Refrigeration Industry – Reefer & Cold-Chain Sensors

Kjærulf Pedersen a/s provides advanced sensor technology for the refrigeration industry. With extensive experience in reefer containers (refrigerated intermodal containers), we deliver solutions that ensure reliable temperature and humidity monitoring, USDA-compliant cold-chain control, and atmosphere management with CO₂ and O₂ sensors for both Controlled Atmosphere (CA) and Modified Atmosphere (MA) transport. Our sensors are designed for seamless RS485/Modbus integration across refrigeration applications including containers, truck & trailer units, cold stores and retail cooling.

Reefer containers and refrigeration industry sensors – Kjærulf Pedersen a/s

Reefers (Refrigerated Intermodal Containers)

A reefer — also called a refrigerated intermodal container — is essential for transporting temperature-sensitive cargo across sea, rail and road. All reefers rely on accurate temperature and humidity sensing, while Controlled Atmosphere (CA) and Modified Atmosphere (MA) containers add CO₂ and O₂ monitoring to optimize cargo quality and shelf life. Kjærulf Pedersen a/s delivers proven sensor solutions for reefer applications, designed for RS485/Modbus integration, long-term durability and reliable operation in demanding environments.

Reefer containers (refrigerated intermodal containers) stacked in a shipping terminal – Kjærulf Pedersen a/s

Sensors for Reefer Containers (Featured Products)

KP-RHRC humidity sensor for refrigerated containers and controlled atmosphere shipping. Prevents condensation, supports RS485 Modbus, and ensures cargo safety.

Humidity Sensor

Monitors relative humidity in reefer containers, enabling control systems to maintain optimal moisture levels and protect cargo quality during cold-chain transport.

USDA insertion temperature probe for reefer containers – Kjærulf Pedersen a/s

USDA Sensor

Provides direct temperature monitoring inside perishable goods with an insertion probe, ensuring USDA-compliant cold-chain integrity.

KPCO2 CO2 sensor for refrigerated containers, controlled atmosphere monitoring, and reefer units. Features NDIR detection and RS485 Modbus integration.

CO₂ Sensor

Monitors CO₂ levels in CA/MA reefers to extend shelf life and maintain optimal cargo conditions.

O2 sensor for refrigerated container (O2-LQ) using Luminescence Quenching technology, ideal for accurate oxygen monitoring in reefer containers and controlled atmosphere transport.

O₂ Sensor

Measures oxygen in CA/MA reefers using advanced Luminescence Quenching (LQ) for precise, low-drift, low-maintenance monitoring.

TempMux-8 multipoint temperature sensor with Modbus RTU for industrial and marine applications

TempMux-8 Module

Combines up to 8 PT1000 sensors into a single Modbus RS485 output, reducing wiring and installation effort while adding diagnostics and averaging.

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Integration & Approvals

Kjærulf Pedersen a/s sensors are designed for easy integration into reefer container control systems and long-term durability in demanding environments:

  • RS485 / Modbus RTU communication for seamless integration

  • Compatible with reefer unit monitoring and control software

  • Designed for harsh environments: vibration, temperature fluctuations, humidity, salt exposure

  • Reliable long-term performance with minimal recalibration and maintenance

Frequently Asked Questions – Reefer Sensors

A reefer is a refrigerated intermodal container used to transport temperature-sensitive cargo across sea, rail, and road.

No. Standard reefer containers are equipped with temperature (and often humidity) sensors. CO₂ and O₂ sensors are only used in Controlled Atmosphere (CA) or Modified Atmosphere (MA) reefers, where the internal gas mix is actively managed.

Kjærulf Pedersen a/s sensors use RS485 / Modbus RTU, ensuring seamless integration with reefer unit control systems for real-time monitoring.

Luminescence Quenching (LQ) sensors measure oxygen optically instead of using a heated zirconia cell. In reefer containers this means lower power consumption, stable readings with minimal drift, and reduced maintenance or recalibration — ensuring reliable atmosphere control during long voyages and fleet operation.

Multipoint monitoring is used to capture temperature variations in different parts of the container. A digital module like TempMux-8 reduces wiring, simplifies installation, and provides status and averaging for more reliable control and diagnostics.

Modified Atmosphere (MA) is a one-time gas adjustment at loading, typically reducing oxygen and adding CO₂ or nitrogen. The atmosphere is not actively controlled afterwards, making MA suitable for short to medium voyages. Controlled Atmosphere (CA) continuously monitors and regulates oxygen, CO₂, humidity, and sometimes ethylene levels throughout the voyage. CA maintains a stable atmosphere over long intercontinental shipments and significantly extends cargo shelf life.

Other Refrigeration Applications

Our sensor technology also applies in truck & trailer units, cold stores, retail counters, and cooling compressors.

Truck & Trailer Refrigeration

Truck & Trailer → Refrigerated truck and trailer units for temperature-controlled transport – Kjærulf Pedersen a/s

Cold Stores & Warehouses

Cold Stores → Cold storage warehouses with refrigeration units for frozen and chilled goods – Kjærulf Pedersen a/s

Counters, Shelves & Islands

Counters → Supermarket refrigeration counters, shelves and island coolers – Kjærulf Pedersen a/s

Cooling Compressors

Compressors → Industrial cooling compressors for refrigeration systems – Kjærulf Pedersen a/s

Talk to Us About Refrigeration & Reefer Sensors

Kjærulf Pedersen a/s delivers sensor solutions for the refrigeration industry — from refrigerated containers (reefers) to truck & trailer units, cold stores, retail counters and industrial cooling. Our portfolio covers temperature, humidity, CO₂, O₂ and multipoint monitoring, designed for reliable integration and long-term performance.

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Contact Us →

Kjærulf Pedersen a/s | Taastrupgaardsvej 8-10 | DK-2630 Taastrup | Tlf.: +45 39 76 02 03 | sales@kp-as.com