ENGINEERING AND ECONOMIC ASPECTS OF THE N.F.T. SYSTEMS

The necessity of high quality products and energy saving technologies aroused a growing interest in the hydroponics, especially the Nutrient Film Technique. The N.F.T. is a scientific and controlled system of growing, but the introduction of N.F.T. needs high installation costs and good scientific knowledge; on the other hand it also leads to good commercial results. There are those who consider the N.F.T. system as a system of growing for control. The field of introduction of new technology in the N.F.T. systems is the electronic control of the nutrient concentration, acidity and ion concentration of the nutrient solution. Up to the present, simple on/off control has been applied in order to maintain the parameters, such as nutrient concentration and pH between fixed set levels by means of the addition of acid or salts to the nutrient solution.

Knowledge of the factors affecting the biological processes is essential to the design and the development of a feasible and modern Nutrient Film Technique system and of the relative control system.

The main problem in the development of an innovative technique is the choice of the moment of the application; the relationship between costs and profits for the introduction of innovative technology is discussed here. The main objective of this paper is to suggest an interpretation and to analyze the advanced adaptive control systems, ion concentration innovative sensors and the costs and limits of their introduction.

A comparative analysis about costs-profits between traditional and innovative control systems has also been developed with respect to the dimension of the hydroponic system.