Dissertations / Theses: 'Surface water source heat'

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Charoenvisal, Kongkun. "Energy Performance and Economic Evaluations of the Geothermal Heat Pump System used in the KnowledgeWorks I and II Buildings, Blacksburg, Virginia." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/33942.

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Heating, Ventilating and Air Conditioning Systems (HVAC) are not only one of the most energy consuming components in buildings but also contribute to green house gas emissions. As a result often environmental design strategies are focused on the performance of these systems. New HVAC technologies such as Geothermal Heat Pump systems have relatively high performance efficiencies when compared to typical systems and therefore could be part of whole-building performance design strategies.

In collaboration with the Virginia Tech Corporate Research Center, Inc., this research studies the energy consumption and cost benefits of the Geothermal Heat Pump System that has been integrated and operated in the KnowledgeWorks I and II buildings located on the Virginia Tech campus.

The purpose of this thesis is to understand the energy and cost benefits of the Geothermal Heat Pumps System when compared to the conventional package variable air volume (VAV) with hot water coil heating and air-source heat pump systems using computer simulation and statistical models. The quantitative methods of building energy performance and life-cycle cost analyses are applied to evaluate the results of simulation models, the in-situ monitoring data, and the associated documents. This understanding can be expanded to the higher level of architectural systems integration.
Master of Science

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Barikan, Chirin. "Hydronic Pavement Systems for Sustainable Winter Road Maintenance in Sweden : A Study of Hamnbacken in Visby." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254668.

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In countries with harsh winter climates extensive winter road maintenance is necessary to achieve traffic accessibility and road safety. These measures have high economic and environmental costs as snow free roads and winter road maintenance in Sweden today is achieved by a combination of mechanical snow clearance and the spreading of salt to prevent ice formation. The salt ends up in the roadside environment and has negative effects on groundwater and vegetation. An alternative to traditional winter road maintenance to obtain non-skid winter roads is the use of hydronic pavement(HP) systems. Existing HP systems in Sweden are powered by district heating which limits the application to urban locations. The goal is to utilize renewable energy sources such as geoenergy which can be used in both rural and urban locations. This thesis suggests Hamnbacken in Visby as a pilot project for a full-scale application of the proposed HP system using surface water source heat.The weather related road surface conditions on Hamnbacken, and the potential of a renewable energysource have been examined in this study and the proposed location has been found favourable for a HP system.
Länder med övervägande kallt vinterklimat är halkbekämpning en nödvändighet för trafikens framkomlighet och säkerhet. Åtgärderna som vidtas för att få snö- och isfria vägar är kostsamma samt har en hög miljöpåverkan, ett vedertagligt exempel är plogning och saltning. Saltet hamnar i slutändan inom vägens omgivande områden och har en negativ påverkan på grundvatten och vegetation. En alternativ lösning till traditionell halkbekämpning är uppvärmda vägar för att uppnå ett halkfritt vinterväglag. Befintliga väguppvärmningssystem i Sverige försörjs av fjärrvärme vilket är en begräsning då tillgången till fjärrvärme finns i anslutning till tätorter. Målet är att utnyttja förnybara energikällor såsom geoenergi som är tillgänglig både i tätorter och på landsbygden. Det här examensarbetet undersöker Hamnbacken i Visby som ett pilotprojekt för en fullskalig implementering av väguppvärmningssystem där sjövärme används som energikälla. Denna studie har undersökt väderrelaterade vägförhållanden på Hamnbacken samt potentialen för användning av sjövärme. Den föreslagna platsens förutsättningar har visat sig vara gynnsamma i detta avseende.

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3

Primartomo, A. "Laser surface treatment using customised heat source profiles." Thesis, Loughborough University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429008.

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4

Joel, Abraham. "Surface runoff : a water source for poor farming communities in drylands /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5753-X.pdf.

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5

Preston, Daniel J. (Daniel John). "Enhanced condensation heat transfer for water and low surface tension fluids." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113167.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 68-79).
Vapor condensation is routinely used as an effective means of transferring heat or separating fluids for applications ranging from personal electronic device thermal management to natural gas processing and electric power generation. Filmwise condensation, where the condensed fluid forms a liquid film, is prevalent in typical industrial-scale systems. Conversely, dropwise condensation, where the condensate forms discrete liquid droplets, results in an improvement in heat transfer performance of up to an order of magnitude compared to filmwise condensation. We explored rare earth oxides (REOs) as a potential coating to induce dropwise condensation of water; specifically, we experimentally demonstrated that the mechanism for REO hydrophobicity results from adsorption of contaminants from the atmosphere. We also used graphene, which is hydrophobic in nature, as a coating to achieve robust dropwise water condensation. With a graphene coating, we demonstrated a 4x improvement in water condensation heat transfer compared to filmwise condensation with robustness superior to state-of-the-art hydrophobic monolayer coatings. Meanwhile, low surface tension condensates pose a unique challenge since they often form a film, even on hydrophobic coatings. Lubricant infused surfaces (LIS) represent a potential solution, where a lubricant immiscible with the low surface tension condensate is infused into a rough structure on the condenser surface to repel the condensate. We developed a detailed surface-energy-based model to provide design guidelines for any arbitrary LIS system. We then characterized heat transfer coefficients during condensation of low surface tension fluids on LIS in a controlled environmental chamber for the first time, where a 5x improvement was demonstrated compared to filmwise condensation. The improved condensation heat transfer coefficients realized by LIS for low surface tension fluids and by REOs and graphene for water present opportunities for significant energy savings in device thermal management, heating and cooling, and power generation.
by Daniel John Preston.
Ph. D.

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6

Malone, Patrick R. "Identifying and Managing Impacts of Point and Non-Point Source Pollution on Surface Water Quality." Digital WPI, 2015. https://digitalcommons.wpi.edu/etd-theses/513.

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Surface waters can be impacted by point and non-point source (NPS) pollution including stormwater culverts, runoff, and septic systems. It is important to develop water quality monitoring plans that can be implemented within resource constraints while still providing useful data. The goal of this research was to develop a sampling strategy to identify the impacts of point and NPS pollution on surface waters. This research incorporates water quality monitoring, land use data, precipitation data, and statistical modeling to improve understanding of pollutant impacts on surface waters. Research was conducted at a 152-acre private lake in western Massachusetts. Lake water samples were collected approximately twice per month over 12 months at ten sample locations selected to isolate land uses, including (1) shoreline samples adjacent to homes with septic systems, (2) shoreline samples at stormwater discharge sites, and (3) control samples at the lake influent, lake effluent, and a private beach. Sampling events included dry and wet weather conditions. Water samples were analyzed for physical, chemical, and microbiological parameters including: pH, conductivity, dissolved oxygen, turbidity, alkalinity, nutrients, anions, organic carbon, and microbial indicators (total coliform, E. coli, enterococci, male-specific and somatic coliphages). The data were statistically analyzed to determine how land use, season, and precipitation affect the risk of contamination to surface waters. Results indicated significant water quality variations by land use, season, and precipitation and identified important correlations between water quality parameters.

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Gustafsson, David. "Boreal land surface water and heat balance : Modelling soil-snow-vegetation-atmosphere behaviour." Doctoral thesis, KTH, Mark- och vattenteknik, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3406.

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The water and heat exchange in thesoil-snow-vegetation-atmosphere system was studied in order toimprove the quantitative knowledge of land surface processes.In this study, numerical simulation models and availabledatasets representing arable land, sub-alpine snowpack, andboreal forest were evaluated at both diurnal and seasonaltimescales. Surface heat fluxes, snow depth, soil temperatures andmeteorological conditions were measured at an agriculturalfield in central Sweden during three winters and two summersfrom 1997 to 2000 within the WINTEX project. A one-dimensionalsimulation model (COUP) was used to simulate the water and heatbalance of the field. Comparison of simulated and measured heatfluxes in winter showed that parameter values governing theupper boundary condition were more important for explainingmeasured fluxes than the formulation of the internal mass andheat balance of the snow cover. The assumption of steady stateheat exchange between the surface and the reference height wasinadequate during stable atmospheric conditions. Independentestimates of the soil heat and water balance together with thecomparison of simulated and measured surface heat fluxes showedthat the eddy-correlation estimates of latent heat fluxes fromthe arable field were on average 40 % too low. The ability of a multi-layered snowpack model (SNTHERM) tosimulate the layered nature of a sub-alpine snowpack wasevaluated based on a dataset from Switzerland. The modelsimulated the seasonal development of snow depth and densitywith high accuracy. However, the models ability to reproducethe strong observed snowpack layering was limited by theneglection of the effect of snow microstructure on snowsettling, and a poor representation of water redistributionwithin the snowpack. The representation of boreal forest in the land surfacescheme used within a weather forecast (ECMWF) model was testedwith a three-year dataset from the NOPEX forest site in centralSweden. The new formulation with separate energy balances forvegetation and the soil/snow beneath the tree cover improvedthe simulation of seasonal and diurnal variations in latent andsensible heat flux. Further improvements of simulated latentheat fluxes were obtained when seasonal variation in vegetationproperties was introduced. Application of the COUP model withthe same dataset showed that simulation of evaporation fromintercepted snow contributed to a better agreement with themeasured sensible heat flux above forests, but also indicatedthat the measurements might have underestimated latent heatflux. The winter sensible heat flux above the forest wasfurther improved if an upper limit of the aerodynamicresistance of 500 s m-1 was applied for stable conditions. A comparison of the water and heat balance of arable landand forest confirmed the general knowledge of the differencesbetween these two surface types. The forest contributed withconsiderably more sensible heat flux to the atmosphere than thearable land in spring and summer due to the lower albedo andrelatively less latent heat flux. Latent heat flux from theforest was higher in winter due to the evaporation ofintercepted snow and rain. The net radiation absorbed by theforest was 60 % higher than that absorbed by the arable land,due to the lower surface albedo in winter. Key words:soil; snow; land surface heat exchange;forest; arable land; eddy-correlation.
QC 20100614

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8

Badri, Seyed Ali Mohammad. "Simulation of Photovoltaic Panel Production as Complement to Ground Source Heat Pump System." Thesis, Högskolan Dalarna, Energi och miljöteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:du-12666.

