Milk pasteurisation without a boiler
How a 20,000 litre-per-day dairy can make all of its 65–90 °C process hot water with heat pumps, and what it saves against a diesel-fired boiler.
▶Video: Process hot water for food, dairy and beverages
V02 · 2–2.5 minPasteurisers, CIP, cooking and washing on stored hot water instead of boiler steam
Video coming soon01Problem statement
- Steam for a hot-water job. The pasteuriser only needs water at 85–90 °C, but the boiler makes steam at 150 °C or more and loses heat in traps, flash and uncollected condensate.
- Fouling and burn-on. Steam injected into a hot-water set has to be throttled hard, and overheating the milk side of the PHE causes fouling.
- Fuel cost per litre. Fuel is usually the largest utility cost per litre of milk processed, and diesel moves with crude prices.
- Losses between fuel and process. Burning diesel in a boiler or heater and distributing the heat loses a quarter or more of the fuel's energy before it reaches the process.
- Compliance, safety and handling. Fired equipment brings boiler inspections, fuel storage and unloading, flue emissions and an attendant on every shift.
02Use case
The reference plant packs pasteurised pouch milk and curd. It processes 20,000 litres a day over a 10-hour shift, runs two CIP cycles and washes crates and cans.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| HTST pasteuriser, heating section | Milk 64 → 75 °C, hot water 85–90 °C | 2,000 L/h × 10 h, 85% regeneration, 15% losses | 284 |
| CIP (lye, acid, hot rinse) | 80 °C | 2 cycles × 2,500 L, 30 → 80 °C | 290 |
| Crate and can washer | 65 °C | 5,000 L/day, 30 → 65 °C | 203 |
| Storage and pipework standing losses | – | about 5% | 39 |
| Total useful heat | 817 | ||
Averaged over 10 running hours, the heat pumps need about 82 kW.
03P&ID
Tags: HP heat pump, TK tank, SG steam generator, P pump, PHE plate heat exchanger, TCV temperature control valve, TIC temperature indicating controller (panel), TT temperature transmitter, MT moisture transmitter, PT pressure transmitter, LT level transmitter, FS flow switch, NC normally closed. Process fluids are heated through their own exchanger, coil or jacket.
04Solution
System description
- 2 × SE-SHT-50C (100 kW total) (SE-SHT cascade heat pump) delivering 90 °C, covering the day's 817 kWh in about 8.2 running hours.
- A 3,000 L insulated storage tank decouples the heat pumps from the process peaks.
- The diesel-fired steam boiler stays connected behind a normally closed valve as standby.
- The pasteuriser's regeneration section already recovers about 85% of the heat. The heat pumps supply only the final 11 K lift and the losses.
- The storage tank covers a full CIP cycle on its own, so the heat pumps run steadily instead of chasing peaks.
- Each user has its own temperature controller and valve, so the pasteuriser holds the 75 °C milk outlet within ±0.5 K.
Selected equipment
| Model | SE-SHT-50C × 2 |
|---|---|
| Heating capacity | 50 kW each, 100 kW total |
| COP | 2.6 at A20 °C / W90 °C (data sheet T1) |
| Power input | about 37.2 kW total at rated conditions |
| Rating | cascade R410A + R515B, rated 90 °C, 95 °C maximum |
| Supply temperature | 90 °C |
| Storage | 3,000 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the top of the tank calls the heat pumps on below 85 °C and off at 90 °C, staging the units in turn so running hours stay even. TT-102 at the bottom gives an early start before a CIP cycle. If the tank top falls below 75 °C the PLC raises an alarm and the operator can open the standby boiler valve.
05Energy saving and ROI
Change any input to match a customer's site. Defaults are typical Indian prices for October 2026. The installed cost is a placeholder; replace it with the actual quotation.
| Existing | Heat pump | |
|---|---|---|
| Daily consumption | – | – |
| Annual energy cost | – | – |
| Cost per 1,000 L milk | – | – |
| CO₂ per year | – | – |
06Benefits
Gentler on the product
Hot water at a steady 85–90 °C reduces milk-side fouling and burn-on compared with steam-heated water sets.
