Case studies · Tyres & rubber · Maharashtra
Zero purge dryer at a tyre plant: −28.9 °C PDP on a −20 °C design, ₹28.9 lakh a year saved
Leading tyre manufacturer, Maharashtra · HRB-ZW zero purge (blower-reactivated) dryer package, 110 Nm³/min
- −28.9 °C PDP delivered (against −20 °C required · 8.9 K margin)
- 0 % Compressed air purged (blower + closed-loop cooling)
- ₹28.9 L Saved every year (against a heatless dryer)
- 199 t CO₂ avoided a year (280,854 kWh not drawn)
The challenge
The plant needed instrument and process air at −20 °C pressure dew point (PDP) on a 3,000 cfm compressor station running about 8,400 hours a year. Every conventional desiccant dryer pays for that drying load partly in compressed air: about 15 % on a heatless unit, 6 % on heated purge and still 2 % on an air-cooled blower purge dryer. On this duty a heatless dryer would vent 712 Nm³ of paid-for air every hour.
What AIRS did
- Complete package from one supplier: water-cooled pre-cooler, cyclonic separator, 0.01 µm pre-filter, HRB-ZW zero purge dryer (110 Nm³/min rated) and after-filter.
- Regeneration by ambient air from the dryer's own blower through an electric heater; the hot bed is then cooled in a sealed loop through a water-cooled cooler — not with dried compressed air.
- PDP-dependent switching from the dryer's controller, so heater and blower run only as long as the moisture load needs.
- Engineered to the site's actual inlet pressure, temperature and cooling water — not to the nameplate.
The result
- −28.9 °C PDP read at the dryer outlet against a −20 °C requirement — with inlet air at 36.7 °C.
- Zero compressed air vented for regeneration or cooling: every Nm³ the compressors make reaches the plant.
- ₹28.9 lakh a year less than a heatless dryer, ₹17.9 lakh less than heated purge and ₹8.2 lakh less than an air-cooled blower purge dryer — after counting the HRB-ZW's own heater and blower energy in full.
- Even in a worst case where hot, saturated air shortens adsorption to 4 hours, the saving against heatless stays at ₹16.7 lakh a year.
Four ways to dry the same air, per year
| Heatless | Heated purge | Blower purge (air-cooled) | AIRS HRB-ZW | |
|---|---|---|---|---|
| Purge air | 15 % | 6 % | 2 % | 0 % |
| Compressed air vented | 712 Nm³/h | 285 Nm³/h | 95 Nm³/h | 0 Nm³/h |
| Total energy a year | 598,374 kWh | 491,350 kWh | 397,303 kWh | 317,520 kWh |
| Cost a year | ₹61.6 lakh | ₹50.6 lakh | ₹40.9 lakh | ₹32.7 lakh |
| HRB-ZW saves | ₹28.9 lakh | ₹17.9 lakh | ₹8.2 lakh | — |
Basis of calculation
3,000 cfm (4,749 Nm³/h) · 8,400 h a year · ₹10.3 per kWh · compressed air at 0.10 kWh per Nm³ · grid 0.71 kg CO₂ per kWh. Heater (66 kW) and blower (11 kW) energy counted at full power for the whole heating phase, which overstates real use. Purge rates are typical published values for each dryer type.
At a glance
| Dryer | HRB-ZW zero purge, 110 Nm³/min rated |
|---|---|
| Site duty | 3,000 cfm at 6 barg |
| Required PDP | −20 °C |
| Delivered PDP | −28.9 °C at 36.7 °C inlet |
| Regeneration | Blower + heater, water-cooled closed-loop cooling |
| Pre-treatment | Pre-cooler, cyclonic separator, 0.01 µm filter |
| Operating hours | About 8,400 h a year |
| Commissioned | September 2026 |
About the equipment · Book an energy saving assessment
Client name withheld under the AIRS confidentiality policy. References are shared on request with the client's consent.
More results
- Smart heatless dryer through peak monsoon: −51.7 °C PDP average on a −40 °C design — Speciality chemicals, Central India: −51.7 °C average PDP in monsoon
- Two smart heatless dryers at a pharma plant: −40 °C PDP held, purge cut from 18 % to 8 % — Pharmaceuticals, South Gujarat: 18 → 8 % purge air