Refrigeration System

NH₃ (Ammonia, R717): The industry standard for industrial refrigeration. Highest thermodynamic efficiency of any common refrigerant. GWP = 0, ODP = 0. Low cost per kg. Classified as B2L (toxic, mildly flammable) — requires safety systems per EN 378. Best for: large systems, low-temperature applications, facilities with existing NH₃ infrastructure.

CO₂ (R744): Growing adoption driven by safety and regulatory trends. Non-toxic, non-flammable (A1 classification). GWP = 1. Excellent low-temperature performance. Higher operating pressures (~40 bar at −5°C vs ~3 bar for NH₃). Best for: facilities where ammonia charge quantity is restricted, indoor equipment rooms, cascade systems with NH₃ on the high side.

Cascade NH₃-CO₂: NH₃ on the high-temperature side, CO₂ on the low-temperature side. Combines NH₃ efficiency with CO₂ safety in occupied spaces. NH₃ charge contained in machinery room; CO₂ circulated to production areas.

Square selects compressor type based on your capacity and operating conditions:

• Screw compressors: 200 kW–2+ MW per unit. Variable Vi (built-in volume ratio) maintains efficiency at part load. Ideal for medium-to-large systems with varying loads.
• Reciprocating compressors: 50–300 kW per unit. Excellent part-load efficiency via cylinder unloading. Ideal for smaller systems or where load varies widely.

For facilities with variable production, we configure compressor sequencing and VFD control to maintain efficiency across the full operating range, not just at design conditions.

Industrial refrigeration systems reject large amounts of heat through the condenser. Much of this heat can be recovered:

• Desuperheater: recovers high-grade heat from compressor discharge gas (70–90°C) for facility hot water
• Oil cooling heat reclaim: compressor oil cooling heat used for underfloor heating or pre-heating
• Condenser heat: lower-grade heat (25–35°C) usable for space heating or defrost water pre-heating
• Typical energy savings: 15–30% reduction in facility heating costs

Ammonia refrigeration systems require comprehensive safety design per EN 378 (Europe) or ASHRAE 15 / IIAR (North America):

• Continuous gas detection: NH₃ sensors with 25 ppm warning, 150 ppm emergency ventilation activation
• Emergency ventilation: mechanical ventilation rated for 30 air changes/hour on gas detection
• Relief valve discharge: piped to safe location, calculated per EN 13136 / ASHRAE 15
• Emergency shutdown: multiple push-button stations, automatic on high gas concentration
• Machinery room design: gas-tight construction, outward-opening doors, external light switches

Square provides complete installation supervision and commissioning:

• Factory-assembled skids reduce on-site work by 40–60%
• Installation by Square’s 200-person global team or supervised local contractor
• Pressure testing, evacuation, and refrigerant charging per procedure
• Full commissioning: performance verification at design conditions
• Operator training: system operation, safety procedures, daily checks
• Documentation: P&ID, electrical schematics, safety manual, maintenance schedule