UHT milk preheating on heat pump hot water
How a 30,000 litre-per-day UHT dairy can take the preheating stage and CIP off its furnace-oil boiler, using heat from its refrigeration plant.
▶Video: Waste-heat recovery heat pumps
V10 · 2–2.5 minLifting warm water from condensers, effluent and process cooling to useful heat
Video coming soon01Problem statement
- The preheating stage runs on steam. After regeneration the milk only needs about 15 K more to reach 95 °C before homogenising and holding, yet this lift is usually made with live steam through a hot-water set.
- Long runs, steady load. A UHT line runs 15 hours or more without a break, so even a small steam leak or trap fault burns fuel all day.
- Refrigeration heat goes to the cooling tower. The ammonia compressors reject hot discharge gas at 60–70 °C, and that heat is thrown away in the evaporative condenser.
- Losses between fuel and process. Burning furnace oil 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 makes UHT toned milk and flavoured milk in aseptic cartons. It processes 30,000 litres a day over a 15-hour run, followed by an intermediate clean and a full CIP. An ammonia plant with ice-bank and chillers cools the raw milk and the finished cartons.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| UHT preheating section | Milk 80 → 95 °C, hot water 110–115 °C | 2,000 L/h × 15 h, after regeneration, 10% losses | 557 |
| UHT plant CIP and intermediate clean | 85 °C | 2 cleans × 2,500 L, 40 → 85 °C | 261 |
| Storage and pipework standing losses | – | about 5% | 41 |
| Total useful heat | 859 | ||
Averaged over 18 running hours, the heat pumps need about 48 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-WWUHT-27 (54 kW total) (SE-WWUHT water-source, R245fa) delivering 115 °C, covering the day's 859 kWh in about 15.9 running hours.
- A 2,000 L insulated storage tank decouples the heat pumps from the process peaks.
- Heat source: ammonia desuperheater and oil-cooler water at about 55 °C. Removing superheat from the ammonia lowers the condenser load and can reduce head pressure slightly.
- The furnace-oil fired steam boiler stays connected behind a normally closed valve as standby.
- A desuperheater on the ammonia discharge line warms a water loop to about 55 °C. The water-source heat pump lifts this heat to 110–115 °C for the preheater.
- The final heating to UHT temperature stays on the existing steam heater. Only the preheating and CIP duties move to the heat pump.
- A pressurised storage tank keeps hot water ready for the intermediate clean, so the heat pump runs at a steady load through the shift.
Selected equipment
| Model | SE-WWUHT-27 × 2 |
|---|---|
| Heating capacity | 27 kW each, 54 kW total |
| COP | 2.93 at the data sheet's rated condition (60/55 °C source water) |
| Power input | about 18.4 kW total at rated conditions |
| Rating | water or steam to 120 °C, R245fa |
| Supply temperature | 115 °C |
| Storage | 2,000 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the top of the tank starts the heat pump below 108 °C and stops it at 115 °C. TIC-201 holds the milk outlet of PHE-201 at 95 °C by trimming the hot-water valve. TT-102 at the tank bottom gives an early start before CIP. If the tank top falls below 100 °C, the steam valve on the existing hot-water set opens as standby.
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
Steam only where it is needed
Steam is used only for the final UHT heating step, so boiler load and condensate losses drop.
Uses heat already paid for
Heat that the ammonia plant rejected to the condenser now does useful work.
Steady preheater temperature
A controlled hot-water supply keeps the milk temperature at the homogeniser stable through a long run.
Lower energy cost
Each kWh of electricity delivers about 2.9 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
- UHT line capacity and run length
- Milk temperature after regeneration
- Ammonia compressor capacity, discharge temperature and hours
- CIP and intermediate clean schedule
- Existing hot-water set and steam pressure
- Present fuel or electricity use and monthly bill
- Sanctioned electrical load and spare capacity
- Space for the heat pumps and storage, with service access
Design notes
- Pressurised loop. Water at 115 °C must stay pressurised above about 2 bar(g) to avoid flashing. Size the expansion vessel and relief valves for this.
- Desuperheater sizing. Desuperheat is roughly 10–15% of the condenser load. Check compressor discharge temperature and running hours before relying on it.
- Fouling. Keep the hot-water side 15–20 K above the milk. A larger approach speeds up fouling in the preheater.
- Electrical. About 18 kW of heat pump input at rated conditions, plus pumps and fans. Check spare sanctioned load before ordering.
- Source stream. The source must give up roughly two-thirds of the heat delivered. Confirm its flow and temperature over a full production day, and filter it before the evaporator.