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This master thesis presents a new technological combination of two environmentally friendly sources of energy in order to provide DHW, and space heating. Solar energy is used for space heating, and DHW production using PV modules which supply direct current directly to electrical heating elements inside a water storage tank. On the other hand a GSHP system as another source of renewable energy provides heat in the water storage tank of the system in order to provide DHW and space heating. These two sources of renewable energy have been combined in this case-study in order to obtain a more efficient system, which will reduce the amount of electricity consumed by the GSHP system.The key aim of this study is to make simulations, and calculations of the amount ofelectrical energy that can be expected to be produced by a certain amount of PV modules that are already assembled on a house in Vantaa, southern Finland. This energy is then intended to be used as a complement to produce hot water in the heating system of the house beside the original GSHP system. Thus the amount of electrical energy purchased from the grid should be reduced and the compressor in the GSHP would need fewer starts which would reduce the heating cost of the GSHP system for space heating and providing hot water.The produced energy by the PV arrays in three different circuits will be charged directly to three electrical heating elements in the water storage tank of the existing system to satisfy the demand of the heating elements. The excess energy can be used to heat the water in the water storage tank to some extent which leads to a reduction of electricity consumption by the different components of the GSHP system.To increase the efficiency of the existing hybrid system, optimization of different PV configurations have been accomplished, and the results are compared. Optimization of the arrays in southern and western walls shows a DC power increase of 298 kWh/year compared with the existing PV configurations. Comparing the results from the optimization of the arrays on the western roof if the intention is to feed AC power to the components of the GSHP system shows a yearly AC power production of 1,646 kWh.This is with the consideration of no overproduction by the PV modules during the summer months. This means the optimized PV systems will be able to cover a larger part of summer demand compared with the existing system.

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Obuladinne, Sai Sujith. "Two-Phase Spray Cooling with Water/2-Propanol Binary Mixtures for High Heat Flux Focal Source." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc955089/.

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Two-phase spray cooling has been an emerging thermal management technique offering high heat transfer coefficients and critical heat flux levels, near-uniform surface temperatures, and efficient coolant usage that enables to design of compact and lightweight systems. Due to these capabilities, spray cooling is a promising approach for high heat flux applications in computing, power electronics, and optics. Two-phase spray cooling inherently depends on saturation temperature-pressure relationships of the working fluid to take advantage of high heat transfer rates associated with liquid-vapor phase change. When a certain application requires strict temperature and/or pressure conditions, thermo-physical properties of the working fluid play a critical role in attaining proper efficiency, reliability, or packaging structure. However, some of the commonly used single-component working fluids have relatively poor properties and heat transfer performance. For example, water is the best coolant in terms of properties, yet in certain applications where the system operates at low temperature ambient, it cannot be implemented due to freezing risk. The common solution for this problem is to use the antifreeze mixtures (binary mixtures of water and alcohol) to reduce the freezing point. In such cases, utilizing binary mixtures to tune working fluid properties becomes an alternative approach. This study has two main objectives; (1) to experimentally investigate the two-phase spray cooling performance of water/2-propanol binary mixture, and (2) to numerically investigate the performance of an advanced heat spreader featuring high and directional thermal conductivity materials for high heat flux focal sources. The first part of the study involves experimental characterization of heat transfer performance. Tests are conducted on a small-scale, closed loop spray cooling system featuring a pressure atomized spray nozzle. The test section, made of copper, measures 10 mm x 10 mm x 2 mm with a plain, smooth surface. A cylindrical copper block, with a matching size square protrusion attached onto the back side of the test section, generates heat using cartridge heaters and simulates high heat flux source. Embedded thermocouples are used to determine the spray surface temperature. The working fluid, water/alcohol mixture, has various concentration levels of 2-propanol by mass fraction 0.0 (pure water), 0.25, 0.50, 0.879 (azeotrope) and 1.0 (pure alcohol)), representing both non-azeotropic and azeotropic cases. Spray cooling tests are performed with a constant flow rate of 5.6 ml/cm².s at subcooled temperatures (~20oC) and atmospheric pressure. Experimental procedure involves controlling the heat flux in increasing steps, and recording the corresponding steady-state temperatures to obtain cooling curves in the form of surface superheat vs. heat flux. The second part of the study investigates an advanced heat spreader design for thermal management of a high heat flux focal source. The heat spreader comprises of three layers: a copper layer that interfaces with the heat source, a high and directional thermal conductivity material (such as CVD diamond and Pyrolytic graphite) layer, and another copper layer that is exposed to two-phase spray cooling. The analysis applies various heat fluxes on the heat source side and the experimentally obtained heat transfer coefficients on the spray side of the spreader design to determine the temperature and heat flux distributions, and examine the potential capabilities of this configuration.

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Elbag, Jr Mark A. "Impact of Surrounding Land Uses on Surface Water Quality." Digital WPI, 2006. https://digitalcommons.wpi.edu/etd-theses/665.

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Source water protection is important to maintain public health by keeping harmful pathogens out of drinking water. Non-point source pollution is often times a major contributor of pollution to surface waters, and this form of pollution can be difficult to quantify. This study examined physical, chemical, and microbiological water quality parameters that may indicate pollution and may help to identify sources of pollution. These included measures of organic matter, particles, and indicator organisms (fecal coliforms and E. coli). The parameters were quantified in the West Boylston Brook, which serves as a tributary to the Wachusett Reservoir and is part of the drinking water supply for the Metropolitan Boston area. Water quality was determined over four seasons at seven locations in the brook that were selected to isolate specific land uses. The water quality parameters were first analyzed for trends by site and by season. Then, a correlation analysis was performed to determine relationships among the water quality parameters. Lastly, ANOVA analyses were used to determine statistically significant variations in water quality along the tributary.

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11

Browning, Drew. "Modeling non-point source pollution in surface water under non-stationary climates and land uses." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1408983669.

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12

Tangwe, Stephen L. "Demonstration of residential air source heat pump water heaters performance in South Africa : systems monitoring and modelling." Thesis, University of Sunderland, 2018. http://sure.sunderland.ac.uk/10269/.

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The purpose of the research was to evaluate the coefficient of performance (COP) of both 150 L split and integrated type air source heat pump (ASHP) water heaters via experimental analysis, statistical tests and mathematical modelling. The ASHP water heaters are used as a potential replacement of inefficient geyser for the production of sanitary hot water due to the excellent efficiency of COP ranging between 2 and 4 and also the capability of reducing the electrical energy consumption by 50-70%. Both types of ASHP water heaters together with a 150 L geyser that served as the control experiment were set up such that distinctive real-time simulated volumes of hot water (100, 50 and 150 L) were drawn off from each of the storage tanks per day over a full year. A data acquisition system (DAS) was designed and built comprising of power meters, flow meter, temperature sensors, ambient temperature and relative humidity sensors in order to monitor the electrical, thermo-physical and environmental contributions of the various hot water heating devices. The hot water set point temperature on each of the technologies was 55oC and the volume drawn off corresponded to the demand during the morning, afternoon and evening, respectively. This mimic the profile of a typical middle or highincome family (3-4 adults) in South Africa. The results depicted that the average annual COP, load factor, and energy saving of the split and integrated type systems was 2.95 and 2.45; 10.2 and 16.7% and 2.770 and 2.499 MWh while the simple payback period was 3.9 and 5.2 years, respectively. The reliefF test revealed that the predictors (ambient temperature and relative humidity) were secondary factors while the electrical energy consumed, the difference in the temperature of the refrigerant at the inlet and outlet of the compressor and condenser were the primary factors to the COP. The derived multiple linear regression models exhibited an excellent determination coefficient of over 90% between the calculated and modelled COP of both types of ASHP water heaters. Finally, the 2D multi-contour plots simulation was accurately used to show the variation of each predictors to the COP. Also, a simulation application to simultaneously compare the COP of both types of ASHP water heaters was developed in the Simulink environment utilising the derived mathematical models. Heat pump manufacturers and energy service companies can employ both the 2D multi-contour plots simulation and the simulation application to show the variation of the specific predictors with the COP and to predict the COP of both types of ASHP water heaters. Conclusively, the research provides substantial evidence for both policy makers and home owners to justify the techno-economic and social benefits of retrofitting a geyser with an ASHP water heater.

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Minic, Ivica D. "An experimental study of a water-source heat pump couple to phase change material thermal energy storage." Thesis, Ulster University, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.694655.

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From the point of economic, environmental and social view our current trends in energy supply and use are unsustainable. Our current energy and climate direction must be changed. Renewable technologies will play crucial role in this change. In order to address these challenges International energy agency (lEA) is developing number of roadmaps for different technologies that can have effects in C02 reduction. There are also roadmaps for renewable technologies. One of them is: "Roadmap for Energy Efficient Heating and Cooling" according to which 20% of increasing Coefficient of Performance (COP) in renewable technologies is planned by the year 2020 and global target in reducing carbon dioxide (C02) for 50% from current levels till 2050. (lEA, 2010) Phase change material (PCM) storages can represent a real challenge to design. One of the challenges is choosing a PCM that is compatible with the system that we want to optimize, and the another is choosing the exact heat exchanger that will give optimal surface area during charging and discharging, due to the fact that PCMs have low thermal conductivity. Clearly, water can be used as a storage medium, but it does not give us the freedom to maintain the system at the desired temperature. In order to gain maximum thermal power from their potential, proper geometrical design needs to be used for each kind of PCM thermal energy storage (TES). The Nusselt equations for heat exchangers used for air and water cannot be applied to PCMs. Extensive research therefore needs to be undertaken in order to investigate the different geometrical configurations of heat exchangers and their interactions with different kinds of PCMs. This thesis summarizes the results from 3 different types of experiments. The first type was with a single tube in water and PCM storage. The second type of experiment was with a multi-tube heat exchanger in PCM-TES. The third type of experiments was with a heat pump system coupled to water/PCM TES. In total 66 tests were performed: 6 experiments with single tube, 42 experiments with multi-tube and 18 experiments with heat pump system. The main contribution presented in this thesis was novel Nusselt number correlations for multi-tube heat exchanger, as heat transfer fluid refrigerant was used and as a storage medium PCM was used.

