Chocolate melting heated with chiller heat
How a confectionery plant handling 10 tonnes of chocolate and compound a day can heat its melting tanks and jackets with heat from its cooling-tunnel chiller, instead of electric heaters.
▶Video: Waste-heat recovery heat pumps
V10 · 2–2.5 minLifting warm water from condensers, effluent and process cooling to useful heat
Video coming soon01Problem statement
- Electric heating everywhere. Melting tanks, storage tanks, pipes and moulds are often kept warm with electric heaters running all day.
- Hot spots spoil chocolate. Electric elements create local hot spots that can burn milk chocolate or crystallise sugar.
- Heat and cooling side by side. The cooling tunnel chiller rejects heat while the tanks next to it are heated electrically.
- 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 enrobed bars, moulded chocolate and compound-coated products. It melts about 10 tonnes of chocolate and compound a day, holds it in jacketed tanks, and tempers it before moulding and enrobing. Cooling tunnels after the enrober and moulding line are served by a chiller.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Melting chocolate and compound | 20 → 50 °C | 10,000 kg × (1.6 kJ/kg·K × 30 K + 50 kJ/kg fat melting) ÷ 3,600 | 272 |
| Storage tanks and pipework | 45 °C | 6 tanks and lines × 2 kW × 20 h | 240 |
| Mould warming before depositing | 30–35 °C air | 2 heaters × 6 kW × 16 h | 192 |
| Storage and pipework standing losses | – | about 5% | 35 |
| Total useful heat | 739 | ||
Averaged over 20 running hours, the heat pumps need about 37 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 Customized water-source cascade machine of about 40 kW, two-stage water-source machine built to duty, lifting 32 °C to 65 °C.
- A 1,500 L insulated storage tank decouples the heat pumps from the process peaks.
- Heat source: cooling-tunnel chiller condenser water at about 32 °C. Cooling the chiller condenser water lowers head pressure and saves chiller power.
- The electric heaters on tanks and jackets stays connected behind a normally closed valve as standby.
- Condenser water from the cooling tunnel chiller, at about 32 °C, is the heat pump source.
- Warm water at 55–60 °C circulates through melting tank and storage tank jackets and pipe tracing.
- The mould heater uses a hot-water coil instead of electric elements.
- The tempering machine's own heating and cooling stays as it is.
Selected equipment
| Machine | Customized water-source cascade |
|---|---|
| Capacity | about 40 kW, built to duty |
| Concept | two-stage water-source machine built to duty, lifting 32 °C to 65 °C |
| COP used | 3.5 (estimate) |
| Supply temperature | 65 °C |
| Storage | 1,500 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 at the tank top starts the heat pump below 60 °C and stops it at 65 °C. TIC-201 holds melting tanks at 50 °C. TIC-202 holds storage tanks at 45 °C. TIC-203 holds mould air at 32 °C. If the tank falls below 55 °C, the existing electric heaters are enabled as 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 tonne of chocolate | – | – |
| CO₂ per year | – | – |
06Benefits
Gentle, even heating
Warm water jackets never exceed 60–65 °C, so chocolate cannot burn.
Chiller and heater working together
The heat pump uses chiller heat and helps cool its condenser water.
Lower electrical load
Removing tank heaters cuts demand charges.
Lower energy cost
Each kWh of electricity delivers about 3.5 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 1/3.5 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
- Chocolate and compound use per day
- Number and size of melting and storage tanks
- Existing heater ratings
- Cooling tunnel chiller capacity and condenser water temperature
- 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
Design notes
- Water in a chocolate plant. Any water leak into chocolate is serious. Use double-walled jackets, pressure-test them, and route pipes away from open product.
- Jacket temperature limit. Keep jacket water at or below 60 °C for milk chocolate to avoid browning.
- Pipe tracing. Water-jacketed product lines need full-length jackets with no cold spots, or chocolate sets in the line.
- Source stream. The source must give up roughly two-thirds of the heat delivered. Confirm its flow and temperature over a full production day, and filter it before the evaporator.
