Helpful Terms[edit | edit source]
General terms Fish aggregating device(FAD): A man-made object used to attract ocean going pelagic fish such as marlin, tuna and mahi-mahi (dolphin fish). Over 300 species of fish gather around FADs.
Irradiance(W*m^-2): the flux of radiant energy per unit area (normal to the direction of flow of radiant energy through a medium). Paper direction Quality of light: different wavelengths which are absorbed by water.
Quantity of light: different intensities.
Periodicity: cycles, may vary daily, or seasonally(Photoperiod).
Photoperiod: the period of time each day during which an organism receives illumination; day length.
Dry weight: the mass of a fish after it has been smoked.
Direction of Paper(More focused papers)[edit | edit source]
- Light sources - influence on growth and reproduction for use in aquaculture in combination with solar cells.
- Design - open-source polymer based module
- pontoon structure for c-Si tilted modules - touching water (cooling conducted up backside of module)
- pontoon structure for c-Si flat modules to be 1-6cm below water
- Thin-film structure for a-Si modules to lay upon water surface
- Structure must be naturally buoyant with cells/cables(walk-way ideal)(to increase options in tethering)
- Structure must be movable around water surface(so not to focus shadow on any given waterbed location)(simple motor, novel connection, rotating mini-sail)
- Surface of polymer/cell characterized to limit bio-fouling
- Polymer analysed to understand long-term degradation in UV/water environments(beach/ocean/inland water compositions)
- Add design concept - combine benefits of thin-film to pontoon structure - water dynamic wave motion, energy pass not absorb
- Light source attached on bottom of pontoon to control light intensity, quality, and duration towards waterbed
- Light measurements to be measured at varying depths below pontoon structure
- Assessment of probable effect on local fish/typical aquaculture breeds
- Generate calculator for all costs involved to this specific region/capability for other regions vs other methods
- Discuss synergistic and negative effects of dual PV and aquaculture.(locations, advantages, drawbacks/how to circumvent)
- Indicate progressive and efficient process for aquaculture development practices
Direction of Paper(General Papers)[edit | edit source]
- 3MW system
- Great example of floatovoltaics being used in the U.K.
- Good for water turbidity approximation
Prospective energy needs in Mediterranean offshore aquaculture: Renewable and sustainable energy solutions[edit | edit source]
- Hunger crisis - 2008 numbers
The thin film flexible floating PV (T3F-PV) array: The concept and development of the prototype[edit | edit source]
Proposing offshore photovoltaic (PV) technology to the energy mix of the Maltese islands[edit | edit source]
Scenarios for use of floating photovoltaic plants in Brazilian reservoirs[edit | edit source]
- efficiency drop of 0.485% per1°C temperature increment above 25C
- Figure 1 has simple and inexpensive design
Analysis of the Potential for Use of Floating Photovoltaic Systems on Mine Pit Lakes: Case Study at the Ssangyong Open-Pit Limestone Mine in Korea[edit | edit source]
- as of 2016.
- efficient reuse for abandoned mine pit lakes
- Assesses payback year - Figure 7
- SunEye210 for onsite shading analysis
- System Advisor Model(SAM) via NREL for determining optimal tilt angle/array spacing
- 4641 solar modules. 87650m^2. Tilt of 40degrees. 971.57 MWh annually. Payback period of 12.3 years. Present value of $897,000 USD. CO2 reduction of 471.21 tCO2/year.
Empirical Research on the efficiency of Floating PV systems compared with Overland PV Systems[edit | edit source]
Global environmental concerns and the escalating demand for energy, coupled with steady progress in renewable energy technologies, are opening up new opportunities for utilization of renewable energy resources. Solar energy is the most abundant, inexhaustible and clean of all the renewable energy resources till date. The power from sun intercepted by the earth is about 1.8 × 1011 MW, which is many times larger than the present rate of all the energy consumption. Photovoltaic technology is one of the finest ways to harness the solar power. This paper reviews the photovoltaic technology, its power generating capability, the different existing light absorbing materials used, its environmental aspect coupled with a variety of its applications. The different existing performance and reliability evaluation models, sizing and control, grid connection and distribution have also been discussed.
- 5 types of solar to be considered
Photovoltaics is already a billion dollar industry. It is experiencing rapid growth as concerns over fuel supplies and carbon emissions mean that governments and individuals are increasingly prepared to ignore its current high costs. It will become truly mainstream when its costs are comparable to other energy sources. At the moment, it is around four times too expensive for competitive commercial production. Three generations of photovoltaics have been envisaged that will take solar power into the mainstream. Currently, photovoltaic production is 90% first-generation and is based on silicon wafers. These devices are reliable and durable, but half of the cost is the silicon wafer and efficiencies are limited to around 20%. A second generation of solar cells would use cheap semiconductor thin films deposited on low-cost substrates to produce devices of slightly lower efficiency. A number of thin-film device technologies account for around 5–6% of the current market. As second-generation technology reduces the cost of active material, the substrate will eventually be the cost limit and higher efficiency will be needed to maintain the cost-reduction trend. Third-generation devices will use new technologies to produce high-efficiency devices. Advances in nanotechnology, photonics, optical metamaterials, plasmonics and semiconducting polymer sciences offer the prospect of cost-competitive photovoltaics. It is reasonable to expect that cost reductions, a move to second-generation technologies and the implementation of new technologies and third-generation concepts can lead to fully cost-competitive solar energy in 10–15 years.
