Which of the following is NOT a component of a basic air-cycle cooling system?

The basic components of an air-cycle cooling system include a compressor, a turbine, heat exchangers, and sometimes an evaporator, depending on the system's design and cooling requirements. In a standard air-cycle cooling system, the function of the evaporator is not typically part of the cycle. Instead, the primary purpose of this system is to cycle compressed air through the components to achieve temperature control effectively.

The compressor is essential as it increases the pressure of the incoming air, while the turbine expands the compressed air, which results in a drop in temperature. Heat exchangers facilitate the transfer of heat between incoming and outgoing air streams, thereby enhancing the cooling process. Together, these elements work to provide a continuous cooling cycle. Therefore, the evaporator, while used in some other cooling systems, is not a core component in a basic air-cycle cooling system.