Autoclave cycles preheated with heat pump hot water
How an IV fluid plant can preheat its water-spray autoclaves and clean steam feed to 105–110 °C with heat pumps, against a diesel-fired steam boiler.
▶Video: Heat pumps for pharma, chemicals and FMCG
V04 · 2–2.5 minJacketed reactors, hot loops, cleanroom reheat and solvent recovery
Video coming soon01Problem statement
- Every cycle starts cold. Autoclave spray water and load start near room temperature, so most of the steam in each cycle goes into heat-up.
- Steam peaks at cycle start. Two autoclaves heating at once pull a large peak from the boiler, which slows heat-up and stretches cycle time.
- Cold feed to clean steam. The clean steam generator is fed with cold purified water and heats it all the way with plant steam.
- 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 fills large-volume IV fluids in bottles and bags. Two water-spray autoclaves run two terminal sterilisation cycles a day each, and a clean steam generator serves the sterile area.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Autoclave spray water heat-up | 30 → 110 °C | 2 cycles × 3,000 L | 557 |
| Product load heat-up | 30 → 110 °C | 2 cycles × 2,500 L IV fluid | 464 |
| Clean steam generator feed | 25 → 105 °C | 6,000 L/day purified water | 557 |
| Storage and pipework standing losses | – | about 5% | 79 |
| Total useful heat | 1,658 | ||
Averaged over 20 running hours, the heat pumps need about 83 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
- A SE-UHT air-source cascade, R245fa machine of about 85 kW, air-source cascade to 120 °C, sized per project.
- 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 heat pumps charge a pressurised tank at up to 120 °C. A new exchanger ahead of the autoclave's steam heater brings spray water and load to about 110 °C.
- The existing steam supply completes the final rise and the sterilisation hold, so the validated cycle is unchanged.
- Purified-water feed to the clean steam generator is preheated to 105 °C through a sanitary exchanger.
Selected equipment
| Machine | SE-UHT air-source cascade, R245fa |
|---|---|
| Capacity | about 85 kW, built to duty |
| Concept | air-source cascade to 120 °C, sized per project |
| COP used | 1.6 (estimate) |
| Supply temperature | 120 °C |
| Storage | 3,000 L insulated tank |
Capacity is sized from the heat demand above. COP is an estimate until Sunniva engineering confirms the design.
Control philosophy
TT-101 holds the tank between 112 and 120 °C. In the heat-up phase the autoclave PLC opens the hot-water valve on PHE-201 until spray water reaches 110 °C, then switches to steam. TIC-202 holds clean steam feed at 105 °C. The boiler remains the full 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 autoclave cycle | – | – |
| CO₂ per year | – | – |
06Benefits
Shorter heat-up
Starting the steam phase at 110 °C cuts the steam heat-up time of each cycle.
Smaller steam peaks
The boiler no longer meets two cold autoclave starts at once.
Validated cycle kept
The sterilisation hold stays on steam, so cycle validation changes are limited to the heat-up phase.
Lower energy cost
Each kWh of electricity delivers about 1.6 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.
Solar-ready
Running hours can be placed in daylight so rooftop solar supplies much of the electricity, which also cuts CO₂ further.
07Engineering pointers
Site data to collect
- Autoclave type, chamber volume and load per cycle
- Cycles per day and present cycle times
- Clean steam generator capacity and feed temperature
- Boiler fuel use for the sterile block
- Validation constraints on cycle changes
- 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
- Pressurised water. Water at 110 to 120 °C needs a closed, pressurised loop with expansion, relief valves and a low-pressure trip.
- Sanitary separation. Spray water and clean steam feed touch the product path. Use double-wall exchangers with the product side at higher pressure.
- Cooling phase. Autoclave cooling water leaves warm. Check whether it can feed a water-source heat pump before choosing air source.
- Ambient correction. Ratings are at 20 °C air. Ask Sunniva for the correction at your site's winter design temperature.
- 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.
- Performance figure. The COP on this page is an engineering estimate, not a data sheet value. Sunniva engineering will confirm it for the actual source and supply temperatures.
