| dc.description.abstract | ABSTRACT Zone cooling is used in greenhouses to maintain the area surrounding the plants at a level of temperature that is not too high and can be tolerated by the plants, even %ugh air temperature inside the greenhouse rises some degrees above the mperature level of outside air. Cooling the root zone by distributing the cooled -vtrient solution is one of the most effective methods of zone cooling. In this experiment, ground environment with a relatively low temperature has been used T reduce the temperature of nutrient solution by placing the nutrient solution tank r, about 7 m depth under the ground (surface). It has been shown that the method as efficient in energy use, because it need only energy forpumping the water from % depth to the floor level through a vertical pipe. Temperature of nutrient solution %wing out from the emitter with the tank placed under the ground (surface) could ze maintained 0.1 to 1.9 OC lower than that sourced from tank placed at floor level. 2 heat transfer model has been developed to predict the nutrient solution temperature "owing out from the vertical pipe. It has been shown that the predicted temperature nutrient solution agreed well with that of the measured temperatures. bywords: drip irrigation system, heat transfer analysis, ground cooling. | id |
