Academic literature on the topic 'Water-supply for stock'
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Journal articles on the topic "Water-supply for stock"
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Evloeva D.U., Evloeva D. U. "PREDICTION OF EQUIPMENT OF THE HOUSING STOCK WITH WATER SUPPLY AND SEWERAGE." Vestnik scientific and methodological council in environmental engineering and water management, no. 21 (2021): 50–55. http://dx.doi.org/10.26897/2618-8732-2021-21-50-55.
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The article defines a well-maintained housing stock. The indicators of the level of improvement of the housing stock, characterizing the specific gravity of the living area, equipped with water supply, sewage, hot water supply, for the period 2000-2019, are analyzed. in Russia. Based on the analyzed data, a prediction was made for the arrangement of the housing stock with water supply and sewerage. Based on the prediction and their analysis, the main conclusions are made.
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WATANABE, Haruhiko, Sheng Ping ZHANG, and Akira SAKAI. "A Stochastic Evaluation Model of Water Supply System Combined with Regional Water Stock Utilization after Earthquake." ENVIRONMENTAL SYSTEMS RESEARCH 26 (1998): 175–81. http://dx.doi.org/10.2208/proer1988.26.175.
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Pérez y Pérez, Luis, and Jesús Barreiro Hurlé. "Una nota sobre la recuperación de costes de los servicios del agua en la cuenca del Gállego." Economía Agraria y Recursos Naturales 7, no. 13 (October 15, 2011): 49. http://dx.doi.org/10.7201/earn.2007.13.03.
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Up to date, water management in Spain has been focused on supply approaches, with the result of providing consumers with this resource at a low price. Developments in the institutional framework regulating water management in the European context (mainly the implementation of the Water Framework Directive) have shifted this approach in order to promote sustainable water use. To achieve this objective, tariff policy must now take into account the water services cost-recovery principle for its different uses. Within this context, this paper estimates the public capital stock related to water supply and assesses the existing level of cost-recovery related to that stock. The methodology used, compares the tax level needed for full-cost recovery with actual revenues from different water-related taxes. The case study area is Gallego River basin in Aragon, and results show the low cost- recovery level for most water services.
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Akers, Harry F., and Suzette A. T. Porter. "The 1945 - 1955 Queensland Artesian Fluoride Experience: A Unique Phenomenon within the Australian Wool Industry." Historical Records of Australian Science 18, no. 2 (2007): 177. http://dx.doi.org/10.1071/hr07007.
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Inquiries into the diminishing supply of artesian water within the Queensland aspect of the Great Artesian Basin began in 1939. These investigations produced a Queensland phenomenon without Australian precedent in terms of rationale, geographical diversity, and commitment of resources. In some regions, exposure of herds to fluoride emerged as an urgent issue because fluoride was perceived as an invasive, invisible, and odourless 'contaminant' in artesian water. This paper discusses the scientific background to, and management of, concerns over the consumption by stock of artesian water with a high concentration of natural bioavailable fluoride. The Queensland Department of Agriculture and Stock managed the problem by scientific investigation, methodical field study, and the application of research findings to animal husbandry. The practical solutions arrived at involved rotation of stock on an age-related basis to and from certain bore supplies, fencing young sheep away from the artesian supply, fencing young sheep near the bore-head, and limiting the use of supplements.
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Ogunremi, J. B., A. K. Dauda, and F. O. Akor. "Methods of improving the quality of fish seed supply to fish farmers in Benue State, Nigeria." Nigerian Journal of Animal Production 45, no. 1 (December 27, 2020): 99–105. http://dx.doi.org/10.51791/njap.v45i1.373.
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Methods of improving the quality of fish seed supply to fish farmers in Benue State were studied. Data were obtained from one hundred and thirty three fish farmers' using multistage random sampling technique. Structured questionnaire was used to obtain information from the respondents; data obtained were analyzed using descriptive statistics and Chi square to test relationship between the variables. The result showed that 53.83% of the fish farmers source their fish seeds from the wild. Methods of improving the quality of fish seed supply through brood-stock management were culture method (97.10%), feeding (94.10%) and genetic composition (97.0%). The major constraints to the methods of improving the quality of fish seed supply were respondents' technical knowhow (99.2%), inconsistent government policy (99.20%), lack of government assistance (97.0%) and inadequate extension services (97.0%). The Chi square analysis showed significant relationship between brood stock management and methods of improving the quality of fish seed supply (p<0.05). Also, significant relationship existed between methods of improving the quality of fish seed supply and constraints, inadequate water supply, scarcity of feed, poor brood stock management and lack of government assistance. Government should encourage the fish seed production industry by providing infrastructures, formulation and effective enforcement of consistent policies and provision of credit facilities to fish farmers.
