Industrial parts washers heated by heat pumps
How an auto component plant washing 30 tonnes of machined parts a day can heat its spray washers with heat pumps, and what it saves against electric immersion heaters.
▶Video: Process heat for engineering and utilities
V06 · 2–2.5 minPlating, phosphating, washers, curing and boiler feedwater
Video coming soon01Problem statement
- Each washer has its own heater bank. Three washers with 24–36 kW of heaters each add up to a large connected load running most of the day.
- Exhaust carries the heat away. Spray washers vent hot, humid air to avoid fogging, and that vapour takes heat with it continuously.
- Cleanliness depends on temperature. If the wash solution runs cool, oil and swarf stay on parts and cleanliness tests fail.
- 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 machines castings and forgings for the automotive industry. Three spray washers with 1,500 L wash tanks clean about 30 tonnes of parts a day before assembly and inspection, over two shifts.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Wash tank warm-up, three washers | 35 → 65 °C | 3 × 1,500 L tanks, 30 K reheat each day | 157 |
| Heating parts during washing | 30 → 65 °C | 30 t steel/day × 0.46 kJ/kg·K × 35 K | 134 |
| Exhaust vapour and casing losses | 60–65 °C | 3 washers × 4 kW × 16 h | 192 |
| Rinse stage make-up | 30 → 60 °C | 4,000 L/day, 30 → 60 °C | 139 |
| Storage and pipework standing losses | – | about 5% | 31 |
| Total useful heat | 653 | ||
Averaged over 18 running hours, the heat pumps need about 36 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
- 1 × SE-SHT-50C (50 kW) (SE-SHT cascade heat pump) delivering 80 °C, covering the day's 653 kWh in about 13.1 running hours.
- A 1,500 L insulated storage tank decouples the heat pumps from the process peaks.
- The electric immersion heaters in washer tanks stays connected behind a normally closed valve as standby.
- A stainless steel coil is added to each wash tank and fed from a common hot-water header.
- One storage tank serves all three washers, so their peaks overlap without each needing its own heater bank.
- The washer heaters stay in place on a lower set point as standby.
Selected equipment
| Model | SE-SHT-50C × 1 |
|---|---|
| Heating capacity | 50 kW each, 50 kW total |
| COP | 2.6 at A20 °C / W90 °C (data sheet T1) |
| Power input | about 18.6 kW total at rated conditions |
| Rating | cascade R410A + R515B, rated 90 °C, 95 °C maximum |
| Supply temperature | 80 °C |
| Storage | 1,500 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the tank top starts the heat pumps below 75 °C and stops them at 80 °C. TIC-201 on each washer modulates its coil valve to hold 65 °C. TIC-202 holds the rinse stage at 60 °C. Washer heaters are set 5 K below the coil set point so they cut in only if hot water runs short.
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 parts | – | – |
| CO₂ per year | – | – |
06Benefits
Lower connected load
Replacing three heater banks with one heat pump plant cuts the electrical load the washers need.
Stable wash temperature
Stored hot water keeps the wash solution at temperature through heavy batches.
Less heater maintenance
Coils fed with 80 °C water foul less than electric elements in oily, alkaline solutions.
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.
Smaller electrical load
The heat pump draws roughly 1/2.6 of the power of the heaters it replaces, which frees sanctioned load and cuts demand charges.
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
- Number of washers, tank volumes and set temperatures
- Tonnes of parts washed per day
- Installed heater kW per washer
- Exhaust fan flow and running hours
- 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
- Oil and sludge. Fit oil skimmers and keep coils clear of the sludge layer. Oily films on the coil cut heat transfer.
- Reduce the exhaust first. Check exhaust fan speed and door seals on each washer. Over-ventilation can double the heat load.
- Electrical. About 19 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
Industrial parts washers heated by heat pumps
How an auto component plant washing 30 tonnes of machined parts a day can heat its spray washers with heat pumps, and what it saves against electric immersion heaters.
▶Video: Process heat for engineering and utilities
V06 · 2–2.5 minPlating, phosphating, washers, curing and boiler feedwater
Video coming soon01Problem statement
- Each washer has its own heater bank. Three washers with 24–36 kW of heaters each add up to a large connected load running most of the day.
- Exhaust carries the heat away. Spray washers vent hot, humid air to avoid fogging, and that vapour takes heat with it continuously.
- Cleanliness depends on temperature. If the wash solution runs cool, oil and swarf stay on parts and cleanliness tests fail.
- 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 machines castings and forgings for the automotive industry. Three spray washers with 1,500 L wash tanks clean about 30 tonnes of parts a day before assembly and inspection, over two shifts.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Wash tank warm-up, three washers | 35 → 65 °C | 3 × 1,500 L tanks, 30 K reheat each day | 157 |
| Heating parts during washing | 30 → 65 °C | 30 t steel/day × 0.46 kJ/kg·K × 35 K | 134 |
| Exhaust vapour and casing losses | 60–65 °C | 3 washers × 4 kW × 16 h | 192 |
| Rinse stage make-up | 30 → 60 °C | 4,000 L/day, 30 → 60 °C | 139 |
| Storage and pipework standing losses | – | about 5% | 31 |
| Total useful heat | 653 | ||
Averaged over 18 running hours, the heat pumps need about 36 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
- 1 × SE-SHT-50C (50 kW) (SE-SHT cascade heat pump) delivering 80 °C, covering the day's 653 kWh in about 13.1 running hours.
- A 1,500 L insulated storage tank decouples the heat pumps from the process peaks.
- The electric immersion heaters in washer tanks stays connected behind a normally closed valve as standby.
- A stainless steel coil is added to each wash tank and fed from a common hot-water header.
- One storage tank serves all three washers, so their peaks overlap without each needing its own heater bank.
- The washer heaters stay in place on a lower set point as standby.
Selected equipment
| Model | SE-SHT-50C × 1 |
|---|---|
| Heating capacity | 50 kW each, 50 kW total |
| COP | 2.6 at A20 °C / W90 °C (data sheet T1) |
| Power input | about 18.6 kW total at rated conditions |
| Rating | cascade R410A + R515B, rated 90 °C, 95 °C maximum |
| Supply temperature | 80 °C |
| Storage | 1,500 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the tank top starts the heat pumps below 75 °C and stops them at 80 °C. TIC-201 on each washer modulates its coil valve to hold 65 °C. TIC-202 holds the rinse stage at 60 °C. Washer heaters are set 5 K below the coil set point so they cut in only if hot water runs short.
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 parts | – | – |
| CO₂ per year | – | – |
06Benefits
Lower connected load
Replacing three heater banks with one heat pump plant cuts the electrical load the washers need.
Stable wash temperature
Stored hot water keeps the wash solution at temperature through heavy batches.
Less heater maintenance
Coils fed with 80 °C water foul less than electric elements in oily, alkaline solutions.
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.
Smaller electrical load
The heat pump draws roughly 1/2.6 of the power of the heaters it replaces, which frees sanctioned load and cuts demand charges.
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
- Number of washers, tank volumes and set temperatures
- Tonnes of parts washed per day
- Installed heater kW per washer
- Exhaust fan flow and running hours
- 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
- Oil and sludge. Fit oil skimmers and keep coils clear of the sludge layer. Oily films on the coil cut heat transfer.
- Reduce the exhaust first. Check exhaust fan speed and door seals on each washer. Over-ventilation can double the heat load.
- Electrical. About 19 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.