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Dew condensation: effect on dust deposition rate

Dew condensation: effect on dust deposition rate. S.A. Biryukov 1 and L.I.Yarmolinsky 2 1 -The Jacob Blaustein Institutes for Desert research, Department of Solar Energy and Environmental Physics. Ben-Gurion University of the Negev, Sde Boqer Campus, 84990, Israel

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Dew condensation: effect on dust deposition rate

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  1. Dew condensation:effect on dust deposition rate S.A. Biryukov1 and L.I.Yarmolinsky2 1-The Jacob Blaustein Institutes for Desert research, Department of Solar Energy and Environmental Physics. Ben-Gurion University of the Negev, Sde Boqer Campus, 84990, Israel 2-The Jacob Blaustein Institutes for Desert research, Albert Katz International School for Desert Studies. Ben-Gurion University of the Negev, Sde Boqer Campus, 84990, Israel

  2. Cleaning Solar collectors from the dust needs spending much water and manpower

  3. Aim Laboratory study of dew condensation influence on the process of dust deposition Solar Power Production in Desert Area Positive factor: High level of solar radiation. Negative factors: High dust concentration in the air. The large difference between night and day temperatures causes dew condensation on solar collectors

  4. Methodology Environmental dust was spread in a deposition chamber and deposited on two horizontal samples (glass slides).

  5. One of the slides was preliminarily cooled down to the temperature lower than the dew point. The second (reference) sample was kept at the room temperature, which was much higher than the dew point (typically, about 25 C).

  6. 1- Dust deposition on the top surface of the slide

  7. 2 - Dust deposition on the bottom surface

  8. 2 - Dust deposition on the bottom surface

  9. After the exposure the particle size distributions on surfaces were measured by computerised microscope

  10. Dust deposition on reference slide. Dust deposition during water condensation on cool slide TOPSURFACE Deposition rates were compared for all samples.

  11. Results (top slide)

  12. Results (top slide) N wet reference / N dry reference

  13. Results (bottom slide)

  14. Discussion and conclusions 1. Gravity and convection 2. Combined Thermophoresis and Diffusiophoresis (Stefan flow)

  15. Discussion and conclusions 1. Experiment demonstrated strong enhancement of dust deposition under conditions of water condensation on the cold surface 2. This enhancement is much higher than the effective enhancement, caused by reduced particles rebound from wetted surface:

  16. Discussion and conclusions 3. Experiments revealed different dependence of this enhancement on particle size for the top and the bottom surfaces:

  17. Discussion and conclusions 4. The additional enhancement for small particles deposition on the top surface may be related to supersaturated conditions in pre-surface interface, which result in condensation of water on dust particles and their growth.

  18. THANK YOU FOR ATTENTION

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