Volcanic carbon dioxide vents show ecosystem effects of ocean acidification[edit | edit source]
The atmospheric partial pressure of carbon dioxide (pCO2) will almost certainly be double that of pre-industrial levels by 2100 and will be considerably higher than at any time during the past few million years. The oceans are a principal sink for anthropogenic CO2 where it is estimated to have caused a 30% increase in the concentration of H1 in ocean surface waters since the early 1900s and may lead to a drop in seawater pH of up to 0.5 units by 2100 (refs 2, 3). Our understanding of how increased ocean acidity may affect marine ecosystems is at present very limited as almost all studies have been in vitro, short-term, rapid perturbation experiments on isolated elements of the ecosystem4,5. Here we show the effects of acidification on benthic ecosystems at shallow coastal sites where volcanic CO2 vents lower the pH of the water column. Along gradients of normal pH (8.1–8.2) to lowered pH (mean 7.8–7.9, minimum 7.4–7.5), typical rocky shore communities with abundant calcareous organisms shifted to communities lacking scleractinian corals with significant reductions in sea urchin and coralline algal abundance. To our knowledge, this is the first ecosystem-scale validation of predictions that these important groups of organisms are susceptible to elevated amounts of pCO2.Sea-grass production was highest in an area at mean pH 7.6 (1,827 matm pCO2 ) where coralline algal biomass was significantly reduced and gastropod shells were dissolving due to periods of carbonate sub-saturation. The species populating the vent sites comprise a suite of organisms that are resilient to naturally high concentrations of pCO2 and indicate that ocean acidification may benefit highly invasive non-native algal species. Our results provide the first in situ insights into how shallow water marine communities might change when susceptible organisms are removed owing to ocean acidification
Meta-analysis reveals negative yet variable effects of ocean acidification on marine organisms[edit | edit source]
Ocean acidification is a pervasive stressor that could affect many marine organisms and cause profound ecological shifts. A variety of biological responses to ocean acidification have been measured across a range of taxa, but this information exists as case studies and has not been synthesized into meaningful comparisons amongst response variables and functional groups. We used meta-analytic techniques to explore the biological responses to ocean acidification, and found negative effects on survival, calcification, growth and reproduction. However, there was significant variation in the sensitivity of marine organisms. Calcifying organisms generally exhibited larger negative responses than non-calcifying organisms across numerous response variables, with the exception of crustaceans, which calcify but were not negatively affected. Calcification responses varied significantly amongst organisms using different mineral forms of calcium carbonate. Organisms using one of the more soluble forms of calcium carbonate (high-magnesium calcite) can be more resilient to ocean acidification than less soluble forms (calcite and aragonite). Additionally, there was variation in the sensitivities of different developmental stages, but this variation was dependent on the taxonomic group. Our analyses suggest that the biological effects of ocean acidification are generally large and negative, but the variation in sensitivity amongst organisms has important implications for ecosystem responses.
Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms[edit | edit source]
Today's surface ocean is saturated with respect to calcium carbonate, but increasing atmospheric carbon dioxide concentrations are reducing ocean pH and carbonate ion concentrations, and thus the level of calcium carbonate saturation. Experimental evidence suggests that if these trends continue, key marine organisms—such as corals and some plankton—will have difficulty maintaining their external calcium carbonate skeletons. Here we use 13 models of the ocean–carbon cycle to assess calcium carbonate saturation under the IS92a 'business-as-usual' scenario for future emissions of anthropogenic carbon dioxide. In our projections, Southern Ocean surface waters will begin to become undersaturated with respect to aragonite, a metastable form of calcium carbonate, by the year 2050. By 2100, this undersaturation could extend throughout the entire Southern Ocean and into the subarctic Pacific Ocean. When live pteropods were exposed to our predicted level of undersaturation during a two-day shipboard experiment, their aragonite shells showed notable dissolution. Our findings indicate that conditions detrimental to high-latitude ecosystems could develop within decades, not centuries as suggested previously.
The developing world remains plagued by lack of access to safe drinking water. Although, many low-cost methods have been developed to treat contaminated water, low-cost methods for water-quality testing are necessary to determine if these appropriate technologies are needed, effective, and reliable. This paper provides a methodology for the design, development, and technical validation of a low-cost open-source water testing platform. A case study is presented where the platform is developed to provide both the colorimetry for BOD/COD and nephalometry to measure turbidity using method ISO 7027. This approach resulted in equipment that is as accurate, but costs between 7.5 and 15 times less than current commercially-available tools. It is concluded that open-source hardware development is a promising solution for the equipment necessary to perform water quality measurements in both developed and developing regions
Water, energy and food are essential for human well-being, poverty reduction and sustainable development. Global projections indicate that demand for freshwater, energy and food will increase significantly over the next decades under the pressure of population growth and mobility, economic development, international trade, urbanisation, diversifying diets, cultural and technological changes, and climate change (Hoff 2011). Agriculture accounts for 70 percent of total global freshwater withdrawals, making it the largest user of water. Water is used for agricultural production, forestry and fishery, along the entire agri-food supply chain, and it is used to produce or transport energy in different forms (FAO 2011a). At the same time, the food production and supply chain consumes about 30 percent of total energy consumed globally (FAO 2011b). Energy is required to produce, transport and distribute food as well as to extract, pump, lift, collect, transport and treat water. Cities, industry and other users, too, claim increasingly more water, energy and land resources, and at the same time, face problems of environmental degradation and in some cases, resources scarcity.
Efforts to meet the needs of 7.2 billion people for food, water, and energy will fail unless these three sectors are fully understood as a system of interdependent components; and solutions are developed based on multi-sector engagement.