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Savvakis, Vasileios. "Evaluation of FLake’s Performance on Water Temperatures and Surface Heat Fluxes at Lake Erken, Sweden." Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-380766.

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In many numerical weather prediction models, the presence of lakes is simulated crudely, with their effect being neglected in the resulting simulations. However, it has been shown how lakes effect not only their surrounding climate directly, but have an effect to the overall weather evolution and ecosystem. It is therefore vital to improve existing models to take lakes into account, by coupling with smaller models specificaly compiled for a reas with lakes. There have been several sophisticated models to parameterizelakes in a geographical area, which are, on the other hand, computationally expensive and time consuming. A model built specifically on simple physical assumptions, named FLake, aims to provide a solution that is not heavy computationally, but is accurate enough and contains all the necessary physics surrounding the heat budget and temperature of a given lake. For this project, FLake was tried on a lake close to Uppsala, named Erken, where the validity of the model was tested against data archives from Erken Laboratory’s measurement tower. The resulting simulations were very promising regarding the water temperatures, as well as giving out acceptable results for the surface heat fluxes above the lake and the duration of the ice period, as it was modeled by FLake and compared with ice data archives.

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Forrest, Eric Christopher. "Nanoscale modification of key surface parameters to augment pool boiling heat transfer and critical heat flux in water and dielectric fluids." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/52799.

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Thesis (S.M. and S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2009.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 123-130).
Surface effects on pool boiling heat transfer and the critical heat flux are well documented but poorly understood. This study investigates the pool boiling characteristics of various fluids, and demonstrates that surface effects can drastically alter the nucleate boiling heat transfer coefficient as well as the critical heat flux. Changes in surface morphology and surface chemistry are suspected to be the primary factors influencing pool boiling heat transfer. The relative impact of surface properties is shown to depend strongly upon the working fluid. To evaluate the effects of chemical constituency and surface texture on the pool boiling of water, nanoparticle thin-film coatings are applied to nickel and stainless steel substrates using the layer-by-layer assembly method. This study shows that such coatings, with thicknesses on the order of one micron or less, are capable of enhancing the critical heat flux of water up to 100%, and enhancing the nucleate boiling heat transfer coefficient over 100%. Through the use of thin-film coatings, the importance of nanoscale surface texture, porosity, and chemical constituency on boiling mechanisms is revealed. Low surface tension dielectric fluids, including a recently developed fluorinated ketone with a low global warming potential, are tested to determine their pool boiling heat transfer capabilities. The potential for nanoparticle-based pool boiling enhancement in well-wetting dielectric fluids is investigated. The role of surface wettability and adhesion tension on the incipience of boiling, nucleate boiling, and critical heat flux are considered.
(cont.) Results indicate that the low global warming potential fluorinated ketone may be a viable alternative in the cooling of electronic devices. Additionally, results demonstrate that enhancement of boiling heat transfer is possible for well-wetting dielectric fluids, with 40% enhancement in the critical heat flux using dilute suspensions of aluminum or silica nanoparticles in the fluorinated ketone.
by Eric Christopher Forrest.
S.M.and S.B.

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Koopman, Andrew Ernest. "USING PATTERNED SURFACE WETTABILITY TO ENHANCE AIR-SIDE HEAT TRANSFER THROUGH FROZEN WATER DROPLET VORTEX GENERATORS." Miami University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=miami1578672613073125.

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Xiao, Huaguo Ji Wei. "Assessing the pollution potential of non-point mine wastes on surface water using a geo-spatial modeling approach." Diss., UMK access, 2004.

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Thesis (Ph. D.)--Dept. of Geosciences and School of Computing and Engineering. University of Missouri--Kansas City, 2004.
"A dissertation in geosciences and computer networking." Advisor: Wei Ji. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed Feb. 28, 2006. Includes bibliographical references (leaves 226-236). Online version of the print edition.

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Nasello, Antonio. "Greywater source heat pump system for heating purposes in a newly built Dutch dwelling." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.

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Around 15% of the thermal energy delivered to buildings is lost through the drain and ends up warming wastewater in the sewer system. A promising solution in reducing the energy consumption of buildings is to recuperate heat from wastewater and using it to produce space heating & domestic hot water by means of heat pumps. Wastewater source heat pumps (WWSHPs) have been largely discussed in existing literature, although a lack of scientific studies in small-scale applications such as detached dwelling has been noted. The purpose of this study is to design a wastewater source heat pump system able to satisfy both space heating & domestic hot water demands. The present work proposed a fully greywater source heat pump and a greywater-air dual source heat pump for heating purposes in a newly built Dutch dwelling. Ten different configurations have been modelled, evaluated, and finally compared to a fully air source heat pump. More specifically, the yearly performances were evaluated hour-by-hour taking into account the climate data from the Dutch reference year with the aid of CoolPack and Microsoft Excel. Methods for the COP enhancement have been proposed, the effects of the variations in size of the greywater storage tank have been evaluated, and the optimal control strategy has been found. Results in seasonal COP obtained from the fully greywater source heat pump systems are lower than the ones obtained from fully air heat pump systems. Instead, greywater-air dual source heat pumps perform better than fully air source heat pumps. On the other hand, the introduction of a secondary heat source would increase the cost and the complexity of the system. Nevertheless, several systems present, albeit slight, saving in energy consumption. In particular, up to 1.10 GJ per year can be saved developing this kind of heat pump system.

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Okeke, Nnadozie Kennedy. "Investigation Into the Source of Contamination of Surface Waters Flowing Through The WrightState University Woods." Wright State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=wright162938168838397.

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Novotný, Roman. "Trubkový výměník pro ohřev oběhové vody." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228881.

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Target of the master´ thesis is a design of heat exchanger air-water with the air flowing inside the pipes and with staggered pipe configuration, based on the engaged and chosen values. Next target is to determine heat exchanger with cross parallel flow and cross countercurrent flow of mediums, pressure drop on both sides air and water and dimensions of intake and outgoing gate on both sides air and water.

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Joel, Yongoua Nana. "Computational design of a smart and efficient control system for a residential air source heat pump water heater." Thesis, University of Fort Hare, 2017. http://hdl.handle.net/10353/4582.

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An air source heat pump (ASHP) water heater is a renewable and energy efficient hot water heating technology. ASHP water heaters are fast gaining maturity in the South African market and in Africa at large due to their low energy consumption (about 67 percent lower than conventional geysers), relatively low installation and operation cost, their environmental friendly nature and possibly the ease to retrofit with the old inefficient technologies. Furthermore, ASHP water heaters make use of some of the most recent advancement in refrigeration technologies enhancing their performance through a wide range of weather conditions. However, residential ASHP water heaters which come at the tail of a series of highly sophisticated models still harbour primitive control designs. One of such control system is the intermittent (on/off) control whereby the ASHP unit responds to a temperature differential threshold rather than instantaneous temperature fluctuations. Unfortunately, this control method contributes to a rapid deterioration of the compressor and other actuators due to high starting current during transient states and partial loading. Capacity control is a better alterative as it offers a more reliable system’s performance as well as a better protection for the system components. However, the drawbacks of implementing such a technology on residential ASHP water heaters is the initial purchasing cost. We use a systematic approach in this research to circumvent the purchasing cost and complete redesign hysteresis. The first step was centered around a hypothetical analysis of the performance of the heat exchangers in a bid to uncover the weakness during the operation of a residential ASHP water heater. It was observed that at ambient temperatures above 22°C notably during summer and winter afternoons, water only harnesses about 75 percent of the total heat rejected. Furthermore, the actuators keep doing work for about 15-20 minutes even after the heat transfer process has ceased completely. Following these observations, a sequential flow algorithm was developed aimed at matching the consumption point to weather variables like ambient temperature and secondly to most efficiently synchronize actuator components for a better energy management. This novel control method can save up to 58 percent of energy compared to the conventional on/off method during summer afternoons and averagely 20 percent during the rest of the day. It also has the merit to be cost effective as it barely requires no component retrofitting.

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Mqayi, Singatha. "Performance of a residential swimming pool air source heat pump water heater installed in Fort Beaufort, South Africa." Thesis, University of Fort Hare, 2017. http://hdl.handle.net/10353/4835.

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Globally, there is growing concern about energy consumption and its diverse effects on the environment. In South Africa, the current status quo is unfavourable in the domain of energy, hence the Department of Energy, Eskom and NERSA have embarked on supporting energy efficiency technologies nationwide as a strategic goal in reducing demand on the national grid. Due to the non conservative consumption of electricity from the grid and the insufficient supply to meet its demand, the importation of crude oil is very certain. In addition, the current and most popular technology for pool water heating in the said country is the resistive element which is inefficient and non-cost-effective. The energy consumption of residential swimming pool water heating is very massive, and tariff structure shows a constant rise. Furthermore, there's a current electricity crisis during the Eskom evening peak. Hence, a reliable, efficient, cost-effective and renewable energy technology such as an air source heat pump is required as a retrofit to the existing resistive element. Furthermore, mathematical modelling is a tool that can be used to mimic the dynamic behaviour of a physical or process system. It is a computational language or mathematical equation used to predict the dynamic behaviour of physical systems [Tangwe et al., 2015]. Various methods such as numerical methods have been considered as the particular types of mathematical modelling which have been employed to predict the performance of swimming pool ASHP water heater. However, they were unreliable and expensive. Consequently, this research focused on the experimental determination of the viability and development of a mathematical model to predict the performance of swimming pool ASHP water heater. The benefit of the development and building of this model was attributed to its low cost and credibility to forecast the performance of swimming pool ASHP water heater. Also, this robust mathematical model can be used by an energy service company and system manufacturer to compute the dynamic coefficient of performance of the swimming pool ASHP water heater. Following the above-mentioned information, the research sought to provide a permanent solution to the Eskom evening peak constraint. This is because energy-efficiency, serves as the bridging block between conventional and renewable energy sources needed by Eskom in a bid to provide a balance energy mix and sustainable energy. The implementation of a swimming pool ASHP water heater guaranteed a conducive environment for the population due to the reduction in environmental pollution.