No boiler for this duty
No IBR registration, inspections or certified attendant for the hot-water load.
CIP ready on time
Stored hot water is available for CIP the moment processing ends.
Lower energy cost
Each kWh of electricity delivers about 2.6 kWh of heat at the required temperature, against well under one kWh of useful heat per kWh of fuel burnt.
No flame on site
No burner, flue or fuel tank for this duty, and no fuel deliveries to schedule.
Built-in redundancy
Several machines share the load. If one is serviced, the others and the storage carry most of the day, with the existing heater in reserve.
07Engineering pointers
Site data to collect
- Milk handled per day and processing hours
- Pasteuriser capacity and regeneration percentage
- CIP schedule and tank volumes
- Crate and can washing volumes
- Present fuel or electricity use and monthly bill
- Sanctioned electrical load and spare capacity
- Space for the heat pumps and storage, with service access
- Winter minimum ambient at site
Design notes
- Food safety. Heat pump water never touches the milk. The pasteuriser, CIP and washer are each heated through their own exchanger or coil.
- Regeneration first. Check the regeneration section is clean and performing before sizing. A fouled regenerator doubles the heating duty.
- Electrical. About 37 kW of heat pump input at rated conditions, plus pumps and fans. Check spare sanctioned load before ordering.
- Winter output. The SE-SHT cascade gives about 80% of rated output at 7 °C ambient and still runs at −20 °C. Size on the coldest design day for northern sites.
- Water quality. Scale forms quickly above 60 °C. Use softened make-up and keep the heat pump loop closed, with process fluids on the far side of an exchanger or coil.
Service and warranty
Sunniva has supplied 5,000+ heat pumps since 2012, with nine service technicians across India, including remote sites such as Leh. All components carry a one-year warranty.
Talk to us
Milk pasteurisation without a boiler
How a 20,000 litre-per-day dairy can make all of its 65–90 °C process hot water with heat pumps, and what it saves against a diesel-fired boiler.
▶Video: Process hot water for food, dairy and beverages
V02 · 2–2.5 minPasteurisers, CIP, cooking and washing on stored hot water instead of boiler steam
Video coming soon01Problem statement
- Steam for a hot-water job. The pasteuriser only needs water at 85–90 °C, but the boiler makes steam at 150 °C or more and loses heat in traps, flash and uncollected condensate.
- Fouling and burn-on. Steam injected into a hot-water set has to be throttled hard, and overheating the milk side of the PHE causes fouling.
- Fuel cost per litre. Fuel is usually the largest utility cost per litre of milk processed, and diesel moves with crude prices.
- Losses between fuel and process. Burning diesel in a boiler or heater and distributing the heat loses a quarter or more of the fuel's energy before it reaches the process.
- Compliance, safety and handling. Fired equipment brings boiler inspections, fuel storage and unloading, flue emissions and an attendant on every shift.
02Use case
The reference plant packs pasteurised pouch milk and curd. It processes 20,000 litres a day over a 10-hour shift, runs two CIP cycles and washes crates and cans.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| HTST pasteuriser, heating section | Milk 64 → 75 °C, hot water 85–90 °C | 2,000 L/h × 10 h, 85% regeneration, 15% losses | 284 |
| CIP (lye, acid, hot rinse) | 80 °C | 2 cycles × 2,500 L, 30 → 80 °C | 290 |
| Crate and can washer | 65 °C | 5,000 L/day, 30 → 65 °C | 203 |
| Storage and pipework standing losses | – | about 5% | 39 |
| Total useful heat | 817 | ||
Averaged over 10 running hours, the heat pumps need about 82 kW.
