The classical theory of the cooling tower does not include a suitable mathematical solution for a direct and quick calculation of gas/liquid temperature profiles. This forces in most of practical cases, for example in case of industrial spray absorbers, to simplify the problem and to assume a complete cooling of exit gases down to the adiabatic saturation temperature of the incoming gases. In the present paper, a new method is described to develop an acceptable mathematical solution for cooling towers, taking into account the main influencing parameters, especially the liquid to gas ratio (L/G) and the actual liquid and gas interface. Calculations with the new solution show, that the exit gas temperature is strongly influenced by the liquid inlet temperature. In case of closed loop and counter current systems, this liquid inlet temperature is more or less close to the adiabatic saturation temperature of the incoming gases. In these cases, the exit gas temperature is only slightly higher than the currently assumed adiabatic saturation temperature of the inlet gases. This is completely different to the open loop systems, where the liquid inlet temperature is not influenced by the incoming gases at all. In these cases, the gas outlet temperature is mostly far from the adiabatic saturation temperature of the inlet gases, so that the current assumption can initiate great errors. (C) 2000 Elsevier Science Ltd. All rights reserved.