A device under test cooling system has a refrigerant line and a fluid line extending through a plurality of successively arranged heat exchangers. A digital scroll compressor has an intake for providing the refrigerant mixture to the compressor and a discharge connecting the compressor to the refrigerant line to provide the refrigerant mixture to the heat exchangers. The compressor includes a plurality of scroll elements between the intake and the discharge for compressing the refrigerant mixture. The compressor includes a valve configured to separate the scroll elements when in an open position to allow refrigerant to flow freely between the intake and the discharge. When the valve is in a closed position, the scroll elements compress the refrigerant. A controller is configured to switch the valve between an open and closed position based on a set duty cycle.