The complexity of this challenge begins with the assertions that: water supply is influence by demands from energy and food sectors; food production requires both water and energy; and, energy requires water for a large fraction of its operations. Climate change, in particular drought, only exacerbates the system balance.
Fortunately, rapid advances in science and innovations in technology and practices are creating capabilities to more effectively understand the connections between food, energy and water systems in new ways. These advances can change the day-to-day practices of farmers, engineers, resource managers, and policy-makers to meet human needs in a far more sustainable manner.
Combining solar photovoltaic panels and food crops for optimising land use: Towards new agrivoltaic schemes[edit | edit source]
The need for new sources of renewable energies and the rising price of fossil fuels have induced the hope that agricultural crops may be a source of renewable energy for the future. We question in this paper the best strategies to convert solar radiation into both energy and food. The intrinsic efficiency of the photosynthetic process is quite low (around 3%) while commercially available monocristalline solar photovoltaic (PV) panels have an average yield of 15%. Therefore huge arrays of solar panels are now envisaged. Solar plants using PV panels will therefore compete with agriculture for land. In this paper, we suggest that a combination of solar panels and food crops on the same land unit may maximise the land use. We suggest to call this an agrivoltaic system. We used Land Equivalent Ratios to compare conventional options (separation of agriculture and energy harvesting) and two agrivoltaic systems with different densities of PV panels. We modelled the light transmission at the crop level by an array of solar panels and used a crop model to predict the productivity of the partially shaded crops. These preliminary results indicate that agrivoltaic systems may be very efficient: a 35e73% increase of global land productivity was predicted for the two densities of PV panels. Facilitation mechanisms similar to those evidenced in agroforestry systems may explain the advantage of such mixed systems. New solar plants may therefore combine electricity production with food production, especially in countries where cropping land is scarce. There is a need to validate the hypotheses included in our models and provide a proof of the concept by monitoring prototypes of agrivoltaic systems.
Productivity and radiation use efficiency of lettuces grown in the partial shade of photovoltaic panels[edit | edit source]
Combining photovoltaic panels (PVPs) and crops on the same land unit were recently proposed as an alternative to the conversion of cropland into photovoltaic plants. This could alleviate the increasing competition for land between food and energy production. In such agrivoltaic systems, an upper layer of PVPs partially shades crops at ground level. The aim of this work was to (i) assess the effect on crop yield of two PVPs densities, resulting in two shade levels equal to 50% and 70% of the incoming radiation and (ii) identify morphological and physiological determinants of the plant response to shade. Experiments were conducted on four varieties of lettuces (two crisphead lettuces and two cutting lettuces), during two seasons. In all cases, the relative lettuce yield at harvest was equal or higher than the available relative radiation. Lettuce yield was maintained through an improved Radiation Interception Efficiency (RIE) in the shade, while Radiation Conversion Efficiency (RCE) did not change significantly. Enhanced RIE was explained by (i) an increase in the total leaf area per plant, despite a decrease in the number of leaves and (ii) a different distribution of leaf area among the pool of leaves, the maximal size of leaves increasing in the shade. Our result provides a framework for the selection of adapted varieties according to their morphological traits and physiological responses to PVP shade, in order to optimize agrivoltaic systems.
Solar maps provide monthly average daily total solar resource information on grid cells. The insolation values represent the resource available to a flat plate collector, such as a photovoltaic panel, oriented due south at an angle from horizontal to equal to the latitude of the collector location. This is typical practice for PV system installation, although other orientations are also used.
- US Energy Data
Operational water consumption and withdrawal factors for electricity generating technologies: a review of existing literature[edit | edit source]
This report provides estimates of operational water withdrawal and water consumption factors for electricity generating technologies in the United States. Estimates of water factors were collected from published primary literature and were not modified except for unit conversions. The water factors presented may be useful in modeling and policy analyses where reliable power plant level data are not available. Major findings of the report include: water withdrawal and consumption factors vary greatly across and within fuel technologies, and water factors show greater agreement when organized according to cooling technologies as opposed to fuel technologies; a transition to a less carbon-intensive electricity sector could result in either an increase or a decrease in water use, depending on the choice of technologies and cooling systems employed; concentrating solar power technologies and coal facilities with carbon capture and sequestration capabilities have the highest water consumption values when using a recirculating cooling system; and non-thermal renewables, such as photovoltaics and wind, have the lowest water consumption factors. Improved power plant data and further studies into the water requirements of energy technologies in different climatic regions would facilitate greater resolution in analyses of water impacts of future energy and economic scenarios. This report provides the foundation for conducting water use impact assessments of the power sector while also identifying gaps in data that could guide future research.
- Solid values to compare water usage with coal vs solar
Polices for Controlling Groundwater Pollution from Concentrated Animal Feeding Operations[edit | edit source]
Animal waste from animal feeding operations (AFOs) is a significant contributor to nitrate contamination of groundwater. Some animal waste also contains heavy metals and salts that may build up in cropland and underlying aquifers. This thesis focuses on pollution reduction from the largest AFOs, in particular, Concentrated Animal Feeding Operations (CAFOs), which present the greatest potential risk among all AFOs to environmental quality and public health. To find cost effective policies for controlling pollution at the field level and at the farm level, a dynamic environmental-economic modeling framework for representative CAFOs is developed.
