Estimation of dew yield from radiative condensers by means of an energy balance model

Valero, José Francisco Maestre; Ragab, R.; Álvarez, Victoriano Martínez; Baille, Alain

doi:10.1016/j.jhydrol.2012.06.046

Cited by 34 publications

(28 citation statements)

References 22 publications

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“…The dew harvest in temperate with dry winter climate results are comparable to some those obtained from Mediterranean places with hot-dry climates, as is shown in experimental studies. The yearly average daily dew harvest ranged from 36.7 to 57.7 g/m 2 for the Mediterranean climate cases, as is shown by Maestre-Valero [16,18]. The average seasonal daily dew harvest was 33 and 36 g/m 2 for hot-dry weather according to Nilson et al [4] and Mileta [14].…”

Section: Monthly and Winter Dew Harvestmentioning

confidence: 87%

“…Gandhidasan and Abualhamayel [9] report a dew harvest rate of 0.22 mm/night from January to February in Dhahran, Saudi Arabia, with an agreement of 14.3% between the theoretical and experimental results. On the other hand, Maestre-Valero et al [18] report 17.4 mm/night and 20.8 mm/night of dew harvest for one year, using white standard foil and black foil, with a Root Mean Square Error (RMSE), of 0.051 mm, and 0.053 mm, respectively. The RMSE represents the sample standard deviation of the differences between predicted values and observed values.…”

Section: Introductionmentioning

confidence: 99%

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Winter Dew Harvest in Mexico City

Ernesto

Jasson

2015

Atmosphere

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This study presents experimental and theoretical results of winter dew harvest in México City in terms of condensation rate. A simplified theoretical model based on a steady-state energy balance on a radiator-condenser was fitted, as a function of the ambient temperature, the relative humidity and the wind velocity. A glass sheet and aluminum sheet white-painted were used as samples over the outdoor experiments. A good correlation was obtained between the theoretical and experimental data. The experimental results show that there was condensation in 68% of the winter nights on both condensers. The total winter condensed mass was 2977 g/m 2 and 2888 g/m 2 on the glass sheet and aluminum sheet white-painted, respectively. Thus, the condensed mass on the glass was only 3% higher than that on the painted surface. The maximum nightly dew harvests occurred during December, which linearly reduced from 50 g/m 2 night to 22 g/m 2 night as the winter months went by. The condensation occurred from 1:00 a.m. to 9:00 a.m., with maximum condensation rates between 6:00 a.m. and 7:00 a.m. The dew harvest can provide a partial alternative to the winter water shortage in certain locations with similar climates to the winter in Mexico City, as long as pollution is not significant.

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Section: Monthly and Winter Dew Harvestmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Winter Dew Harvest in Mexico City

Ernesto

Jasson

2015

Atmosphere

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“…First, due to the effects of gap-filling in rainy days (Kang et al, 2012), dews (Maestre-Valero et al, 2012), and fogs (Beiderwieden et al, 2008;Eugster et al, 2006), the measured ET may be underestimated. Second, the underestimated ET caused by gap-filling in rainy days (Kang et al, 2012), dews (Maestre-Valero et al, 2012), and fogs (Beiderwieden et al, 2008;Eugster et al, 2006) may overestimate T/ET. Third, during days with open canopy, the low temperature (Shi et al, 2008a) caused small measured water vapor fluxes below the canopy, which made the measured T (the difference between two layers water vapor fluxes) and T/ET overestimated.…”

Section: Model Performances and Uncertaintiesmentioning

confidence: 99%

Spatiotemporal variations of T/ET (the ratio of transpiration to evapotranspiration) in three forests of Eastern China

Zhu

et al. 2015

Ecological Indicators

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The ratio of transpiration to evapotranspiration (T/ET) Forest a b s t r a c t Evapotranspiration (ET), which is comprised by evaporation from soil surface (E), transpiration (T) and evaporation from the intercepted water by canopy (EI), plays an important role in maintaining global energy balance and regulating climate. Quantifying the spatiotemporal variations of T/ET (the ratio of T to ET) can improve our understandings on the role of vegetation ecophysiological processes in climate regulation. Using eddy covariance measurements at three forest ecosystems (Changbaishan temperate broad-leaved Korean pine mixed forest (CBS), Qianyanzhou subtropical coniferous plantation (QYZ) and Dinghushan subtropical evergreen mixed forest (DHS)) in north-south transect of Eastern China (NSTEC), we run the revised Shuttleworth-Wallace model (S-W model), validated its performance with the water vapor fluxes measured at two layers, and quantified the spatiotemporal variations of T/ET. The S-W model performed well in simulating ET and T/ET. The mean value of annual T/ET at three forests during the observation period all exceeded 0.6. The diurnal variation of canopy stomal conductance (G c ) dominated that of T/ET. The seasonal dynamics of T/ET was mainly shaped by that of leaf area index (LAI), vapor pressure deficit (VPD) and air temperature (T a ) through altering G c and the portion that the energy absorbed by canopy (P EC ) at temperate forest (CBS), while the seasonal dynamics of T/ET at subtropical forests (QYZ and DHS) were mainly affected by T a , net radiation, VPD, and soil water content through altering G c and soil surface conductance (G s ). The variation of mean annual G c governed the interannual varaition and spatial variation of T/ET. Therefore, forests in Eastern China played an important role in regulating climate through T and G c primarily affected the spatial and temproal variations of the role of forest T in regulating climate.

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“…Then, although the environment (tropical, dry, temperate, continental) and sky view will be the same for any condensers at the same location, the precise shape and materials of the condenser do matter, in particular its infra-red emissivity, shape and thermal characteristics. Standard planar condensers of 1m × 1m collection area, inclined 30° from horizontal (which enable water collection by gravity) and thermally insulated from below are currently used (Berkowicz, 2007;Jacobs et al, 2008;Maestre-Valero et al, 2012, Sharan, 2006Lekouch et al, 2012). Their yield can vary by at least 20% at the same location depending on their orientation as regards to wind direction and nearby obstacles (Lekouch et al, 2012;Clus et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Dew observed on cars as a proxy for quantitative measurements

Beysens

Pruvost²,

Pruvost³

2016

Journal of Arid Environments

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We describe a simple method to obtain absolute dew determination in any environment, based on observing dew formed at sunrise on cars. Cars are used as dew condensers where dew yield varies on three different parts that nearly all car exhibits: roof top, windshield and window side. The presence or absence of dew at the sunrise at these particular positions provides an observation scale index n with 4 levels, which is used to quantify dew yield. We show that the index n is proportional to the condensed dew volume h (mm) as measured on a standard planar condenser, inclined 30 ° from horizontal, following h=Kn. The validation of this scale and the determination of K (= 0.067 mm within 20-30% uncertainty) is performed with long term experiments in different areas where dew is observed on several cars, either directly weighted on rooftops or calculated from meteo data. This method can thus be of great help to determine without sophisticated measurements or trained observers the dew potential in many places in the world, in particular in arid and semi-arid environment, where dew can help to answer water demand and means to evaluate the dew potential are often limited or lacking.

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Estimation of dew yield from radiative condensers by means of an energy balance model

Cited by 34 publications

References 22 publications

Winter Dew Harvest in Mexico City

Winter Dew Harvest in Mexico City

Spatiotemporal variations of T/ET (the ratio of transpiration to evapotranspiration) in three forests of Eastern China

Dew observed on cars as a proxy for quantitative measurements

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