OnlyKem Smart Packaged Refrigeration System for Reliable Cold Room Performance

One Coordinated System for Cold Room Applications

A cold room refrigeration system should not be evaluated only by the compressor or the outdoor unit. System control, refrigerant regulation, defrosting, temperature sensing, protection and service access all affect long-term performance. OnlyKem Smart Packaged Units are developed as a coordinated system for these requirements.

1. Mid- and Low-Temperature Options

OnlyKem provides different configurations for cold storage applications. The documented operating ranges are:

• Mid-temperature: +10°C to -18°C;

• Low-temperature: +5°C to -30°C;

• Nominal capacity range: 3 HP to 15 HP;

• Pre-charged refrigerant: R404A, according to the documented series configuration.

The final refrigerant and operating condition should be confirmed according to the destination market, equipment model and project requirements.

2. Dual EXV Control for More Accurate Refrigeration Regulation

The system uses electronic expansion valve control. In low-temperature configurations, dual EXV control supports the main refrigeration circuit and the low-temperature refrigerant injection function. This helps regulate refrigerant flow and supports compressor protection under demanding operating conditions.

Compared with a basic fixed-control arrangement, the dual-EXV configuration provides more control points for system adjustment. It is suitable for projects that require stable operation across changing loads.

3. Intelligent Hot-Gas Defrost on Demand

The system supports intelligent hot-gas defrost on demand. The four-way reversing valve can change the refrigerant circulation direction to accelerate defrosting. This helps reduce temperature fluctuation in the cold room and limit the impact on stored products during the defrost cycle.

The system also records operating data before defrosting and uses it as a reference for the next defrost cycle, helping the unit return to the target refrigeration condition more quickly.

4. Multiple Sensors, Self-Diagnosis and Safety Protection

The documented system includes at least seven sensors. More operating data allows the controller to regulate the system more precisely. The sensors are designed to be interchangeable according to the documented configuration.

The intelligent control system can provide:

• Fault self-diagnosis;

• Intelligent alarm and fault codes;

• MOP control with maximum and minimum temperature limits based on compressor performance;

• Protection against liquid slugging when superheat is too low;

• Automatic restart after a power outage when electricity is restored.

These functions help make troubleshooting more direct and can reduce unnecessary maintenance time and downtime.

5. Air Cooler Designed for Heat Exchange and Drainage

The unit cooler uses internally threaded copper pipes to increase the heat exchange area. The coils are arranged along the airflow direction with an interleaved copper pipe layout to support airflow and heat exchange.

The cooler also features a two-layer drain pan. One layer helps block air bypass and improve return-air exchange efficiency. The other layer collects defrost water and supports the heating pipe. Together, the two layers help with:

• Faster drainage;

• Reduced air leakage through the gap;

• Heating pipe support during defrosting.

The documented cooler configuration also includes a copper drain connection designed for low-temperature conditions.

6. Protection Against Corrosion in Cold Room Environments

Cold rooms are exposed to moisture, low temperatures and repeated defrosting. OnlyKem product materials specify stainless steel for the water box, drain pipe and unit cooler drain pan. Stainless steel screws, galvanized sheet metal with outdoor coating and corrosion-protected copper tubes are also used in the documented design.

The structure uses rivet nuts or screw-and-washer connections to reduce damage to the sheet-metal coating during assembly and maintenance. This supports a more durable equipment structure in humid operating environments.

7. A Complete Configuration Rather Than a Single Component

The documented packaged system configuration includes key refrigeration and protection components such as:

• Compressor;

• Condenser and condenser fan;

• Suction accumulator;

• Receiver and oil separator;

• Filter drier and sight glass;

• Low-pressure sensor and high-pressure switch;

• Current transformer;

• Main EXV and refrigerant-injection EXV;

• Intelligent controller and temperature sensors;

• AC contactor;

• Unit cooler.

A complete configuration helps the customer evaluate the system as a whole, instead of separately coordinating multiple suppliers for core components.

Why Choose OnlyKem Smart Packaged Units?

OnlyKem focuses on coordinated system design, not just individual refrigeration components. The main advantages include dual EXV regulation, intelligent hot-gas defrost, multiple sensors, fault self-diagnosis, automatic restart, corrosion-resistant details and pre-factory commissioning.

Optional solutions can include remote monitoring, a DC inverter refrigeration proposal and an exclusive design based on the customer’s application.

If you are planning a new cold room, please send us the room dimensions, product type, target temperature, local voltage, ambient conditions and destination country. OnlyKem can review the requirements and recommend a suitable packaged refrigeration configuration.

**Contact OnlyKem for a complete cold room refrigeration solution built around your project.