الفهرس Only 14 pages are availabe for public view
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Abstract
The temperature of earth at a certain depth about 3m from soil surface remains nearly constant. It was recorded 23.2 {u00B0}C and 22.2 {u00B0}C during the summer and winter months, respectively. This constant temperature is called the undisturbed temperature of earth which remains higher than the outside temperature in winter and lower than the outside temperature in summer. The earth tube heat exchanger technique was used to utilize the stability of deep soil temperature for worming the indoor air of greenhouse during winter season, and reducing the indoor air temperature during the summer season. When ambient air is drawn through buried pipes, the air is cooled in summer and heated in winter, before it is used for ventilation. The earth air heat exchanger can fulfil in both purpose heating in winter and cooling in summer. This research study investigates the experimental studies on earth air heat exchanger system in U shape single pass connected to a greenhouse (24 m² ) in the summer and winter climate. The experimental work was executed in the experimental farm of Faculty of Agriculture, Cairo University, Egypt, and mean altitude above sea level of 5 m. The overall thermal efficiency of the ETHE system under 50mm diameter, 3m depth during summer months (cooling process) and winter months (heating process), was 73.85 % and 72.90 % respectively