Pool boiling study on candidature of pentane, methanol and water for near room temperature cooling

To assess their suitability in enhanced cooling at near ambient temperatures, the pool boiling heat transfer performance and critical heat flux, (CHF), of pentane, methanol and water was measured for a flat, face-up, polished surface. By controlling the vapour pressure the working temperature range of the fluids is extended down to 30degC and up to 180degC. The optimum working temperature range of each fluid was determined for the same condition. Below 80degC the CHF of pentane is the highest at 45W/cm², from 80degC to 110degC, methanol is highest at 65W/cm², and above 110degC water with a CHF as high as 260W/m² at 180degC. The CHF of all three liquids was seen to follow a power law dependence with saturation pressure, and agrees satisfactorily with the Kutateladze/Zuber equation using an adjusted constant K of 1.7 - compared to the original value of 1.3. The higher heat flux is explained by the roughness of the boiling surface condition, which enhances the CHF of all three liquids to the same degree