scholarly journals Cleaning of Floating Photovoltaic Systems: A Critical Review on Approaches from Technical and Economic Perspectives

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 2018
Author(s):  
Rafi Zahedi ◽  
Parisa Ranjbaran ◽  
Gevork B. Gharehpetian ◽  
Fazel Mohammadi ◽  
Roya Ahmadiahangar
Keyword(s):  
Water Resources ◽  
Water Surface ◽  
Scaling Up ◽  
Water Evaporation ◽  
Economic Aspects ◽  
High Population Density ◽  
Pv Systems ◽  
Water Based ◽  
Generating Capacity ◽  
Economic Perspectives

There are some environmental factors, such as ambient temperature, dust, etc., which cause a reduction in the efficiency of Photovoltaic (PV) systems. Installation of PV panels on the water surface, commonly known as Floating Photovoltaic (FPV) systems, is one solution to employ PV panels in a cooler environment, achieve higher efficiency, and reduce water evaporation. FPV systems open up new opportunities for scaling up solar generating capacity, especially in countries with high population density and valuable lands, as well as countries with high evaporation rates and water resources deficiency. Since the FPV system is an almost new concept, its cleaning techniques have not been comprehensively studied. While FPV systems are located on the surface of water resources and reservoirs, the water quality can limit the application of different cleaning techniques. Therefore, this paper investigates different techniques of FPV systems cleaning and categorizes them into water-based and water-free approaches. In addition, their cleaning frequencies, as well as economic aspects, are presented and discussed to determine their merits and demerits for using them in FPV systems.

RATE OF EVAPORATION FROM A FREE-WATER SURFACE AS INFLUENCED BY EXPOSURE

1961 ◽  
Vol 41 (1) ◽  
pp. 199-203 ◽  
Author(s):  
A. C. Carder
Keyword(s):  
Water Surface ◽  
Meteorological Factors ◽  
Free Water ◽  
Water Evaporation ◽  
High Wind ◽  
Progressive Decrease ◽  
Factors Affecting ◽  
Wind Velocities ◽  
Rate Of Evaporation ◽  
Low Rate

In a 3-year free-water evaporation study, an evaporimeter tank in the open field lost 34.5 per cent more water than a tank sheltered by buildings and trees. Meteorological factors responsible for this difference appear to be high wind velocities and long daily periods of sunshine. Changes in temperature regime had no effect.Difference in evaporation from the two tanks led to examination of data obtained over 35 years from the sheltered tank. It was found that, although there was a progressive decrease in amount of evaporation over the years from this tank, rainfall at the same time had increased and that the effect of this increase on evaporation was roughly equal to that of all other factors affecting evaporation, such as a change in exposure, etc. Thus, the comparatively low rate of evaporation from the sheltered tank was undoubtedly due in part to the proximity of buildings and trees which had been established.

scholarly journals ANALISIS KEBERLANJUTAN PEMBANGUNAN BENDUNGAN WAY SEKAMPUNG, LAMPUNG

2018 ◽  
Vol 9 (1) ◽  
pp. 43-52
Author(s):  
Mirza Nirwansyah ◽  
Cecep Kusmana ◽  
Eriyatno Eriyatno ◽  
M.Yanuar J. Purwanto
Keyword(s):  
Water Resources ◽  
Catchment Area ◽  
Environmental Damage ◽  
Scaling Analysis ◽  
Land Conversion ◽  
On Demand ◽  
Dimensional Scaling ◽  
Water Based ◽  
Floods And Droughts ◽  
Multi Dimensional Scaling

The availability of water resources provides many benefits for the welfare of all human being. The Decrease of the availability of water resources is caused by various reasons, including as environmental damage of catchment area, human activities, land conversion, and the issue of global warming. The problems caused an increase in floods and droughts. Dam development can reduce the risk of flood and drought through a reservoir operation by using less water during rainy season and using much water during dry season. The sustainability of water resources in Way Sekampung can be identified by three main indicators, which are ecology, economic, and sosio-cultural by using the MDS (Multi Dimensional Scaling) analysis, There are two item become the focus of this research i.e. sedimentation and water balance. These factors are considered as the most important factors in planning a dam. Operationally, this policy will be applied by supplying water based on demand, strengthening water resources institutions, improving infrastructure facilities and developing technology.

scholarly journals Soil salinization under different climate change scenarios: A global scale analysis

2021 ◽  
Author(s):  
Nima Shokri ◽  
Amirhossein Hassani ◽  
Adisa Azapagic
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Soil Salinity ◽  
Global Scale ◽  
Soil Salinization ◽  
Water Evaporation ◽  
Climate Change Scenarios ◽  
Spatio Temporal ◽  
Salt Affected Soils

