What description fits a unit that uses axial propeller fans and a gas-powered suction outlet control valve?

A unit that utilizes axial propeller fans and a gas-powered suction outlet control valve is best described as a pumped liquid evaporator.

In this context, the axial propeller fans are important for moving air over the evaporator coils, which helps to facilitate the heat exchange process. The use of a gas-powered suction outlet control valve indicates that the system is designed to manage the flow of refrigerant efficiently, particularly in response to the cooling demands. This type of operation is characteristic of a pumped liquid evaporator system, where the liquid refrigerant is pumped through the evaporator, absorbing heat and turning into a gas for cooling purposes.

While the other options incorporate elements of refrigeration systems, they don't specifically match the combination of features presented in the question. A liquid evaporator typically does not use axial fans as its main air-moving mechanism, an air-cooled condenser primarily involves heat rejection rather than absorption, and a chilled water system functions on a different principle involving chilled water circulation rather than direct refrigerant evaporation within the air stream. Therefore, the combination of axial fans and a gas-powered control valve is unique to the functionality seen in pumped liquid evaporators.