A drying tunnel for fruits or vegetables which at least comprises: - an impulsion and heating chamber; and - a plenum, configured for receiving an outgoing hot air generated in the impulsion and heating chamber; wherein the plenum in turn comprises: - openings, with a cross section selected from the group consisting of circular and oval, arranged in a staggered pattern, located on a lower surface of said plenum, with an opening density between 150 to 300 openings per square metre; wherein said openings are configured for expelling a distributed hot air from inside the plenum in a perpendicular way towards a conveyor system, configured for moving fruits and vegetables to be dried; wherein the plenum comprises a rectangular cross section decreasing along the length thereof, as it moves away from the inlet of the outgoing hot air from the impulsion and heating chamber; and wherein said decreasing rectangular cross section is configured for maintaining the pressure conditions inside and releasing distributed hot air under the same pressure and temperature conditions throughout the entire conveyor system, achieving a uniform flow distribution over all the openings by means of the geometry of the plenum, wherein the static pressure of the plenum, when it receives the outgoing hot air from the impulsion and heating chamber, is comprised between 300 and 800 Pa, and wherein the outlet velocity of the distributed hot air through the openings is comprised between 20 m/s and 50 m/s. - an impulsion and heating chamber; and - a plenum, configured for receiving an outgoing hot air generated in the impulsion and heating chamber; wherein the plenum in turn comprises: - openings, with a cross section selected from the group consisting of circular and oval, arranged in a staggered pattern, located on a lower surface of said plenum, with an opening density between 150 to 300 openings per square metre; wherein said openings are configured for expelling a distributed hot air from inside the plenum in a perpendicular way towards a conveyor system, configured for moving fruits and vegetables to be dried; wherein the plenum comprises a rectangular cross section decreasing along the length thereof, as it moves away from the inlet of the outgoing hot air from the impulsion and heating chamber; and wherein said decreasing rectangular cross section is configured for maintaining the pressure conditions inside and releasing distributed hot air under the same pressure and temperature conditions throughout the entire conveyor system, achieving a uniform flow distribution over all the openings by means of the geometry of the plenum, wherein the static pressure of the plenum, when it receives the outgoing hot air from the impulsion and heating chamber, is comprised between 300 and 800 Pa, and wherein the outlet velocity of the distributed hot air through the openings is comprised between 20 m/s and 50 m/s. - openings, with a cross section selected from the group consisting of circular and oval, arranged in a staggered pattern, located on a lower surface of said plenum, with an opening density between 150 to 300 openings per square metre; wherein said openings are configured for expelling a distributed hot air from inside the plenum in a perpendicular way towards a conveyor system, configured for moving fruits and vegetables to be dried; wherein the plenum comprises a rectangular cross section decreasing along the length thereof, as it moves away from the inlet of the outgoing hot air from the impulsion and heating chamber; and wherein said decreasing rectangular cross section is configured for maintaining the pressure conditions inside and releasing distributed hot air under the same pressure and temperature conditions throughout the entire conveyor system, achieving a uniform flow distribution over all the openings by means of the geometry of the plenum, wherein the static pressure of the plenum, when it receives the outgoing hot air from the impulsion and heating chamber, is comprised between 300 and 800 Pa, and wherein the outlet velocity of the distributed hot air through the openings is comprised between 20 m/s and 50 m/s. wherein said openings are configured for expelling a distributed hot air from inside the plenum in a perpendicular way towards a conveyor system, configured for moving fruits and vegetables to be dried; wherein the plenum comprises a rectangular cross section decreasing along the length thereof, as it moves away from the inlet of the outgoing hot air from the impulsion and heating chamber; and wherein said decreasing rectangular cross section is configured for maintaining the pressure conditions inside and releasing distributed hot air under the same pressure and temperature conditions throughout the entire conveyor system, achieving a uniform flow distribution over all the openings by means of the geometry of the plenum, wherein the static pressure of the plenum, when it receives the outgoing hot air from the impulsion and heating chamber, is comprised between 300 and 800 Pa, and wherein the outlet velocity of the distributed hot air through the openings is comprised between 20 m/s and 50 m/s.