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Sato, Alberto D. "Study of Upward-Facing Spray Cooling with Water at Atmospheric Pressure." Scholar Commons, 2006. http://scholarcommons.usf.edu/etd/3868.

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Spray cooling is a high heat removal technique which has been used widely in many industries, especially metallurgical, where the control of the temperatures of metals is an important factor to obtain the desired microstructure; and also in microelectronics where is very important to obtain high heat fluxes at relatively low surface temperatures. In this study, an open loop spray cooling system has been fabricated to provide an upward-facing spray over a 12 mm diameter test surface. A full cone spray nozzle was used to deliver deionized water to the test surface at five pressures (10, 15, 20, 25 and 30 psi), and at three different distances to the test surface (3, 7 and 12 mm). The volumetric flow rate at the surface used in the experiments depended on both the pressures and the distances. For a distance of 3 mm and 7 mm, the volumetric flow rate range from 336.6 to 627 ml/min while for 12 mm, the range was from 336.6 to 484.28 ml/min. Heat fluxes of 1.92 to 451 W/cm2, 2.1 to 417.3 W/cm2 and 1.9 to 409.5 W/cm2 for distances of 3, 7 and 12 mm respectively were registered at different input power levels. For all the three distances, the volumetric flow rate affects the heat flux, especially for 3 mm; and this effect decreases for higher distances. However, the distance between the nozzle and the test surface has little effect on the heat flux at low pressures but at higher pressures, the difference in heat flux is mainly due to the fact that part of the spray does not impinge the test surface.

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Pullan, Stephanie. "Modelling of pesticide exposure in ground and surface waters used for public water supply." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/8605.

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Diffuse transfers of pesticides from agricultural land to ground and surface waters can lead to significant drinking water quality issues. This thesis describes the development and application of a parameter-efficient, numerical model to predict pesticide concentrations in raw water sources within an integrated hydrological framework. As such, it fills an unoccupied niche that exists in pesticide fate modelling for a computationally undemanding model that contains enough process complexity to be applicable in a wide range of catchments and hydrogeological settings in the UK and beyond. The model represents the key processes involved in pesticide fate (linear sorption and first-order degradation) and transport (surface runoff, lateral throughflow, drain flow, percolation to the unsaturated zone, calculated using a soil water balance) in the soil at a daily time step. Soil properties are derived from the national soil database for England and Wales and are used to define the boundary conditions at the interface between the subsoil and the unsaturated zone. This is the basis of the integrated hydrological framework which enables the application of the model to both surface water catchments and groundwater resources. The unsaturated zone model accounts for solute transport through two flow domains (accounting for fracture flow and intergranular matrix flow) in three hydrogeological settings (considering the presence and permeability of superficial deposits). The model was first applied to a small headwater sub-catchment in the upper Cherwell. Performance was good for drainflow predictions (Nash Sutcliffe Efficiency > 0.61) and performed better than the MACRO model and as well as the modified MACRO model. Surface water model performance was evaluated for eight pesticides in five different catchments. Performance was generally good for flow prediction (Nash Sutcliffe Efficiency > 0.59 and percentage bias below 10 %, in the validation period for all but two catchments). The 90th percentile measured concentration was captured by the model in 62 % of catchment-pesticide combinations. In theremaining cases predictions were within, at most, a factor of four of measured 90th percentile concentrations. The rank order of the frequency of pesticides detected over 0.1 μg L-1 was also predicted reasonably well (Spearman’s rank coefficient > 0.75; p < 0.05 in three catchments). Pesticide transport in the unsaturated zone model was explored at the point scale in three aquifers (chalk, limestone and sandstone). The results demonstrate that representing the unsaturated zone processes can have a major effect on the timing and magnitude of pesticide transfers to the water table. In comparison with the other catchment scale pesticide fate models that predict pesticide exposure at a daily time-step, the model developed stands out requiring only a small number of parameters for calibration and quick simulation times. The benefit of this is that the model can be used to predict pesticide exposure in multiple surface and groundwater resources relatively quickly which makes it a useful tool for water company risk assessment. The broad-scale approach to pesticide fate and transport modelling presented here can help to identify and prioritise pesticide monitoring strategies, to compare catchments in order to target catchment management and to highlight potential problems that could arise under different future scenarios.

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Chingombe, Wisemen. "Effects of land-cover - land-use on water quality within the Kuils - Eerste River catchment." Thesis, University of Western Cape, 2012. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_5893_1373463134.

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The most significant human impacts on the hydrological system are due to land-use change. The conversion of land to agricultural, mining, industrial, or residential uses significantly alters the hydrological characteristics of the land surface and modifies pathways and rates of water flow. If this occurs over large or critical areas of a catchment, it can have significant short and long-term impacts, on the quality of water. While there are methods available to quantify the pollutants in surface water, methods of linking non-point source pollution to water quality at catchment scale are lacking. Therefore, the research presented in this thesis investigated modelling techniques to estimate the effect of land-cover type on water quality. The main goal of the study was to contribute towards improving the understanding of how different land-covers in an urbanizing catchment affect surface water quality. The aim of the research presented in this thesis was to explain how the quality of surface runoff varies on different land-cover types and to provide guidelines for minimizing water pollution that may be occurring in the Kuils-Eerste River catchment. The research objectives were
(1) to establish types and spatial distribution of land-cover types within the Kuils-Eerste River catchment, (2) to establish water quality characteristics of surface runoff from specific land-cover types at the experimental plot level, (3) to establish the contribution of each land-cover type to pollutant loads at the catchment scale. Land-cover characteristics and water quality were investigated using GIS and Remote Sensing tools. The application of these tools resulted in the development of a land-cover map with 36 land classifications covering the whole catchment. Land-cover in the catchment is predominantly agricultural with vineyards and grassland covering the northern section of the catchment. Vineyards occupy over 35% of the total area followed by fynbos (indigenous vegetation) (12.5 %), open hard rock area (5.8 %), riparian forest (5.2 %), mountain forest

(5 %), dense scrub (4.4 %), and improved grassland (3.6 %). The residential area covers about 14 %. Roads cover 3.4 % of the total area. Surface runoff is responsible for the transportation of large quantities of pollutants that affect the quality of water in the Kuils-Eerste River catchment. The different land-cover types and the distribution and concentration levels of the pollutants are not uniform. Experimental work was conducted at plot scale to understand whether land-cover types differed in their contributions to the concentration of water quality attributes emerging from them. Four plots each with a length of 10 m to 12 m and 5 m width were set up. Plot I was set up on open grassland, Plot II represented the vineyards, Plot III covered the mountain forests, and Plot IV represented the fynbos land-cover. Soil samples analyzed from the experimental plots fell in the category of sandy soil (Sa) with the top layer of Plot IV (fynbos) having loamy sand (LmSa). The soil particle sizes range between fine sand (59.1 % and 78.9 %) to coarse sand (between 7 % and 22 %). The content of clay and silt was between 0.2 % and 2.4 %. Medium sand was between 10.7 % and 17.6 %. In terms of vertical distribution of the particle sizes, a general decrease with respect to the size of particles was noted from the top layer (15 cm) to the bottom layer (30 cm) for all categories of the particle sizes. There was variation in particle size with depth and location within the experimental plots.Two primary methods of collecting water samples were used
grab sampling and composite sampling. The quality of water as represented by the samples collected during storm events during the rainfall season of 2006 and 2007 was
used to establish
water quality characteristics for the different land-cover types. The concentration of total average suspended solids was highest in the following land-cover types, cemeteries (5.06 mg L^-1), arterial roads/main roads (3.94 mg L^-1), low density residential informal squatter camps (3.21 mg L^-1) and medium density residential informal townships (3.21 mg L^-1). Chloride concentrations were high on the following land-cover types, recreation grass/ golf course (2.61 mg L^-1), open area/barren land (1.59 mg L^-1), and improved grassland/vegetation crop (1.57 mg L^-1). The event mean concentration (EMC) values for NO₃-N were high on commercial mercantile (6 mg L^-1) and water channel (5 mg L^-1). The total phosphorus concentration mean values recorded high values on improved grassland/vegetation crop (3.78 mg L^-1), medium density residential informal townships (3mgL^-1) and low density residential informal squatter camps (3 mg L^-1). Surface runoff may also contribute soil particles into rivers during rainfall events, particularly from areas of disturbed soil, for example areas where market gardening is taking place. The study found that different land cover types contributed differently to nonpoint source pollution. A GIS model was used to estimate the diffuse pollution of five pollutants (chloride, phosphorus, TSS, nitrogen and NO₃-N) in response to land cover variation using water quality data. The GIS model linked land cover information to diffuse nutrient signatures in response to surface runoff using the Curve Number method and EMC data were developed. Two models (RINSPE and N-SPECT) were used to estimate nonpoint source pollution using various GIS databases. The outputs from the GIS-based model were compared with recommended water quality standards. It was found that the RINSPE model gave accurate results in cases where NPS pollution dominate the total pollutant inputs over a given land cover type. However, the N-SPECT model simulations were too uncertain in cases where there were large numbers of land cover types with diverse NPS pollution load. All land-cover types with concentration values above the recommended national water quality standard were considered as areas that needed measures to mitigate the adverse effects of nonpoint pollution. The expansion of urban areas and agricultural land has a direct effect on land cover types within the catchment. The land cover changes have adverse effect which has a potential to contribute to pollution.

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26

Ge, Chang. "The Seasonal Dynamics of Removal of Nitrogen in Free Water Surface Constructed Wetlands in cold climate." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-40816.

