Accumulator for heat pump systems

An accumulator for a heat pump system, the accumulator comprising:

• a u-tube mounted within a housing, the u-tube comprising:
• an inlet section at a first distance from a floor of the housing and having an opening within the housing;
• an outlet section at the first distance from the floor of the housing and having an opening mounted in an outlet opening in the housing;
• and
• a u-shaped section that fluidly couples the inlet section to the outlet section and extends to a second distance from the floor, the second distance less than the first distance.

A method, comprising:

• providing a vaporized refrigerant into a horizontal inlet section of a u-tube of an accumulator of a heat pump system;
• providing oil into the u-tube via an orifice in a substantially vertical u-shaped section of the u-tube that fluidly couples the horizontal inlet section of the u-tube to a horizontal outlet section of the u-tube;
• and
• providing the vaporized refrigerant mixed with at least some of the oil through the horizontal outlet section of the u-tube.