- Great source for info and policy on CAFOs
Aquavoltaics: Synergies for dual use of water area for solar photovoltaic electricity generation and aquaculture[edit | edit source]
This paper reviews the fields of floatovoltaic(FV) technology (water deployed solar photovoltaic systems) and aquaculture (farming of aquatic organisms) to investigate the potential of hybrid floatovoltaic-aquaculture synergistic applications for improving food-energy-water nexus sustainibility. If a U.S. national average value of solar flux is used then current aquaculture surface areas in use, if incorporated with appropriate solar technology could account for 10.3% of total U.S. energy consumption as of 2016.
- Potential synergies between FVs and aquaculture include, increase in water conservation, controlled aquatic environment and ecosystem restoration
- Controlling parameters such as nutrients, photoperiod (using FPV powered LEDs)
- Combining multiple aquatic species, more robust aquavoltaic system
- Detrimental elements between FVs and aquaculture - reduced available light for aquatic organisms and biofouling
- Unexplored micro-encapsulated phase change material(MEPCM)
- Blue LED most versatile for improving plant growth, affecting fish behavior and controlling plant diseases
- Comparison of different installations (thin-film FV, surface mounted and submerged FV)
- Good review article for possible ways of synergies between floatovoltaics and aquaculture
- Possible ideas for article
- impact of different LEDs on aquaculture
- MEPCM application in floatovoltaics
Direction of Paper(Light effects based)[edit | edit source]
- Useful for reference
- Not Used
Photoperiod and light intensity effects on growth and utilization of nutrients by the aquaculture feed microalga, Tetraselmis chui[edit | edit source]
Some effects of light intensity and photoperiod on the sea bass larvae (Dicentrarchus labrax (L.)) reared at the Centre Oceanologique de Bretagne[edit | edit source]
- Not Used
Effects of photoperiod on growth, survival and feeding periodicity of larval and juvenile barramundi Lates calcarifer (Bloch)[edit | edit source]
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Effects of continuous additional light on growth and sexual maturity in Atlantic salmon, Salmo salar, reared in sea cages[edit | edit source]
The effects of density, light and shelter on the growth and survival of African catfish (Clarias gariepinus Burchell), 1822 fingerlings[edit | edit source]
- Not Used
Fatty acid and elemental composition of the marine diatom Chaetoceros gracilis Schütt. Effects of silicate deprivation, temperature and light intensity[edit | edit source]
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Continuous light increases growth rate of Atlantic salmon (Salmo salar L.) postsmolts in sea cages[edit | edit source]
- Not Used
Effects of photoperiod and light intensity on growth and activity of juvenile haddock (Melanogrammus aeglefinus)[edit | edit source]
- Not Used
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Effects of continuous light and short-day photoperiod on smolting, seawater survival and growth in Atlantic salmon (Salmo salar)[edit | edit source]
- Not Used
Light-emitting diodes' light qualities and their corresponding scientific applications[edit | edit source]
Applications of light-emitting diodes in researches conducted in aquatic environment[edit | edit source]
Suspended sediment causes a range of environmental damage, including benthic smothering, irritation of fish gills, and transport of absorbed contaminants. Much of the impact, while sediment remains suspended, is related to its light attenuation, which reduces visual range in water and light availability for photosynthesis. Thus measurement of the optical attributes of suspended matter in many instances is more relevant than measurement of its mass concentration. Nephelometric turbidity, an index of light scattering by suspended particles, has been widely used as a simple,cheap, instrumental surrogate for suspended sediment, that also relates more directly than mass concentration to optical effects of suspended matter. However, turbidity is only a relative measure of scattering (versus arbitrary standards) that has no intrinsic environmental relevance until calibrated to a 'proper' scientific quantity. Visual clarity (measured as Secchi or black disc visibility) is a preferred optical quantity with immediate environmental relevance to aesthetics, contact recreation, and fish habitat. Contrary to common perception, visual clarity measurement is not particularly subjective and is more precise than turbidity measurement. Black disc visibility is inter-convertible with beam attenuation, a fundamental optical quantity that can be monitored continuously by beam transmissometry. Visual clarity or beam attenuation should supplant nephelometric turbidity in many water quality applications, including environmental standards.
Direction of Paper(material/solar based)[edit | edit source]
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Mechanical, thermal and microstructure evaluation of HDPE after weathering in Rio de Janeiro City[edit | edit source]
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Mechanical property and molecular weight distribution changes with photo- and chemical-degradation on LDPE films[edit | edit source]
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Comparison of UV-degradation depth-profiles in polyethylene, polypropylene and an ethyleneepropylene copolymer[edit | edit source]
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Thermal and electrical performance of a water-surface floating PV integrated with a water-saturated MEPCM layer[edit | edit source]
Thermal and electrical performances of a water-surface floating PV integrated with double water-saturated MEPCM layers[edit | edit source]
Design and installation of floating type photovoltaic energy generation system using FRP members[edit | edit source]
- Not Used
The accumulation of dust on the surface of a photovoltaic module decreases the radiation reaching the solar cell and produces losses in the generated power. Dust not only reduces the incoming radiation on the solar cell but also changes the dependence on the angle of incidence of such radiation. This work presents the results of a study carried out at the University of Malaga to quantify radiation losses caused by soiling on the surface of photovoltaic modules. Our results show that the mean of the daily irradiation losses in a year caused by dust deposited on the surface of a photovoltaic module is around 4%. After long periods without rain, daily irradiation losses can be higher than 20%. In addition, the irradiance losses are not constant throughout the day, and they are strongly dependent on the angle of incidence and the ratio between diffuse and direct radiations. The irradiance losses as a function of solar time are symmetric with respect to noon, where they reach the minimum value. We also propose a simple theoretical model that describes the qualitative behaviour of the irradiance losses during the day. This model takes into account the percentage of dirty surface and the diffuse/direct irradiance ratio. Copyright © 2012 John Wiley & Sons, Ltd.
