Heat exchange apparatus , comprising: - at least one heat exchanger comprising tube means provided with at least one inlet of a process fluid to be cooled and at least one outlet of the cooled process fluid; - ventilation means for generating a flow of a cooling gas passing through said tube means; - at least one evaporative body arranged to be traversed by said flow before said heat exchanger ; - supply means for supplying an evaporative liquid to wet said evaporative body to humidify said flow; - at least one temperature sensor for measuring the temperature (Tout) of the process fluid at the outlet of said tube means; - control means configured to control said evaporative liquid supply means based on the temperature (Tout) measured by said temperature sensor characterized in that said control means is configured to receive a lower limit (Vinf) and an upper limit (Vsup) of the cooling gas flow and to control said ventilation means and said supply means based on the temperature (Tout) measured by said temperature sensor so that, when the flow (V) of the cooling gas is higher than said lower limit (Vinf) and lower than said upper limit (Vsup) and the supply flow of the evaporative liquid is non-zero, if the measured temperature (Tout) is less than or equal to a predetermined value, then the flow (V) of the cooling gas is lowered while the supply flow of the evaporative liquid is not lowered , and so that, when the flow (V) of the cooling gas is equal to said lower limit (Vinf) and the supply flow of the evaporative liquid is non-zero, if the measured temperature (Tout) is less than or equal to a predetermined value, then the supply flow of the evaporative liquid is lowered while the flow (V) of the cooling gas is not lowered , and so that, when the flow (V) of the cooling gas is lower than said upper limit (Vsup) and higher than said lower limit (Vinf) and the supply flow of the evaporative liquid is non-zero, if the measured temperature (Tout) is greater than or equal to a predetermined value, then the flow (V) of the cooling gas is increased, while the supply flow of the evaporative liquid is not increased, and so that, when the flow (V) of the cooling gas is equal to said upper limit (Vsup) and the flow rate of the evaporative liquid is non-zero, if the measured temperature (Tout) is greater than or equal to a predetermined value, then the supply flow of the evaporative liquid is increased, while the flow (V) of the cooling gas is not increased. - at least one heat exchanger comprising tube means provided with at least one inlet of a process fluid to be cooled and at least one outlet of the cooled process fluid; - ventilation means for generating a flow of a cooling gas passing through said tube means; - at least one evaporative body arranged to be traversed by said flow before said heat exchanger ; - supply means for supplying an evaporative liquid to wet said evaporative body to humidify said flow; - at least one temperature sensor for measuring the temperature (Tout) of the process fluid at the outlet of said tube means; - control means configured to control said evaporative liquid supply means based on the temperature (Tout) measured by said temperature sensor <EOS>