Performance Enhancement of a Close-loop Thermosyphon Boiler via the use of Water-ethanol Mixtures

Anuwat Bumrungkij; Thanaphol Sukchana

Authors

Anuwat Bumrungkij Department of Mechanical Engineering, Faculty of Engineering and Architecture, Rajamangala University of Technology Suvarnabhumi, Phranakhon Si Ayutthaya, Thailand
Thanaphol Sukchana Department of Mechanical Engineering, Faculty of Engineering and Architecture, Rajamangala University of Technology Suvarnabhumi, Phranakhon Si Ayutthaya, Thailand

Keywords:

Boiler, Thermosyphon, Ethanol, Performance, Mixing Ratio

Abstract

The present study investigated the effect of mixing ratio of ethanol in distilled water, which was used as the mixed working fluid in a closed-loop thermosyphon boiler (CLTSB). The objective was to evaluate the heat transfer performance in relation to the ethanol mixing ratio. The evaporator of the CLTSB has a volume of 95 percent of the total system volume. A vapor line and liquid return line are made of copper tubes, with an internal diameter of 20 mm. Ethanol-distilled water mixture ratio was varied in the range of 10-90%; constant heat flux in the range of 50–300 kW/m² was tested. The water-cooled condenser, operated at a constant inlet temperature of 25 °C and a constant mass flow rate, was used. The results showed that the ethanol mixing ratio of 40% helped increase the heat transfer performance when the value of heat flux was lower than 200 kW/m². In contrast, when the ethanol mixing ratio was higher than 40%, the enhancement effect was lower with increasing mixing ratio.

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