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In Sweden and other Nordic countries, Free Water Surface (FWS) constructed wetlands are widely used for advanced sewage treatment. This study was performed in an experimental wetlands system in order to research the seasonal dynamics and interferences in N removal under cold climate condition. According to the result of study, as expected, N removal in FWS wetlands is strong related to temperature, the removal rates are higher in late summer and autumn than in spring and early summer. Removal at similar temperatures are quite different when they are in different months. For instance, in the study, the average N removal in June is significant different from N removal in September (P＜0.001), indicating that there are other factors affecting the N removal, different treatment wetlands have different situations. N removal in two different periods (March to July & August to December) were extracted for covariance analysis, it indicated that they are significant different. Besides that, the r2-value of correlation test showed that total N removal rate in FWS constructed wetlands is higher in relation to temperature in autumn and winter (r2-value is 0.4449) than in spring and summer (r2-value is 0.3857). Generally speaking, the dynamics of N removal in FWS wetlands is not steady and variable even at similar temperatures. Finally, I find the temperature of excess heating from district heating which has been used by the residents’ house in Sweden is high enough to heat up the temperature in FWS wetlands. That is a valuable improvement to be put forward.

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27

Ma, Chih-Yu. "Occurrence and characterization of antibiotic-resistant Escherichia coli in wastewater and surface water." Kyoto University, 2020. http://hdl.handle.net/2433/259030.

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28

Turnock, Stephen Richard. "An investigation of the heat transfer and transport mechanisms which control surface water during glaze ice accretion." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/35938.

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Myers, John R. "Evaluation and Mitigation of the Temporal Evolution of Microbial Contamination Risk in Surface Water Systems." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1522418268900325.

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30

Persson, Tony. "Evaporation and Heat-flux Aggregation in Heterogeneous Boreal Landscapes." Doctoral thesis, Uppsala University, Department of Earth Sciences, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4326.

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The boreal forests represent 8 % of all forested areas on the earth and have a significant role in the control of greenhouse gases and an impact on global climate change. The main objective of this thesis is to increase the understanding of how evaporation and heat-flux processes in the boreal forest zone are affecting the regional and global climate.

A meteorological mesoscale model with an advanced land-surface parameterization has been utilized to study aggregation of fluxes of water vapour and heat. The model has been compared against four other methods for flux estimation in a southern boreal landscape. The results show that the mesoscale model is successfully reproducing 24-hour averages of fractionally weighted mast measurements of sensible and latent heat flux.

The model was also evaluated against in-situ observations of surface fluxes and other meteorological variables. The results reveal that a correct initialization of soil moisture is crucial to simulate a realistic partitioning of the sensible and latent heat fluxes. Significant differences in surface fluxes and friction velocities between two apparently similar forest sites indicate the need for careful assessment of areal representativity when comparing mesoscale model results with in-situ observations.

A parameterization for the absorption of solar radiation of high-latitude sparse forests was implemented and tested in the model that significantly improved the simulation of high wintertime midday sensible heat fluxes. A scheme for heat storage in vegetation was also implemented which improved the results, but the scheme needs further evaluation for high latitude forests.

Two commonly used strategies for the description of land-surface heterogeneity, the effective parameter approach and the mosaic approach, were tested in the mesoscale model against airborne observations of sensible and latent heat fluxes. The results show that the mosaic approach produces better results especially when small lakes are present in model grid-squares.

Norra halvklotets barrskogsbälte representerar 8 % av all skogsbeklädd mark på jorden och har stor betydelse för kontrollen av växthusgaser och påverkan på globala klimatförändringar. Syftet med denna avhandling är att öka förståelsen av hur avdunstning och värmeflöden i den boreala skogszonen påverkar klimatet regionalt och globalt.

En meteorologisk mesoskalemodell med en avancerad landyteparameterisering har använts för att studera aggregering av avdunstning och värmeflöden. Modellen jämfördes med fyra andra metoder för uppskattning av värmeflöden i den boreala skogszonens södra delar. Resultaten visade att mesoskalemodellen reproducerar 24-timmarsmedelvärden av sensibelt och latent värmeflöde från areellt viktade mastmätningar med bra resultat.

Modellen utvärderades även mot markbaserade mätningar av sensibelt och latent värme och andra meteorologiska variabler. Resultaten visar att en korrekt initialisering av markvatteninnehållet är avgörande för att simulera en realistisk uppdelning av de sensibla och latenta värmeflödena. Markanta skillnader i markyteflöden och friktionshastigheter mellan två liknande skogsmätstationer påvisar nödvändigheten av en noggrann bedömning av den areella representativiteten när man jämför resultat från mesoskalemodellen med markbaserade mätningar.

En parameterisering för absorption av solstrålning i glesa skogsbestånd på höga breddgrader infördes och testades i modellen vilket markant förbättrade simuleringen av de höga sensibla värmeflöden som observerats vid middagstid på vintern. Ett uttryck för att beskriva värmelagring i vegetationen infördes också vilket förbättrade resultaten, men uttrycket behöver vidare utvärdering för skogsbestånd på höga breddgrader.

Två ofta använda strategier för att beskriva markytans heterogenitet, effektiva parametermetoden och mosaikmetoden, testades i mesoskalemodellen mot flygburna observationer av sensibla och latenta värmeflöden. Resultaten visar att mosaikmetoden ger bättre resultat särskilt när mindre sjöar förekommer i modellrutorna.

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Janjua, Azeem. "Modelling and optimisation of a decentralised heat network and energy centre in London Docklands." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-377488.

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The following project aims to create a decentralised heat network development methodology which makes best use of heat sources and loads and can be widely applied to evaluate the energy economics of a heat network scheme and energy centre. As the energy transition takes shape, the key is connectivity and the potential now, or in the future to aid progressive development of energy systems and technologies rather than traditional models that consider schemes individually in isolation and not holistically; where with the latter we’re more likely to end up with robust, future-proof solutions. A methodology was formulated which encompassed various elements of decentralised energy masterplanning approaches and enabled heat demand loads and associated profiles to be simulated. The development of an optimisation model enabled strategies to be devised (maximisation of energy generation and revenue independently) over a set technology lifetime for the energy centre. The results have concluded that the maximisation of revenue optimisation strategy is the most viable economically. An energy generation optimisation for the energy centre produced optimal results in terms of its heat generation profile, however, the scheme was not economically viable due to significantly high capital costs associated with piping connections to multiple clusters. A CO2 emission analysis was carried out for a selection of energy technologies (CHP, heat pumps and gas boilers) for the heat network energy centre. An evaluation of the results has concluded that the optimal selection of technology for the energy centre for the minimisation of CO2 emissions is heat pumps. When selecting combinations of technologies for peak and base loads within the energy centre, heat pumps (base load) and gas boilers (peak load) are optimal when aiming to maximise revenue generation whilst minimising CO2 emissions. In this case, reductions in associated CO2 emissions have been calculated to achieve up to 89.07% when compared to a base case gas boiler technology (energy centre) scenario alone. The methodology and models developed in this project can be widely applied to decentralised heat network projects in London in order to identify optimal development and expansion strategies and evaluate the energy economics of schemes.

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Cho, Jae-Pil. "A comprehensive modeling approach for BMP impact assessment considering surface and ground water interaction." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/27890.

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The overall goal of this study was to develop a comprehensive tool for assessing the effectiveness of selected BMPs on both hydrology and water quality and to demonstrate the applicability of the system by considering 1) temporally and spatially changing land use management practice in an agricultural watershed and 2) interaction between surface and ground water over the entire system. A user interface and Dynamic Agricultural Non-point Source Assessment Tool (DANSAT) were developed to achieve this goal. DANSAT is the only distributed-parameter, physically-base, continuous-simulation, and multi-soil layer model for simulating impacts of agricultural BMPs on hydrology and water qulality in small agricultural watersheds. DANSAT was applied to QNB plot (18m Ã 27m) and two agricultural watersheds in Virginia, including Owl Run watershed (1140 ha) and QN2 in the Nomini Creek watershed (216 ha), to evaluate the model components and its performance in predicting runoff, sediment yield, and pesticide load. DANSAT performed well in predicting total runoff and temporal variations in surface runoff for both field-scale and watershed-scale applications. Total percent errors between the measured and predicted results were less than 10% except for one case (39.8% within a subwatershed of Owl Run watershed), while the daily Nash-Sutcliffe model efficiencies were greater than 0.5 in all applications. Predicted total sediment yields were within Â±35% of observed values in all applications. However, the performance of DANSAT in predicting temporal trend and spatial distribution of sediment loads was acceptable only within Owl Run watershed, where high correlations between flow rates and sediment loads exist. The predicted total pesticide loads were within Â±100% of observed values. DANSAT failed to simulate the temporal occurrence of pesticide loads with a 0.42 daily Nash-Sutcliffe efficiency value. The Dual-Simulation (DS) was developed within the linked ground water approach to resolve problems encountered due to the existence of different temporal scales between DANSAT and the existing ground water models such as MODFLOW and MT3D. The linked approach performed better in predicting the seasonal trend of total runoff compared to the integrated approach by showing an increase in monthly Nash-Sutcliffe efficiency value from 0.53 to 0.60. Surface and subsurface output variables were sensitive to the changes in spatially distributed soil parameters such as total porosity and field capacity. A maximum grid size of 100 m was recommended to be appropriate for representing spatial distribution of topographic, land use, and soil characteristics based on accuracy analysis during the GIS manipulation processes. Larger time-step based on predefined acceptable maximum grid size, decreased the computational time dramatically. Overall sensitivity to different grid sizes and time-steps was smallest for hydrology components followed by sediment and pesticide components. Dynamic crop rotation was considered by DANSAT, and the model successfully simulated the impacts of temporal and spatial changes in crop rotations on hydrology and water quality for both surface and subsurface areas. DANSAT could prove to be a useful tool for non-point source pollution managers to assess the relative effectiveness of temporally and spatially changing BMPs on both surface and ground water quantity and quality.
Ph. D.

