An assembly set including a drip tray and a fan assembly, wherein the assembly set is configured to be provided in a machine compartment of a refrigerator, wherein the fan assembly includes: a fan configured to generate air flow by rotation thereof; and a frame configured to support the fan; wherein the drip tray includes: a bottom panel; an outer wall extending upwardly from the bottom panel; an opening defined at the outer wall; an inner wall extending upwardly from the bottom panel, wherein the inner wall is connected to the outer wall at the opening and extends inward from the outer wall so that the outer wall and the inner wall form a closed loop; a water storage space defined by the closed loop and the bottom panel; a fan assembly mounting space defined by a space surrounded by the inner wall and the opening, in which at least a portion of the fan assembly is mounted; wherein the opening is laterally and outwardly open to communicate with the fan assembly mounting space; wherein the fan assembly is configured to be at least partially inserted into or withdrawn out of the fan assembly mounting space through the opening; and wherein the inner wall is configured to guide insertion of the frame of the fan assembly laterally into the fan assembly mounting space, wherein the inner wall includes a first inner wall and a second inner wall, and both extend in a direction parallel to a short side of the bottom panel, and a third inner wall that connects distal ends of the first and second inner walls to each other, characterized in that the inner wall supports the fan assembly when the fan assembly is received in the fan assembly mounting space, and the fan assembly is configured to be guided in the length direction along the first and second inner walls of the fan assembly accommodation space. a fan configured to generate air flow by rotation thereof; and a frame configured to support the fan; a bottom panel; an outer wall extending upwardly from the bottom panel; an opening defined at the outer wall; an inner wall extending upwardly from the bottom panel, wherein the inner wall is connected to the outer wall at the opening and extends inward from the outer wall so that the outer wall and the inner wall form a closed loop; a water storage space defined by the closed loop and the bottom panel; a fan assembly mounting space defined by a space surrounded by the inner wall and the opening, in which at least a portion of the fan assembly is mounted; wherein the opening is laterally and outwardly open to communicate with the fan assembly mounting space; wherein the fan assembly is configured to be at least partially inserted into or withdrawn out of the fan assembly mounting space through the opening; and wherein the inner wall is configured to guide insertion of the frame of the fan assembly laterally into the fan assembly mounting space, wherein the inner wall includes a first inner wall and a second inner wall, and both extend in a direction parallel to a short side of the bottom panel, and a third inner wall that connects distal ends of the first and second inner walls to each other, characterized in that the inner wall supports the fan assembly when the fan assembly is received in the fan assembly mounting space, and the fan assembly is configured to be guided in the length direction along the first and second inner walls of the fan assembly accommodation space.