Retort water preheated from retort cooling water
How a cannery running 12 retort cycles a day can preheat its retort water to 110 °C with a heat pump that recovers retort cooling-water heat, cutting furnace-oil use.
▶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
- Slow come-up. Bringing product and process water up to temperature takes much of the cycle time and most of the steam.
- Cooling heat is thrown away. After sterilisation, product is cooled with water that leaves at 50–70 °C and goes to drain or a cooling tower.
- Steam peaks. Several retorts starting together cause steam peaks that the boiler struggles to meet.
- 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 packs ready-to-eat curries, sweet corn and fruit in syrup in cans and retort pouches. Four water-immersion retorts run about 12 cycles a day, with about 1 tonne of product per cycle. Each retort has a storage drum for process water that is reused cycle to cycle.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Retort process water reheat | 85 → 110 °C | 12 cycles × 2,000 L returned to storage drum | 697 |
| Product and can come-up | 65 → 110 °C | 12 cycles × 1,000 kg product, 10% for can and basket metal | 594 |
| Can and jar washer | 60 °C | 6,000 L/day, 30 → 60 °C | 209 |
| Storage and pipework standing losses | – | about 5% | 75 |
| Total useful heat | 1,575 | ||
Averaged over 18 running hours, the heat pumps need about 87 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
- 4 × SE-WWUHT-27 (108 kW total) (SE-WWUHT water-source, R245fa) delivering 120 °C, covering the day's 1,575 kWh in about 14.6 running hours.
- A 3,500 L insulated storage tank decouples the heat pumps from the process peaks.
- Heat source: retort cooling-water return at about 55 °C. Cooling the retort water return reduces cooling tower load and can shorten the retort cooling step.
- The furnace-oil fired steam boiler stays connected behind a normally closed valve as standby.
- Retort cooling water is collected in an insulated tank at about 55 °C and used as the heat pump source.
- The heat pump heats the retort storage drums to about 110 °C between cycles through a coil or external exchanger.
- The existing steam supply brings each retort from 110 °C to the sterilising temperature. This shortens the steam step and lowers peaks.
- The can and jar washer runs from the same hot-water loop.
Selected equipment
| Model | SE-WWUHT-27 × 4 |
|---|---|
| Heating capacity | 27 kW each, 108 kW total |
| COP | 2.93 at the data sheet's rated condition (60/55 °C source water) |
| Power input | about 36.8 kW total at rated conditions |
| Rating | water or steam to 120 °C, R245fa |
| Supply temperature | 120 °C |
| Storage | 3,500 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the tank top starts the heat pump below 112 °C and stops it at 120 °C. TIC-201 heats each storage drum to 110 °C between cycles in a set order. The retort controller and its steam valve keep full control of the sterilisation step. If the tank falls below 105 °C, drums are topped up with steam as before.
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 tonne of product | – | – |
| CO₂ per year | – | – |
06Benefits
Lower steam peaks
Retorts start from preheated water, so the boiler sees smaller, shorter peaks.
Shorter cycles
Less come-up time can allow more cycles per day.
Cooling water reused
Heat from cooling each batch preheats the next one.
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
- Number of retorts, type and cycles per day
- Product load per cycle and fill temperature
- Storage drum volume and return temperature
- Cooling water volume and outlet temperature
- Steam use per cycle
- 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
- Scheduled process unchanged. The validated sterilisation step stays on steam with its existing controls. The heat pump only preheats.
- Pressure rating. Water at 110–120 °C needs a loop held above about 2.5 bar(g). Check the drum and coil pressure ratings.
- Cooling water hygiene. Retort cooling water must stay chlorinated. Use a closed exchanger so heat pump water never mixes with it.
- Electrical. About 37 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.
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Retort water preheated from retort cooling water
How a cannery running 12 retort cycles a day can preheat its retort water to 110 °C with a heat pump that recovers retort cooling-water heat, cutting furnace-oil use.
▶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
- Slow come-up. Bringing product and process water up to temperature takes much of the cycle time and most of the steam.
- Cooling heat is thrown away. After sterilisation, product is cooled with water that leaves at 50–70 °C and goes to drain or a cooling tower.
- Steam peaks. Several retorts starting together cause steam peaks that the boiler struggles to meet.
- 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 packs ready-to-eat curries, sweet corn and fruit in syrup in cans and retort pouches. Four water-immersion retorts run about 12 cycles a day, with about 1 tonne of product per cycle. Each retort has a storage drum for process water that is reused cycle to cycle.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Retort process water reheat | 85 → 110 °C | 12 cycles × 2,000 L returned to storage drum | 697 |
| Product and can come-up | 65 → 110 °C | 12 cycles × 1,000 kg product, 10% for can and basket metal | 594 |
| Can and jar washer | 60 °C | 6,000 L/day, 30 → 60 °C | 209 |
| Storage and pipework standing losses | – | about 5% | 75 |
| Total useful heat | 1,575 | ||
Averaged over 18 running hours, the heat pumps need about 87 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
- 4 × SE-WWUHT-27 (108 kW total) (SE-WWUHT water-source, R245fa) delivering 120 °C, covering the day's 1,575 kWh in about 14.6 running hours.
- A 3,500 L insulated storage tank decouples the heat pumps from the process peaks.
- Heat source: retort cooling-water return at about 55 °C. Cooling the retort water return reduces cooling tower load and can shorten the retort cooling step.
- The furnace-oil fired steam boiler stays connected behind a normally closed valve as standby.
- Retort cooling water is collected in an insulated tank at about 55 °C and used as the heat pump source.
- The heat pump heats the retort storage drums to about 110 °C between cycles through a coil or external exchanger.
- The existing steam supply brings each retort from 110 °C to the sterilising temperature. This shortens the steam step and lowers peaks.
- The can and jar washer runs from the same hot-water loop.
Selected equipment
| Model | SE-WWUHT-27 × 4 |
|---|---|
| Heating capacity | 27 kW each, 108 kW total |
| COP | 2.93 at the data sheet's rated condition (60/55 °C source water) |
| Power input | about 36.8 kW total at rated conditions |
| Rating | water or steam to 120 °C, R245fa |
| Supply temperature | 120 °C |
| Storage | 3,500 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the tank top starts the heat pump below 112 °C and stops it at 120 °C. TIC-201 heats each storage drum to 110 °C between cycles in a set order. The retort controller and its steam valve keep full control of the sterilisation step. If the tank falls below 105 °C, drums are topped up with steam as before.
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 tonne of product | – | – |
| CO₂ per year | – | – |
06Benefits
Lower steam peaks
Retorts start from preheated water, so the boiler sees smaller, shorter peaks.
Shorter cycles
Less come-up time can allow more cycles per day.
Cooling water reused
Heat from cooling each batch preheats the next one.
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
- Number of retorts, type and cycles per day
- Product load per cycle and fill temperature
- Storage drum volume and return temperature
- Cooling water volume and outlet temperature
- Steam use per cycle
- 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
- Scheduled process unchanged. The validated sterilisation step stays on steam with its existing controls. The heat pump only preheats.
- Pressure rating. Water at 110–120 °C needs a loop held above about 2.5 bar(g). Check the drum and coil pressure ratings.
- Cooling water hygiene. Retort cooling water must stay chlorinated. Use a closed exchanger so heat pump water never mixes with it.
- Electrical. About 37 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.