The accumulation of dust on the surface of a photovoltaic module decreases the radiation reaching the solar cell and produces losses in the generated power. Dust not only reduces the radiation on the solar cell, but also changes the dependence on the angle of incidence of such radiation. This work presents the results of a study carried out at the University of Malaga to quantify losses caused by the accumulation of dust on the surface of photovoltaic modules. Our results show that the mean of the daily energy loss along a year caused by dust deposited on the surface of the PV module is around 4.4%. In long periods without rain, daily energy losses can be higher than 20%. In addition, the irradiance losses are not constant throughout the day and are strongly dependent on the sunlight incident angle and the ratio between diffuse and direct radiations. When studied as a function of solar time, the irradiance losses are symmetric with respect noon, where they reach the minimum value. We also propose a simple theoretical model that, taking into account the percentage of dirty surface and the diffuse/direct radiation ratio, accounts for the qualitative behavior of the irradiance losses during the day.
Impact of dust on solar photovoltaic (PV) performance: Research status, challenges and recommendations[edit | edit source]
The peaking of most oil reserves and impending climate change are critically driving the adoption of solar photovoltaic's (PV) as a sustainable renewable and eco-friendly alternative. Ongoing material research has yet to find a breakthrough in significantly raising the conversion efficiency of commercial PV modules. The installation of PV systems for optimum yield is primarily dictated by its geographic location (latitude and available solar insolation) and installation design (tilt, orientation and altitude) to maximize solar exposure. However, once these parameters have been addressed appropriately, there are other depending factors that arise in determining the system performance (efficiency and output). Dust is the lesser acknowledged factor that significantly influences the performance of the PV installations.
Thermal stability of phase change materials used in latent heat energy storage systems: A review[edit | edit source]
Successful utilization of the latent heat energy storage system depends considerably on the thermal reliability and stability of the phase change materials (PCMs) used. Thermal stability of phase change material can be established by measuring the thermo-physical properties of the PCM after a number of repeated thermal cycles. A comprehensive knowledge of thermal stability of the PCMs as functions of number of repeated thermal cycles is essential to ensure the long-term performance and economic feasibility of the latent heat storage systems. In this paper, a detailed review is reported for thermal stability of different groups of PCMs. The PCMs are categorized as organic (paraffins and non-paraffins), inorganic (salt hydrates and metallics) and eutectics (organic eutectics and inorganic eutectics). Further, a broad database of different PCMs is developed for which thermal cycling tests were carried out by different researchers and reported in the literature. Some conclusions are derived after critical evaluation of thermal stability of different groups of PCMs. This review will assist to identify the most reliable PCM to be used for a particular application of latent heat energy storage system.
The performance of a parabolic trough photovoltaic/thermal collector with a geometric concentration ratio of 37× is described. Measured results under typical operating conditions show thermal efficiency around 58% and electrical efficiency around 11%, therefore a combined efficiency of 69%. The impact of non-uniform illumination on the solar cells is investigated using purpose built equipment that moves a calibrated solar cell along the line of the receiver and measures short circuit current. The measured illumination flux profile along the length shows significant variation, despite the mirror shape error being less than 1 mm for most of the mirror area. The impact of the illumination non-uniformities due to the shape error, receiver support post shading and gaps between the mirrors is shown to have a significant effect on the overall electrical performance. The flux profile transverse to the receiver length is also investigated. Peak flux intensities are shown to be around 100 suns. The impact on efficiency due to open circuit voltage reduction is discussed.
- useful for showing the effects of concentrators on solar cells
- primarily a temperature gradation forms(up to 14C higher in center) which leads to decreased performance.
EVA browning and the time-dependence of I−V curve parameters on PV modules with and without mirror-enhancement in a desert environment[edit | edit source]
Two independent experiments are described that were performed on samples of EVA-laminated photovoltaic modules which form part of a grid-connected PV system in the Negev desert. Both types of experiment provide quantitative assessments of the rate at which module output power decreases when mirror-enhancement is employed under such conditions. One of the experiments, performed on 60 modules which have been exposed to mirror-enhanced solar radiation for the past 8.4 years, compared the measured I−V curve parameters of these modules with corresponding measurements that had been made 3.4 years earlier. The second experiment consisted of monthly I−V curve measurements, spread over the last 3.4 years, on three specific mirror-enhanced modules and on another three from which the mirrors had been removed. These experiments indicated that the mirror-enhanced modules are continuing to degrade at a comparable rate to an indirect estimate that had previously been made, i.e. approximately 1% per year. On the other hand, the modules from which mirrors were removed 3.4 years ago, although visually as "brown" as the others are degrading at an, as yet, unmeasurably small rate.
- shows the increase in degradation when mirrors are used. good long term study.
- moderately useful.
