Medicinal herbs dried with active content preserved
How an ayurvedic raw material unit drying 2.1 tonnes of fresh herbs a day can use a closed-loop heat pump dryer, and what it saves against electric heater tray dryers.
▶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
- Heat destroys actives. Essential oils and heat-sensitive compounds degrade above about 50 °C. Buyers test for marker compounds and reject weak lots.
- Colour and appearance. Leaves that turn brown or black in drying lose value even if their active content is acceptable.
- Electric heaters are costly. Tray dryers with electric heaters run at a COP of 1 and vent warm air continuously.
- 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 unit dries leaves such as tulsi and moringa, roots such as ashwagandha and shatavari, and flowers such as hibiscus and rose for ayurvedic manufacturers, about 2.1 tonnes of fresh material a day. It works one shift for sorting and washing and dries overnight.
| Product | Drying | Basis | Water removed, kg/day | Conventional heat, kWh/day |
|---|---|---|---|---|
| Leaves (tulsi, moringa) | Air 40–45 °C | 1,000 kg/day, 80% → 8% | 783 | 1,409 |
| Roots (ashwagandha, shatavari) | Air 45–50 °C | 800 kg/day sliced roots, 70% → 10% | 533 | 960 |
| Flowers (hibiscus, rose) | Air 40 °C | 300 kg/day, 85% → 10% | 250 | 450 |
| Total | 1,566 | 2,819 | ||
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 1,566 kg of water a day in roughly 16 running hours.
- The electric heater tray dryer stays connected behind a normally closed valve as standby.
- A closed-loop heat pump dryer holds air at 40–50 °C and low humidity, so drying is fast without high temperature.
- Separate recipes for leaves, roots and flowers set temperature and humidity for each material.
- Aroma stays in the chamber air instead of being vented.
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 material being dried. A return-air humidity sensor sets the dehumidifying duty. The batch ends on a target return-air humidity or set time, and a moisture check confirms the result.
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 herb | – | – |
| CO₂ per year | – | – |
06Benefits
Higher marker content
Low-temperature drying retains more of the heat-sensitive compounds that buyers test for.
Green leaves, bright flowers
Gentle drying keeps natural colour, which helps grading.
Clean, traceable batches
Closed chambers and recorded drying recipes support GMP documentation at the buyer's end.
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
- Materials dried and daily quantities
- Moisture in and target moisture out
- Buyer specifications for colour and marker compounds
- Present drying method and time
- 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
- Cross-contamination. Clean the chamber and coils between different herbs. Strong-smelling materials can taint the next batch.
- Microbial load. Wash and drain material well before loading, and do not let wet material wait for hours before drying.
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
Medicinal herbs dried with active content preserved
How an ayurvedic raw material unit drying 2.1 tonnes of fresh herbs a day can use a closed-loop heat pump dryer, and what it saves against electric heater tray dryers.
▶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
- Heat destroys actives. Essential oils and heat-sensitive compounds degrade above about 50 °C. Buyers test for marker compounds and reject weak lots.
- Colour and appearance. Leaves that turn brown or black in drying lose value even if their active content is acceptable.
- Electric heaters are costly. Tray dryers with electric heaters run at a COP of 1 and vent warm air continuously.
- 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 unit dries leaves such as tulsi and moringa, roots such as ashwagandha and shatavari, and flowers such as hibiscus and rose for ayurvedic manufacturers, about 2.1 tonnes of fresh material a day. It works one shift for sorting and washing and dries overnight.
| Product | Drying | Basis | Water removed, kg/day | Conventional heat, kWh/day |
|---|---|---|---|---|
| Leaves (tulsi, moringa) | Air 40–45 °C | 1,000 kg/day, 80% → 8% | 783 | 1,409 |
| Roots (ashwagandha, shatavari) | Air 45–50 °C | 800 kg/day sliced roots, 70% → 10% | 533 | 960 |
| Flowers (hibiscus, rose) | Air 40 °C | 300 kg/day, 85% → 10% | 250 | 450 |
| Total | 1,566 | 2,819 | ||
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 1,566 kg of water a day in roughly 16 running hours.
- The electric heater tray dryer stays connected behind a normally closed valve as standby.
- A closed-loop heat pump dryer holds air at 40–50 °C and low humidity, so drying is fast without high temperature.
- Separate recipes for leaves, roots and flowers set temperature and humidity for each material.
- Aroma stays in the chamber air instead of being vented.
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 material being dried. A return-air humidity sensor sets the dehumidifying duty. The batch ends on a target return-air humidity or set time, and a moisture check confirms the result.
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 herb | – | – |
| CO₂ per year | – | – |
06Benefits
Higher marker content
Low-temperature drying retains more of the heat-sensitive compounds that buyers test for.
Green leaves, bright flowers
Gentle drying keeps natural colour, which helps grading.
Clean, traceable batches
Closed chambers and recorded drying recipes support GMP documentation at the buyer's end.
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
- Materials dried and daily quantities
- Moisture in and target moisture out
- Buyer specifications for colour and marker compounds
- Present drying method and time
- 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
- Cross-contamination. Clean the chamber and coils between different herbs. Strong-smelling materials can taint the next batch.
- Microbial load. Wash and drain material well before loading, and do not let wet material wait for hours before drying.
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.