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Ebrahim, Girma Y., Jonathan F. Lautze, and Karen G. Villholth. "Managed Aquifer Recharge in Africa: Taking Stock and Looking Forward." Water 12, no. 7 (June 27, 2020): 1844. http://dx.doi.org/10.3390/w12071844.
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Climatic variability and change result in unreliable and uncertain water availability and contribute to water insecurity in Africa, particularly in arid and semi-arid areas and where water storage infrastructure is limited. Managed aquifer recharge (MAR), which comprises purposeful recharge and storage of surface runoff and treated wastewater in aquifers, serves various purposes, of which a prominent one is to provide a means to mitigate adverse impact of climate variability. Despite clear scope for this technology in Africa, the prevalence and range of MAR experiences in Africa have not been extensively examined. The objective of this article is provide an overview of MAR progress in Africa and to inform the potential for future use of this approach in the continent. Information on MAR from 52 cases in Africa listed in the Global MAR Portal and collated from relevant literature was analyzed. Cases were classified according to 13 key characteristics including objective of the MAR project, technology applied, biophysical conditions, and technical and management challenges. Results of the review indicate that: (i) the extent of MAR practice in Africa is relatively limited, (ii) the main objective of MAR in Africa is to secure and augment water supply and balance variability in supply and demand, (iii) the surface spreading/infiltration method is the most common MAR method, (iv) surface water is the main water source for MAR, and (v) the total annual recharge volume is about 158 Mm3/year. MAR schemes exist in both urban and rural Africa, which exemplify the advancement of MAR implementation as well as its out scaling potential. Further, MAR schemes are most commonly found in areas of high inter-annual variability in water availability. If properly planned, implemented, managed, maintained and adapted to local conditions, MAR has large potential in securing water and increasing resilience in Africa. Ultimately, realizing the full potential of MAR in Africa will require undertaking hydrogeological and hydrological studies to determine feasibility of MAR, especially in geographic regions of high inter-annual climate variability and growing water demand. This, supported by increased research to gauge success of existing MAR projects and to address challenges, would help with future siting, design and implementation of MAR in Africa.
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Repnikov, A. I., Yu P. Serdobintsev, and M. P. Kukhtik. "DEVELOPMENT OF A NEURAL NETWORK FOR DETERMINING THE CAVITATION STOCK OF PUMPING UNITS." IZVESTIA VOLGOGRAD STATE TECHNICAL UNIVERSITY, no. 3(250) (March 26, 2021): 69–71. http://dx.doi.org/10.35211/1990-5297-2021-3-250-69-71.
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An automated emergency prevention system for the water supply system based on a neural network has been developed. The training sample is collected and loaded into the neural network. The algorithm of the neural network is developed and described. The constructed neural network protects the pumping equipment from cavitation.
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Nogueira, Mayra, Fernanda de Rezende Pinto, Ana Paula Nunes, Cintia Sobue Lorenzon Guariz, and Luiz Augusto do Amaral. "Effluents quality during the grow-out phase of the amazon shrimp macrobrachium amazonicum." Ciência Animal Brasileira 15, no. 2 (June 2014): 159–67. http://dx.doi.org/10.1590/1809-6891v15i219521.
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In recent years shrimp culture farms have been one of the most growing sectors in aquaculture. Research has been carried out in order to establish a sustainable production maintaining profit and low environmental impact. Current investigation analyzed source and effluent water produced during the final grow-out phase of the Amazon shrimp (Macrobrachium amazonicum). Twelve natural-bottom ponds, with continuous water flow and stock density comprising 40, 60, 80 and 100 young shrimps/m² were analyzed. The experiment design comprised totally randomized blocks with four treatments and three replications. Microbiological analyses for Escherichia coli was attempted, coupled to physical and chemical analyses for pH, temperature, total suspended solids, total nitrogen, nitrite, nitrate, biochemical oxygen demand and chemical oxygen demand of water supply and pond effluents. Results show that whereas effluent quality complied with current legal rules, there was no significant difference between supply and effluent water for the analyzed variables and between stock densities. Under the conditions investigated and the intensification of culture in the final grow-out phase up to a density of 100 young shrimps/m², the production of M. amazonicum reveals low potential for environmental impact for the variables analyzed.
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Tadokoro, H., H. Koibuchi, S. Takahashi, S. Kakudou, Y. Takata, D. Moriya, and M. Sasakawa. "Water supply control system for smarter electricity power usage adopting demand-response scheme." Water Supply 20, no. 1 (October 11, 2019): 140–47. http://dx.doi.org/10.2166/ws.2019.143.