- 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
Chocolate melting heated with chiller heat
How a confectionery plant handling 10 tonnes of chocolate and compound a day can heat its melting tanks and jackets with heat from its cooling-tunnel chiller, instead of electric heaters.
▶Video: Waste-heat recovery heat pumps
V10 · 2–2.5 minLifting warm water from condensers, effluent and process cooling to useful heat
Video coming soon01Problem statement
- Electric heating everywhere. Melting tanks, storage tanks, pipes and moulds are often kept warm with electric heaters running all day.
- Hot spots spoil chocolate. Electric elements create local hot spots that can burn milk chocolate or crystallise sugar.
- Heat and cooling side by side. The cooling tunnel chiller rejects heat while the tanks next to it are heated electrically.
- 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 enrobed bars, moulded chocolate and compound-coated products. It melts about 10 tonnes of chocolate and compound a day, holds it in jacketed tanks, and tempers it before moulding and enrobing. Cooling tunnels after the enrober and moulding line are served by a chiller.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Melting chocolate and compound | 20 → 50 °C | 10,000 kg × (1.6 kJ/kg·K × 30 K + 50 kJ/kg fat melting) ÷ 3,600 | 272 |
| Storage tanks and pipework | 45 °C | 6 tanks and lines × 2 kW × 20 h | 240 |
| Mould warming before depositing | 30–35 °C air | 2 heaters × 6 kW × 16 h | 192 |
| Storage and pipework standing losses | – | about 5% | 35 |
| Total useful heat | 739 | ||
Averaged over 20 running hours, the heat pumps need about 37 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 Customized water-source cascade machine of about 40 kW, two-stage water-source machine built to duty, lifting 32 °C to 65 °C.
- A 1,500 L insulated storage tank decouples the heat pumps from the process peaks.
- Heat source: cooling-tunnel chiller condenser water at about 32 °C. Cooling the chiller condenser water lowers head pressure and saves chiller power.
- The electric heaters on tanks and jackets stays connected behind a normally closed valve as standby.
- Condenser water from the cooling tunnel chiller, at about 32 °C, is the heat pump source.
- Warm water at 55–60 °C circulates through melting tank and storage tank jackets and pipe tracing.
- The mould heater uses a hot-water coil instead of electric elements.
- The tempering machine's own heating and cooling stays as it is.
Selected equipment
| Machine | Customized water-source cascade |
|---|---|
| Capacity | about 40 kW, built to duty |
| Concept | two-stage water-source machine built to duty, lifting 32 °C to 65 °C |
| COP used | 3.5 (estimate) |
| Supply temperature | 65 °C |
| Storage | 1,500 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 at the tank top starts the heat pump below 60 °C and stops it at 65 °C. TIC-201 holds melting tanks at 50 °C. TIC-202 holds storage tanks at 45 °C. TIC-203 holds mould air at 32 °C. If the tank falls below 55 °C, the existing electric heaters are enabled as 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 tonne of chocolate | – | – |
| CO₂ per year | – | – |
06Benefits
Gentle, even heating
Warm water jackets never exceed 60–65 °C, so chocolate cannot burn.
Chiller and heater working together
The heat pump uses chiller heat and helps cool its condenser water.
Lower electrical load
Removing tank heaters cuts demand charges.
Lower energy cost
Each kWh of electricity delivers about 3.5 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 1/3.5 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
- Chocolate and compound use per day
- Number and size of melting and storage tanks
- Existing heater ratings
- Cooling tunnel chiller capacity and condenser water temperature
- 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
Design notes
- Water in a chocolate plant. Any water leak into chocolate is serious. Use double-walled jackets, pressure-test them, and route pipes away from open product.
- Jacket temperature limit. Keep jacket water at or below 60 °C for milk chocolate to avoid browning.
- Pipe tracing. Water-jacketed product lines need full-length jackets with no cold spots, or chocolate sets in the line.
- Source stream. The source must give up roughly two-thirds of the heat delivered. Confirm its flow and temperature over a full production day, and filter it before the evaporator.
- 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.