Paint booth and oven air from heat pumps
How a general industrial paint shop can heat its spray booth and flash-off air and preheat oven fresh air with heat pumps, and what it saves against diesel-fired air heaters.
▶Video: Hot air from heat pump hot water
V05 · 2–2.5 minAir coils for spray dryers, stenters, kilns, paint booths and ovens
Video coming soon01Problem statement
- Large air volumes. Booths move tens of thousands of cubic metres of air an hour, so even a small temperature rise needs a lot of heat.
- Humidity spoils finish. Cold or humid booth air causes blushing and poor flow of the paint, so air must be conditioned through the year.
- Oven fresh air starts cold. Oven make-up air enters at ambient, and the burner spends much of its fuel just bringing it up to temperature.
- Losses between fuel and process. Burning diesel 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 paints tractor and implement parts. It runs one 25,000 m³/h spray booth, a flash-off zone and a convection curing oven over two shifts.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Spray booth fresh air | Air 25 °C | 7,500 m³/h fresh air × 1.2 kg/m³ × 1.005 kJ/kg·K × 8 K yearly average × 16 h | 322 |
| Flash-off zone air | Air 45 °C | 5,000 m³/h × 1.2 kg/m³ × 1.005 kJ/kg·K × 15 K × 16 h | 402 |
| Curing oven fresh-air preheat | Air 30 → 80 °C | 3,000 m³/h × 1.2 kg/m³ × 1.005 kJ/kg·K × 50 K × 16 h | 804 |
| Storage and pipework standing losses | – | about 5% | 76 |
| Total useful heat | 1,604 | ||
Averaged over 16 running hours, the heat pumps need about 100 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
- 1 × SE-SHT-110C (110 kW) (SE-SHT cascade heat pump) delivering 90 °C, covering the day's 1,604 kWh in about 14.6 running hours.
- A 3,500 L insulated storage tank decouples the heat pumps from the process peaks.
- The diesel-fired indirect air heaters stays connected behind a normally closed valve as standby.
- Hot-water coils are added to the booth supply unit and the flash-off air unit, upstream of the existing burners.
- A preheat coil on the oven fresh-air intake lifts make-up air to about 80 °C, and the oven burner adds only the final rise to cure temperature.
- The existing burners stay in series after the coils and trim to set point.
Selected equipment
| Model | SE-SHT-110C × 1 |
|---|---|
| Heating capacity | 110 kW each, 110 kW total |
| COP | 2.7 at A20 °C / W90 °C (data sheet T1) |
| Power input | about 40.5 kW total at rated conditions |
| Rating | cascade R410A + R515B, rated 90 °C, 95 °C maximum |
| Supply temperature | 90 °C |
| Storage | 3,500 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the tank top starts the heat pumps below 85 °C and stops them at 90 °C. TIC-201 and TIC-202 modulate the booth and flash-off coil valves to hold supply air temperature, and the burners trim only if the coil cannot hold set point. TIC-203 holds oven intake air at 80 °C. Booth coil valves close automatically when the booth fans stop.
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 | – | – |
| CO₂ per year | – | – |
06Benefits
Better finish quality
Steady booth air temperature helps paint flow and reduces blushing on humid days.
Smaller oven burner load
Preheated make-up air means the oven burner fires less and the oven recovers faster after door openings.
No combustion in booth air
Water coils add heat without any risk of flue gas leaking into the booth supply.
Lower energy cost
Each kWh of electricity delivers about 2.7 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.
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
- Booth airflow and fresh-air fraction
- Flash-off and oven fresh-air flows
- Oven cure temperature and burner rating
- Monthly diesel use for booth and oven
- Present fuel or electricity use and monthly bill
- Sanctioned electrical load and spare capacity
- Space for the heat pumps and storage, with service access
- Winter minimum ambient at site
Design notes
- Coil frost and fouling. Fit filters ahead of each coil. In colder regions add frost protection or glycol to the booth coil.
- Oven exhaust. Oven exhaust carries solvent. Keep the preheat coil on the fresh-air side only, outside any classified area.
- Electrical. About 40 kW of heat pump input at rated conditions, plus pumps and fans. Check spare sanctioned load before ordering.
- Winter output. The SE-SHT cascade gives about 80% of rated output at 7 °C ambient and still runs at −20 °C. Size on the coldest design day for northern sites.
- 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.
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.