The photovoltaic technology is limited by costs, by the availability of spaces for photovoltaic fields and by the storage problems. The solution suggested in this work is the use of artificial basins or small lakes for installing PV floating plants with the following characteristics: a tracking system around the vertical axis, a panels cooling system achieved with water sprinklers and a set of reflectors that, by concentrating the radiation, increase the energy harvesting. We call these plants FTCC, the acronym of Floating, Tracking, Cooling, Concentrating. Additional benefits are possible using hydroelectric basins in particular when they are equipped, as often happens, with pumping facilities. In these structures, the existing pumping devices allow to store the energy produced by the FTCC avoiding energy dispersion problems and the electric grid stress. Three FTCC system solutions are presented and discussed theoretically and experimental results are also discussed. They are characterized by different levels of geometrical concentration, Cg: <;1.5, ≈2 and ≈20. In particular the first two systems use flat reflectors, whereas the third one uses parabolic mirrors. An important issue that arises when these systems are designed and operated is the uniformity of irradiance on the PV surface. This can be reached by means of an effective sensing and tracking of the system taking into account the relative position of sun and reflectors, as well as the acceptance angle of the concentrators. A first plant of 200 kWp based on these concepts is completed and grid connected in Suvereto - Livorno (Li Italy); another 30 kWp pilot plant has been built nearby Pisa (Italy).
- cooling via water dramatically increases the lifetime of the module due to the removal of thermal stresses.
- These systems when put on water become economically competitive.
- largely synergistic with hydroelectric damns and their water basins.
A new method to determine the effects of hydrodynamic surface coatings on the snow shedding effectiveness of solar photovoltaic modules[edit | edit source]
As solar photovoltaic (PV) installations have become more common in regions that experience substantial snowfall, losses in energy production due to snow coverage have grown in concern. Several post-production surface coatings have been proposed to enhance snow shedding to reduce these snow related losses. In this paper, a novel methodology is developed to determine the effectiveness of a snow clearing from a PV module and is used to evaluate the snow shedding effectiveness of any module surface treatment. Measured PV output is compared to modeled PV output in a generalizable method that allows for the determination of the length of time a panel is covered with snowfall using electrical performance data. This model accounts for module degradation during long-term outdoor testing and other external factors effecting performance, such as persistent soiling losses. This methodology was tested on modules that had one of four hydrodyanmic surface coatings, as well as one module with a prismatic glass front in order to determine the snow clearing effectiveness of these surfaces as compared to conventional plain glass. The methodology was validated, but the surface coatings tested did not have an appreciable positive effect on snow clearance, and in some cases tended to impede the shedding of snow. The physical mechanisms responsible for the results are discussed.
- Potentially useful coatings.
- Would need to investigate the effect on the surround water(absorption, bioaborption)
Multi-axes sun-tracking system with PLC control for photovoltaic panels in Turkey[edit | edit source]
In the present study, the azimuth and solar altitude angles of the sun were calculated for a period of 1 year at 37.6° latitude in the Northern hemisphere, where Turkey is located, and according to these angles, an electromechanical system which tracks the sun on both axes and which is controlled via a programmable logic control (PLC) and an analog module was designed and implemented.
After the mechanical control unit of the designed system was started, the performance measurements of the solar panel were carried out first when the solar panel was in a fixed position and then the solar panel was controlled while tracking the sun on azimuth and solar altitude angles and the necessary measurements were performed. It was observed that the control system operated without a problem. Besides, when the data obtained from the measurements were compared, it was seen that 42.6% more energy was obtained in the two-axes sun-tracking system when compared to the fixed system.
- Useful for tracking to flat angle on land comparison
In this paper, an electromechanical, two axes sun tracking system is designed and constructed. The programming method of control with an open loop system is employed where the programmable logic controller is used to control the motion of the sun tracking surface.
An experimental study was performed to investigate the effect of using two axes tracking on the solar energy collected. The collected energy was measured and compared with that on a fixed surface tilted at 32° towards the south. The results indicate that the measured collected solar energy on the moving surface was significantly larger than that on a fixed surface. The two axes tracking surface showed a better performance with an increase in the collected energy of up to 41.34% compared with the fixed surface.
- Useful for tracking to flat angle on land comparison
To investigate the optical performance of the vertical single-axis (v-axis, in short) tracked solar panels as compared with fixed and full 2-axis tracked solar panels, a mathematical procedure to estimate the annual collectible radiation on fixed and tracked panels is suggested based on the monthly horizontal radiation. Calculation results showed that the yearly optimal tilt-angle of a v-axis tracked solar panel for maximizing the annual energy collection was almost linearly proportional to the site latitude, and the corresponding maximum annual collectible radiation on such tracked panel was about 96% of solar radiation annually collected by a dual-axis tracked panel. Compared with a traditional fixed south-facing solar panel inclined at the optimal tilt-angle, the annual collectible radiation due to the use of the v-axis sun-tracking was increased by 28% in the areas with abundant solar resources and increased by16% in the areas with poor solar resources. An empirical correlation for a quick estimation of yearly optimal tilt-angles of v-axis tracked solar panels was also proposed based on climatic data of 31 sites in China.
- Comparison for single axis tracking land based solar modules
Direction of Paper(Aquaculture based)[edit | edit source]
Integrated aquaculture: rationale, evolution and state of the art emphasizing seaweed biofiltration in modern mariculture[edit | edit source]
Aquaponic Systems: Nutrient recycling from fish wastewater by vegetable production[edit | edit source]
This chapter describes the possibility to combine wastewater treatment in recirculating aquaculture systems (RAS) with the production of crop plants biomass. In an aquaponic RAS established in Waedenswil, Zurich, the potential of three crop plants was assessed to recycle nutrients from fish wastewater. A special design of trickling filters was used to provide nitrification of fish wastewater: Light-expanded clay aggregate (LECA) was filled in a layer of 30 cm in vegetable boxes, providing both surface for biofilm growth and cultivation area for crop plants. Aubergine, tomato and cucumber cultures were established in the LECA filter and nutrient removal rates calculated during 42–105 days. The highest nutrient removal rates by fruit harvest were achieved during tomato culture: over a period of >3 months, fruit production removed 0.52, 0.11 and 0.8 g m2 d1 for N, P and K in hydroponic and 0.43, 0.07 and 0.4 g m2 d1 for N, P and K in aquaponic. In aquaponic, 69% of nitrogen removal by the overall system could thus be converted into edible fruits. Plant yield in aquaponic was similar to conventional hydroponic production systems. The experiments showed that nutrient recycling is not a luxury reserved for rural areas with litlle space limitation; instead, the additionally occupied surface generates income by producing marketable goods. By converting nutrients into biomass, treating wastewater could become a profitable business.