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Abstract Demand-response is a scheme in which electricity suppliers and consumers collaborate for smarter usage of electricity aiming to mitigate the gap between supply and demand. It makes electricity consumers receive incentives through curtailing or increasing power demand during a certain period subject to request from the power infrastructure. Water utilities, as heavy electricity consumers, could participate in the scheme through shifting power demand by modifying pump operation schedule, utilizing reservoirs' buffering stock capability. We developed a conveyance/transmission pump scheduling algorithm to be applied in the scheme that requires a quick modification of pumping schedule to respond to a request. In addition, we made test bedding through a simulation approach utilizing actual data from Osaka Water Supply Authority to show the scheme's potential for waterworks and the effectiveness of the algorithm.
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Huynh, Tu Thanh, and Nghiem Van Truong. "Solutions to enhance job satisfaction of An Giang power and water supply joint stock company’s employees." Science and Technology Development Journal 18, no. 3 (August 30, 2015): 121–34. http://dx.doi.org/10.32508/stdj.v18i3.865.
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This article aims to identify factors that affect job satisfaction of employees of An Giang Power and Water Supply Joint Stock Company and suggest solutions to enhance their satisfaction. Six factors affecting the job satisfaction are as follows (ranked in the order of importance): (1) Training and promotion; (2) company policies; (3) co - workers; (4) working conditions; (5) leadership; and (6) the nature of work, in which all factors are found to have a positive correlation with the job satisfaction, except for the nature of work having a negative impact.
Dissertations / Theses on the topic "Water-supply for stock"
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Askham, Theresa. "Water sustainability : measurement, management, engagement, and disclosure of selected water-intensive companies on the Johannesburg Stock Exchange." Diss., 2016. http://hdl.handle.net/10500/20222.
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Many parts of the world, but South Africa specifically, are facing a water crisis, not only because of the scarcity of water, but also the quality of the water that is available. Companies are the primary users of water and can therefore have the most significant impact on saving water. It is thus imperative to determine how companies are measuring, managing, engaging with their stakeholders and disclosing water-related risks in their businesses. This study was conducted on the premise that South African companies have not as yet grasped the seriousness of the water crisis. Thirty JSE-listed companies classified as being water intensive were selected for the study. Their sustainability/integrated/annual reports for 2011 and 2013 were downloaded from the internet and analysed to determine if and how they were mitigating their water-related risks. The Ceres Aqua Gauge™ was used as the framework for this study. It was established during the analysis of the selected companies’ reports that, with the exception of food producers and food retailers, the companies had grasped the seriousness of the water crisis. One area of particular concern that was evident in all the companies was the lack of attention directed towards supply chain water management. Companies need to address water risks in their supply chain, and to also turn the water crisis from a threat into an opportunity. Investors need to engage with and put pressure on companies to improve their water management practices.Business Management
M. Ph. Accounting Sciences (Management Accounting)
Books on the topic "Water-supply for stock"
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Company, Saint John Water. Statement of the affairs of the company, published for the information of the public, preparatory to offering the new stock £10,000. Saint John, N.B: Printed at the Chronicle office by Durant & Co., 1988.
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United States. Congress. House. Committee on Science. Subcommittee on Environment, Technology, and Standards. Homeland security research and development at the EPA: Taking stock and looking ahead : hearing before the Subcommittee on Environment, Technnology, and Standards, Committee on Science, House of Representatives, One Hundred Eighth Congress, second session, May 19, 2004. Washington: U.S. G.P.O., 2004.
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Zenin, A. A. Formirovanie khimicheskogo sostava vody i donnykh otlozheniĭ rek, vodokhranilishcha i mori︠a︡, povedenie ti︠a︡zhelykh metallov v nikh i stok khimicheskikh veshchestv. Sankt-Peterburg: Gidrometeoizdat, 1994.
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United States. Congress. Senate. Committee on Energy and Natural Resources. Willow Creek winter stock water, Idaho: Report (to accompany S. 686). [Washington, D.C.?: U.S. G.P.O., 1985.
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US GOVERNMENT. Homeland Security Research and Development at the EPA: Taking Stock and Looking Ahead: Hearing Before the Subcommittee on Environment, Technology, and. Government Printing Office, 2004.
Find full textBook chapters on the topic "Water-supply for stock"
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"Balancing Fisheries Management and Water Uses for Impounded River Systems." In Balancing Fisheries Management and Water Uses for Impounded River Systems, edited by R. Scott Hale, Donald J. Degan, William H. Renwick, Michael J. Vanni, and Roy A. Stein. American Fisheries Society, 2008. http://dx.doi.org/10.47886/9781934874066.ch34.
