Geometry and surface manipulation impact on passive dew and rain collection

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Sammanfattning

In water-scarce regions, passive dew collectors may serve as vital supplementary water sources by collecting dew and rainwater, especially in arid or semi-arid African areas. This study examined enhancements to the standard passive dew collectors through a field experiment, which includes modification such as increased surface roughness through sandblasting (25 % coverage), adjusting panel geometry with sharp edges, and adding five cotton wires on the condensing surface. The dew was collected through gravity induced collection method, meaning it was not scraped from the panels. The experiment was conducted in a field condition in Helsinki, Finland between Jun 17 and Aug 31, 2022. Panel performance was analysed and compared based on their respective cumulative dew and image analysis of droplets behavioural changes during a dew night event occurring between 10 pm and 4 am. Over the 75 days (43 dew events), the partially sandblasted and standard panel each collected 3.4 mm of dew, while the wire panel accumulated 3.0 mm and ridge 2.7 mm. Aside from the partially sandblasted panel, both ridge and wire panels consistently demonstrated lower dew collection rates than the standard panel, with average reduction of 24 % and 16 %, respectively. Theoretical dew amounts were modelled, confirming only dew-related events with a matching trend. However, the model overestimate dew amounts, especially during low-yield events. This discrepancy may be attributed to the experiment's passive gravity-induced collection method, which resulted in incomplete droplet collection. The neglected amount could explain the difference between measured and modelled dew. The partially sandblasted panel exhibited better performance under specific meteorological conditions, notably when relative humidity level >75 %. Additionally, over the entire duration of the experiment the wire panel improved rainwater collection by 4.3 mm (8 % increase, total 56.3 mm) compared with the standard panel (52.0 mm).
Originalspråkengelska
TidskriftAgricultural and Forest Meteorology
Volym356
Sidor (från-till)110180
Antal sidor1
ISSN0168-1923
DOI
StatusPublicerad - 15 sep. 2024
MoE-publikationstypA1 Tidskriftsartikel-refererad

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