Performance Study of Solar Heat Pipe with Different Working Fluids and Fill Ratios

This paper elaborates on the testing of solar heat pipes using different working fluids, fill ratios and tilt angles.Methanol, Acetone and water are used as working fluids, with fill ratios 25%, 50%, 75% and 100%.Experiments were carried out at 60 0 and 35 0 inclinations.Heat pipe condenser section is placed inside a water basin containing 200ml of water.The evaporator section is exposed to sunlight where the working fluid gets heated and it becomes vapour and moves towards the condenser section.In the condenser section the heat is given to the water in the basin and the vapour becomes liquid and comes back to the evaporator section due to gravitational force.Two modes of experiments are carried out: 1) using a parabolic collector and 2) using heat pipe with evacuated tubes.On comparative study, optimum fill ratio is been found to be 25% in every case and acetone exhibited slightly more efficiency than methanol and water.As far as the heat pipe orientation is concerned, 60 0 inclination of the heat pipe showed better performance than 35 0 .