5,450 |
| Electric heater | 66.7 kWh/hr | ₹4,805 |
| LPG hot water generator | 5.6 kg/hr | ₹4,224 |
| PNG hot water generator | 7.4 SCM/hr | ₹3,270 |
| Industrial heat pump (SE-HT) | 21 kWh/hr (COP ≈ 3.1) | ₹1,509 |
*Indicative, at diesel ₹92/L, LPG ₹95/kg, PNG ₹55/SCM and electricity ₹9/kWh; fired units at 88 % efficiency, electric heater at 98 %; heat pump COP from the published SE-HT performance map at 25 °C ambient and 70 °C water.
What it adds up to
Over 300 working days, the diesel option costs about ₹16.4 lakh a year and the heat pump about ₹4.5 lakh, a saving of roughly ₹11.8 lakh a year.
When a fired generator still makes sense
- Above 90–95 °C, or for very large instantaneous loads, a Neohydrics hot water generator with a Riello burner is simpler. It also suits sites where electrical capacity is limited.
- For pretreatment tanks of up to 5,000 L at 75 °C, Neo Hot replaces electric immersion heaters directly.
- Heat pumps for 80, 95 and 120 °C cover most process water duties without combustion.
Put your own litres, temperatures and fuel prices into the calculator to see your numbers.