Environmental control systems for an aircraft having a vapor compression system with a flash liquid expander turbine

An environmental control system (ECS) of an aircraft for delivering ECS supply air to a cabin, the system comprising:

• an ECS controller;
• a first mixer that is operationally coupled to the ECS controller, the first mixer receives the ECS supply air;
• a first vapor cycle system (VCS) that is downstream of the first mixer and fluidly coupled to the first mixer, wherein,
• the first VCS includes:
• a first working fluid;
• a first compressor;
• a first condenser located downstream of the first compressor;
• a first turbine that is a flash liquid expander (FLE) turbine, located downstream of the first condenser, that receives the first working fluid as a liquid and outputs the first working fluid as a two-phase mixture;
• a first interconnecting shaft coupling the first compressor and the first turbine;
• a first evaporator located downstream of the first turbine and upstream of the first compressor;
• a second mixer located downstream of the first VCS and operationally coupled to the ECS controller;
• and
• a bypass connected in parallel with the first VCS, between the first mixer and the second mixer,
• wherein, in operation:
• the ECS controller, in predetermined operational conditions, controls the first mixer to direct the ECS supply air to the second mixer via one or both of the first VCS and the bypass;
• and
• the second mixer directs the ECS supply air to the cabin.