In the modern food industry, quick-freezing and cold storage technology is the core method to ensure that meat, aquatic products, and agricultural goods remain fresh from origin to table. However, as the “lifeblood” of refrigeration systems, liquid ammonia, Freon, and liquid nitrogen used for ultra-low temperature freezing pose significant safety hazards while providing low-temperature environments.

Once refrigeration pipelines suffer corrosion, aging, or physical impact leading to leakage, it can not only destroy high-value stored goods but also cause poisoning, chemical burns, or even explosion accidents. Nexisense focuses on gas sensing technology for the refrigeration industry, using intelligent monitoring systems to confine invisible refrigerant leakage risks within a “safe cage.”

Ice-Beneath Hazards in the Quick-Freezing and Cold Storage Industry: Core Gases Analysis

1. Liquid Ammonia (NH3): Efficient Yet Dangerous Refrigerant

Liquid ammonia is widely used in medium and large cold storage facilities due to its high refrigeration efficiency and low cost. However, ammonia gas is highly irritating and corrosive.

• Health Hazards: Even extremely low concentrations can irritate the respiratory tract. High-concentration inhalation may cause pulmonary edema, suffocation, or even death.

• Physical Injury: Skin contact can cause severe chemical burns and frostbite.

• Explosion Risk: The explosive limit of ammonia in air is 15% - 28%. In enclosed spaces, it can easily trigger secondary disasters.

2. Freon: Invisible Greenhouse and Asphyxiation Risk

Small and medium-sized cold storage facilities commonly use R22, R134a, and R404A refrigerants. Although colorless and odorless, large leaks can displace oxygen inside chambers, causing unconscious suffocation. They also contribute to ozone layer depletion.

3. Liquid Nitrogen (LN2): Oxygen Deficiency Risk from Rapid Freezing

During operation or discharge of liquid nitrogen quick-freezing machines, large amounts of nitrogen gas rapidly dilute oxygen in localized spaces. If ventilation is insufficient and oxygen concentration drops below 19% Vol, operators face life-threatening risks.

Nexisense Product Matrix for the Quick-Freezing and Cold Storage Industry: Multi-Dimensional Safety Protection

For the special working conditions of high humidity, low temperature, and enclosed environments in cold storage, Nexisense has built a closed-loop monitoring system from fixed online detection to portable inspection.

Fixed Sentinel: SGA-500 Series Online Liquid Ammonia/Refrigerant Detector

This is the core monitoring device for machine rooms and cold chambers:

• Original imported sensors: High-precision electrochemical or infrared sensors with excellent repeatability and 3–5 years service life.

• Low-temperature resistant design: Specially compensated circuit design ensures stable operation in -40°C cold storage without data drift due to cold.

• Intelligent linkage interface: Equipped with relay outputs to directly link spray systems (to absorb ammonia), forced ventilation fans (to dilute concentration), or solenoid valves (to shut off leakage sources).

  
  

Inspection Tool: SGA-600 Series Portable Liquid Ammonia Detector

Suitable for equipment maintenance and daily inspection:

• Multiple sampling modes: Portable diffusion type (wearable), pump-suction type (remote sampling), and probe type (deep gap detection).

• High-decibel alarm: Ensures operators clearly receive alarm signals even under the high background noise of refrigeration units.

Central Brain: SGA-800 Series Gas Alarm Controller

Installed in cold storage monitoring rooms or guard rooms:

• Multi-point aggregation: Real-time display of concentration values from each cold room and machine room.

• Black box recording: Automatic storage of alarm records for accident tracing and safety compliance audits.

Intelligent Linkage: Nexisense Emergency Response Logic

In the quick-freezing and cold storage industry, merely “alarming” is not enough—rapid emergency response is key to loss reduction. Through SGA-500, Nexisense achieves three-level linkage:

1. Warning Level (Low Alarm): When ammonia concentration reaches 25ppm, the ventilation system automatically starts to dilute concentration while the monitoring room issues an alert to inspect pipelines.

2. Mandatory Level (High Alarm): When concentration exceeds 50ppm, the system forcibly activates the automatic spray system. Utilizing ammonia’s high solubility in water for physical absorption, air toxicity is reduced while cutting off the refrigeration main pump power.

3. Personnel Protection Level: On-site sound and light alarms are fully activated, notifying all personnel to evacuate via designated routes.

Why Do Cold Chain Leaders Choose Nexisense?

1. High humidity condensation resistance: Frequent door opening in cold storage leads to condensation. Nexisense probes are coated with conformal coating and hydrophobic structural design to prevent short circuits from moisture.

2. Rapid response: For sudden ammonia leaks, sensor T90 response time is less than 20 seconds, much faster than industry average.

3. Compliance: Meets national fire protection and ammonia refrigeration safety standards, supporting fire acceptance inspection.

4. Low maintenance cost: Supports intelligent module quick replacement without requiring professional gas calibration technicians.

   
   

In-Depth Analysis and Frequently Asked Questions (FAQ)

Q1: Cold storage environments typically range from -20°C to -40°C. Ordinary sensors may fail due to freezing. How does Nexisense solve this?
A1: Nexisense adopts dual extreme-temperature protection, including optional built-in heating modules and special anti-freeze electrolytes, ensuring instant and accurate response even at -40°C.

Q2: Ammonia (NH3) is highly corrosive. How does the detector resist long-term exposure?
A2: With anti-corrosion polymer coating, nano-level conformal coating, 316L stainless steel housing, and hydrophobic filter membranes, Nexisense effectively blocks ammonia corrosion and extends service life.

Q3: Why install both low and high range ammonia detectors in machine rooms?
A3: Low range (0–100ppm) detects micro leaks for personnel safety. High range (0–1000ppm or 0–100% LEL) supports explosion prevention. Nexisense integrates both ranges for tiered alarms.

Q4: How to prevent condensation-related false alarms?
A4: Using asymmetric breathable structure, PTFE hydrophobic membrane, and signal filtering algorithms to ensure alarm accuracy.

Q5: What is the spray linkage logic?
A5: Level 1 activates ventilation; Level 2 triggers automatic spray via solenoid valve; water mist dissolves ammonia and prevents spread.

Q6: How should SGA-600 be configured in logistics vehicles?
A6: Pump-suction type with one-key self-test is recommended. Sampling before door opening prevents accidental exposure.

Q7: Can ammonia and CO2 be monitored simultaneously?
A7: Yes. Nexisense supports multi-gas monitoring including NH3, CO2, and O2 using NDIR infrared sensors for CO2.

Q8: How to handle compliance inspections?
A8: Equipment includes certification reports and explosion-proof certificates, with one-click data export for audit traceability.

Conclusion

Gas monitoring in the quick-freezing and cold storage industry is a technological battle against low temperature, humidity, and toxicity. With the excellent cold resistance of the SGA series and intelligent linkage logic, Nexisense builds an invisible safety firewall across every link of the cold chain.

Has your cold storage system passed the latest safety compliance inspection? Contact Nexisense professional engineers for 1V1 technical selection services from machine room layout to automated spray linkage, enabling safe and cost-efficient cold chain operations.