- Integrated farming systems
Opportunities and challenges for the development of an integrated seaweed-based aquaculture activity in Chile: determining the physiological capabilities of Macrocystis and Gracilaria as biofilters[edit | edit source]
Seaweed production is a reality in Chile. More than ten species are commercially used to produce phycocolloids, fertilizers, plant growth control products, human food or animal fodder and feed additives. These multiple uses of algae offer a number of possibilities for coupling this activity tosalmon, abalone and filter-feeder farming. In this context, different experiments carried out in Chile have demonstrated that Gracilaria chilensis and Macrocystis pyrifera have great potential in the development of an integrated aquaculture strategy. The present Integrated Multi-Trophic Aquaculture (IMTA) approach study showed that Gracilaria can be cultured best at 1 m depth whereas Macrocystis has an especially good growth response at 3 m depth. Both species use available nitrogen efficiently. On the other hand, high intensities of solar radiation (UV and PAR) can be critical at low depths of cultivation, and our results indicate that both species show photosynthetic susceptibility mainly at noon during the summer. The demand of Macrocystis for abalone feeding is increasing, thus improving the opportunity for developing an integrated nutrient waste recycling activity in Chile. Although Gracilaria shows a higher nitrogen uptake capacity than Macrocystis, its market value does not yet allow a massive commercial scaling.
- Integrated aquacultures
The retinular responses of common squid Todarodes pacificus for energy efficient fishing lamp using LED[edit | edit source]
Blue light has outstanding transmission characteristics in the sea, and is known to cause the most sensitive visual response in common squid Todarodes pacificus. Application of a light emitting diode (LED) that can efficiently emit monochromatic light is expected to bring enormous energy savings. LED can produce cost-effective low-wattage irradiance at the specific wavelength. This study investigated the retinular responses of common squid T. pacificus to colored LED lights and light adaptation conditions based on the Perkinje effect, which is the tendency for the luminance sensitivity of the human eye to shift depending on the bright and dark adaptation states. The changes of the retinular response to blue, red and white LED were investigated in the bright and dark adaptation conditions in the water tank experiment. The degree of light adaptation was similar between the bright adaptation state and dark adaptation state to blue light, which suggests that squid retina is highly sensitive to blue light as it has been reported to date. On the other hand, the degree of light adaptation to red LED light showed a tendency to increase, albeit slightly, over time. However, the degree of light adaptation to white light with wide wavelength band showed similar tendencies as to the case of red light in the dark adaptation condition, and was actually superior to the case of blue light in the bright adaptation condition. Also, the degree of light adaptation of the retina cells collected from the sea experiment was found to be between the range of 20 and 40%. From these results, blue light may be regarded as an excellent luring source as the retina of squid is highly sensitive to it, but it cannot be determined as the most ideal LED color for the purpose of catching fish.
The effect of light intensity and spectrum on the incidence of first feeding by larval haddock[edit | edit source]
Under full-spectrum white light, feeding success of haddock Melanogrammus aeglefinus first feeding larvae, as measured both by proportion of larvae feeding and mean prey consumed, peaked at 1·7–18 mol s1 m2. Feeding was significantly reduced at lower and higher intensities. A similar result was observed for larvae feeding under blue (470 nm) light, with significantly greater feeding success at intermediate light intensity (1·8 mol s1 m2). When different light qualities were compared, larvae had significantly greater feeding success when exposed to blue (470 nm) light than either full-spectrum white or green (530 nm) light. Haddock larvae were capable of prey capture under all light treatments tested, indicating a necessary degree of adaptive flexibility in feeding response. The results are consistent with predisposition of haddock larvae to optimal feeding in a visual environment comparable with open ocean nursery grounds. Information on the impact of light on haddock first feeding can be incorporated into models of larval growth, survival, year-class strength and recruitment, and assist in developing husbandry protocols to maximize larval survival in aquaculture.
Effects of light on Atlantic cod (Gadus morhua) larvae performances: focus on spectrum[edit | edit source]
Most farmed marine fish species are carnivorous visual feeders which mainly rely on visual photoreceptors to detect their prey. As such the light environment can directly affect feeding behaviour and consequently larval growth and survival. Light is a complex environmental factor that depends on the lighting systems used (intensity and spectrum), photoperiod, water absorbance properties as well as the specific light sensitivities of the species being reared. While it is well documented that light intensity (Downing and Litvak 1999; Puvanendran & Brown, 2002; Brown et al., 2003) and to a lesser degree photoperiod (Downing and Litvak, 2000) can play a significant role in improving gadoid larvae growth and survival, little is known on the importance of light spectral properties with very few studies on marine larvae reported to date (Villamizar et al., 2009). This communication will present the findings from a number of studies during which the impact of light intensity and spectrum on cod larvae growth and survival to weaning were investigated. The optimised rearing of Atlantic cod is of great commercial interest as juvenile supply is one of the key production bottlenecks that limits this industry.
