<![CDATA[AbstractRoot zone cooling system is needed to alleviate high-temperature injury for high-yield greenhouse vegetables production. Analysis of heat transfer along the cooling pipe is very important in designing the root zone cooling system. The objectives of this research were (1) to analyze heat transfer in cooling pipe for zone cooling in a hydroponic system, (2) to validate the heat transfer dynamics model to predict the water temperature at the outlet of the cooling pipe, and (3) to perform model simulations for various types of pipe materials and lengths in several thermal conditions in the greenhouse. Root zone cooling system was performed by flowing water (10oC) through a steel pipe along 25 m to the root zone. The analysis showed a decrease up to 2.8oC in the planting medium temperature 28.6oC from control 31.4oC. The validation of heat transfer model was conducted by comparing the predicted water temperature to that of measured on linear regression plot. The result showed a straight line Y=1.0026X and the coefficient of determination (R2) 0.9867. Based on data analysis, the temperature of water reaches 1oC in steel and copper cooling pipes along 40 m and significantly different from the PVC that is 0.8oC. AbstrakRoot zone cooling system diperlukan dalam mengurangi kerusakan akibat tingginya suhu agar hasil produksi sayuran rumah tanaman meningkat. Analisis pindah panas di sepanjang pipa pendingin sangat penting dalam perancangan root zone cooling system. Tujuan penelitian ini adalah (1) melakukan analisis pindah panas pada pipa pendingin untuk zone cooling dalam sistem hidroponik, (2) melakukan validasi model dinamik pindah panas untuk memprediksi suhu air pada bagian outlet pipa pendingin, dan (3) melakukan simulasi model untuk berbagai bahan dan panjang pipa pada beberapa kondisi termal rumah tanaman. Root zone cooling system dilakukan dengan mengalirkan air (10oC) melalui pipa steel sepanjang 25 m ke perakaran tanaman. Hasil analisis menunjukkan adanya penurunan suhu media tanam hingga 2.8oC yaitu 28.6oC dari suhu kontrol 31.4oC. Validasi model pindah panas dilakukan dengan membandingkan angka suhu air hasil prediksi dengan hasil pengukuran dalam grafik regresi linear. Hasil validasi model pindah panas didapatkan garis lurus Y=1.0026X dan koefisien determinasi (R2) 0.9867. Berdasarkan analisis data, kenaikan suhu air mencapai 1oC pada pipa pendingin steel maupun tembaga sepanjang 40 m dan berbeda nyata dengan PVC yaitu 0.8oC]]>
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