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<em>Abstract</em>.—In Ohio reservoirs, a perceived excess of available gizzard shad <em>Dorosoma cepedianum </em>prey and poor recruitment of stocked walleyes <em>Sander vitreus </em>during the 1970s resulted in research to develop and expand a program to stock saugeyes (walleye × sauger <em>S. canadensis</em>), a hybrid better suited for shallow, productive, and turbid reservoirs with short water-residence times. Development of successful production techniques increased saugeye stocking from fewer than 1.2 million to 6–10 million fingerlings (28–42 mm) per year during 1980 through 1990, presenting the challenge of determining stocking rates suited to available prey. To improve <em>Sander </em>spp. stocking practices, we assessed prey supply by quantifying fish biomass in Ohio reservoirs using acoustic technology. Fish biomass varied from 10 to 897 kg/ha as estimated by 53 acoustic surveys conducted on 16 reservoirs during 1999–2006. Among 15 variables associated with reservoir productivity, 84% of the variability in fish biomass was explained by watershed area, trophic state, reservoir area, and reservoir volume; watershed area plus trophic state explained 77% of this variability. Dominance of fish prey smaller than 150 mm, which represented more than 80% of fishes sampled in acoustic surveys, revealed that reservoir fish biomass largely reflected the upper limit of prey fish biomass morphologically available to age-1 and older <em>Sander </em>spp. Gizzard shad represented more than 50% of the fishes captured in 92% of gill-netting surveys conducted in conjunction with acoustic surveys. Unexpectedly, reservoirs with extensive prey biomass occasionally had poor recruitment for <em>Sander </em>spp., and these reservoirs often were stocked at lower rates than ones with better recruitment. Fisheries managers in Ohio can improve stocking practices by using acoustic surveys to predict reservoir capacity for stocked sport fish based on reservoir attributes, then applying these results to details of reservoir-specific recruitment of stocked fishes and their consumptive demand. Refining this supply and demand approach will require continual progress in understanding reservoir ecosystems and their watersheds.
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Lorbiecki, Marybeth. "A Cowboy in Love: 1909– 1912." In A Fierce Green Fire. Oxford University Press, 2016. http://dx.doi.org/10.1093/oso/9780199965038.003.0010.
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Twenty-two-year-old Aldo Leopold arrived in Albuquerque, New Mexico Territory, in July 1909, burning with the “fervor of a sawdust evangelist.” The Forest Service had sent him to his first choice—District 3, encompassing the twenty-one forests of the South and Southwest. His duties were outlined in his manual: preserve a perpetual supply of timber for home industries, prevent destruction of forest cover (which regulates the flow of streams), and protect local industries from unfair competition in the use of forest and range. The district chief was Arthur Ringland, a stocky, energetic Yale graduate only a few years older than Leopold. Ringland sensed the new graduate’s enthusiasm and assigned him to the wildest lands in the district—the Apache National Forest in Arizona Territory. The land had originally belonged to the Apache Nation, but in 1886, the US Army forced most of the members onto a nearby reservation. This left but a few ranchers, farmers, and miners in the region. The forest headquarters rested in Springerville, Arizona, a two-day stagecoach ride from the last railroad stop. No automobiles carved tire treads over these plateaus and canyons. Travel was by foot, horse, or mule. Forest Assistant Leopold, the newest greenhorn among many, wasted no time in purchasing a feisty gray stallion called Jiminy Hicks, a saddle, a rope, and a few good roping lessons. Within the month, he also acquired pistols and a “rubber butt plate” for those long days in the saddle. The rubber plate came in handy since Aldo put in a good deal of time astride Jiminy Hicks. Throughout July and the beginning of August, Leopold inspected trees, marked them for cutting, planted seed plots, fixed fences, and met the other rangers. Working under Supervisor John D. Guthrie, Aldo contributed his two bits on policy decisions about grazing permits, water rights, and timber sales. Guthrie’s long hours and dedicated stance inspired the young ranger. The simplicity of life on the range, where one had to live out of a pack, made Leopold feel tough and free. On his own time, he hunted, mapped out the forest for himself, climbed mountains, and tested trout streams.
Conference papers on the topic "Water-supply for stock"
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Moaveni, Saeed. "Thermal Analysis of a Solar Hot Water System and a Stock Tank." In ASME 2009 3rd International Conference on Energy Sustainability collocated with the Heat Transfer and InterPACK09 Conferences. ASMEDC, 2009. http://dx.doi.org/10.1115/es2009-90106.
