A ventilation system including a building having a space inside, a subterranean facility arranged in a basement of the building and having a subterranean space inside, a communication passage establishing communication between the space and the subterranean space, and a ventilation hole establishing communication between an earth outside the building and the subterranean space is provided. A fuel cell unit having an exhaust port is arranged in the subterranean space. The communication passage has a lateral wall protruding downward from a ceiling of the subterranean space. The lateral wall is arranged on the exhaust port side when the communication passage is arranged on a straight line linking the exhaust port and a second opening portion of the ventilation hole on the subterranean space side. The lateral wall is arranged on the straight line side when the communication passage is arranged at a position spaced apart from the straight line.

A ventilation system including a building having a space inside, a subterranean facility arranged in a basement of the building and having a subterranean space inside, a communication passage establishing communication between the space and the subterranean space, and a ventilation hole establishing communication between an earth outside the building and the subterranean space is provided. A fuel cell unit having an exhaust port is arranged in the subterranean space. The communication passage has a lateral wall protruding downward from a ceiling of the subterranean space. The lateral wall is arranged on the exhaust port side when the communication passage is arranged on a straight line linking the exhaust port and a second opening portion of the ventilation hole on the subterranean space side. The lateral wall is arranged on the straight line side when the communication passage is arranged at a position spaced apart from the straight line.

A ventilation system including a building having a space inside, a subterranean facility arranged in a basement of the building and having a subterranean space inside, a communication passage establishing communication between the space and the subterranean space, and a ventilation hole establishing communication between an earth outside the building and the subterranean space is provided. A fuel cell unit having an exhaust port is arranged in the subterranean space. The communication passage has a lateral wall protruding downward from a ceiling of the subterranean space. The lateral wall is arranged on the exhaust port side when the communication passage is arranged on a straight line linking the exhaust port and a second opening portion of the ventilation hole on the subterranean space side. The lateral wall is arranged on the straight line side when the communication passage is arranged at a position spaced apart from the straight line.

A ventilation system including a building having a space inside, a subterranean facility arranged in a basement of the building and having a subterranean space inside, a communication passage establishing communication between the space and the subterranean space, and a ventilation hole establishing communication between an earth outside the building and the subterranean space is provided. A fuel cell unit having an exhaust port is arranged in the subterranean space. The communication passage has a lateral wall protruding downward from a ceiling of the subterranean space. The lateral wall is arranged on the exhaust port side when the communication passage is arranged on a straight line linking the exhaust port and a second opening portion of the ventilation hole on the subterranean space side. The lateral wall is arranged on the straight line side when the communication passage is arranged at a position spaced apart from the straight line.