Vapor cycle air-conditioning system

ram air, which is dependent on aircraft speed. Figure 3-12 is a schematic diagram of the VEA6-1 vapor cycle ACS. In the E-2 configuration, the vapor cycle system cools, filters, and distributes avionics compartment air at a temperature of 38°±5°F. The system consists of a vapor cycle cooling scoop assembly, an evaporator group assembly, and air distribution ducting interconnected by refrigerant lines and electrical wiring. The evaporator assembly (fig. 3-13) is a compact, quick-change package that can be easily installed, removed, and serviced as a unit. The assembly is composed of five quick-dis- connect couplings; two shock mounts; tem- perature controls; a hydraulic, motor-driven, self-lubricating Freon compressor; a receiver; a subcooler; a thermostatic expansion valve; an evaporator; hydraulic motor-driven fan; and an oil separator. The vapor cycle cooling scoop assembly is mounted on the top of the fuselage and consists of a condenser assembly, ejector nozzles, an actuator and flap, and a refrigerant pressure actuator control switch. The Freon 12 in the closed system is the primary coolant. The forced air that is drawn through the evaporator in a continuous cycle is the secondary coolant. The electronic equipment is cooled by the secondary coolant, which removes heat by direct contact with the equipment to be Figure 3-12.—Vapor cycle air-conditioning system. 3-18