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33

Frazee, Joseph W. "Effects of forest harvesting best management practices on surface water quality in the Virginia coastal plain." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-09042008-063552/.

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Hand, Carson T. "Atmospheric Water Harvesting: An Experimental Study of Viability and the Influence of Surface Geometry, Orientation, and Drainage." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2009.

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Fresh water collection techniques have gained significant attention due to global dwindling of fresh water resources and recent scares such as the 2011-2017 California drought. This project explores the economic viability of actively harvesting water from fog, and techniques to maximize water collection. Vapor compression and thermoelectric cooling based dehumidifier prototypes are tested in a series of experiments to assess water collection capability in foggy environments, and what parameters can increase that capability. This testing shows an approximate maximum collection rate of 1.25 L/kWh for the vapor compression prototype, and 0.32 L/kWh for the thermoelectric cooling prototype; compared to 315 L/kWh for desalination or 12 L/m2/day for passive meshes. Exploration of parameters on the thermoelectric cooling prototype show a potential increase in water collection rate of 29% with the addition of a Teflon coating to the collection surface, 15% by clearing the collection surface, and 89% by tilting certain collection surfaces by 60-75°. In combination, these parameters could push active atmospheric water harvesting into economic viability where significant infrastructure investment is not feasible.

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Lomrén, Erik. "Utvärdering av en sjö- och borrhålsbaserad värmepumpsanläggning i Stockholm." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-24548.

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Lågtempererade värmekällor som ytvatten och borrhålslager kan i samverkan med en värmepump ses som outnyttjade energikällor. En sjö- och borrhålsbaserad anläggning kan ha en hög total effektivitet om både värme och kylbehov finns och en stor fördel är att frikyla kan användas från sjö och borrhål under delar av året. Kungsbrohuset byggdes 2008 - 2010 med målsättningen att bli världens mest energieffektiva kontorsbyggnad. Mer specifikt var målsättningen att köpt energi skulle vara hälften av boverkets regler. Av den totala bruksarean på 27 000 m2 utgörs ca 19 500 m2 av kontorsyta. Anläggningen värms och kyls huvudsakligen av en värmepump med en värmeeffekt på 350 kW. Vintertid används värmepumpen för både värme och kyla då ett stort kylbehov även finns under uppvärmningssäsongen till serverrum mm. När värmepumpen inte räcker till så används fjärrvärme och fjärrkyla/sjökyla för att täcka behovet. Vid byggnationen installerades en ledning mellan kungsbrohuset och centralstationen för att på centralstationen utnyttja frikyla från sjön samtidigt som kungsbrohuset fick möjligheten att utnyttja värmen i köldbärarreturen. Målet med studien var att utvärdera anläggningen med fokus på tre huvudsakliga frågor. Att undersöka om värmepumpen har högsta möjliga temperatur på förångningssidan vintertid var den första. Den andra frågan var om frikyla från sjön utnyttjades optimalt. Den tredje frågan var att jämföra den projekterade energianvändningen med det verkliga utfallet. Studien utfördes genom besiktningar på plats, insamling av energistatistik samt att studera anläggningen genom driftdator, driftkort, flödesscheman etc. Vintertid så har den egna köldbärarreturen använts nästan uteslutande som värmekälla till värmepumpen då dess temperatur är högre än borrhålslagrets. Utnyttjandet av frikyla från sjön har inte fungerat optimalt då fjärrkyla har använts under vintermånaderna trots att sjöns temperatur är låg. Detta kan åtgärdas genom omprogrammering av villkor för aktivering av frikylan. Jämförelsen mellan projekterad köpt fastighetsenergi på 47 kWh/m2, år med det verkliga utfallet visade att användningen är något högre i verkligheten och hamnade på 55 kWh/m2, år efter att processkylan räknats bort då den inte räknas som fastighetsenergi. Anläggningen är totalt sett väldigt effektiv och har en mycket låg användning av köpt energi. Att kylbehov finns även vintertid gör att värmepumpens effektivitet blir maximal då nyttig energi utnyttjas på båda sidorna.

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Xiao, Weizhong. "EFFECT OF SOURCE WATER BLENDING ON COPPER RELEASE IN PIPE DISTRIBUTION SYSTEM: THERMODYNAMIC AND EMPIRICAL MODELS." Doctoral diss., University of Central Florida, 2004. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4409.

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This dissertation focuses on copper release in drinking water. Qualitative and quantitative assessment of Cu and Fe corrosion by process water quality was assessed over one year in a field study using finished waters produced from seven different treatment process and eighteen pilot distribution systems (PDSs) that were made from unlined cast iron and galvanized steel pipes, and lined cement and PVC pipes taken from actual distribution systems. Totally seven different waters were studied, which consisted of three source waters: groundwater, surface, and simulated brackish water designated as G1, S1, and RO. With certain pre-established blending ratios, these three waters were blended to form another three waters designated as G2, G3, and G4. Enhanced surface water treatment was CFS, ozonation and GAC filtration, which was designated as S1. The CFS surface water was nanofiltered, which is S2. All seven finished waters were stabilized and chloraminated before entering the PDSs. Corrosion potential was compared qualitatively and quantitatively for all seven waters by monitoring copper and iron release from the PDSs. This dissertation consists of four major parts. (1) Copper corrosion surface characterization in which the solid corrosion products formed in certain period of exposure to drinking water were tried to be identified with kinds of surface techniques. Surface characterization indicated that major corrosion products consists of cuprite (Cu2O) as major underneath corrosion layer and tenorite (CuO), cupric hydroxide (Cu(OH)2) on the top surface. In terms of dissolution/precipitation mechanism controlling the copper concentration in bulk solution, cupric hydroxide thermodynamic model was developed. (2) Theoretical thermodynamic models were developed to predict the copper release level quantitatively based on controlling solid phases identified in part (1). These models are compared to actual data and relative assessment is made of controlling solid phases. (3) Non-linear and linear regression models were developed that accommodated the release to total copper for varying water quality. These models were verified using independent data and provide proactive means of assessing and controlling copper release in a varying water quality environment. (4) Simulation of total copper release was conducted using all possible combinations of water quality produced by blending finished waters from ground, surface and saline sources, which involves the comparison of copper corrosion potentials among reverse osmosis, nanofiltration, enhanced coagulation, lime softening, and conventional drinking water treatment.
Ph.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil and Environmental Engineering

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Alsaiari, Abdulmohsen Omar. "Augmentation of Jet Impingement Heat Transfer on a Grooved Surface Under Wet and Dry Conditions." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/98502.

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Array jet impingement cooling experiments were performed on flat and grooved surfaces with the surface at a constant temperature. For the flat surface, power and temperature measurements were performed to obtain convection coefficients under a wide range of operating conditions such as jet speed, orifice to surface stand-of distance, and open area percentage. Cooling performance (CP) was calculated as the ratio between heat transfer and fan power. An empirical model was developed to predict jet impingement heat transfer taking into account the entrainment effects. Experimental results showed that jet impingement can provide high transfer rates with lower rates of cooling cost in comparison to contemporary conventional techniques in the industry. CP values over 279 were measured which are significantly higher than the standard values of 70 to 95 in current technology. The model enhanced prediction accuracy by taking into account the entrainment effects; an effect that is rarely considered in the literature. Experiments on the grooved surfaces were performed at dry and wet surface conditions. Under dry conditions, results showed 10%~55% improvement in heat transfer when compared to the flat surface. Improvement percentage tends to be higher at wider gaps between the array of orifices and the grooved surface. An improvement of 30%~40% was observed when increasing Re either by increasing orifice diameter or jet speed. Similar improvement was observed at higher flow open area percentages. No significant improvement in heat transfer resulted from decreasing the size of the grooves from 3.56mm to 2.54mm. Similarly, no noticeable change in heat transfer resulted from changing the relative position of the jets striking the surface at the top of the grooves to the bottom of the grooves. Deeper grooves with twice the depth gave statistically similar average heat transfer coefficients as shallower grooves. Under wet conditions, a hybrid cooling technique approach was proposed by using air jets impinging on a grooved surface with the grooves containing water. The approached is proposed and evaluated experimentally for its feasibility as an alternative for cooling towers of thermoelectric power plants. Convection heat and mass transfer coefficients were measured experimentally using the heat mass transfer analogy. Results showed that hybrid jet impingement provided high magnitudes of heat flux at low jet speeds and flow rates. High coefficients of performance CP > 3000, and heat fluxes > 8,000W/m2 were observed. Hybrid jet impingement showed 500% improvement as compared to jet impingement on a dry flat surface. CP values of hybrid jet impingement is 600% to 1,500% more as compared to performance of air-cooled condensers and wet cooling towers. Water use for hybrid jet impingement cooling is efficient since evaporation energy is absorbed from the surface directly instead of cooling air to near wet-bulb temperature.
PHD

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Parhizkar, Masoumeh. "Modelling coupled surface water-groundwater flow and heat transport in a catchment in a discontinuous permafrost zone in Umiujaq, Northern Québec." Doctoral thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/66690.