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During the cold winter months in the Midwestern States, a common problem that many livestock farmers face is to prevent the cattle drinking water, in a stock tank, from freezing. There are commercial water heating systems that consist of drinking fountains, submersible, or floating heaters. However, these units have typically high initial and operating costs. In this paper, we present the analysis and design of a low cost solar system that are made with tractor inner tubes and other readily available materials. Car and tractor inner tubes make good solar collectors because of their mechanical strength and thermophysical properties. The low cost solution reported here could also be used to address warm water supply and or space heating needs in developing countries. In this paper, the transient thermal response of wooden stock tanks with Fourier numbers around 0.01 is considered. Exact analytical solutions in the form of infinite series are used. The product solution of a cylinder and a plane wall is used to model the stock tank. Moreover, given the small Fourier number, a series of numerical experiments were performed to determine the number of terms that must be retained from the infinite series solutions to obtain accurate results. A theoretical model for the solar collector was also developed, and a series of physical experiments were performed to verify the theoretical models of the stock tank and the collector. The experimental results show that theoretical models, developed in this paper, predict the thermal behaviors of the collector and the stock tank well.
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Anderson, Peter, James Wonson, and W. John Dartnall. "Rigorous Design Process for a Groundwater Pump for Low-Yield Water Wells: A Case Study." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-39557.
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Ground-water pumping in remote areas, such as Australian farms, was for many years traditionally done by wind pumps in order to satisfy the needs of stock. Since the 1980’s solar pumps of varying designs have become popular for pumping water from farm dams and tube wells. Wind pumps, solar pumps, engine or electric motor driven pumps and even animal/human powered pumps have a future in many remote situations in the world for stock watering, irrigation and for village water supply in developing countries. In these markets there is a wide-spread view that local manufacture of the pumps is preferable, as is well documented in the literature on village water supply in developing countries. Submersible pumps that are either of the multi-stage centrifugal class or that use the progressive cavity principle have increased in popularity in the low well yield environment. However, where well yields are extremely low the efficiency of these pumps also becomes low and oversized pumps of these kinds are often inappropriately applied. Quite often in the low yield situation, tube wells are also oversized in that they are drilled to large diameters and depths so as to provide storage in order to accommodate the water demand requirements of the user. This practice leads to unnecessary deterioration of both pump and well. Designing for low production volume manufacture presents unique challenges for the designer in attempting to design a robust, versatile but cost-effective product. The design challenges include, achievement of: - high efficiency, reliability, longevity, simplicity, versatility with a minimum parts count, and all this at a low cost. A case study is presented in this paper in which the design issues are outlined. A rigorous design process has been applied in this case study.
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Colella, Whitney G., and Viraj Srivastava. "Examining the Integration of Fuel Cell Systems Into Buildings Through Simulation." In ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology collocated with the ASME 2012 6th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/fuelcell2012-91474.
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The widespread use of combined heat and power (CHP) distributed generation (DG) for buildings could significantly increase energy efficiency and reduce greenhouse gas and air pollution emissions. By displacing both electricity from conventional centralized power plants and heat from decentralized boilers, CHP DG could reduce primary feedstock fuel consumption in the U.S. by approximately 20%, or 6,000 terawatt hours. However, optimally integrating CHP DG within buildings is challenging. This work aims to elucidate optimal system sizing and design of micro-CHP fuel cell systems (FCSs) integrated with commercial buildings. This modeling effort compares and contrasts the performance of high temperature polymer electrolyte membrane (PEM) fuel cell systems (HTPEM FCSs) and solid oxide fuel cell (SOFC) systems for commercial buildings. A parallel research effort is independently analyzing measured data from HTPEM FCSs installed in commercial buildings. Measured data from that effort is integrated into this modeling work. In certain regions, there has been a research and development and commercialization trend moving from using low temperature PEM FCSs (e.g. with a stack temperature of around 80°C) to using HTPEM FCSs (e.g. with a stack temperature of around 160°C) and to using SOFC systems (e.g. with a stack temperature of around 700°C) for CHP building applications, given the higher temperature of the available waste heat from these systems. In this work FCS performance data is coupled with building energy system models from the U.S. Department of Energy (DOE) using EnergyPlus™ whole-building energy simulation software. Using these baseline reference commercial building model data, parameters are examined including heat demand for space heating and for domestic hot water heating over time, temperatures and water flow rates associated with this heat demand, and building electrical demand over time, to evaluate FCS integration within the building. Examining the data obtained through the simulation exercise in this work, it is found that in a large office building, with heat demand temperatures in the range of 82°C for space heating and 60°C for hot water heating, an HTPEM FCS with an exhaust temperature of 47°C can potentially access, at a maximum, 19% of the total building heating demand. By contrast, in a small office building, with heat demand temperatures in the range of 23°C (supply air temperature) for space heating and 60°C for hot water heating, it is found that this HTPEM FCS can potentially access, at a maximum, 90% of the total building heating demand. Examining the temporal characteristics of the building heat demand to determine FCS sizing, it is found that a maximum of 50% of the time, the heat demand can be served with an HTPEM FCS with a thermal capacity of 8 kilowatts (kW) (0.05 kW for small office) and an electrical capacity of approximately 4.5 kilowatts-electric (kWe) (0.45 kWe for small office). A maximum of 80% of the time, the heat demand can be served with an HTPEM FCS with a thermal capacity of 85 kW (0.16 kW for small office) and an electrical capacity of approximately 73 kWe (0.14 kWe for small office). The simulation results further indicate that an SOFC has advantages over an HTPEM FCS that originate from its higher exhaust temperature (between 25°C and 315°C), which allows it to meet a greater percentage of the building heating demand (up to 100%). This enables an SOFC to serve a larger percentage of the building stock and a wider variety of building heating systems. Furthermore, if the CHP FCSs are grid independent (i.e., it is not possible to supply electrical power back to the grid), then the heat-to-power ratio of an FCS can be an important parameter. In such a scenario, the heat-to-power ratio of an SOFC (approximately 0.33) is closer to the heat-to-power ratio of a building (approximately 0.081, averaged over an entire year). In a stand-alone configuration, when the CHP DG has a heat-to-power ratio that more closely matches that of the buildings, the utilization of the DG system is likely to be higher and its economics and environmental impacts more favorable.
