Spices dried with colour and aroma intact
How a spice processing unit drying about 2.4 tonnes of fresh spice a day can switch to a closed-loop heat pump dryer, and what it saves against a briquette-fired kiln.
▶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
- Colour sets the price. Green cardamom loses its colour above about 50 °C, and chilli fades with hot air. Lower colour means a lower auction price.
- Smoke and uneven heat. Wood-fired kilns give smoke taint and hot spots, so batches dry unevenly and need constant turning.
- Aroma lost with the exhaust. Volatile oils leave with the hot, moist exhaust air of open-cycle dryers.
- 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 unit sits in a growing district and dries green cardamom, red chilli, black pepper and boiled turmeric for traders, about 2.4 tonnes of fresh spice a day in season. Drying runs in batches of 12 to 24 hours.
| Product | Drying | Basis | Water removed, kg/day | Conventional heat, kWh/day |
|---|---|---|---|---|
| Green cardamom | Air 45–50 °C | 800 kg/day capsules, 80% → 10% | 622 | 1,120 |
| Red chilli | Air 50–55 °C | 600 kg/day pods, 75% → 10% | 433 | 780 |
| Black pepper | Air 50–55 °C | 500 kg/day berries, 70% → 11% | 331 | 597 |
| Boiled turmeric fingers | Air 55 °C | 500 kg/day, 70% → 10% | 333 | 600 |
| Total | 1,720 | 3,097 | ||
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 1,720 kg of water a day in roughly 18 running hours.
- The briquette or firewood fired drying kiln stays connected behind a normally closed valve as standby.
- A closed-loop heat pump dryer recirculates air through tray trolleys, removing moisture on the cold coil and reheating the air with condenser heat.
- Each spice gets its own temperature recipe, with cardamom held below 50 °C.
- There is no flue gas in the drying air, so there is no smoke taint.
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 drying air to the recipe for the spice being dried. A return-air humidity sensor sets the dehumidifying duty and moves the batch into a lower-humidity finishing stage. The batch ends on a target return-air humidity or set time.
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 fresh spice | – | – |
| CO₂ per year | – | – |
06Benefits
Greener cardamom, redder chilli
Controlled low-temperature drying keeps colour, which buyers pay for.
More aroma retained
Closed-loop air keeps volatile oils in the chamber instead of venting them.
No smoke taint
Clean, indirect heat avoids the smoky notes of wood-fired kilns.
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
- Spices dried and daily quantity in season
- Moisture in and target moisture out
- Colour grade requirements from buyers
- Season length for each spice
- 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
- Food safety. Spices are prone to mould and aflatoxin if drying is slow. Size the dryer to reach safe moisture within the recipe time.
- Corrosion. Chilli and turmeric dust is abrasive and staining. Use coated coils, filters before the coils and stainless trays.
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
Spices dried with colour and aroma intact
How a spice processing unit drying about 2.4 tonnes of fresh spice a day can switch to a closed-loop heat pump dryer, and what it saves against a briquette-fired kiln.
▶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
- Colour sets the price. Green cardamom loses its colour above about 50 °C, and chilli fades with hot air. Lower colour means a lower auction price.
- Smoke and uneven heat. Wood-fired kilns give smoke taint and hot spots, so batches dry unevenly and need constant turning.
- Aroma lost with the exhaust. Volatile oils leave with the hot, moist exhaust air of open-cycle dryers.
- 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 unit sits in a growing district and dries green cardamom, red chilli, black pepper and boiled turmeric for traders, about 2.4 tonnes of fresh spice a day in season. Drying runs in batches of 12 to 24 hours.
| Product | Drying | Basis | Water removed, kg/day | Conventional heat, kWh/day |
|---|---|---|---|---|
| Green cardamom | Air 45–50 °C | 800 kg/day capsules, 80% → 10% | 622 | 1,120 |
| Red chilli | Air 50–55 °C | 600 kg/day pods, 75% → 10% | 433 | 780 |
| Black pepper | Air 50–55 °C | 500 kg/day berries, 70% → 11% | 331 | 597 |
| Boiled turmeric fingers | Air 55 °C | 500 kg/day, 70% → 10% | 333 | 600 |
| Total | 1,720 | 3,097 | ||
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 1,720 kg of water a day in roughly 18 running hours.
- The briquette or firewood fired drying kiln stays connected behind a normally closed valve as standby.
- A closed-loop heat pump dryer recirculates air through tray trolleys, removing moisture on the cold coil and reheating the air with condenser heat.
- Each spice gets its own temperature recipe, with cardamom held below 50 °C.
- There is no flue gas in the drying air, so there is no smoke taint.
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 drying air to the recipe for the spice being dried. A return-air humidity sensor sets the dehumidifying duty and moves the batch into a lower-humidity finishing stage. The batch ends on a target return-air humidity or set time.
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 fresh spice | – | – |
| CO₂ per year | – | – |
06Benefits
Greener cardamom, redder chilli
Controlled low-temperature drying keeps colour, which buyers pay for.
More aroma retained
Closed-loop air keeps volatile oils in the chamber instead of venting them.
No smoke taint
Clean, indirect heat avoids the smoky notes of wood-fired kilns.
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
- Spices dried and daily quantity in season
- Moisture in and target moisture out
- Colour grade requirements from buyers
- Season length for each spice
- 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
- Food safety. Spices are prone to mould and aflatoxin if drying is slow. Size the dryer to reach safe moisture within the recipe time.
- Corrosion. Chilli and turmeric dust is abrasive and staining. Use coated coils, filters before the coils and stainless trays.
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.