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
Autoclave cycles preheated with heat pump hot water
How an IV fluid plant can preheat its water-spray autoclaves and clean steam feed to 105–110 °C with heat pumps, against a diesel-fired steam boiler.
▶Video: Heat pumps for pharma, chemicals and FMCG
V04 · 2–2.5 minJacketed reactors, hot loops, cleanroom reheat and solvent recovery
Video coming soon01Problem statement
- Every cycle starts cold. Autoclave spray water and load start near room temperature, so most of the steam in each cycle goes into heat-up.
- Steam peaks at cycle start. Two autoclaves heating at once pull a large peak from the boiler, which slows heat-up and stretches cycle time.
- Cold feed to clean steam. The clean steam generator is fed with cold purified water and heats it all the way with plant steam.
- 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 fills large-volume IV fluids in bottles and bags. Two water-spray autoclaves run two terminal sterilisation cycles a day each, and a clean steam generator serves the sterile area.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Autoclave spray water heat-up | 30 → 110 °C | 2 cycles × 3,000 L | 557 |
| Product load heat-up | 30 → 110 °C | 2 cycles × 2,500 L IV fluid | 464 |
| Clean steam generator feed | 25 → 105 °C | 6,000 L/day purified water | 557 |
| Storage and pipework standing losses | – | about 5% | 79 |
| Total useful heat | 1,658 | ||
Averaged over 20 running hours, the heat pumps need about 83 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
- A SE-UHT air-source cascade, R245fa machine of about 85 kW, air-source cascade to 120 °C, sized per project.
- 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 heat pumps charge a pressurised tank at up to 120 °C. A new exchanger ahead of the autoclave's steam heater brings spray water and load to about 110 °C.
- The existing steam supply completes the final rise and the sterilisation hold, so the validated cycle is unchanged.
- Purified-water feed to the clean steam generator is preheated to 105 °C through a sanitary exchanger.
Selected equipment
| Machine | SE-UHT air-source cascade, R245fa |
|---|---|
| Capacity | about 85 kW, built to duty |
| Concept | air-source cascade to 120 °C, sized per project |
| COP used | 1.6 (estimate) |
| Supply temperature | 120 °C |
| Storage | 3,000 L insulated tank |
Capacity is sized from the heat demand above. COP is an estimate until Sunniva engineering confirms the design.
Control philosophy
TT-101 holds the tank between 112 and 120 °C. In the heat-up phase the autoclave PLC opens the hot-water valve on PHE-201 until spray water reaches 110 °C, then switches to steam. TIC-202 holds clean steam feed at 105 °C. The boiler remains the full 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 autoclave cycle | – | – |
| CO₂ per year | – | – |
06Benefits
Shorter heat-up
Starting the steam phase at 110 °C cuts the steam heat-up time of each cycle.
Smaller steam peaks
The boiler no longer meets two cold autoclave starts at once.
Validated cycle kept
The sterilisation hold stays on steam, so cycle validation changes are limited to the heat-up phase.
Lower energy cost
Each kWh of electricity delivers about 1.6 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.
Solar-ready
Running hours can be placed in daylight so rooftop solar supplies much of the electricity, which also cuts CO₂ further.
07Engineering pointers
Site data to collect
- Autoclave type, chamber volume and load per cycle
- Cycles per day and present cycle times
- Clean steam generator capacity and feed temperature
- Boiler fuel use for the sterile block
- Validation constraints on cycle changes
- 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
- Pressurised water. Water at 110 to 120 °C needs a closed, pressurised loop with expansion, relief valves and a low-pressure trip.
- Sanitary separation. Spray water and clean steam feed touch the product path. Use double-wall exchangers with the product side at higher pressure.
- Cooling phase. Autoclave cooling water leaves warm. Check whether it can feed a water-source heat pump before choosing air source.
- Ambient correction. Ratings are at 20 °C air. Ask Sunniva for the correction at your site's winter design temperature.
- 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.
- Performance figure. The COP on this page is an engineering estimate, not a data sheet value. Sunniva engineering will confirm it for the actual source and supply temperatures.
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.