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Ahn, Jong-Woo, Jinglin He, and Song-Yul Choe. "Design of Air, Water, Temperature and Hydrogen Controls for a PEM Fuel Cell System." In ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology collocated with ASME 2011 5th International Conference on Energy Sustainability. ASMEDC, 2011. http://dx.doi.org/10.1115/fuelcell2011-54554.
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Polymer electrolyte membrane (PEM) fuel cell is the potential power source for vehicle applications, where supply of fuels and rejection of heat play significant roles in ensuring performance and durability. Operations of the fuel cells require four subsystems, air supply system, water and thermal management and hydrogen delivery system. Air supply system consists of a blower and a gas-to-gas humidifier. The air is supplied to the stack by the blower and humidified by a gas-to-gas humidifier using stack exhaust gas. Controls for the air supply system are designed based on a static feed-forward control and a state feedback control with integrator to maintain the oxygen excess ratio at a desired level regardless of any load applied. Flow rates of air controlled by a voltage of an electric motor driving a blower should be able to supply oxygen to dynamically follow changes of loads, whereby oxygen excess rate should be kept at a level that prevents oxygen starvation. At the same time, water in the stack should be maintained optimally to keep from low proton conductivity and water flooding in porous materials. Therefore, supplying air is humidified with a humidifier that captures moistures exiting the stack. In order to manipulate the amount of humidity, we propose to use an extra bypass valve, which opening is controlled to optimally maintain humidification of the membrane and avoid water flooding. Thermal management system consists of two thermal circuits because of cooling effectiveness, where the inner thermal circuit is made of a bypass valve, a heat exchanger, a water reservoir and a water pump, while the outer thermal circuit is made of a radiator along with a fan, a coolant reservoir and a pump. In order to maintain the stack working temperature at a desired temperature and reduce parasitic powers, a state feedback controller with integrator is employed. Fuel delivery system is a hybridized one that consists of two recirculation lines with an ejector and a blow in order to increase efficiency of fuel usage. The supply line is made of a hydrogen tank, a flow control valve and a low pressure regulator. Controls are designed to track a flow rate where pressure is kept at constant and purging operations are allowed. In this paper, controls for four subsystems of fuel cell system were proposed and examined on a dynamic one dimensional model for a stack that considers non isothermal and two-phase effects. Optimized state feedback controllers with integrator and observers are used to improve control performances and results are presented.
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Waite, Michael, and Vijay Modi. "Calibrated Building Energy Models for Community-Scale Sustainability Analyses." In ASME 2014 8th International Conference on Energy Sustainability collocated with the ASME 2014 12th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/es2014-6642.
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Building energy contributes approximately 40% of U.S. greenhouse gas emissions and 75% of emissions in some urban areas. Evaluating modifications to existing building stocks is essential to a proper assessment of GHG reduction policy at various levels. With deeper penetration of intermittent renewable energy resources, supply and demand effects at a high resolution (e.g. hourly) will become more important as variations in grid emissions will become more significant. City-level hourly electricity load data is available; however, effects of building stock changes on usage profiles are not easily analyzed, and on-site fossil fuel usage — the dominant loads in many urban areas — are generally only available annually. Building energy models allow for detailed simulation of building systems, but existing building models must be calibrated to actual energy usage to predict the effects of energy conservation measures. Reference building models developed by the U.S. Department of Energy for the EnergyPlus software tool were used as the basis for a set of calibrated building energy models to perform community-scale energy conservation measures on the dominant building classes in NYC (i.e. residential and office buildings). A statistical analysis of zip code-level annual electricity and fuel usage data was performed to determine electricity, space heating fuel and domestic hot water (DHW) fuel usage intensities (EUIs) for three broad building categories encompassing these building types in New York City. Several parameters were adjusted for each model until simulations produced the EUIs from the statistical analysis: Thermal envelope characteristics, peak electric equipment and lighting loads, DHW flow requirements, cooling equipment coefficient of performance and heating equipment efficiency. Cooling energy demands were adjusted based on the electricity demand vs. temperature behavior during the cooling season. The hourly daily usage schedules of internal electric and lighting loads were then adjusted for all models, targeting the actual hourly electricity demands for NYC. Because hourly changes affect annual EUIs, the calibrations were performed iteratively until the model outputs, weighted by each building type’s total NYC square footage, equaled the annual EUIs for each building type and the hourly electricity demand data. This paper shows that this comprehensive calibration approach can achieve root-mean-square deviation (RMSD) of 7% from the average annual electricity demand for these building types, compared to a 31% RMSD for an approach using annual energy calibration only.