- 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
UHT milk preheating on heat pump hot water
How a 30,000 litre-per-day UHT dairy can take the preheating stage and CIP off its furnace-oil boiler, using heat from its refrigeration plant.
▶Video: Waste-heat recovery heat pumps
V10 · 2–2.5 minLifting warm water from condensers, effluent and process cooling to useful heat
Video coming soon01Problem statement
- The preheating stage runs on steam. After regeneration the milk only needs about 15 K more to reach 95 °C before homogenising and holding, yet this lift is usually made with live steam through a hot-water set.
- Long runs, steady load. A UHT line runs 15 hours or more without a break, so even a small steam leak or trap fault burns fuel all day.
- Refrigeration heat goes to the cooling tower. The ammonia compressors reject hot discharge gas at 60–70 °C, and that heat is thrown away in the evaporative condenser.
- Losses between fuel and process. Burning furnace oil 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 makes UHT toned milk and flavoured milk in aseptic cartons. It processes 30,000 litres a day over a 15-hour run, followed by an intermediate clean and a full CIP. An ammonia plant with ice-bank and chillers cools the raw milk and the finished cartons.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| UHT preheating section | Milk 80 → 95 °C, hot water 110–115 °C | 2,000 L/h × 15 h, after regeneration, 10% losses | 557 |
| UHT plant CIP and intermediate clean | 85 °C | 2 cleans × 2,500 L, 40 → 85 °C | 261 |
| Storage and pipework standing losses | – | about 5% | 41 |
| Total useful heat | 859 | ||
Averaged over 18 running hours, the heat pumps need about 48 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-WWUHT-27 (54 kW total) (SE-WWUHT water-source, R245fa) delivering 115 °C, covering the day's 859 kWh in about 15.9 running hours.
- A 2,000 L insulated storage tank decouples the heat pumps from the process peaks.
- Heat source: ammonia desuperheater and oil-cooler water at about 55 °C. Removing superheat from the ammonia lowers the condenser load and can reduce head pressure slightly.
- The furnace-oil fired steam boiler stays connected behind a normally closed valve as standby.
- A desuperheater on the ammonia discharge line warms a water loop to about 55 °C. The water-source heat pump lifts this heat to 110–115 °C for the preheater.
- The final heating to UHT temperature stays on the existing steam heater. Only the preheating and CIP duties move to the heat pump.
- A pressurised storage tank keeps hot water ready for the intermediate clean, so the heat pump runs at a steady load through the shift.
Selected equipment
| Model | SE-WWUHT-27 × 2 |
|---|---|
| Heating capacity | 27 kW each, 54 kW total |
| COP | 2.93 at the data sheet's rated condition (60/55 °C source water) |
| Power input | about 18.4 kW total at rated conditions |
| Rating | water or steam to 120 °C, R245fa |
| Supply temperature | 115 °C |
| Storage | 2,000 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the top of the tank starts the heat pump below 108 °C and stops it at 115 °C. TIC-201 holds the milk outlet of PHE-201 at 95 °C by trimming the hot-water valve. TT-102 at the tank bottom gives an early start before CIP. If the tank top falls below 100 °C, the steam valve on the existing hot-water set opens as standby.
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
Steam only where it is needed
Steam is used only for the final UHT heating step, so boiler load and condensate losses drop.
Uses heat already paid for
Heat that the ammonia plant rejected to the condenser now does useful work.
Steady preheater temperature
A controlled hot-water supply keeps the milk temperature at the homogeniser stable through a long run.
Lower energy cost
Each kWh of electricity delivers about 2.9 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
- UHT line capacity and run length
- Milk temperature after regeneration
- Ammonia compressor capacity, discharge temperature and hours
- CIP and intermediate clean schedule
- Existing hot-water set and steam pressure
- Present fuel or electricity use and monthly bill
- Sanctioned electrical load and spare capacity
- Space for the heat pumps and storage, with service access
Design notes
- Pressurised loop. Water at 115 °C must stay pressurised above about 2 bar(g) to avoid flashing. Size the expansion vessel and relief valves for this.
- Desuperheater sizing. Desuperheat is roughly 10–15% of the condenser load. Check compressor discharge temperature and running hours before relying on it.
- Fouling. Keep the hot-water side 15–20 K above the milk. A larger approach speeds up fouling in the preheater.
- Electrical. About 18 kW of heat pump input at rated conditions, plus pumps and fans. Check spare sanctioned load before ordering.
- Source stream. The source must give up roughly two-thirds of the heat delivered. Confirm its flow and temperature over a full production day, and filter it before the evaporator.
- 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.