The Secop SC18CL (formerly managed under the Danfoss brand) is a heavy-duty, hermetic reciprocating compressor widely utilized in commercial refrigeration. Engineered for high reliability, it is specifically designed to handle low and medium back pressure demands under demanding ambient conditions.

Here is a detailed breakdown of its applications, technical functionality, and core mechanical features.

1. Core Applications

The SC18CL is designated as an LBP/MBP (Low Back Pressure / Medium Back Pressure) compressor. It operates within an evaporating temperature range of -45°C to -5°C (-49°F to 23°F), making it highly versatile for freezing and medium-temp preservation.

Primary Equipment Deployments:

• Commercial Freezers & Coolers: Large reach-in storage freezers, display cabinets, and supermarket island freezers.

• Gastronomy & Commercial Kitchens: Professional catering fridges, blast chillers, preparation tables, and ice cream makers/slush machines.

• Ice Makers: Professional cube and flake ice machines that require sustained low-temperature operation.

• Medical & Laboratory Cooling: Low-temperature storage units for biomedical samples, vaccines, and laboratory reagents requiring strictly controlled conditions.

• Small Condensing Units: Acts as the primary drive unit for custom-built or pre-assembled remote condensing systems.

2. Technical Functionality & Electrical Design

The functionality of the SC18CL is rooted in its robust motor configuration and specific mechanical parameters optimized for high-density refrigerants.

Motor Configuration: CSCR (Capacitor Start, Capacitor Run)

The SC18CL utilizes a CSCR motor system (also referred to as CSR).

• High Starting Torque (HST): It incorporates a starting relay and an 80µF start capacitor paired with a 10µF run capacitor. This setup generates a powerful initial torque, allowing the compressor to start smoothly even under high differential pressures (e.g., when restarting shortly after a cycle cutout or when utilizing expansion valves).

• Energy Efficiency: Once running, the run capacitor optimizes current consumption and phase angle, keeping the running current around 3.7A to 4.2A under load.

Displacement and Pumping Mechanism

• Displacement: It features a large cylinder displacement of 17.69 cm³ (1.08 cu.in.).

• Compression Type: It uses a traditional reciprocating piston assembly running at a fixed speed of 2900 RPM (at 50Hz). This displacement size enables strong mass flow rates required to pull down temperatures rapidly in commercial environments.

Thermal & Coolant Dynamics

• Refrigerant Compatibility: Tailored specifically for R404A and R507—refrigerants known for efficient low-temperature heat transfer but notorious for high operating pressures. It is also rated for R452A in specific newer variants.

• Oil System: Pre-charged with 550cc to 600cc of Polyolester (POE) oil (viscosity: 32 cSt). POE oil is highly miscible with HFC refrigerants like R404A, ensuring proper oil return from the evaporator back to the crankcase to protect the moving parts.

• Forced Cooling Requirement: Due to the heat generated during low-temp compression of R404A, the SC18CL relies on Fan Cooling (F2 rating). It requires a continuous airflow of 3.0 m/s across the compressor shell to dissipate heat and prevent the internal motor windings from overheating.

3. Key Technical Specifications Summary

Feature / Parameter	Specification Details
Power Supply	220–240V / 50Hz / Single Phase
Nominal Power	Approximately 5/8 HP
Evaporating Temperature Range	-45°C to -5°C
Cooling Capacity Example (ASHRAE LBP)	~803 W at standard check conditions
Locked Rotor Amps (LRA)	20.4 A
Rated Load Amps (RLA)	~4.2 A
Max. Refrigerant Charge Limit	1300g
Net Weight	13.8 kg (without electrical components)
Connectors (Suction / Discharge / Process)	Suction: 10.2 mm | Discharge: 6.2 mm | Process: 6.2 mm (All copper)

Disclaimer: A write up with the helps of Gemini.