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Yu, Lili, Weilin Zhuge, Yangjun Zhang, and Jie Peng. "Comparative Investigation on Waste Heat Driven Air Supply Systems for PEM Fuel Cells." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-57115.
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The air supply system plays a key role for Proton Exchange Membrane (PEM) fuel cells. The performance of PEM fuel cells can be significantly improved by increasing the air supply pressure and air stoichiometric ratio. However, the increased electrical power consumption of the conventional motor driven air compressor operated at higher pressure would reduce the overall efficiency of the PEM fuel cell system. This paper proposes three novel air supply systems in which the compressor is driven by the waste heat recovered by the Organic Rankine Cycle (ORC) from the stack cooling water and the exhaust gas. The influences of air supply pressure and air stoichiometric ratio on the PEM fuel cell performance and exhaust gas are investigated through the fuel cell stack model. The performance analysis of the air supply system is carried out using a thermodynamic simulation model. And the proposed three air systems are compared to an air system driven by the exhaust gas and the assisted motor. Results show that both the air pressure and air stoichiometric ratio are improved significantly. The gross output electric power and the net efficiency of the PEM fuel cells are also improved greatly because of higher operating pressure and the elimination of the compressor power consumption. Among the 3 proposed air systems, the air system which has a self-circulation to maintain the stack temperature has the best performance and is most stable in operation.
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Friedman, David J., Anthony Eggert, P. Badrinarayanan, and Joshua Cunningham. "Balancing Stack, Air Supply, and Water/Thermal Management Demands for an Indirect Methanol PEM Fuel Cell System." In SAE 2001 World Congress. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2001. http://dx.doi.org/10.4271/2001-01-0535.
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McKay, D. A., W. T. Ott, and A. G. Stefanopoulou. "Modeling, Parameter Identification, and Validation of Reactant and Water Dynamics for a Fuel Cell Stack." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81484.
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This paper describes a simple two-phase flow dynamic model that predicts the experimentally observed temporal behavior of a proton exchange membrane fuel cell stack and a methodology to experimentally identify tunable physical parameters. The model equations allow temporal calculation of the species concentrations across the gas diffusion layers, the vapor transport across the membrane, the degree of flooding in the electrodes, and then predict the resulting decay in cell voltage over time. A nonlinear optimization technique is used for the identification of two critical model parameters, namely the membrane water vapor diffusion coefficient and the thickness of the liquid water film covering the fuel cell active area. The calibrated model is validated for a 24 cell, 300 cm2 stack with a supply of pressure regulated pure hydrogen.
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Bethapudi, Sasank Viswanath, N. Rajalakshmi, and K. S. Dhathathreyan. "PEMFC Stack Activation Through Thermal Management." In ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology collocated with the ASME 2013 Heat Transfer Summer Conference and the ASME 2013 7th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/fuelcell2013-18203.
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Activation of PEM fuel cell stack is an important factor in setting peak power of stack before its steady operations. Several methods of activation for larger capacity stacks involve operation of the stacks initially at low voltages under highly humidified conditions and at high temperatures. This is expected to improve proton conductivity of the membrane. For large area cells this method can create hot spots due to high current and non-uniform temperature distribution. Hence, an alternative approach for activating PEMFC stack at low current for vehicular applications has been investigated in this study. Conventional stack activation requires continuous supply of coolant. However for vehicular applications, a closed loop thermal management system is required. During the course of developing such a close loop thermal management system for transportation application, we have identified that the same system can be used in activating a PEM fuel cell stack. In the present study a 5kW PEMFC stack, operating on dry reactants, has been activated using a closed loop thermal management system. The activation has been carried out over a period of 620 minutes with 6 start/stop cycles. Through the start stop cycles the power delivered by the stack steadily increased from 2.5kW, to 5kW. Further, heat developed inside the fuel cell, as removed by the coolant water, has been studied and there is a proportional increase in the overall heat removed by the coolant to the total power delivered by the fuel cell. The start stop cycles are regulated based on the single cell voltages and stack temperature. Each cycle is stopped when the stack temperature reaches a set temperature of 50°C. The advantage of this procedure is that it will result in long life of the fuel cell stack, uniform membrane equilibration, and will avert hot spot generation in the electrodes at low cell potential.