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Les systèmes hydrogéologiques devraient réagir au changement climatique de manière complexe. En région froide, la simulation de l'effet du changement climatique nécessite un modèle hydrologique intégré de pointe. Dans cette recherche, un modèle numérique entièrement couplé en 3D a été développé pour simuler l’écoulement des eaux souterraines et le transport de chaleur dans un bassin versant dans la région d'Umiujaq, dans le nord du Québec, au Canada. Le bassin versant est situé dans une zone de pergélisol discontinue et contient une épaisse couche glaciofluviale à grains grossiers formant un bon aquifère sous une unité gélive de silts marins sensible au gel. Une étude de terrain détaillée a été réalisée pour mesurer les caractéristiques du bassin versant telles que les propriétés hydrauliques et thermiques et la distribution des unités géologiques. Trois méthodes différentes disponibles dans le logiciel PEST sont utilisées pour caler le modèle 3D par rapport aux charges hydrauliques mesurées. Les résultats ont montré que l'utilisation de méthodes de calage simplifiées, telles que la méthode de zonation, n'est pas efficace dans cette zone d'étude, qui est très hétérogène. L’utilisation d’un calage plus détaillé par les méthodes du système PEST de points pilotes a permis de mieux s’adapter aux valeurs observées. Cependant, le temps de calcul était élevé. L'effet de la condition initiale pour la simulation du transport de chaleur est étudié en appliquant une condition initiale différente au modèle. Les résultats montrent que l'inclusion du processus de démarrage dans les simulations produit des températures simulées plus stables. Les zones du modèles à des profondeurs plus élevées, en-dessous de la profondeur de pénétration des variations saisonnières de température, nécessitent des temps de simulation plus longs pour être en équilibre avec les conditions limites appliquées. Les résultats montrent que l'application de la température moyenne de surface en tant que condition limite pour la simulation du transport de chaleur donne un meilleur ajustement aux valeurs observées en été qu'en hiver. En hiver, du fait de l’épaisseur variable de la neige dans le bassin versant, l’utilisation d’une température de surface uniforme diminue la qualité de l’ajustement aux valeurs observées. L'inclusion de l'advection dans la simulation du transport de chaleur accélère le taux d'augmentation de la température. De plus, l'eau chaude qui pénètre dans le sous-sol augmente la température souterraine dans les zones de recharge. Lorsque les eaux souterraines s'écoulent, elles perdent de l'énergie thermique. Par conséquent, le taux d’augmentation de la température dans les zones de décharge est inférieur à celui des zones de recharge.
Groundwater systems are expected to respond to climate change in a complex way. In cold regions, simulating the effect of climate change requires a state-of-the-art integrated hydrologic model. In this research, a fully coupled 3D numerical model has been developed to simulate groundwater-surface water flow and heat transport in a 2-km² catchment in Umiujaq, Nunavik (northern Quebec), Canada. The catchment is located in a discontinuous permafrost zone. It contains a lower aquifer, consisting of a thick coarse-grained glaciofluvial layer, overlain by a frost-susceptible silty marine unit and a perched upper aquifer. Detailed field investigations have been carried out to characterize the catchment, including its hydraulic and thermal properties and the subsurface geology. Three different calibration methods using the inverse calibration code PEST were used to calibrate the 3D flow model against measured hydraulic heads, assuming a fixed distribution of low hydraulic conductivity for discontinuous permafrost blocks. Heat transfer was not considered for this calibration. Results showed that using simplified calibration methods, such as the zoning method, is not efficient in this study area, which is highly heterogeneous. Using a more detailed calibration, such as the pilot-points method of PEST, gave a better fit to observed values. However, the computational time was significantly higher. In subsequent simulations, which included heat transport, different approaches for assigning initial temperatures during model spin-up were investigated. Results show that including the spin-up process in the simulations produces more realistic simulated temperatures. Furthermore, the spin-up improves the model fit to deeper subsurface temperatures because areas of the subsurface below the depth where seasonal surface temperature variations penetrate require longer simulation times to reach equilibrium with the applied boundary conditions. Applying the annual average surface temperature as the boundary condition to the heat transport simulation provided a better fit to observed values in the summer compared to winter. During winter, because of different snow thicknesses throughout the catchment, using a uniform surface temperature results in a poor fit to observed values. v Simulations show that warm water entering the subsurface increases the subsurface temperature in the recharge areas. As groundwater flows through the subsurface, it loses thermal energy. Therefore, discharging water is cooler than recharging water. This causes the rate of temperature rise to be lower in discharge areas than in recharge areas. The modelling results have helped provide insights into 3D simulation of coupled water flowheat transfer processes. Furthermore, it will help users of cryo-hydrogeological models in understanding effective parameters in development and calibration of model to develop their own site-specific models.

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Nagai, Haruyasu. "Development of a New Atmosphere-Soil-Vegetation Model to Study Heat, Water, and CO2 Exchanges between the Atmosphere and Land-surface." 京都大学 (Kyoto University), 2004. http://hdl.handle.net/2433/147889.

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40

Back, Natalii. "Bergvärme som energikälla." Thesis, Mälardalen University, School of Sustainable Development of Society and Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-712.

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2008-05-26

Bedrock heat as an energy source

The sun has warmed up the bedrock and this heat can be used for warming up houses. Approximately 100 – 200 meters down in the bedrock the temperature of the heat is stable. This is a source of energy that can be used by installing a heat pump system. The ground source heat pumps are low maintenance and can last for many years. There is also a pollution risk for the groundwater and therefore the wells in the area. Before the ground source heat pump can be installed the municipality need to give permission, according to the environmental code. To install the system without permission is a crime against the environmental code. A requirement when applying for permission to install the heat pump system is to get the neighbours to agree with the place for the bore hole. The neighbour can appeal against the environmental and health authorities’ decision to give permission to install the ground source heat pump system. However there needs to be more research done regarding the environmental effects that may occur in the future, if the ground source heatpump system continues to increase as rapidly as today.

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41

Fang, Yuan [Verfasser], and Eckehard [Gutachter] Specht. "Influence of nozzle type and configuration and surface roughness on heat transfer during metal quenching with water / Yuan Fang ; Gutachter: Eckehard Specht." Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2019. http://d-nb.info/1219966088/34.

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Caramori, Paulo Henrique. "Structural analysis of airborne flux traces and their link to remote sensing of vegetation and surface temperature." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41012.

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This thesis examines the link between airborne flux estimates of CO$ sb2$, sensible heat, and water vapor, and surface parameters retrieved by remote sensing. Chapter 1 analyses the relationship between surface temperature and vegetation indices, obtained from the Advanced Very High Resolution Radiometer on board of NOAA-9 and -10 satellites, and fluxes of sensible heat, latent heat, and CO$ sb2$, estimated from aircraft. Linear relationships between CO$ sb2$ and the Normalized Difference Vegetation Index (NDVI) or the Simple Ratio vegetation index (SR) are found on a daily basis, but a highly nonlinear relationship appears for the seasonal variation. Latent Heat fluxes showed the poorest correlations with surface parameters. A seasonal linear relationship appeared between sensible heat and NDVI. Local extreme flux values due to the intermittency of boundary layer dynamics largely contribute to lower the correlations; such variations are the reason for the difficulties in relating fluxes obtained from single overpasses and over short distances to fixed points at the surface. This problem is further examined in Chapter 2, in which conditional sampling of airborne flux estimates is used to characterize the turbulent structures that are carrying flux, and their link to the surface. The analysis confirms that few extreme events may carry a significant fraction of the flux. Missing or hitting one of these structures may translate into very large oscillations on the flux estimate that are often not directly coupled to surface characteristics. A much clearer surface 'signature' emerges when measurements are taken within the surface layer, since the reorganization of turbulent structures that takes place with increasing height will result in a merging of the signature that came from different sources at the surface. This helps to explain some of the poor correlations obtained in Chapter 1 and reinforces the need for a better understanding of the distributions of these tu

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Chu, Yi-Fei. "The incorporation of hourly goes data in a surface heat flux model and its impacts on operational temperature predictions in bodies of water /." The Ohio State University, 1998. http://rave.ohiolink.edu/etdc/view?acc_num=osu14879491500689.

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44

Pearce, Austin Willis. "Assessing Phosphorus Sources with Synoptic Sampling in the Surface Waters of a Mixed-Use, Montane Watershed." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6374.

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Few elements in surface waters are monitored as closely as phosphorus (P) due to its role in the eutrophication and degradation of surface waters. Limiting P mobilization from source areas is, therefore, a central goal of water quality protection plans. But the work of locating sources in mixed-use watersheds is challenged by the spatial and temporal variability of critical source areas (CSAs) of P. Synoptic sampling is a proven method for capturing the spatial variation of water quality parameters in surface waters, though it's not often used to track temporal dynamics across the same study area. Phosphorus fractionation is an analytical method that divides the total P (TP) in water into fractions, which for this study included total dissolved P (TDP), particulate P (PP), dissolved reactive P (DRP), and dissolved organic P (DOP). The objective of this study was to demonstrate the utility of combining temporally repeated synoptic sampling with simple P fractionation as a unique strategy for locating and characterizing CSAs of P. Seven synoptic sampling campaigns were conducted over a two-year period (March 2015 – July 2016) in a rural, montane watershed in north central Utah, USA. In each campaign, we sampled 18 sites across three tributaries (Main Creek, Spring Creek, and Little Hobble Creek) during three distinct, annual hydrologic periods (rising flow, peak flow, and baseflow). Temporal repetition clearly identified the rising flow period as the period with greatest P loading in the watershed. Combining repeated synoptic sampling and P fractionation successfully identified CSAs of P and most probable transfer pathways. Specifically, stream segments along lower Spring Creek and Main Creek were associated with the greatest increases of PP loads during periods of rising flow and peak flow. In the same time periods, the greatest DOP loads stemmed from forested areas as well as areas in the lower watershed associated with winter grazing of cattle. The watershed exhibited a significant background concentration of DRP from groundwater-driven subsurface sources in the lower half of the watershed that persisted year-round. These assessments can be used to develop management practices that limit various P loads from these respective critical source areas. The characterization of CSAs could not have been made using only a traditional synoptic sampling approach. This study demonstrated that the combination of repeated synoptic sampling and P fractionation can be an effective technique for locating and characterizing critical P source areas in order to guide best management practices that improve surface water quality.

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Duran, Arnaud. "Numerical simulation of depth-averaged flows models : a class of Finite Volume and discontinuous Galerkin approaches." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20066/document.

