Welcome to the forum.
I had this, sounds like water sloshing and gurgling about under the dash. It was air entering the cooling system via a leak on the stat housing. New stat, stat housing, water pump, coolant drain, flush then refill and most importantly of all - bleed the cooling system to prevent air locks cured the noise.
Or it could be the refrigerant as you say trying to flow around the air con pipes. You can go to or get a mobile air con specialist out to your car to check it out for you.
Have you just started using the air con after the winter? Could just be lack of lubricant thru the system caused by long periods of no use over the winter which is preventing the valves from opening and closing properly. Again an air con specialist can add oil into the refrigerant.
HTH
Andrew