Hot ultrapure water without electric heaters
How a PCB and electronics assembly plant using 20,000 litres of hot DI and ultrapure water a day can heat it with heat pumps, and what it saves against electric inline heaters.
▶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
- Purity limits the heating method. UPW cannot touch ordinary metals, so it is usually heated with electric quartz or PVDF inline heaters, which are costly to run.
- Hot rinses run all day. Rinse water at 60 °C flows continuously on plating and etching lines, so the heating load is large and steady.
- Loop losses. Hot UPW loops recirculate around the clock to stay sterile and lose heat along their length.
- Electric heating is expensive heat. Resistance heaters turn one kWh of electricity into one kWh of heat, at the full commercial tariff. A heat pump moves two to four kWh of heat for the same unit.
- Large connected load. Heater banks take a big share of the sanctioned load and push up maximum-demand charges.
02Use case
The reference plant makes multilayer PCBs and runs a cleaning line for semiconductor packaging. It uses hot DI water for rinses after plating and etching, and a hot ultrapure water loop at 80 °C for final cleaning, three shifts a day.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Hot DI rinse for PCB lines | 25 → 60 °C | 15,000 L/day, 25 → 60 °C | 610 |
| Hot UPW for final cleaning | 25 → 80 °C | 5,000 L/day, 25 → 80 °C | 319 |
| Hot UPW loop recirculation losses | 80 °C | 120 m PVDF loop × 25 W/m × 24 h | 72 |
| Storage and pipework standing losses | – | about 5% | 50 |
| Total useful heat | 1,051 | ||
Averaged over 20 running hours, the heat pumps need about 53 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-SHT-16C (64 kW total) (SE-SHT cascade heat pump) delivering 90 °C, covering the day's 1,051 kWh in about 16.4 running hours.
- A 2,000 L insulated storage tank decouples the heat pumps from the process peaks.
- The electric inline UPW heaters stays connected behind a normally closed valve as standby.
- Heat pump water heats DI and UPW through dedicated exchangers made of materials approved for ultrapure service.
- The DI rinse exchanger takes most of the load at 60 °C, which keeps the heat pumps efficient.
- The existing electric inline heater stays on the UPW loop as a trim heater for the last few degrees and as standby.
Selected equipment
| Model | SE-SHT-16C × 4 |
|---|---|
| Heating capacity | 16 kW each, 64 kW total |
| COP | 2.7 at A20 °C / W90 °C (data sheet T1) |
| Power input | about 23.8 kW total at rated conditions |
| Rating | cascade R410A + R515B, rated 90 °C, 95 °C maximum |
| Supply temperature | 90 °C |
| Storage | 2,000 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the tank top starts the heat pumps below 85 °C and stops them at 90 °C. TIC-201 holds DI rinse supply at 60 °C. TIC-202 heats the UPW loop to about 78 °C, and the electric trim heater holds the final 80 °C. Loss of heat pump supply switches the UPW loop to full electric heating automatically.
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 | – | – |
| CO₂ per year | – | – |
06Benefits
Purity maintained
Heat pump water stays on the utility side of the exchanger and never contacts DI or UPW.
Large steady saving
Continuous rinse heating is an ideal heat pump load with long running hours.
Electric heater kept for trim
The trim heater gives precise final temperature and full redundancy.
Lower energy cost
Each kWh of electricity delivers about 2.7 kWh of heat at the required temperature, against well under one kWh of useful heat per kWh of fuel burnt.
Smaller electrical load
The heat pump draws roughly 1/2.7 of the power of the heaters it replaces, which frees sanctioned load and cuts demand charges.
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
- Hot DI and UPW flows and temperatures
- Exchanger material requirements
- UPW loop length and recirculation flow
- Installed electric heater kW
- 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
- Wetted materials. Use PVDF, PFA or electropolished 316L exchangers on the UPW side. Check resistivity and TOC limits with the water system supplier.
- Leak protection. Keep the utility side at a lower pressure than the UPW side, so any leak goes from UPW to utility and never the other way.