<p>Population growth and climate change is projected to increase the pressure on land and water resources, especially in arid and semi-arid regions. This pressure is expected to affect all driving mechanisms of soil salinization comprising alteration in soil hydrological balance, sea salt intrusion, wet/dry deposition of wind-born saline aerosols — leading to an increase in soil salinity. Soil salinity influences soil stability, bio-diversity, ecosystem functioning and soil water evaporation (1). It can be a long-term threat to agricultural activities and food security. To devise sustainable action plan investments and policy interventions, it is crucial to know when and where salt-affected soils occur. However, current estimates on spatio-temporal variability of salt-affected soils are majorly localized and future projections in response to climate change are rare. Using Machine Learning (ML) algorithms, we related the available measured soil salinity values (represented by electrical conductivity of the saturated paste soil extract, EC<sub>e</sub>) to some environmental information (or predictors including outputs of Global Circulation Models, soil, crop, topographic, climatic, vegetative, and landscape properties of the sampling locations) to develop a set of data-driven predictive tools to enable the spatio-temporal predictions of soil salinity. The outputs of these tools helped us to estimate the extent and severity of the soil salinity under current and future climatic patterns at different geographical levels and identify the salinization hotspots by the end of the 21<sup>st</sup> century in response to climate change. Our analysis suggests that a soil area of 11.73 Mkm<sup>2</sup> located in non-frigid zones has been salt-affected in at least three-fourths of the 1980 - 2018 period (2). At the country level, Brazil, Peru, Sudan, Colombia, and Namibia were estimated to have the highest rates of annual increase in the total area of soils with an EC<sub>e</sub> ≥ 4 dS m<sup>-1</sup>. Additionally, the results indicate that by the end of the 21<sup>st</sup> century, drylands of South America, southern and Western Australia, Mexico, southwest United States, and South Africa will be the salinization hotspots (compared to the 1961 - 1990 period). The results of this study could inform decision-making and contribute to attaining the United Nation’s Sustainable Development Goals for land and water resources management.</p><p>1. Shokri-Kuehni, S.M.S., Raaijmakers, B., Kurz, T., Or, D., Helmig, R., Shokri, N. (2020). Water Table Depth and Soil Salinization: From Pore-Scale Processes to Field-Scale Responses. Water Resour. Res., 56, e2019WR026707. https://doi.org/ 10.1029/2019WR026707</p><p>2. Hassani, A., Azapagic, A., Shokri, N. (2020). Predicting Long-term Dynamics of Soil Salinity and Sodicity on a Global Scale, Proc. Nat. Acad. Sci., 117, 52, 33017–33027. https://doi.org/10.1073/pnas.2013771117</p>

A Scaling-up Approach from Experimental Tunnel to Spray Dryer

2010 ◽  
Vol 6 (1) ◽  
Author(s):  
Xuan-You Li ◽  
Ireneusz Zbicinski ◽  
Jing Wu
Keyword(s):  
Spray Drying ◽  
Scale Up ◽  
Scaling Up ◽  
Pilot Scale ◽  
Drying Kinetics ◽  
Water Evaporation ◽  
Small Scale ◽  
Spray Dryer ◽  
Cfd Modelling ◽  
Initial Water

A scaling-up approach from drying of a thin layer wet material in a experimental tunnel to a pilot scale spray drying was developed through determining drying kinetics of quick evaporation process. Maltodextin was selected as solid material in solution to be dried. Critical moisture contents as a function of initial water evaporation rate (drying rate) shows that there is the same variation between the small scale test tunnel and the pilot scale spray dryer. Result of CFD modelling demonstrates that drying kinetics obtained from the small-scale tunnel could be properly applied to scale-up the spray drying process.

Integration of Water-Based PV Systems

2018 ◽  
pp. 213-233
Author(s):  
Marco Rosa-Clot ◽  
Giuseppe Marco Tina
Keyword(s):  
Pv Systems ◽  
Water Based

scholarly journals Effect of air parameters, water temperature, and number of pool occupants on moisture gains

2018 ◽  
Vol 70 ◽  
pp. 02006
Author(s):  
Agnieszka Garnysz-Rachtan ◽  
Zbigniew Zapałowicz
Keyword(s):  
Water Temperature ◽  
Water Surface ◽  
Evaporation Rate ◽  
Water Evaporation ◽  
Physical Parameters ◽  
Air Humidity ◽  
Air Velocity ◽  
Relative Air Humidity ◽  
Thermal Calculations ◽  
The Right

Thermal calculations for indoor swimming pools require that amount of water evaporated from the pool's water surface, as well as water evaporated from the floor surrounding the pool and from the bodies of the occupants are to be determined. It means in practice that amount of vapor transferred to the air in the pool hall depends most of all on physical parameters of water and air. One of more important factors that affect water evaporation is also the way the pool is operated. The present article shows only chosen relations applied to determine the values of evaporation rate from occupied pool. The relations also account for the mode of pool's operation. The aim of the paper is to analyse the effect of changes of temperature and of relative air humidity in the hall, of water temperature and of air velocity above the water surface, as well as of the number of occupants on moisture gains in the hall. The above data let choose the right relation to be applied in calculations for the water evaporation rate.

