Temperature Reduction in Hydroponic Planting System Using Heat Pipe

Abstract

This paper presents an establishment of a mathematical model to determine the optimal size of heat pipe (thermosyphon) heat exchanger for reduce the inlet air temperature in evaporative cooling system of greenhouse. The condition of a mathematical model is the total length of heat pipe is 1.5 m. A mathematical model will determine the optimal value of evaporator section and condenser section. The range of evaporator length is 0.5 – 1.4 m with an increment of 0.1 m and condenser length is in range of 0.1 – 1.0 m with an increment of 0.1 m. The inlet air temperature in evaporative cooling of greenhouse is depend on ambient temperature about 35 degree Celsius. While, the cooling water temperature is 20 degree Celsius. Evaporative pad of evaporative cooling system is 2 m in width and 7 m in length. From the conditions above, the optimize results from a mathematical model are as follows: evaporator section length is 0.9 m and condenser section length is 0.6 m moreover, it was shown that investment, net saving and maximum heat rate are 79.83 Thousand Baht, 0.552 Million Baht and 15.6 kW respectively.