Thermal and water management in irrigating lands in the arid and semi-arid regions

Abstract

Excess heat and scarcity of water are the two major problems, which are usually encountered in irrigating lands especially in the arid and semi-arid regions. This paper introduces a technical approach of managing agricultural lands in the arid and semi arid regions through determination of daily water requirement and amount of heat the land is being exposed at various meteorological conditions. Through setting up a mathematical model consisting of basic heat and mass transfer equations and fluid properties, daily rate of water evaporation, different modes of heat transfer such as radiation, convection and heat transfer by evaporation at a wide range relative humidities are determined. Furthermore, the analyses are performed at two different scenarios at average air velocities of 1 and 5 m/s. Our findings showed that the volume of water evaporation at relative humidity and air temperature of φ=50% and T ∞=20 °C is 22% higher than at φ=100% and T ∞=20 °C. Moreover, at a specified φ and T ∞, the total rate of heat transfer at air velocity of 5 m/s is at least 25% higher than the total rate of heat transfer at air velocity of 1 m/s.