I have an existing central air conditioning unit and the line dryers on the liquid and suction lines have been replaced recently, do the arrows on the side of the line dryers have a particular meaning, such as they indicate the direction of flow of the liquid and/or suction lines?

Liquid points to inside with flow. Suction points to the outside with flow. This is on a strait A/C system only.

A heat pump drier that points each way on the liquid line will work fine with A/C only also.