An experimental study has been carried out on a water sprayed air flow aimed at cooling the air upstream of a heat exchanger in order to improve the heat transfer. A pilot has been built allowing injecting droplets in air in various conditions while controlling flow rates, temperature and humidity. The emphasis has been put on the spray evaporation resulting in a temperature decrease and humidity increase in the air flow. An actual increase in the heat exchanged (up to 3 times more) for an air initially entering in surrounding conditions (temperature between 293 and 308 K and relative humidity between 47.5% and 19.7%) has been reached when injecting upstream droplets smaller than 25 mm, in an air flow crossing the exchanger. A validation of a numerical study on the heat exchanges in the air flow has been also achieved. Results will be applied for the optimization of the water flow providing the best compromise between heat exchanged and water consumption.