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Ce travail est consacré au développement de schémas numériques pour approcher les solutions de modèles d'écoulement type “depth averaged”. Dans un premier temps, nous détaillons la construction d'approches Volumes Finis pour le système Shallow Water avec termes sources sur maillages non structurés. En se basant sur une reformulation appropriée des équations, nous mettons en place un schéma équilibré et préservant la positivité de la hauteur d'eau, et suggérons des extensions MUSCL adaptées. La méthode est capable de gérer des topographies irrégulières et exhibe de fortes propriétés de stabilité. L'inclusion des termes de friction fait l'objet d'une analyse poussée, aboutissant à l'établissement d'une propriété type “Asymptotic Preserving” à travers l'amélioration d'un autre récent schéma Volumes Finis. La seconde composante de cette étude concerne les méthodes Elements Finis type Galerkin discontinu. Certaines des idées avancées dans le contexte Volumes Finis sont employées pour aborder le système Shallow Water surmaillages triangulaires. Des résultats numériques sont exposés et la méthode se révèle bien adaptée à la description d'une large variété d'écoulements. Partant de ces observations nous proposons finalement d'exploiter ces caractéristiques pour étendre l'approche à une nouvelle famille d'équations type Green-Nadghi. Des validations numériques sont également proposées pour valider le modèle numérique
This work is devoted to the development of numerical schemes to approximatesolutions of depth averaged flow models. We first detail the construction of Finite Volume approaches for the Shallow Water system with source terms on unstructured meshes. Based on a suitable reformulation of the equations, we implement a well-balanced and positive preserving approach, and suggest adapted MUSCL extensions. The method is shown to handle irregular topography variations and demonstrates strong stabilities properties. The inclusion of friction terms is subject to a thorough analysis, leading to the establishment of some Asymptotic Preserving property through the enhancement of another recent Finite Volume scheme.The second aspect of this study concerns discontinuous Galerkin Finite Elementmethods. Some of the ideas advanced in the Finite Volume context areemployed to broach the Shallow Water system on triangular meshes. Numericalresults are exposed and the method turns out to be well suited to describe a large variety of flows. On these observations we finally propose to exploit its features to extend the approach to a new family of Green-Nadghi equations. Numerical experiments are also proposed to validate this numerical model

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Boris, Obrovski. "Razvoj inovativne optičke senzorske tehnologije za hemijsku analizu neorganskih polutanata u akvatičnom medijumu." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2020. https://www.cris.uns.ac.rs/record.jsf?recordId=114078&source=NDLTD&language=en.

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Osnovni cilj teze bio je razvoj nove i inovativne senzorske metode za merenje neorganskih parametara u površinskim vodama i vodama zatvorenih bazena. Kolorimetriski fiber-optički senzor (KFOS) je osposobljen za merenje pet parametara u površinskoj vodi (ortofosfata, ukupnog hlora, hroma (VI), nitrita i sulfata) i za merenje dva parametra u bazenskim vodama (rezidualnog hlora i ukupnog hlora). Pored prilagođavanja nove metode urađena je i analiza kvaliteta reke Dunav u Novom Sadu na osnovu čega su odabrani parametri za merenje sa KFOS metodom.
The main goal of the thesis was to develop a new and innovative sensor method for measuring inorganic parameters in surface waters and waters of indoor pools. The Colorimetric Fiber Optic Sensor (CFOS) is capable for measuring five parameters in surface water (orthophosphate, total chlorine, chromium (VI), nitrite and sulfate) and for measuring two parameters in pool water (residual chlorine and total chlorine). In addition to adjusting the new method, an analysis of the quality of the Danube River in Novi Sad was performed and based on which parameters for measuring with the KFOS method were selected.

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Ilisei, Gheorghe. "Numerical analysis using simulations for a geothermal heat pump system. : Case study: modelling an energy efficient house." Thesis, Högskolan i Gävle, Energisystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-29101.

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The ground source resources are becoming more and more popular and now the ground source heat pumps are frequently used for heating and cooling different types of buildings. This thesis aims at giving a contribution in the development of the thermal modelling of borehole heat storage systems. Furthermore, its objective is to investigate the possibility of implementing of a GSHP (ground source heat pump) with vertical boreholes, in order to deliver the heating and cooling demand for a passive house and to emphasize some certain advantages of this equipment even in the case of a small building (e.g. residential house). A case study is presented to a suitable modelling tool for the estimation of the thermal behaviour of these systems GSHP by combining the outcome from different modelling programs. In order to do that, a very efficient residential solar house (EFden House – a passive residential single-family house, which was projected and built in Bucharest with academic purposes) is being analysed. The numerical results are produced using the software DesignBuilder, EED (Earth Energy Designer) and a sizing method for the length of the boreholes (ASHRAE method). The idea of using 2 different modelling programs and another sizing method for the borehole heat exchanger design (ASHRAE method) is to make sure that all the calculations and results are valid and reliable when analysing such a system theoretically (in the first phases of implementing a project), before performing a geotechnical study or a thermal response test in order to assess the feasibility of such a project beforehand. The results highlight that the length of the borehole, which is the main design parameter and also a good index in estimating the cost of the system, is directly influenced by the other fundamental variables like thermal conductivity of the grout, of the soil and the heat carrier fluid. Also, some correlations between these parameters and the COP (coefficient of performance) of the system were made. The idea of sizing the length of boreholes using two different methods shows the reliability of the modelling tool. The results showed a difference of only 2.5%. Moreover, the length of borehole is very important as it was calculated that can trigger a difference in electricity consumption of the GSHP up to 28%. It also showed the fact that the design of the whole system can be done beforehand just using modelling tools, without performing tests in-situ. The method aims at being considered as an efficient tool to estimate the length of the borehole of a GSHP system using several modelling tools.

The presentation was made via Skype due to the programme being online based

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Guarnieri, Raniero Alberto. "Novel Approaches to the Design of Domestic Solar Hot Water Systems." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16056/.

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Domestic solar hot water units, if properly designed, are capable of providing all hot water needs in an environmentally friendly and cost-effective way. Despite 50 years of development, commercial technology has not yet achieved substantial market penetration compared to mainstream electric and gas options. Therefore, alternate designs are warranted if they can offer similar or greater performance for a comparable cost to conventional units. This study proved that such alternatives are possible by designing and testing two novel solar hot water systems (SHWS). The first system used compound parabolic collector (CPC) panels to concentrate solar energy and produce steam. The steam moved from a rooftop downward into a heat exchange pipe within a ground level water tank, heating the water, condensing and falling into a receptacle. The operation was entirely passive, since the condensate was pulled up due to the partial vacuum that occurred after system cooling. Efficiencies of up to 40% were obtained. The second system used an air heater panel. Air was circulated in open and closed loop configuration (air recycling) by means of a fan/blower motor and was forced across a compact heat exchanger coupled to a water tank. This produced a natural thermosiphon flow heating the water. Air recycling mode provided higher system efficiencies: 34% vs. 27%. The concurrent development of an analytical model that reasonably predicted heat transfer dynamics of these systems allowed 1) performance optimisation for specific input/starting operating conditions and 2) virtual design improvements. The merit of this model lay in its acceptable accuracy in spite of its simplicity. By optimising for operating conditions and parameter design, both systems are capable of providing over 30 MJ of useful domestic hot water on clear days, which equates roughly to an increase of 35°C in a 200 L water tank. This will satisfy, on average, daily hot water requirements for a 4-person household, particularly in low-latitude regions (eg. Queensland). Preliminary costing for these systems puts them on par with conventional units, with the passive, remotely coupled, low maintenance, CPC SHWS comparable to higher end models. The air heater SHWS, by contrast, was much more economical and easier to build and handle, but at the trade-off cost of 1) the need for an active system, 2) increased maintenance and running costs and 3) the requirement for a temperature control mechanism that would protect the panel body by dumping hot air trapped inside if stagnation were to occur.

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Brown, Mitic Constance Maria. "Flux associations and their relationship to the underlying heterogeneous surface characteristics." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35988.

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This thesis consists of analysis of three different data sets: (i) Aircraft-based eddy correlation data collected above irrigated and non-irrigated agricultural land in Southern California during the California Ozone Deposition Experiment (CODE) summer 1991; (ii) micrometeorological tower data, collected over grape and cotton canopies as part of CODE; (iii) aircraft-based eddy correlation flux data above two grid sites in the Canadian boreal forest during the Boreal Ecosystem-Atmosphere Study (BOREAS), spring and summer of 1994 and 1996.
Results from the CODE aircraft data document composition and size of the dominant structures, which transport heat and gases (H2O, CO 2 and ozone) over water stressed and non-water stressed surfaces, and the relative frequency with which structures carrying only a single scalar, or given combinations of scalars, were encountered along the flight paths. Interpretation of results provides further evidence for the existence of a second (nonphysiological) sink for ozone. The relative preponderance of structures that carry moisture, carbon dioxide and ozone simultaneously, particularly in the gradient-up mode, reflects the importance of vegetation as co-located source/sink for these scalars. The detrending procedures described in this study may help to define a more effective separation between local and mesoscale events in biosphere-atmosphere interaction.
Results from the CODE tower data indicates a single vegetated ozone sink for the grape site, but a vegetated as well as a non-vegetated sink for the cotton site. For both sites, structures simultaneously transporting significant flux contributions of CO2, H2O, heat and ozone dominate during unstable conditions. During stable conditions, unmixed single flux structures dominated over cotton but not over grape. The results of this study contribute empirical evidence about the relationship between ozone uptake and the physical and physiological state of vegetation, as well as the limitations placed on eddy scales in simulation models.
Results from the BOREAS aircraft data shows a decoupling between the surface and the atmosphere, where the patterns of vegetation, greenness and surface temperature may be quite dissimilar to those of the fluxes of sensible heat, latent heat and---to a lesser degree---CO2. Reasons for this lie in the extraordinary boundary layer conditions, high vapour pressure deficit, moist soil and hot canopies, and the response of the vegetation to these conditions. Analysis of the coherent structure compositions to some extent permits the characterization of the different sources and sinks. Overall, this study shows the importance of understanding the various interacting components of soil, vegetation and atmosphere when attempting to design process-based models for predictions in 'micrometeorologiacally' complex ecosystems.

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Merrick, Natsuko N. "Microbial Source Tracking: Watershed Scale Study of Pathogen Origin, Fate, and Transport in the Upper Sugar Creek Watershed, Northeast Ohio." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1276703299.

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Dissertations / Theses on the topic 'Surface water source heat'

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