Bottle washer baths heated by heat pumps
How a bottling plant washing 96,000 returnable bottles a day can heat its 55–85 °C washer baths with heat pumps, and what it saves against a PNG-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 coils in caustic. Steam coils in the hot caustic baths run very hot, which bakes on labels and scale and needs frequent descaling.
- Glass shock limits. Bottles must step up and down in temperature gradually. Steam-heated zones swing when the line stops and starts, which raises breakage.
- Continuous make-up. Rinse zones take in fresh water all shift, so the heat demand never stops while the line runs.
- Losses between fuel and process. Burning PNG 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 fills soft drinks and beer in returnable glass on a 12,000 bottle-per-hour line for 8 hours a day. A smaller can line rinses cans with warm water before filling.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Bottle heating in caustic zones | 80–85 °C | 96,000 bottles × 0.35 kg glass × 0.84 kJ/kg·K × 50 K | 392 |
| Caustic tank surface and shell losses | 80–85 °C | 2 tanks × 6 m² surface × 1.0 kW/m² × 10 h | 120 |
| Hot rinse zone make-up | 55–65 °C | 12,000 L/day, 28 → 60 °C | 446 |
| Can rinser | 55 °C | 4,000 L/day, 28 → 55 °C | 125 |
| Storage and pipework standing losses | – | about 5% | 54 |
| Total useful heat | 1,137 | ||
Averaged over 16 running hours, the heat pumps need about 71 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
- 3 × SE-SHT-25C (75 kW total) (SE-SHT cascade heat pump) delivering 90 °C, covering the day's 1,137 kWh in about 15.2 running hours.
- A 2,500 L insulated storage tank decouples the heat pumps from the process peaks.
- The PNG-fired steam boiler stays connected behind a normally closed valve as standby.
- The caustic baths are heated by circulating lye through an external plate exchanger fed with 90 °C hot water, replacing the steam coils.
- Rinse zones and the can rinser take hot water at lower temperature from the same loop, which cools the return and helps heat pump efficiency.
- The storage tank covers the morning heat-up of the caustic baths before the line starts.
Selected equipment
| Model | SE-SHT-25C × 3 |
|---|---|
| Heating capacity | 25 kW each, 75 kW total |
| COP | 2.6 at A20 °C / W90 °C (data sheet T1) |
| Power input | about 27.9 kW total at rated conditions |
| Rating | cascade R410A + R515B, rated 90 °C, 95 °C maximum |
| Supply temperature | 90 °C |
| Storage | 2,500 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the tank top calls the heat pumps on below 85 °C and off at 90 °C. TT-102 at the bottom starts the units early for the morning heat-up. TIC-201 holds caustic at 80–85 °C, TIC-202 holds the rinse zones and TIC-203 the can rinser. The boiler stays 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 bottles | – | – |
| CO₂ per year | – | – |
06Benefits
Less scale and baked label pulp
Lower surface temperatures in the caustic exchanger reduce scale and burnt-on deposits compared with steam coils.
Fewer broken bottles
Zone temperatures stay steady through line stops, which reduces thermal shock.
Baths ready at start-up
Stored hot water brings the baths up to temperature before the first shift.
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
- Line speed and running hours
- Bottle weight and washer zone temperatures
- Caustic bath volumes and surface areas
- Rinse water make-up rate
- Can line rinse 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
- Caustic-side materials. Use stainless steel plates and EPDM gaskets rated for hot caustic. Fit a strainer to catch label pulp before the exchanger.
- Heat recovery first. Check that the washer's own zone-to-zone recovery is working. A failed recovery stage adds a large avoidable load.
- Electrical. About 28 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
Bottle washer baths heated by heat pumps
How a bottling plant washing 96,000 returnable bottles a day can heat its 55–85 °C washer baths with heat pumps, and what it saves against a PNG-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 coils in caustic. Steam coils in the hot caustic baths run very hot, which bakes on labels and scale and needs frequent descaling.
- Glass shock limits. Bottles must step up and down in temperature gradually. Steam-heated zones swing when the line stops and starts, which raises breakage.
- Continuous make-up. Rinse zones take in fresh water all shift, so the heat demand never stops while the line runs.
- Losses between fuel and process. Burning PNG 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 fills soft drinks and beer in returnable glass on a 12,000 bottle-per-hour line for 8 hours a day. A smaller can line rinses cans with warm water before filling.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Bottle heating in caustic zones | 80–85 °C | 96,000 bottles × 0.35 kg glass × 0.84 kJ/kg·K × 50 K | 392 |
| Caustic tank surface and shell losses | 80–85 °C | 2 tanks × 6 m² surface × 1.0 kW/m² × 10 h | 120 |
| Hot rinse zone make-up | 55–65 °C | 12,000 L/day, 28 → 60 °C | 446 |
| Can rinser | 55 °C | 4,000 L/day, 28 → 55 °C | 125 |
| Storage and pipework standing losses | – | about 5% | 54 |
| Total useful heat | 1,137 | ||
Averaged over 16 running hours, the heat pumps need about 71 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
- 3 × SE-SHT-25C (75 kW total) (SE-SHT cascade heat pump) delivering 90 °C, covering the day's 1,137 kWh in about 15.2 running hours.
- A 2,500 L insulated storage tank decouples the heat pumps from the process peaks.
- The PNG-fired steam boiler stays connected behind a normally closed valve as standby.
- The caustic baths are heated by circulating lye through an external plate exchanger fed with 90 °C hot water, replacing the steam coils.
- Rinse zones and the can rinser take hot water at lower temperature from the same loop, which cools the return and helps heat pump efficiency.
- The storage tank covers the morning heat-up of the caustic baths before the line starts.
Selected equipment
| Model | SE-SHT-25C × 3 |
|---|---|
| Heating capacity | 25 kW each, 75 kW total |
| COP | 2.6 at A20 °C / W90 °C (data sheet T1) |
| Power input | about 27.9 kW total at rated conditions |
| Rating | cascade R410A + R515B, rated 90 °C, 95 °C maximum |
| Supply temperature | 90 °C |
| Storage | 2,500 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the tank top calls the heat pumps on below 85 °C and off at 90 °C. TT-102 at the bottom starts the units early for the morning heat-up. TIC-201 holds caustic at 80–85 °C, TIC-202 holds the rinse zones and TIC-203 the can rinser. The boiler stays 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 bottles | – | – |
| CO₂ per year | – | – |
06Benefits
Less scale and baked label pulp
Lower surface temperatures in the caustic exchanger reduce scale and burnt-on deposits compared with steam coils.
Fewer broken bottles
Zone temperatures stay steady through line stops, which reduces thermal shock.
Baths ready at start-up
Stored hot water brings the baths up to temperature before the first shift.
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
- Line speed and running hours
- Bottle weight and washer zone temperatures
- Caustic bath volumes and surface areas
- Rinse water make-up rate
- Can line rinse 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
- Caustic-side materials. Use stainless steel plates and EPDM gaskets rated for hot caustic. Fit a strainer to catch label pulp before the exchanger.
- Heat recovery first. Check that the washer's own zone-to-zone recovery is working. A failed recovery stage adds a large avoidable load.
- Electrical. About 28 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.