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Measured dropwise condensation heat transfer coefficients from moist air under near-quiescent conditions
Condensation heat transfer from moist air is critical in dehumidification, fog collection, and cooling tower water reclamation; however, it is less studied than steam condensation. Although there are many visualization studies of dropwise condensation, few dropwise condensation heat transfer coefficients were reported in the literature for moist air. In this work, condensation occurred on a Teflon-coated, aluminum plate which was placed in an environmental chamber with controlled temperatures and relative humidities; air flowed from the plate’s bottom to top at velocities of 3–4 m/s. The plate was cooled on the backside by dry air flowing through five channels in an additively-manufactured, ABS plastic heat exchanger. The apparatus was validated using a heating case at temperatures above the dew point. Dropwise condensation was observed and heat transfer coefficients of approximately 40 W/m2K and 120 W/m2K were measured for the ambient conditions of 40 °C at 40% relative humidity (RH) and 40 °C at 60% RH, respectively. The thermal resistance from diffusion exceeds the thermal resistance of the droplets during condensation from moist air; enhancement mechanisms could focus on improving diffusion.
Measured dropwise condensation heat transfer coefficients from moist air under near-quiescent conditions
Condensation heat transfer from moist air is critical in dehumidification, fog collection, and cooling tower water reclamation; however, it is less studied than steam condensation. Although there are many visualization studies of dropwise condensation, few dropwise condensation heat transfer coefficients were reported in the literature for moist air. In this work, condensation occurred on a Teflon-coated, aluminum plate which was placed in an environmental chamber with controlled temperatures and relative humidities; air flowed from the plate’s bottom to top at velocities of 3–4 m/s. The plate was cooled on the backside by dry air flowing through five channels in an additively-manufactured, ABS plastic heat exchanger. The apparatus was validated using a heating case at temperatures above the dew point. Dropwise condensation was observed and heat transfer coefficients of approximately 40 W/m2K and 120 W/m2K were measured for the ambient conditions of 40 °C at 40% relative humidity (RH) and 40 °C at 60% RH, respectively. The thermal resistance from diffusion exceeds the thermal resistance of the droplets during condensation from moist air; enhancement mechanisms could focus on improving diffusion.
Measured dropwise condensation heat transfer coefficients from moist air under near-quiescent conditions
Huber, Ryan A. (author) / Derby, Melanie M. (author)
Science and Technology for the Built Environment ; 29 ; 223-229
2023-02-07
7 pages
Article (Journal)
Electronic Resource
Unknown
Coefficients of heat transfer as measured under natural weather conditions
| Engineering Index Backfile | 1928
| British Library Online Contents | 2019