Oil management in refrigeration systems

A refrigeration assembly comprising:

• a receiver tank comprising:
• an interior volume configured to enclose a first working fluid;
• an inlet port configured to conduct the first working fluid into the interior volume;
• and
• an outlet port configured to conduct the first working fluid out of the interior volume;
• a heat exchanger disposed within the receiver tank, the heat exchanger configured to direct a second working fluid through the receiver tank, the heat exchanger comprising:
• a coiled tubing configured to fluidly decouple the second working fluid from the first working fluid in the interior volume, the coiled tubing comprising a first end and a second end;
• a fluid inlet configured to couple to and receive the second working fluid from a supply line;
• a first piping assembly disposed within the receiver tank, the first piping assembly positioned between the fluid inlet and the first end of the coiled tubing, the first piping assembly comprising a first double riser and a first P-trap, the first double riser comprising:
• a first riser fluidly coupled to the fluid inlet and the first end of the coiled tubing, the first riser configured to flow the second working fluid from the fluid inlet to the first end of the coiled tubing;
• and
• a second riser fluidly coupled to the fluid inlet and the first end of the coiled tubing by the first P-trap, the second riser downstream of the first P-trap, the second riser configured to flow the second working fluid from the fluid inlet to the first end of the coiled tubing;
• a fluid outlet configured to couple to and conduct the second working fluid to a return line;
• and
• a second piping assembly disposed within the receiver tank, the second piping assembly positioned between the fluid outlet and the second end of the coiled tubing, the second piping assembly comprising a second double riser and a second P-trap, the second double riser comprising:
• a third riser fluidly coupled to the second end of the coiled tubing and the fluid outlet, the third riser configured to flow the second working fluid from the second end of the coiled tubing to the fluid outlet;
• and
• a fourth riser fluidly coupled to the second end of the coiled tubing and the fluid outlet by the second P-trap, the fourth riser downstream of the second P-trap, the fourth riser configured to flow the second working fluid from the second end of the coiled tubing to the fluid outlet.