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Izenson, Michael G., and Roger W. Hill. "Water Balance in PEM Fuel Cells." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-33168.
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Fuel cells based on polymer electrolyte membranes (PEMs) are attractive power sources because they are efficient, non-polluting, and do not rely on non-renewable fossil fuels. Water management is a critical design issue for these fuel cells because the PEM must be maintained at the proper water content to remain ionically conducting without flooding the electrodes. Furthermore, portable PEM power systems should operate at water balance. That is, water losses from the cell should be balanced by the rate of water production from the fuel cell reaction. A portable system that operates at water balance does not require an external supply of water. The rate of water production depends on the cell’s electrochemical characteristics. The rate of water loss depends on the flow rates of reactants and products, transport of water and fuel across the PEM, and the stack operating temperature. This paper presents the basic design relationships that govern water balance in a PEM fuel cell. Specific calculations are presented based on data from hydrogen/air and direct methanol fuel cells currently under development for portable power systems. We will show how the water balance operating point depends on the cell operating parameters and show the sensitivity to off-design conditions.
Reports on the topic "Water-supply for stock"
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Day, St John, Tim Forster, and Ryan Schweitzer. Water Supply in Protracted Humanitarian Crises: Reflections on the sustainability of service delivery models. Oxfam, UNHCR, September 2020. http://dx.doi.org/10.21201/2020.6362.
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UNHCR estimates that the average time spent by a refugee in a camp is 10 years, while the average refugee camp remains for 26 years. WASH (water, sanitation and hygiene) is a crucial component of humanitarian response and longer-term recovery. Humanitarian agencies and host governments face many challenges in protracted situations and complex long-term humanitarian crises. One key issue is how water supplies should be managed in the long term. Who is best placed to operate and manage WASH services and which delivery model is the most viable? At the end of 2019, there were 15.7 million refugees in protracted situations, representing 77% of all refugees. This report takes stock of the various alternative service delivery models, to enable humanitarian and development agencies to work together to smooth the transition from emergency relief to sustainable services.
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Guidati, Gianfranco, and Domenico Giardini. Joint synthesis “Geothermal Energy” of the NRP “Energy”. Swiss National Science Foundation (SNSF), February 2020. http://dx.doi.org/10.46446/publication_nrp70_nrp71.2020.4.en.
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Near-to-surface geothermal energy with heat pumps is state of the art and is already widespread in Switzerland. In the future energy system, medium-deep to deep geothermal energy (1 to 6 kilometres) will, in addition, play an important role. To the forefront is the supply of heat for buildings and industrial processes. This form of geothermal energy utilisation requires a highly permeable underground area that allows a fluid – usually water – to absorb the naturally existing rock heat and then transport it to the surface. Sedimentary rocks are usually permeable by nature, whereas for granites and gneisses permeability must be artificially induced by injecting water. The heat gained in this way increases in line with the drilling depth: at a depth of 1 kilometre, the underground temperature is approximately 40°C, while at a depth of 3 kilometres it is around 100°C. To drive a steam turbine for the production of electricity, temperatures of over 100°C are required. As this requires greater depths of 3 to 6 kilometres, the risk of seismicity induced by the drilling also increases. Underground zones are also suitable for storing heat and gases, such as hydrogen or methane, and for the definitive storage of CO2. For this purpose, such zones need to fulfil similar requirements to those applicable to heat generation. In addition, however, a dense top layer is required above the reservoir so that the gas cannot escape. The joint project “Hydropower and geo-energy” of the NRP “Energy” focused on the question of where suitable ground layers can be found in Switzerland that optimally meet the requirements for the various uses. A second research priority concerned measures to reduce seismicity induced by deep drilling and the resulting damage to buildings. Models and simulations were also developed which contribute to a better understanding of the underground processes involved in the development and use of geothermal resources. In summary, the research results show that there are good conditions in Switzerland for the use of medium-deep geothermal energy (1 to 3 kilometres) – both for the building stock and for industrial processes. There are also grounds for optimism concerning the seasonal storage of heat and gases. In contrast, the potential for the definitive storage of CO2 in relevant quantities is rather limited. With respect to electricity production using deep geothermal energy (> 3 kilometres), the extent to which there is potential to exploit the underground economically is still not absolutely certain. In this regard, industrially operated demonstration plants are urgently needed in order to boost acceptance among the population and investors.