Cheese vats and whey heated by heat pumps
How a cheese plant handling 10,000 litres of milk a day can heat its vats and whey with heat pump hot water instead of a diesel-fired boiler.
▶Video: Process hot water for food, dairy and beverages
V02 · 2–2.5 minPasteurisers, CIP, cooking and washing on stored hot water instead of boiler steam
Video coming soon01Problem statement
- Steam is too hot for a cheese vat. Setting and cooking happen at 32–40 °C. Steam in the vat jacket overshoots easily and can scorch curd near the wall.
- Cooking rate is critical. The curd must be raised about 1 K every few minutes. Hand-throttled steam valves make this hard to repeat batch to batch.
- Whey heating is an extra load. Whey has to be warmed to about 50 °C for separation and ultrafiltration, which adds a second steam user for a low-temperature job.
- Losses between fuel and process. Burning diesel 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 cheddar and processed cheese from 10,000 litres of pasteurised milk a day, giving about one tonne of cheese. Milk is stored cold after pasteurisation and warmed in jacketed vats. Whey is clarified and warmed before ultrafiltration.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Vat milk warming to set temperature | 10 → 32 °C | 10,000 L/day from cold storage | 272 |
| Curd cooking | 32 → 40 °C | 10,000 L vat contents, 10% jacket losses | 99 |
| Whey warming for separation and UF | 35 → 50 °C | 8,500 L whey/day | 144 |
| Storage and pipework standing losses | – | about 5% | 26 |
| Total useful heat | 541 | ||
Averaged over 12 running hours, the heat pumps need about 45 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 60 °C, covering the day's 541 kWh in about 10.8 running hours.
- A 1,500 L insulated storage tank decouples the heat pumps from the process peaks.
- The diesel-fired steam boiler stays connected behind a normally closed valve as standby.
- Hot water at 55–60 °C circulates through the vat jackets. The small temperature difference gives a gentle, even heating rate.
- A mixing valve on each vat follows the cooking ramp set by the cheesemaker.
- The whey heater takes water from the same tank, so one hot-water loop covers both duties.
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 | 60 °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 55 °C and stops them at 60 °C. TIC-201 on each vat follows the set ramp, for example 1 K every 5 minutes, using the jacket mixing valve. TIC-202 holds whey at 50 °C. If the tank falls below 45 °C, the existing steam supply to the jacket circuit is 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 cheese | – | – |
| CO₂ per year | – | – |
06Benefits
Repeatable cooking ramp
The vat follows the same temperature curve every batch, which helps texture and moisture consistency.
No scorching
Jacket water at 55–60 °C cannot burn curd on to the vat wall.
Simple jackets
Jackets run on low-pressure hot water, with no steam traps or condensate return at the vats.
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.
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
- Milk to cheese per day and number of vats
- Vat size and jacket type
- Milk temperature at vat filling
- Cooking profile used
- Whey volume and processing route
- 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
- Jacket flow. Hot-water jackets need more flow than steam. Check jacket connections and fit a circulation pump per vat or group.
- Whey quality. Hold whey below 55 °C to avoid denaturing proteins before ultrafiltration.
- 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.
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Cheese vats and whey heated by heat pumps
How a cheese plant handling 10,000 litres of milk a day can heat its vats and whey with heat pump hot water instead of a diesel-fired boiler.
▶Video: Process hot water for food, dairy and beverages
V02 · 2–2.5 minPasteurisers, CIP, cooking and washing on stored hot water instead of boiler steam
Video coming soon01Problem statement
- Steam is too hot for a cheese vat. Setting and cooking happen at 32–40 °C. Steam in the vat jacket overshoots easily and can scorch curd near the wall.
- Cooking rate is critical. The curd must be raised about 1 K every few minutes. Hand-throttled steam valves make this hard to repeat batch to batch.
- Whey heating is an extra load. Whey has to be warmed to about 50 °C for separation and ultrafiltration, which adds a second steam user for a low-temperature job.
- Losses between fuel and process. Burning diesel 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 cheddar and processed cheese from 10,000 litres of pasteurised milk a day, giving about one tonne of cheese. Milk is stored cold after pasteurisation and warmed in jacketed vats. Whey is clarified and warmed before ultrafiltration.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Vat milk warming to set temperature | 10 → 32 °C | 10,000 L/day from cold storage | 272 |
| Curd cooking | 32 → 40 °C | 10,000 L vat contents, 10% jacket losses | 99 |
| Whey warming for separation and UF | 35 → 50 °C | 8,500 L whey/day | 144 |
| Storage and pipework standing losses | – | about 5% | 26 |
| Total useful heat | 541 | ||
Averaged over 12 running hours, the heat pumps need about 45 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 60 °C, covering the day's 541 kWh in about 10.8 running hours.
- A 1,500 L insulated storage tank decouples the heat pumps from the process peaks.
- The diesel-fired steam boiler stays connected behind a normally closed valve as standby.
- Hot water at 55–60 °C circulates through the vat jackets. The small temperature difference gives a gentle, even heating rate.
- A mixing valve on each vat follows the cooking ramp set by the cheesemaker.
- The whey heater takes water from the same tank, so one hot-water loop covers both duties.
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 | 60 °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 55 °C and stops them at 60 °C. TIC-201 on each vat follows the set ramp, for example 1 K every 5 minutes, using the jacket mixing valve. TIC-202 holds whey at 50 °C. If the tank falls below 45 °C, the existing steam supply to the jacket circuit is 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 cheese | – | – |
| CO₂ per year | – | – |
06Benefits
Repeatable cooking ramp
The vat follows the same temperature curve every batch, which helps texture and moisture consistency.
No scorching
Jacket water at 55–60 °C cannot burn curd on to the vat wall.
Simple jackets
Jackets run on low-pressure hot water, with no steam traps or condensate return at the vats.
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.
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
- Milk to cheese per day and number of vats
- Vat size and jacket type
- Milk temperature at vat filling
- Cooking profile used
- Whey volume and processing route
- 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
- Jacket flow. Hot-water jackets need more flow than steam. Check jacket connections and fit a circulation pump per vat or group.
- Whey quality. Hold whey below 55 °C to avoid denaturing proteins before ultrafiltration.
- 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.