Green-ware dried without cracks or LPG
How a ceramic unit drying 6,000 kg of green-ware a day can replace LPG-fired hot-air dryers with closed-loop heat pump drying at controlled humidity.
▶Video: Industrial drying and dehumidifying
V09 · 2–2.5 minSludge, green-ware, pharma granules and storage rooms
Video coming soon01Problem statement
- Cracking from fast drying. Hot dry air dries the surface before the core, so pieces shrink unevenly and crack or warp. Losses of 5 to 10% are common.
- Humidity is hard to control. A burner can raise temperature, but it cannot hold the high humidity needed in the first stage of drying.
- Mould life. Plaster moulds dried too hot lose strength and absorbency, so they wear out in fewer casts.
- Losses between fuel and process. Burning LPG 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 tableware, planters and sanitary pieces by jiggering and slip casting. It dries about 6,000 kg of green-ware a day before firing and re-dries 1,500 kg of plaster moulds.
| Product | Drying | Basis | Water removed, kg/day | Conventional heat, kWh/day |
|---|---|---|---|---|
| Green-ware drying | Air 40 → 65 °C, staged humidity | 6,000 kg green-ware/day, 20% → 2% moisture | 1,102 | 1,984 |
| Plaster mould re-drying | Air 40–45 °C | 1,500 kg moulds/day, 18% → 8% moisture | 163 | 293 |
| Total | 1,265 | 2,277 | ||
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
- 3 × SE-AA-DR-21 (63 kW total) heat pump drying modules, removing about 1,265 kg of water a day in roughly 17 running hours.
- The LPG-fired hot-air chamber dryers stays connected behind a normally closed valve as standby.
- The dryer runs a staged recipe: warm humid air first, then rising temperature and falling humidity once shrinkage is over.
- Water removed from the ware leaves as condensate, so the chamber is not vented and heat is not thrown away.
- A separate low-temperature recipe dries plaster moulds at 40–45 °C between casting shifts.
Selected equipment
| Model | 3 × SE-AA-DR-21 |
|---|---|
| Heating capacity | 21 kW each, 63 kW total |
| Dehumidifying | about 74 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 follows a time-based temperature profile and a humidity controller in DC-201 holds relative humidity for each stage. The dryer adjusts dehumidification to follow the curve. The LPG burner stays as standby for urgent orders.
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 green-ware | – | – |
| CO₂ per year | – | – |
06Benefits
Fewer drying cracks
Controlled humidity in the early stage lets the core and surface shrink together.
Longer mould life
Moulds dried below 45 °C keep their strength and absorbency for more casts.
Repeatable recipes
Each product gets its own stored drying curve, so results do not depend on the operator.
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.
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
- Green-ware weight dried per day and moisture after forming
- Present drying time and crack rejection rate
- Chamber sizes and loading method
- Mould quantity and present drying method
- LPG use per month
- 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
- Leather-hard stage. Most cracking happens before the leather-hard point. Keep humidity high and air speed low until shrinkage stops.
- Dust. Dry clay dust loads the evaporator coil. Fit return-air filters and clean the coil on a fixed schedule.
- Brick plants. Large brick kilns already have waste kiln heat. Heat pump drying suits smaller chambers, specials and units without kiln heat recovery.
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
Green-ware dried without cracks or LPG
How a ceramic unit drying 6,000 kg of green-ware a day can replace LPG-fired hot-air dryers with closed-loop heat pump drying at controlled humidity.
▶Video: Industrial drying and dehumidifying
V09 · 2–2.5 minSludge, green-ware, pharma granules and storage rooms
Video coming soon01Problem statement
- Cracking from fast drying. Hot dry air dries the surface before the core, so pieces shrink unevenly and crack or warp. Losses of 5 to 10% are common.
- Humidity is hard to control. A burner can raise temperature, but it cannot hold the high humidity needed in the first stage of drying.
- Mould life. Plaster moulds dried too hot lose strength and absorbency, so they wear out in fewer casts.
- Losses between fuel and process. Burning LPG 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 tableware, planters and sanitary pieces by jiggering and slip casting. It dries about 6,000 kg of green-ware a day before firing and re-dries 1,500 kg of plaster moulds.
| Product | Drying | Basis | Water removed, kg/day | Conventional heat, kWh/day |
|---|---|---|---|---|
| Green-ware drying | Air 40 → 65 °C, staged humidity | 6,000 kg green-ware/day, 20% → 2% moisture | 1,102 | 1,984 |
| Plaster mould re-drying | Air 40–45 °C | 1,500 kg moulds/day, 18% → 8% moisture | 163 | 293 |
| Total | 1,265 | 2,277 | ||
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
- 3 × SE-AA-DR-21 (63 kW total) heat pump drying modules, removing about 1,265 kg of water a day in roughly 17 running hours.
- The LPG-fired hot-air chamber dryers stays connected behind a normally closed valve as standby.
- The dryer runs a staged recipe: warm humid air first, then rising temperature and falling humidity once shrinkage is over.
- Water removed from the ware leaves as condensate, so the chamber is not vented and heat is not thrown away.
- A separate low-temperature recipe dries plaster moulds at 40–45 °C between casting shifts.
Selected equipment
| Model | 3 × SE-AA-DR-21 |
|---|---|
| Heating capacity | 21 kW each, 63 kW total |
| Dehumidifying | about 74 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 follows a time-based temperature profile and a humidity controller in DC-201 holds relative humidity for each stage. The dryer adjusts dehumidification to follow the curve. The LPG burner stays as standby for urgent orders.
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 green-ware | – | – |
| CO₂ per year | – | – |
06Benefits
Fewer drying cracks
Controlled humidity in the early stage lets the core and surface shrink together.
Longer mould life
Moulds dried below 45 °C keep their strength and absorbency for more casts.
Repeatable recipes
Each product gets its own stored drying curve, so results do not depend on the operator.
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.
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
- Green-ware weight dried per day and moisture after forming
- Present drying time and crack rejection rate
- Chamber sizes and loading method
- Mould quantity and present drying method
- LPG use per month
- 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
- Leather-hard stage. Most cracking happens before the leather-hard point. Keep humidity high and air speed low until shrinkage stops.
- Dust. Dry clay dust loads the evaporator coil. Fit return-air filters and clean the coil on a fixed schedule.
- Brick plants. Large brick kilns already have waste kiln heat. Heat pump drying suits smaller chambers, specials and units without kiln heat recovery.
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.