Biomass and wood chips dried with heat pumps
How a pellet and gasifier fuel plant drying 6 tonnes of sawdust and chips a day can use a closed-loop heat pump dryer, and what it costs and saves against burning part of its own biomass.
▶Video: Heat pump dryers for food and agri products
V08 · 2–2.5 minClosed-loop drying of spices, fruit, fish, grain and more
Video coming soon01Problem statement
- Burning product to dry product. A share of the plant's own biomass is burned to dry the rest, which cuts saleable output.
- Fire and spark risk. Hot furnace gas in a rotary dryer is a known cause of dryer fires and dust explosions.
- Uneven moisture. Pellet mills need feed at a steady 10–12% moisture. Drum dryers drift with feed moisture and weather.
- 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 plant makes wood pellets from sawmill dust and supplies dried wood chips to industrial gasifiers, handling about 6 tonnes of wet feed a day over two shifts. Drying today uses a biomass furnace and rotary drum.
| Product | Drying | Basis | Water removed, kg/day | Conventional heat, kWh/day |
|---|---|---|---|---|
| Sawdust for pellets | Air 60–65 °C | 4,000 kg/day, 40% → 12% | 1,273 | 2,291 |
| Wood chips for gasifiers | Air 55–60 °C | 2,000 kg/day, 30% → 15% | 353 | 635 |
| Total | 1,626 | 2,926 | ||
Conventional hot-air dryers use about 1.8 kWh of heat per kg of water removed. That figure is the baseline the savings are measured against.
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-AA-DR-84 (84 kW) heat pump drying module, removing about 1,626 kg of water a day in roughly 17 running hours.
- The biomass-fired hot-air furnace stays connected behind a normally closed valve as standby.
- A closed-loop heat pump dryer feeds warm, dry air to a low-temperature belt dryer for sawdust and chips.
- No combustion gas enters the dryer, so spark and fire risk are much lower.
- All the biomass that was burned for drying becomes saleable product.
Selected equipment
| Model | 1 × SE-AA-DR-84 |
|---|---|
| Heating capacity | 84 kW each, 84 kW total |
| Dehumidifying | about 98 L/h total (pro rata to the published 12–120 L/h range) |
| Drying air | rated 70 °C, 75 °C maximum |
| Refrigerant | R134a |
| Ambient | −5 to 43 °C |
| Water removed per kWh | about 2.4 kg |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TIC-201 holds air at 60–65 °C for sawdust and slightly lower for chips. A return-air humidity sensor sets dehumidifying duty. Belt speed is set from an outlet moisture meter to hold feed at 10–12% for the pellet mill.
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 wet feed | – | – |
| CO₂ per year | – | – |
06Benefits
More product to sell
Biomass that was burned in the furnace can be sold as pellets or chips.
Lower fire risk
Drying air at 65 °C with no sparks is much safer than furnace gas.
Steady pellet quality
Even feed moisture gives stronger, more durable pellets.
Heat recovered from the moisture
The evaporator condenses water out of the air and the condenser puts that latent heat back into the drying air, so about 2.4 kg of water leaves per kWh of electricity.
Closed loop, clean product
Air recirculates inside the chamber. No dust, smoke or outside humidity reaches the product, whatever the weather.
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
- Feed types and daily tonnes
- Moisture in and target moisture out
- Biomass burned for drying today and its sale value
- Present dryer type and airflow
- 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
- Economics. The baseline fuel is cheap biomass, so savings depend on the sale value of the biomass no longer burned. Check this before sizing.
- Dust. Fine wood dust clogs coils and is a fire risk. Fit filters, keep coils clean and follow dust-handling safety practice.
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
Biomass and wood chips dried with heat pumps
How a pellet and gasifier fuel plant drying 6 tonnes of sawdust and chips a day can use a closed-loop heat pump dryer, and what it costs and saves against burning part of its own biomass.
▶Video: Heat pump dryers for food and agri products
V08 · 2–2.5 minClosed-loop drying of spices, fruit, fish, grain and more
Video coming soon01Problem statement
- Burning product to dry product. A share of the plant's own biomass is burned to dry the rest, which cuts saleable output.
- Fire and spark risk. Hot furnace gas in a rotary dryer is a known cause of dryer fires and dust explosions.
- Uneven moisture. Pellet mills need feed at a steady 10–12% moisture. Drum dryers drift with feed moisture and weather.
- 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 plant makes wood pellets from sawmill dust and supplies dried wood chips to industrial gasifiers, handling about 6 tonnes of wet feed a day over two shifts. Drying today uses a biomass furnace and rotary drum.
| Product | Drying | Basis | Water removed, kg/day | Conventional heat, kWh/day |
|---|---|---|---|---|
| Sawdust for pellets | Air 60–65 °C | 4,000 kg/day, 40% → 12% | 1,273 | 2,291 |
| Wood chips for gasifiers | Air 55–60 °C | 2,000 kg/day, 30% → 15% | 353 | 635 |
| Total | 1,626 | 2,926 | ||
Conventional hot-air dryers use about 1.8 kWh of heat per kg of water removed. That figure is the baseline the savings are measured against.
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-AA-DR-84 (84 kW) heat pump drying module, removing about 1,626 kg of water a day in roughly 17 running hours.
- The biomass-fired hot-air furnace stays connected behind a normally closed valve as standby.
- A closed-loop heat pump dryer feeds warm, dry air to a low-temperature belt dryer for sawdust and chips.
- No combustion gas enters the dryer, so spark and fire risk are much lower.
- All the biomass that was burned for drying becomes saleable product.
Selected equipment
| Model | 1 × SE-AA-DR-84 |
|---|---|
| Heating capacity | 84 kW each, 84 kW total |
| Dehumidifying | about 98 L/h total (pro rata to the published 12–120 L/h range) |
| Drying air | rated 70 °C, 75 °C maximum |
| Refrigerant | R134a |
| Ambient | −5 to 43 °C |
| Water removed per kWh | about 2.4 kg |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TIC-201 holds air at 60–65 °C for sawdust and slightly lower for chips. A return-air humidity sensor sets dehumidifying duty. Belt speed is set from an outlet moisture meter to hold feed at 10–12% for the pellet mill.
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 wet feed | – | – |
| CO₂ per year | – | – |
06Benefits
More product to sell
Biomass that was burned in the furnace can be sold as pellets or chips.
Lower fire risk
Drying air at 65 °C with no sparks is much safer than furnace gas.
Steady pellet quality
Even feed moisture gives stronger, more durable pellets.
Heat recovered from the moisture
The evaporator condenses water out of the air and the condenser puts that latent heat back into the drying air, so about 2.4 kg of water leaves per kWh of electricity.
Closed loop, clean product
Air recirculates inside the chamber. No dust, smoke or outside humidity reaches the product, whatever the weather.
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
- Feed types and daily tonnes
- Moisture in and target moisture out
- Biomass burned for drying today and its sale value
- Present dryer type and airflow
- 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
- Economics. The baseline fuel is cheap biomass, so savings depend on the sale value of the biomass no longer burned. Check this before sizing.
- Dust. Fine wood dust clogs coils and is a fire risk. Fit filters, keep coils clean and follow dust-handling safety practice.
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.