Dairy Milk Chiller: Temperature Controller Build

Fresh milk must cool from 37C to below 4C within 2 hours. A sensor-controlled chiller ensures FSSAI compliance and fetches premium prices at cooperative procurement centres.

Why Rapid Chilling Matters

Bacteria double every 20 minutes at body temperature. Chilling to 4C slows growth 100-fold. Unchilled milk sours within 6 hours in Indian summer, representing complete loss of value.

FSSAI Standards

FSSAI mandates 4C within 2 hours. DS18B20 waterproof probe in milk container provides continuous monitoring. Log time-temperature profile on SD card for compliance documentation.

Building the Controller

Arduino controls compressor relay based on DS18B20 reading. Target 4C with 0.5C hysteresis to prevent cycling. Buzzer alerts when target reached.

Sensor Integration

DS18B20 through sealed grommet in milk container. Second DS18B20 in coolant circuit for efficiency monitoring. DHT22 for ambient temperature logging.

Bulk vs Immersion Chiller

Modified refrigerator: copper coil in milk container connected to existing compressor. Rs 3,000-5,000 modification. Or immersion chiller for multiple small containers.

ROI for Small Dairies

Chilled milk premium: Rs 2-4/litre. 30 litres daily = Rs 60-120/day = Rs 1,800-3,600/month additional income. System pays for itself in 1-2 months.

Frequently Asked Questions

Storage temperature?

4C per FSSAI. DS18B20 provides continuous monitoring.

Modified refrigerator?

Yes. Copper coil + compressor in milk container. Rs 3,000-5,000.

Premium for chilled milk?

Rs 2-4/litre at cooperatives. Rs 1,800-3,600/month for 30L daily production.

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