A display device comprising: a housing; a display module mounted in the housing; a closed-loop air circulation system (1, 2); an open-loop air circulation system; and a heat exchanger for transferring heat from the closed-loop air circulation system (1, 2) to the open-loop air circulation system, wherein the closed-loop air circulation system (1, 2) comprises: - a first channel defined between a front surface of the display module and a front surface of the housing so as to extend along the front surface of the display module; and - a second channel defined between one side surface of the display module and one side surface of the housing that is opposite the one side surface of the display module so as to extend along the one side surface of the display module in a longitudinal direction thereof, wherein the first channel is configured to receive air from a first end of the second channel and to discharge the air to a second end of the second channel, wherein the open-loop air circulation system comprises: - an inlet port for receiving air from an outside provided on at least one side surface of the housing; - an outlet port for discharging the air to the outside; and a third channel defined between the inlet port and the outlet port forms an open space isolated from the first channel and the second channel, and wherein the display device further comprises: at least one fan provided at an upper part or a lower part of the display module such that the first channel receives air and discharges the received air to the second channel. a housing; a display module mounted in the housing; a closed-loop air circulation system (1, 2); an open-loop air circulation system; and a heat exchanger for transferring heat from the closed-loop air circulation system (1, 2) to the open-loop air circulation system, wherein the closed-loop air circulation system (1, 2) comprises: - a first channel defined between a front surface of the display module and a front surface of the housing so as to extend along the front surface of the display module; and - a second channel defined between one side surface of the display module and one side surface of the housing that is opposite the one side surface of the display module so as to extend along the one side surface of the display module in a longitudinal direction thereof, - a first channel defined between a front surface of the display module and a front surface of the housing so as to extend along the front surface of the display module; and - a second channel defined between one side surface of the display module and one side surface of the housing that is opposite the one side surface of the display module so as to extend along the one side surface of the display module in a longitudinal direction thereof, wherein the first channel is configured to receive air from a first end of the second channel and to discharge the air to a second end of the second channel, wherein the open-loop air circulation system comprises: - an inlet port for receiving air from an outside provided on at least one side surface of the housing; - an outlet port for discharging the air to the outside; and - an inlet port for receiving air from an outside provided on at least one side surface of the housing; - an outlet port for discharging the air to the outside; and a third channel defined between the inlet port and the outlet port forms an open space isolated from the first channel and the second channel, and wherein the display device further comprises: at least one fan provided at an upper part or a lower part of the display module such that the first channel receives air and discharges the received air to the second channel.