Effects of irradiance and light spectrum on growth of the scleractinian coral Galaxea fascicularis — Applicability of LEP and LED lighting to coral aquaculture[edit | edit source]
Due to global degradation of coral reefs and high demand for scleractinian corals, aquaculture of these marine organisms is gaining importance. To make coral aquaculture economically viable, optimisation of culture protocols is vital. We determined the effects of irradiance and light spectrum on the growth of a model scleractinian coral species, Galaxea fascicularis (Linnaeus 1767). Single polyps (n=10) were cultured under six different treatments; LED (light emitting diode) at a PPFD of 40–60, 125–150 and 275–325 μmol m−2 s−1; and LEP (light emitting plasma) at a PPFD of 40–60, 125–150 and 275–325 μmol m−2 s−1. Specific growth and survival rates were monitored over a 69-day interval. Mean specific growth rates were 0.031±0.006 day−1 for the LED 40–60 treatment, 0.030±0.007 day−1 for LED 125–150, 0.022±0.009 day−1 for LED 275–325, 0.024±0.011 day−1 for LEP 40–60, 0.040±0.008 day−1 for LEP 125–150, and 0.031±0.006 day−1 for LEP 275–325. Coral survival rate at the end of the growth interval was 95%. A significant main effect of irradiance on coral specific growth rate was found (factorial ANOVA, P= 0.018), whereas spectrum did not show a significant main effect (factorial ANOVA, P=0.085). A significant interactive effect between irradiance and spectrum was found (factorial ANOVA, P=0.013), as LEP lighting resulted in higher coral growth rates at the two higher irradiance levels applied. The effect of irradiance and its interaction with spectrum were likely modulated by water flow rates. Our results show that balanced as well as light sources skewed towards the blue part of the spectrum result in high coral growth. Specifically, LEP and LED have shown to be suitable lighting technologies for coral aquaculture, where LEP yields higher G. fascicularis growth rates at higher irradiance levels.
The aquaculture industry in the United States of America has become well established over the last 35 years but faces significant challenges to maintain continued growth. Total aquaculture production of 496 907 tonnes in 2008 generated USD 924 million. The mainstay of the industry is the production of channel catfish (Ictalurus punctatus) which occurs largely in earthen ponds in the southeastern States of Mississippi, Louisiana, Arkansas, and Alabama. Catfish represent 81 percent of the 287 132 tonnes of finfish produced in 2008 and 65 percent of the finfish value of USD 601 million. Catfish production increased steadily from the early 1980s reaching 300 000 tonnes in 2003, but has since declined by about 22 percent as a result of high feed costs and intense competition from imported, frozen fillet products from Asia. The culture of rainbow trout occurs throughout the country but occurs primarily in raceways in the northwestern State of Idaho. Production is relatively stable averaging about 24 000 tonnes in the decade from 1998 to 2008. Atlantic salmon is produced in ocean net pens off the northeastern coast with annual production fluctuating around 15 000 tonnes over the last decade. While, great potential exists to expand net pen culture of marine finfish, there is considerable opposition and until a supportive policy and regulatory regime are in place significant expansion of this industry sector is unlikely.
Shellfish are cultured in every coastal state but three primary production centres are located along coasts of the northeastern region, the Gulf of Mexico and the Pacific Northwest, primarily in Washington State. Shellfish production increased significantly from 1998 to 2008 representing 35 percent of the total industry value in 2008 generating USD 323 million with the average Annual Percentage Rate (APR) of six primary cultured species reaching 12.8 percent.
Implications of widespread algal biofuels production on macronutrient fertilizer supplies: Nutrient demand and evaluation of potential alternate nutrient sources[edit | edit source]
Biofuels from microalgae are currently the subject of many research projects to determine their feasibility as a replacement for fossil fuels. In order to be a successful candidate, there must be enough fertilizers available to support large scale production. Commercial fertilizers are available for biofuel production from the world fertilizer surplus, but due to nitrogen and phosphorus future production limitations, biofuels would ideally not use any of these resources to be a long term sustainable fuel. Nitrogen, phosphorus and potassium requirements were determined for two algal species, Chlorella and Nannochloropsis, to produce 19 billion l per year (BLPY). At this scale, both algal species would use 32–49%, 32–49% and less than 1% of the world surplus values of nitrogen, phosphorus and potassium, respectively. Nutrient recycling options and alternative sources of nutrients were evaluated to determine their potential contribution of lowering the synthetic fertilizer requirement. Results show that all of the recycling scenarios reduce the nutrient requirements, but catalytic hydrothermal gasification has the largest reduction of 95% of the nitrogen and 90% of the phosphorus. Contributions from all alternative sources can also provide only 5% or less of the required nitrogen when produced in the gulf region. For phosphorus in the same region, poultry concentrated animal feeding operations can provide up to 28% of the requirement of Chlorella. To find the least amount of nitrogen that may be used, catalytic hydrothermal gasification was combined with all of the alternative nutrients available in the gulf region. The maximum amount of biofuels that could be produced in this location without using any synthetic fertilizers is 50 ± 20 BLPY from Chlorella and 45 ± 19 BLPY from Nannochloropsis. This study shows that the nutrient requirement for biofuel production from microalgae will not be a limitation if recycling methods within the process chain and alternative sources of nutrients are utilized.
- Used for area measurements for in paper example.
References[edit | edit source]
- UK solar's first steps on the water [WWW Document], n.d. . Solar Power Portal. URL http://www.solarpowerportal.co.uk/guest_blog/uk_solars_first_steps_on_the_water (accessed 4.19.16).