Wax melted and held with heat pump hot water
How a plant melting 8 tonnes of paraffin wax a day and making bitumen emulsion can melt, hold and prepare at 80–110 °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
- Holding heat all day and night. Wax and emulsion tanks must stay hot continuously, so the fired heater never stops even when production does.
- Local overheating. Thermic fluid coils at high temperature discolour wax and can break emulsions near the coil.
- Fire risk. Hot oil systems near molten wax add a fire hazard if a coil leaks.
- 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 blends paraffin wax for candles and packaging and makes bitumen emulsion for road works. It melts about 8 tonnes of wax a day and keeps three heated storage tanks hot around the clock.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Paraffin wax melting, sensible | 30 → 90 °C | 8,000 kg/day (10,000 L at 0.8 kg/L), cp 2.5 kJ/kg·K | 333 |
| Paraffin wax melting, latent heat | 55–65 °C | 8,000 kg × 210 kJ/kg | 467 |
| Heated storage tank holding | 85–95 °C | 3 tanks × 4 kW losses × 24 h | 288 |
| Emulsifier soap solution | 30 → 60 °C | 6,000 L/day | 209 |
| Storage and pipework standing losses | – | about 5% | 65 |
| Total useful heat | 1,362 | ||
Averaged over 20 running hours, the heat pumps need about 68 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 70 kW, air-source cascade to 120 °C, sized per project.
- A 2,500 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 pressurised storage tank at up to 120 °C. Hot water replaces thermic fluid in the wax melting and storage tank coils.
- Soap solution for bitumen emulsion is heated in its own tank from the same loop.
- Bitumen heating to milling temperature stays on the existing thermic fluid heater.
Selected equipment
| Machine | SE-UHT air-source cascade, R245fa |
|---|---|
| Capacity | about 70 kW, built to duty |
| Concept | air-source cascade to 120 °C, sized per project |
| COP used | 1.6 (estimate) |
| Supply temperature | 120 °C |
| Storage | 2,500 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 starts the heat pumps below 110 °C and stops them at 120 °C. TIC-201 to TIC-203 hold each tank at its set-point through its own valve. The thermic fluid heater stays as standby and continues to serve bitumen heating.
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 wax | – | – |
| CO₂ per year | – | – |
06Benefits
Holding load off the heater
Night and weekend tank holding runs on the heat pumps alone.
Better wax colour
Coil surfaces stay at or below 120 °C, which avoids yellowing near the coils.
Lower fire risk
Water coils in wax tanks replace hot oil coils in the most exposed duty.
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
- Wax and bitumen quantities per day
- Tank sizes, holding temperatures and insulation condition
- Emulsion production volumes
- Thermic fluid heater fuel use
- Coil areas in existing tanks
- 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 sizing. Hot water at up to 120 °C gives less driving force than thermic fluid. Check coil area in each tank before the change.
- Pressurised loop. Water above 100 °C needs a closed loop at 3 bar or more with expansion and relief valves.
- Freeze-up of lines. Wax sets in lines if heating stops. Keep tracing on the hot-water loop with an alarm on low temperature.
- 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
Wax melted and held with heat pump hot water
How a plant melting 8 tonnes of paraffin wax a day and making bitumen emulsion can melt, hold and prepare at 80–110 °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
- Holding heat all day and night. Wax and emulsion tanks must stay hot continuously, so the fired heater never stops even when production does.
- Local overheating. Thermic fluid coils at high temperature discolour wax and can break emulsions near the coil.
- Fire risk. Hot oil systems near molten wax add a fire hazard if a coil leaks.
- 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 blends paraffin wax for candles and packaging and makes bitumen emulsion for road works. It melts about 8 tonnes of wax a day and keeps three heated storage tanks hot around the clock.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Paraffin wax melting, sensible | 30 → 90 °C | 8,000 kg/day (10,000 L at 0.8 kg/L), cp 2.5 kJ/kg·K | 333 |
| Paraffin wax melting, latent heat | 55–65 °C | 8,000 kg × 210 kJ/kg | 467 |
| Heated storage tank holding | 85–95 °C | 3 tanks × 4 kW losses × 24 h | 288 |
| Emulsifier soap solution | 30 → 60 °C | 6,000 L/day | 209 |
| Storage and pipework standing losses | – | about 5% | 65 |
| Total useful heat | 1,362 | ||
Averaged over 20 running hours, the heat pumps need about 68 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 70 kW, air-source cascade to 120 °C, sized per project.
- A 2,500 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 pressurised storage tank at up to 120 °C. Hot water replaces thermic fluid in the wax melting and storage tank coils.
- Soap solution for bitumen emulsion is heated in its own tank from the same loop.
- Bitumen heating to milling temperature stays on the existing thermic fluid heater.
Selected equipment
| Machine | SE-UHT air-source cascade, R245fa |
|---|---|
| Capacity | about 70 kW, built to duty |
| Concept | air-source cascade to 120 °C, sized per project |
| COP used | 1.6 (estimate) |
| Supply temperature | 120 °C |
| Storage | 2,500 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 starts the heat pumps below 110 °C and stops them at 120 °C. TIC-201 to TIC-203 hold each tank at its set-point through its own valve. The thermic fluid heater stays as standby and continues to serve bitumen heating.
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 wax | – | – |
| CO₂ per year | – | – |
06Benefits
Holding load off the heater
Night and weekend tank holding runs on the heat pumps alone.
Better wax colour
Coil surfaces stay at or below 120 °C, which avoids yellowing near the coils.
Lower fire risk
Water coils in wax tanks replace hot oil coils in the most exposed duty.
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
- Wax and bitumen quantities per day
- Tank sizes, holding temperatures and insulation condition
- Emulsion production volumes
- Thermic fluid heater fuel use
- Coil areas in existing tanks
- 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 sizing. Hot water at up to 120 °C gives less driving force than thermic fluid. Check coil area in each tank before the change.
- Pressurised loop. Water above 100 °C needs a closed loop at 3 bar or more with expansion and relief valves.
- Freeze-up of lines. Wax sets in lines if heating stops. Keep tracing on the hot-water loop with an alarm on low temperature.
- 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.