Enhanced Vapor Injection (EVI) Technology: Boosting Refrigeration Efficiency in Electric Trucks

Enhanced Vapor Injection (EVI) technology has emerged as a critical innovation in transport refrigeration, offering significant performance improvements over conventional cycles.

The vapor-compression cycle uses four main components: compressor, condenser, expansion valve, and evaporator. The compressor draws low-pressure vapor from the evaporator, compresses it, and discharges to the condenser.

EVI is an advanced compressor technology that injects refrigerant vapor at intermediate pressure into the compression chamber. This boosts mass flow rate without requiring larger displacement, and reduces discharge temperature by cooling during compression.

• Enhanced low-temperature performance: EVI maintains higher capacity at evaporating temperatures of -20C and below, essential for frozen food transport.
• Improved energy efficiency: COP can be 15 to 25 percent higher than single-stage systems, extending battery range for electric trucks.
• Wider operating envelope: Reduced discharge temperature protects the compressor, extending component life.
• Faster pulldown: Increased mass flow reduces compartment temperature more quickly after door openings.

The NEWBASE NBESR-1000A and NBSRE520 incorporate EVI in their variable-frequency compressors (HIGHLY DTE752LKTQ9JK and DTH356). Combined with DC inverter drive, EVI enables rapid cooling while maintaining low power consumption in insulation mode.

EVI implementation requires an additional expansion device and flash tank arrangement. Control algorithms must coordinate main and injection valves. Despite complexity, the performance benefits make EVI increasingly standard in high-performance transport refrigeration.