Unusual Fast Evaporation From Nanoholes

2012 ◽  
Author(s):  
Zhi Huang ◽  
Yuanchen Hu ◽  
Kang Liu ◽  
Xuejiao Hu
Keyword(s):  
Water Surface ◽  
Evaporation Rate ◽  
Physical Phenomenon ◽  
Gravimetric Method ◽  
Industrial Applications ◽  
Water Evaporation ◽  
Good Prediction ◽  
Confined Space ◽  
Affecting Factors ◽  
Air Conditioning Systems

Water evaporation is an important physical phenomenon that occurs in nature and several industrial applications such as food drying processes, cooling in air-conditioning systems and desalination. In all these systems, it is necessary to have a good prediction and control of evaporation rate as a function of various system parameters. Attempts to understand the affecting factors have mostly focus on the flow rates of gas or water streams, relative humidity of the air, presence of dissolved or suspended material in the water, temperatures of the air and water streams. However, as water surface partially covered (less surface area) is generally thought to have lower evaporation rate, little notice has ever put on it. Here we consider the evaporation case of water surface covered with nano-through-hole lid (NHL) of which the radius size is nearly equal to the average free path of the vapor. Using a gravimetric method, we experimentally measured the evaporation rate of water at the orifice of the nano-holes. The results indicate that the evaporation rate is 1–6 times faster than the non-sheltered water surface with the same liquid area. Moreover, with the porosity of the lid decreasing, the evaporation rate per unit area increases. A theoretical model is developed for this novel phenomenon from the view of molecular dynamics during evaporation and vapor diffusion. We envision that this finding may have new inspirations on phase change phenomenon in nano-confined space and put forward one new way for promoting evaporation of liquid.

scholarly journals Contrasting roles of interception and transpiration in the hydrological cycle – Part 2: Moisture recycling

2014 ◽  
Vol 5 (1) ◽  
pp. 281-326 ◽  
Author(s):  
R. J. van der Ent ◽  
L. Wang-Erlandsson ◽  
P. W. Keys ◽  
H. H. G. Savenije
Keyword(s):  
Land Use ◽  
Water Resources ◽  
Hydrological Cycle ◽  
Land Use Changes ◽  
Open Water ◽  
Companion Paper ◽  
Water Evaporation ◽  
Residence Times ◽  
Moisture Recycling ◽  
The Tropics

Abstract. The contribution of land evaporation to local and remote precipitation (i.e., moisture recycling) is of significant importance to sustain water resources and ecosystems. But how important are different evaporation components in sustaining precipitation? This is the first paper to present moisture recycling metrics for partitioned evaporation. In the companion paper, Part 1, evaporation was partitioned into vegetation interception, floor interception, soil moisture evaporation and open water evaporation (constituting the direct, purely physical fluxes, largely dominated by interception), and transpiration (delayed, biophysical flux). Here, we track these components forward as well as backward in time. We also include age tracers to study the atmospheric residence times of these evaporation components. As the main result we present a new image of the global hydrological cycle that includes quantification of partitioned evaporation and moisture recycling as well as the atmospheric residence times of all fluxes. We demonstrate that evaporated interception is more likely to return as precipitation on land than transpired water. On average, direct evaporation (essentially interception) is found to have an atmospheric residence time of eight days, while transpiration typically resides nine days in the atmosphere. Interception recycling has a much shorter local length scale than transpiration recycling, thus interception generally precipitates closer to its evaporative source than transpiration, which is particularly pronounced outside the tropics. We conclude that interception mainly works as an intensifier of the local hydrological cycle during wet spells. On the other hand, transpiration remains active during dry spells and is transported over much larger distances downwind where it can act as a significant source of moisture. Thus, as various land-use types can differ considerably in their partitioning between interception and transpiration, our results stress that land-use changes (e.g., forest to cropland conversion) do not only affect the magnitude of moisture recycling, but could also influence the moisture recycling patterns and lead to a redistribution of water resources. As such, this research highlights that land-use changes can have complex effects on the atmospheric branch of the hydrological cycle.

scholarly journals Rights to Own and Operate a Hydro Floating Solar Project in Thailand

2021 ◽  
pp. 133-149
Author(s):  
Piti Eiamchamroonlarp
Keyword(s):  
Water Resources ◽  
Water Surface ◽  
Industry Structure ◽  
Electricity Industry ◽  
Energy Industry ◽  
Regulatory Regime ◽  
Legal Basis ◽  
Network Access ◽  
Electricity Network

This paper finds that the current electricity regulatory regime, established by the Energy Industry Act B.E. 2550 (2007), together with the current electricity industry structure—the enhanced single buyer model—serves as a favorable legal basis for a state electricity enterprise, especially the Electricity Generating Authority of Thailand (EGAT), to own and operate a hydro-floating solar project in Thailand. However, it argues that, despite their ability to obtain the relevant licenses under the Energy Industry Act B.E. 2550 (2007) as well as enter into power purchase agreements with state electricity enterprises or private customers, the rights of private hydro-floating solar project operators to own and operate a hydro-floating solar project on the surface of public water resources are undermined by uncertainty pertaining to the possessory right over the water surface of public water resources, as well as unfair or discriminatory practices concerning electricity network access.

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