- Electrical. About 24 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
Hot ultrapure water without electric heaters
How a PCB and electronics assembly plant using 20,000 litres of hot DI and ultrapure water a day can heat it with heat pumps, and what it saves against electric inline heaters.
▶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
- Purity limits the heating method. UPW cannot touch ordinary metals, so it is usually heated with electric quartz or PVDF inline heaters, which are costly to run.
- Hot rinses run all day. Rinse water at 60 °C flows continuously on plating and etching lines, so the heating load is large and steady.
- Loop losses. Hot UPW loops recirculate around the clock to stay sterile and lose heat along their length.
- Electric heating is expensive heat. Resistance heaters turn one kWh of electricity into one kWh of heat, at the full commercial tariff. A heat pump moves two to four kWh of heat for the same unit.
- Large connected load. Heater banks take a big share of the sanctioned load and push up maximum-demand charges.
02Use case
The reference plant makes multilayer PCBs and runs a cleaning line for semiconductor packaging. It uses hot DI water for rinses after plating and etching, and a hot ultrapure water loop at 80 °C for final cleaning, three shifts a day.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Hot DI rinse for PCB lines | 25 → 60 °C | 15,000 L/day, 25 → 60 °C | 610 |
| Hot UPW for final cleaning | 25 → 80 °C | 5,000 L/day, 25 → 80 °C | 319 |
| Hot UPW loop recirculation losses | 80 °C | 120 m PVDF loop × 25 W/m × 24 h | 72 |
| Storage and pipework standing losses | – | about 5% | 50 |
| Total useful heat | 1,051 | ||
Averaged over 20 running hours, the heat pumps need about 53 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-SHT-16C (64 kW total) (SE-SHT cascade heat pump) delivering 90 °C, covering the day's 1,051 kWh in about 16.4 running hours.
- A 2,000 L insulated storage tank decouples the heat pumps from the process peaks.
- The electric inline UPW heaters stays connected behind a normally closed valve as standby.
- Heat pump water heats DI and UPW through dedicated exchangers made of materials approved for ultrapure service.
- The DI rinse exchanger takes most of the load at 60 °C, which keeps the heat pumps efficient.
- The existing electric inline heater stays on the UPW loop as a trim heater for the last few degrees and as standby.
Selected equipment
| Model | SE-SHT-16C × 4 |
|---|---|
| Heating capacity | 16 kW each, 64 kW total |
| COP | 2.7 at A20 °C / W90 °C (data sheet T1) |
| Power input | about 23.8 kW total at rated conditions |
| Rating | cascade R410A + R515B, rated 90 °C, 95 °C maximum |
| Supply temperature | 90 °C |
| Storage | 2,000 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the tank top starts the heat pumps below 85 °C and stops them at 90 °C. TIC-201 holds DI rinse supply at 60 °C. TIC-202 heats the UPW loop to about 78 °C, and the electric trim heater holds the final 80 °C. Loss of heat pump supply switches the UPW loop to full electric heating automatically.
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 | – | – |
| CO₂ per year | – | – |
06Benefits
Purity maintained
Heat pump water stays on the utility side of the exchanger and never contacts DI or UPW.
Large steady saving
Continuous rinse heating is an ideal heat pump load with long running hours.
Electric heater kept for trim
The trim heater gives precise final temperature and full redundancy.
Lower energy cost
Each kWh of electricity delivers about 2.7 kWh of heat at the required temperature, against well under one kWh of useful heat per kWh of fuel burnt.
Smaller electrical load
The heat pump draws roughly 1/2.7 of the power of the heaters it replaces, which frees sanctioned load and cuts demand charges.
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
- Hot DI and UPW flows and temperatures
- Exchanger material requirements
- UPW loop length and recirculation flow
- Installed electric heater kW
- 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
- Wetted materials. Use PVDF, PFA or electropolished 316L exchangers on the UPW side. Check resistivity and TOC limits with the water system supplier.
- Leak protection. Keep the utility side at a lower pressure than the UPW side, so any leak goes from UPW to utility and never the other way.
- Electrical. About 24 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.