03P&ID
Tags: HP heat pump, TK tank, SG steam generator, P pump, PHE plate heat exchanger, TCV temperature control valve, TIC temperature indicating controller (panel), TT temperature transmitter, MT moisture transmitter, PT pressure transmitter, LT level transmitter, FS flow switch, NC normally closed. Process fluids are heated through their own exchanger, coil or jacket.
04Solution
System description
- 2 × SE-SHT-50C (100 kW total) (SE-SHT cascade heat pump) delivering 90 °C, covering the day's 817 kWh in about 8.2 running hours.
- A 3,000 L insulated storage tank decouples the heat pumps from the process peaks.
- The diesel-fired steam boiler stays connected behind a normally closed valve as standby.
- The pasteuriser's regeneration section already recovers about 85% of the heat. The heat pumps supply only the final 11 K lift and the losses.
- The storage tank covers a full CIP cycle on its own, so the heat pumps run steadily instead of chasing peaks.
- Each user has its own temperature controller and valve, so the pasteuriser holds the 75 °C milk outlet within ±0.5 K.
Selected equipment
| Model | SE-SHT-50C × 2 |
|---|---|
| Heating capacity | 50 kW each, 100 kW total |
| COP | 2.6 at A20 °C / W90 °C (data sheet T1) |
| Power input | about 37.2 kW total at rated conditions |
| Rating | cascade R410A + R515B, rated 90 °C, 95 °C maximum |
| Supply temperature | 90 °C |
| Storage | 3,000 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the top of the tank calls the heat pumps on below 85 °C and off at 90 °C, staging the units in turn so running hours stay even. TT-102 at the bottom gives an early start before a CIP cycle. If the tank top falls below 75 °C the PLC raises an alarm and the operator can open the standby boiler valve.
05Energy saving and ROI
Change any input to match a customer's site. Defaults are typical Indian prices for October 2026. The installed cost is a placeholder; replace it with the actual quotation.
| Existing | Heat pump | |
|---|---|---|
| Daily consumption | – | – |
| Annual energy cost | – | – |
| Cost per 1,000 L milk | – | – |
| CO₂ per year | – | – |
06Benefits
Gentler on the product
Hot water at a steady 85–90 °C reduces milk-side fouling and burn-on compared with steam-heated water sets.
No boiler for this duty
No IBR registration, inspections or certified attendant for the hot-water load.
CIP ready on time
Stored hot water is available for CIP the moment processing ends.
Lower energy cost
Each kWh of electricity delivers about 2.6 kWh of heat at the required temperature, against well under one kWh of useful heat per kWh of fuel burnt.
No flame on site
No burner, flue or fuel tank for this duty, and no fuel deliveries to schedule.
Built-in redundancy
Several machines share the load. If one is serviced, the others and the storage carry most of the day, with the existing heater in reserve.
07Engineering pointers
Site data to collect
- Milk handled per day and processing hours
- Pasteuriser capacity and regeneration percentage
- CIP schedule and tank volumes
- Crate and can washing volumes
- Present fuel or electricity use and monthly bill
- Sanctioned electrical load and spare capacity
- Space for the heat pumps and storage, with service access
- Winter minimum ambient at site
Design notes
- Food safety. Heat pump water never touches the milk. The pasteuriser, CIP and washer are each heated through their own exchanger or coil.
- Regeneration first. Check the regeneration section is clean and performing before sizing. A fouled regenerator doubles the heating duty.
- Electrical. About 37 kW of heat pump input at rated conditions, plus pumps and fans. Check spare sanctioned load before ordering.
- Winter output. The SE-SHT cascade gives about 80% of rated output at 7 °C ambient and still runs at −20 °C. Size on the coldest design day for northern sites.
- Water quality. Scale forms quickly above 60 °C. Use softened make-up and keep the heat pump loop closed, with process fluids on the far side of an exchanger or coil.
Service and warranty
Sunniva has supplied 5,000+ heat pumps since 2012, with nine service technicians across India, including remote sites such as Leh. All components carry a one-year warranty.