Distillery wash preheated with recovered cooling-water heat
How a 5 KLPD grain distillery can preheat its wash and mashing water with heat pumps running on its own cooling water, and what it saves against a briquette-fired boiler.
▶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
- Steam for the final preheat. After the recuperator the wash still needs to rise from about 70 °C to 85 °C before the beer column. This is done with live steam.
- Cooling and heating side by side. Fermenters and condensers reject heat to the cooling tower while the boiler heats water for mashing.
- Summer fermentation. In hot months the cooling tower struggles to keep fermenters at 32–34 °C, which lowers yield.
- Losses between fuel and process. Burning briquettes 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 distillery makes 5,000 litres of grain spirit a day from about 12 tonnes of broken rice and maize, running round the clock. Fermented wash goes to the beer column through a spent-wash recuperator. Fermenters and column condensers share a cooling tower loop.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Wash preheating before beer column | 70 → 85 °C | 50,000 L/day wash after recuperator, cp 4.0, ρ 1.02 | 850 |
| Mashing slurry water | 35 → 65 °C | 12 t grain × 2.5 L/kg = 30,000 L | 1,045 |
| Storage and pipework standing losses | – | about 5% | 95 |
| Total useful heat | 1,990 | ||
Averaged over 20 running hours, the heat pumps need about 99 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
- 4 × SE-WWUHT-27 (108 kW total) (SE-WWUHT water-source, R245fa) delivering 90 °C, covering the day's 1,990 kWh in about 18.4 running hours.
- A 3,500 L insulated storage tank decouples the heat pumps from the process peaks.
- Heat source: fermenter and condenser cooling water at about 45 °C. Fermenters and condensers get colder cooling water, which helps hold fermentation at 32–34 °C in summer.
- The briquette-fired steam boiler stays connected behind a normally closed valve as standby.
- The heat pumps take heat from the cooling water returning from fermenters and condensers at about 45 °C.
- A wide-gap plate exchanger after the spent-wash recuperator lifts wash from 70 °C to 85 °C with 90 °C hot water.
- Mashing slurry water is heated in its own tank, so the jet cooker steam is used only for the liquefaction step.
Selected equipment
| Model | SE-WWUHT-27 × 4 |
|---|---|
| Heating capacity | 27 kW each, 108 kW total |
| COP | 2.93 estimated for a 45 °C source (the data sheet is rated on a 60/55 °C source) |
| Rating | water or steam to 120 °C, R245fa |
| Supply temperature | 90 °C |
| Storage | 3,500 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 calls the heat pumps on below 85 °C and off at 90 °C. TT-102 at the bottom starts a unit early before a mashing batch. TIC-201 holds the wash at 85 °C into the beer column and TIC-202 holds the slurry water tank. The existing steam preheater stays 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 1,000 L spirit | – | – |
| CO₂ per year | – | – |
06Benefits
Cooler fermenters in summer
Taking heat out of the cooling water gives the fermenters colder water when they need it most.
Steadier column feed
Wash enters the beer column at a constant temperature, which steadies column operation.
Less boiler steam
Steam is kept for liquefaction and distillation where it is really needed.
Lower energy cost
Each kWh of electricity delivers about 2.9 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
- Wash volume per day and temperature after recuperator
- Mashing water volume and temperature
- Cooling water flow and temperatures from fermenters and condensers
- Present steam use per kilolitre of spirit
- 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
- Wash fouling. Wash carries solids and yeast. Use a wide-gap or tubular exchanger with a cleaning connection on the wash side.
- Cooling water treatment. Connect to the tower loop through a plate exchanger so dosed tower water never enters the heat pumps.
- 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
Distillery wash preheated with recovered cooling-water heat
How a 5 KLPD grain distillery can preheat its wash and mashing water with heat pumps running on its own cooling water, and what it saves against a briquette-fired boiler.
▶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
- Steam for the final preheat. After the recuperator the wash still needs to rise from about 70 °C to 85 °C before the beer column. This is done with live steam.
- Cooling and heating side by side. Fermenters and condensers reject heat to the cooling tower while the boiler heats water for mashing.
- Summer fermentation. In hot months the cooling tower struggles to keep fermenters at 32–34 °C, which lowers yield.
- Losses between fuel and process. Burning briquettes 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 distillery makes 5,000 litres of grain spirit a day from about 12 tonnes of broken rice and maize, running round the clock. Fermented wash goes to the beer column through a spent-wash recuperator. Fermenters and column condensers share a cooling tower loop.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Wash preheating before beer column | 70 → 85 °C | 50,000 L/day wash after recuperator, cp 4.0, ρ 1.02 | 850 |
| Mashing slurry water | 35 → 65 °C | 12 t grain × 2.5 L/kg = 30,000 L | 1,045 |
| Storage and pipework standing losses | – | about 5% | 95 |
| Total useful heat | 1,990 | ||
Averaged over 20 running hours, the heat pumps need about 99 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
- 4 × SE-WWUHT-27 (108 kW total) (SE-WWUHT water-source, R245fa) delivering 90 °C, covering the day's 1,990 kWh in about 18.4 running hours.
- A 3,500 L insulated storage tank decouples the heat pumps from the process peaks.
- Heat source: fermenter and condenser cooling water at about 45 °C. Fermenters and condensers get colder cooling water, which helps hold fermentation at 32–34 °C in summer.
- The briquette-fired steam boiler stays connected behind a normally closed valve as standby.
- The heat pumps take heat from the cooling water returning from fermenters and condensers at about 45 °C.
- A wide-gap plate exchanger after the spent-wash recuperator lifts wash from 70 °C to 85 °C with 90 °C hot water.
- Mashing slurry water is heated in its own tank, so the jet cooker steam is used only for the liquefaction step.
Selected equipment
| Model | SE-WWUHT-27 × 4 |
|---|---|
| Heating capacity | 27 kW each, 108 kW total |
| COP | 2.93 estimated for a 45 °C source (the data sheet is rated on a 60/55 °C source) |
| Rating | water or steam to 120 °C, R245fa |
| Supply temperature | 90 °C |
| Storage | 3,500 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 calls the heat pumps on below 85 °C and off at 90 °C. TT-102 at the bottom starts a unit early before a mashing batch. TIC-201 holds the wash at 85 °C into the beer column and TIC-202 holds the slurry water tank. The existing steam preheater stays 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 1,000 L spirit | – | – |
| CO₂ per year | – | – |
06Benefits
Cooler fermenters in summer
Taking heat out of the cooling water gives the fermenters colder water when they need it most.
Steadier column feed
Wash enters the beer column at a constant temperature, which steadies column operation.
Less boiler steam
Steam is kept for liquefaction and distillation where it is really needed.
Lower energy cost
Each kWh of electricity delivers about 2.9 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
- Wash volume per day and temperature after recuperator
- Mashing water volume and temperature
- Cooling water flow and temperatures from fermenters and condensers
- Present steam use per kilolitre of spirit
- 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
- Wash fouling. Wash carries solids and yeast. Use a wide-gap or tubular exchanger with a cleaning connection on the wash side.
- Cooling water treatment. Connect to the tower loop through a plate exchanger so dosed tower water never enters the heat pumps.
- 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.