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Paint booth and oven air from heat pumps
How a general industrial paint shop can heat its spray booth and flash-off air and preheat oven fresh air with heat pumps, and what it saves against diesel-fired air heaters.
▶Video: Hot air from heat pump hot water
V05 · 2–2.5 minAir coils for spray dryers, stenters, kilns, paint booths and ovens
Video coming soon01Problem statement
- Large air volumes. Booths move tens of thousands of cubic metres of air an hour, so even a small temperature rise needs a lot of heat.
- Humidity spoils finish. Cold or humid booth air causes blushing and poor flow of the paint, so air must be conditioned through the year.
- Oven fresh air starts cold. Oven make-up air enters at ambient, and the burner spends much of its fuel just bringing it up to temperature.
- Losses between fuel and process. Burning diesel 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 paints tractor and implement parts. It runs one 25,000 m³/h spray booth, a flash-off zone and a convection curing oven over two shifts.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Spray booth fresh air | Air 25 °C | 7,500 m³/h fresh air × 1.2 kg/m³ × 1.005 kJ/kg·K × 8 K yearly average × 16 h | 322 |
| Flash-off zone air | Air 45 °C | 5,000 m³/h × 1.2 kg/m³ × 1.005 kJ/kg·K × 15 K × 16 h | 402 |
| Curing oven fresh-air preheat | Air 30 → 80 °C | 3,000 m³/h × 1.2 kg/m³ × 1.005 kJ/kg·K × 50 K × 16 h | 804 |
| Storage and pipework standing losses | – | about 5% | 76 |
| Total useful heat | 1,604 | ||
Averaged over 16 running hours, the heat pumps need about 100 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
- 1 × SE-SHT-110C (110 kW) (SE-SHT cascade heat pump) delivering 90 °C, covering the day's 1,604 kWh in about 14.6 running hours.
- A 3,500 L insulated storage tank decouples the heat pumps from the process peaks.
- The diesel-fired indirect air heaters stays connected behind a normally closed valve as standby.
- Hot-water coils are added to the booth supply unit and the flash-off air unit, upstream of the existing burners.
- A preheat coil on the oven fresh-air intake lifts make-up air to about 80 °C, and the oven burner adds only the final rise to cure temperature.
- The existing burners stay in series after the coils and trim to set point.
Selected equipment
| Model | SE-SHT-110C × 1 |
|---|---|
| Heating capacity | 110 kW each, 110 kW total |
| COP | 2.7 at A20 °C / W90 °C (data sheet T1) |
| Power input | about 40.5 kW total at rated conditions |
| Rating | cascade R410A + R515B, rated 90 °C, 95 °C maximum |
| Supply temperature | 90 °C |
| Storage | 3,500 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the tank top starts the heat pumps below 85 °C and stops them at 90 °C. TIC-201 and TIC-202 modulate the booth and flash-off coil valves to hold supply air temperature, and the burners trim only if the coil cannot hold set point. TIC-203 holds oven intake air at 80 °C. Booth coil valves close automatically when the booth fans stop.
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 | – | – |
| CO₂ per year | – | – |
06Benefits
Better finish quality
Steady booth air temperature helps paint flow and reduces blushing on humid days.
Smaller oven burner load
Preheated make-up air means the oven burner fires less and the oven recovers faster after door openings.
No combustion in booth air
Water coils add heat without any risk of flue gas leaking into the booth supply.
Lower energy cost
Each kWh of electricity delivers about 2.7 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.
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
- Booth airflow and fresh-air fraction
- Flash-off and oven fresh-air flows
- Oven cure temperature and burner rating
- Monthly diesel use for booth and oven
- Present fuel or electricity use and monthly bill
- Sanctioned electrical load and spare capacity
- Space for the heat pumps and storage, with service access
- Winter minimum ambient at site
Design notes
- Coil frost and fouling. Fit filters ahead of each coil. In colder regions add frost protection or glycol to the booth coil.
- Oven exhaust. Oven exhaust carries solvent. Keep the preheat coil on the fresh-air side only, outside any classified area.
- Electrical. About 40 kW of heat pump input at rated conditions, plus pumps and fans. Check spare sanctioned load before ordering.
- Winter output. The SE-SHT cascade gives about 80% of rated output at 7 °C ambient and still runs at −20 °C. Size on the coldest design day for northern sites.
- 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.
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.