Heat transfer mechanisms governing the performance of tilted planar dew condensers
Résumé
In the context of passive atmospheric water harvesting, the thermal performance of planar dew condensers is primarily governed by radiative cooling and convective heat exchange with air. This study investigates the key parameters controlling dew condensation on a tilted plane, with particular emphasis on tilt angle, wind speed, and wind orientation. Both numerical simulations and experimental measurements were conducted on a 1 m² condenser tilted at 30° at a well-characterized site (Ajaccio airport, France). Surface temperatures were monitored using infrared thermography and thermocouples, while dew yield was quantified by a pluviometer and direct collection. The results show that radiative cooling efficiency decreases significantly for tilt angles above 20-30°. On the other hand, the water collection efficiency increases with the tilt angle, leading therefore to an optimum around 30°. Convective heat transfer coefficients and dew yields are found to be strongly dependent on condenser-wind orientation, with frontward wind conditions enhancing condensation compared to backward wind, though still remaining lower than those of a horizontal reference condenser. These findings highlight the critical role of wind-surface interactions in governing plane/air heat transfer and provide guidelines for the design and modeling of efficient planar dew condensers.
Mots clés
- wind heating radiative heat losses dew Passive water harvesting Planar condenser Radiative cooling Heat and mass exchange Convective
- wind heating radiative heat losses dew Passive water harvesting
- Convective
- Wind orientation
- Convective heat transfer
- Heat and mass exchange
- Radiative cooling
- Planar condenser
- Passive water harvesting