Soap fats melted and held without oil firing
How a soap and detergent plant handling 10 tonnes of fats a day can melt, hold and mix at 50–80 °C with heat pumps, against a furnace-oil fired thermic fluid heater.
▶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
- Fats set in tanks and lines. Stearin and fatty acids solidify below 50 to 60 °C, so tanks and lines need heat around the clock.
- Overheating darkens product. Hot thermic fluid coils scorch fats locally, causing colour and odour defects in soap.
- Small loads on a big heater. Tank holding loads are small and steady, but the fired heater runs all night to serve them.
- 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 makes toilet and laundry soap from palm stearin and fatty acids, and liquid detergents. It melts about 10 tonnes of fats a day and blends 15,000 litres of liquid detergent on two shifts.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Fat and oil melting, sensible | 25 → 70 °C | 10,000 kg/day (11,100 L at 0.9 kg/L), cp 2.0 kJ/kg·K | 250 |
| Fat melting, latent heat | 50–60 °C | 10,000 kg × 200 kJ/kg | 556 |
| Storage tank holding | 65 °C | 4 tanks × 3 kW losses × 24 h | 288 |
| Liquid detergent batch water | 30 → 60 °C | 15,000 L/day | 522 |
| Storage and pipework standing losses | – | about 5% | 81 |
| Total useful heat | 1,697 | ||
Averaged over 20 running hours, the heat pumps need about 85 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
- 2 × SE-SHT-50C (100 kW total) (SE-SHT cascade heat pump) delivering 90 °C, covering the day's 1,697 kWh in about 17.0 running hours.
- A 3,000 L insulated storage tank decouples the heat pumps from the process peaks.
- The furnace-oil fired thermic fluid heater stays connected behind a normally closed valve as standby.
- The heat pumps charge a storage tank at 85–90 °C. Hot water replaces thermic fluid in the melting tank coils and tank heating.
- Fat storage tanks are held at 65 °C on a small, steady hot-water flow day and night.
- Liquid detergent batch water is heated through PHE-203 directly from the hot-water loop.
Selected equipment
| Model | SE-SHT-50C × 2 |
|---|---|
| Heating capacity | 50 kW each, 100 kW total |
| COP | 2.6 at A20 °C / W90 °C (data sheet T1) |
| Power input | about 37.2 kW total at rated conditions |
| Rating | cascade R410A + R515B, rated 90 °C, 95 °C maximum |
| Supply temperature | 90 °C |
| Storage | 3,000 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 starts the heat pumps below 82 °C and stops them at 90 °C. TIC-201 holds the melting tank at 70 °C and TIC-202 holds storage tanks at 65 °C. The thermic fluid heater stays as standby for the saponification and drying steps that need higher temperature.
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 soap | – | – |
| CO₂ per year | – | – |
06Benefits
Better colour and odour
Hot water at 85–90 °C cannot scorch fats on the coil surface.
No night firing
Holding loads run on the heat pumps, so the fired heater can be shut down outside production.
Faster melting
Stored hot water gives a high heating rate at the start of each melt.
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
- Fats and oils handled per day and their melting points
- Tank sizes and holding temperatures
- Liquid detergent batch volumes
- Thermic fluid heater fuel use
- Production steps above 120 °C
- 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
- Coil area. Hot water at 90 °C has a smaller temperature difference than thermic fluid. Check coil area in the melting tank and add coils where needed.
- Line tracing. Hot-water tracing on fat lines must stay above the fat's melting point. Insulate lines fully and alarm low tracing temperature.
- Higher-temperature steps. Saponification and soap drying may need more than 120 °C. Keep these on the existing heater.
- Electrical. About 37 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
Soap fats melted and held without oil firing
How a soap and detergent plant handling 10 tonnes of fats a day can melt, hold and mix at 50–80 °C with heat pumps, against a furnace-oil fired thermic fluid heater.
▶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
- Fats set in tanks and lines. Stearin and fatty acids solidify below 50 to 60 °C, so tanks and lines need heat around the clock.
- Overheating darkens product. Hot thermic fluid coils scorch fats locally, causing colour and odour defects in soap.
- Small loads on a big heater. Tank holding loads are small and steady, but the fired heater runs all night to serve them.
- 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 makes toilet and laundry soap from palm stearin and fatty acids, and liquid detergents. It melts about 10 tonnes of fats a day and blends 15,000 litres of liquid detergent on two shifts.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Fat and oil melting, sensible | 25 → 70 °C | 10,000 kg/day (11,100 L at 0.9 kg/L), cp 2.0 kJ/kg·K | 250 |
| Fat melting, latent heat | 50–60 °C | 10,000 kg × 200 kJ/kg | 556 |
| Storage tank holding | 65 °C | 4 tanks × 3 kW losses × 24 h | 288 |
| Liquid detergent batch water | 30 → 60 °C | 15,000 L/day | 522 |
| Storage and pipework standing losses | – | about 5% | 81 |
| Total useful heat | 1,697 | ||
Averaged over 20 running hours, the heat pumps need about 85 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
- 2 × SE-SHT-50C (100 kW total) (SE-SHT cascade heat pump) delivering 90 °C, covering the day's 1,697 kWh in about 17.0 running hours.
- A 3,000 L insulated storage tank decouples the heat pumps from the process peaks.
- The furnace-oil fired thermic fluid heater stays connected behind a normally closed valve as standby.
- The heat pumps charge a storage tank at 85–90 °C. Hot water replaces thermic fluid in the melting tank coils and tank heating.
- Fat storage tanks are held at 65 °C on a small, steady hot-water flow day and night.
- Liquid detergent batch water is heated through PHE-203 directly from the hot-water loop.
Selected equipment
| Model | SE-SHT-50C × 2 |
|---|---|
| Heating capacity | 50 kW each, 100 kW total |
| COP | 2.6 at A20 °C / W90 °C (data sheet T1) |
| Power input | about 37.2 kW total at rated conditions |
| Rating | cascade R410A + R515B, rated 90 °C, 95 °C maximum |
| Supply temperature | 90 °C |
| Storage | 3,000 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 starts the heat pumps below 82 °C and stops them at 90 °C. TIC-201 holds the melting tank at 70 °C and TIC-202 holds storage tanks at 65 °C. The thermic fluid heater stays as standby for the saponification and drying steps that need higher temperature.
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 soap | – | – |
| CO₂ per year | – | – |
06Benefits
Better colour and odour
Hot water at 85–90 °C cannot scorch fats on the coil surface.
No night firing
Holding loads run on the heat pumps, so the fired heater can be shut down outside production.
Faster melting
Stored hot water gives a high heating rate at the start of each melt.
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
- Fats and oils handled per day and their melting points
- Tank sizes and holding temperatures
- Liquid detergent batch volumes
- Thermic fluid heater fuel use
- Production steps above 120 °C
- 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
- Coil area. Hot water at 90 °C has a smaller temperature difference than thermic fluid. Check coil area in the melting tank and add coils where needed.
- Line tracing. Hot-water tracing on fat lines must stay above the fat's melting point. Insulate lines fully and alarm low tracing temperature.
- Higher-temperature steps. Saponification and soap drying may need more than 120 °C. Keep these on the existing heater.
- Electrical. About 37 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.