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1
Maboda, Sivuyile. "Do solar water heaters improve access to hot water and reduce electricity costs? : the complexities of implementing energy poverty interventions in South African Townships : a case study of Nyanga Township." Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/12232.
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Includes abstract.Includes bibliographical references (leaves 58-63).
Solar energy is abundantly available in South Africa, but it is a highly under-utilised resource. One way of efficiently using the resource is solar water heating (swh), a natural process whereby hot water for domestic and/or industrial use is heated by the sun. In 2009, a national swh strategy was drafted by the Department of Energy, which specifies a target to install 1 million heaters in households by 2015. Provincial and local governments have also developed their own swh strategies and the roll out of swhs has started in some municipalities (i.e. the Nelson Mandela Bay Municipality and the City of Cape Town).
2
Almutairi, Hamad Hhn. "Low energy air conditioning for hot climates." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/low-energy-air-conditioning-for-hot-climates(8e4fe7e9-c0d0-4bc3-8b81-96ced66331e1).html.
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Fossil fuels are the major sources of electrical power generation in the world. Among all fossil fuels, oil is considered as the most sought-after fuel. The burden on countries that provide subsidized electricity produced from oil-fired power plants is noteworthy. Kuwait is a notable example of these countries. Electricity in Kuwait is heavily consumed by residential air conditioning, which comprises 60% of the total electricity generated at peak times on a hot summer day. From this perspective, residential air conditioning in Kuwait was selected to undergo further investigation regarding low energy air conditioning choices. Three solutions to control the rapid growth of demand for electricity by residential air conditioning are examined. The first solution investigated assesses the orientation and grouping of houses in Kuwait in order to examine their effect on cooling load and electrical energy consumption for future houses. Four residential cases were developed; each case comprises six typical houses. The cases identified are: (1) single block facing east-west, (2) single block facing north-south, (3) double block facing east-west and (4) double block facing north-south. Cooling loads are calculated using the DesignBuilder building thermal simulation software. Case (2) is found to have the smallest cooling load, and case (1) the largest. The estimated savings from applying case (2) compared to the average of the four cases for the future houses planned to be built by the government by the year 2016 (i.e. approximately 20,000 houses) are found to be approximately .US 33 million of power system capital costs, 15 GWh per year of electrical energy consumption and 11 kilotons per year of CO2 emissions. In the second solution, a lifecycle cost analysis is performed to evaluate the economic feasibilities of electricity driven chilled water system compared to predominant air conditioning system in Kuwaiti houses which is Packaged- Direct Expansion. The study considers the total cash paid by the consumer and the total cash paid by the government, since electricity is subsidized in Kuwait. The study finds that the chilled water system is not cost-effective for consumers due to high installation cost. However, a chilled water system would be cost-effective for the government because it consumes 40%less electrical energy than Packaged-DX. So, the study suggests subsidising the installation of chilled water systems so that the installation cost to the consumer is the same as for Packaged-DX systems. In the third solution, the study examines the viability of a single-effect LiBr absorption chiller driven by steam extracted from the steam turbine in the configuration of a combined cycle power plant (CCPP). The analysis shows that CCPP with absorption chiller yields less net electrical power available to utility grid compared to similar CCPP giving electricity to the grid and to Direct-Expansion air conditioning systems for the same cooling requirements. The reasons for that are the reduction in steam turbine power output resulted from steam extraction, and the amount of electrical energy required to operate the configuration of CCPP with absorption chiller.
3
Šmarda, Milan. "Vytápění panelového domu tepelným čerpadlem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231737.
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Diploma thesis deals with change of heating source for a block of flats with aim to reduce heating costs. Thesis contains calculations of energy requirements of house, including requirements for heating and domestic hot water preparation. Several ways of heating by a heat pump were designed based on the calculated values. Each variant of the designed heating system is compared with current operational costs. Possible cost economies and maximum value of investment costs of the heating system were assessed
4
Pekkala, Ossian. "Integrated heat exchanger for shower cabins : Legal issues, cost efficiency, designing a prototype." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-22088.
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The global energy usage have been growing and is expected to grow in the forthcoming years. The negative effects of increased energy use are greatly depending on the type of base raw materials required for converting the energy and the negative consequences those have on the environment. From the energy used, fossil fuels stands for the largest part. Excess use of fossil fuels have been shown to have considerable negative effects on the environment, including, but not limited to global warming. Renewable energy is today the world’s fastest growing energy source limiting the negative consequences of growing energy use. The commercial and residential buildings stands together for about 40 % of the total energy usage. Residential buildings alone stands for 20 % of the total world delivered energy consumption by end-use sector. In EU the average residential energy use amounts to 25 % and for individual countries like Sweden and Finland it is 21 %. The EU energy efficiency directive from year 2012 sets a target to save 20 % of the unions primary energy usage by year 2020 compared to the year 1990. The EU countries also agreed in October 2014 on a new energy efficiency target of at least 27 % by the year 2030. To reach this goal, improved energy efficiency are required in all sectors. Finland’s energy efficiency law for buildings from 2013 greatly reduces the minimum energy usage allowed for new buildings. Finland is also preparing for a new law that would by 2020 require all new buildings to be zero or close to zero energy buildings. This is defined by the Ministry of the Environment as buildings that have very high energy efficiency, where the already greatly reduced energy demand is satisfied extensively by renewable energy. As part of the goal to greatly increase buildings energy efficiency, this work focus on heat exchangers for showers. The purpose of this project is to investigate how two different heat exchangers works for shower cabins. This is done by testing a system where the heat exchangers are linked together. The system works by transferring heat from the drainage water and the moist air to the incoming colder drinking water before the cold water is heated in the mixerto desired shower temperature. The measurements are taken for different simulated shower situations. The Heat exchangers efficiency are calculated and the energy savings are examined with annual energy savings. The payback time shows that the system is not currently viable. The efficiency need to be improved, the main issue being the constituent materials heat transfer attributes between cold and hot water. The results are discussed and it is concluded that the system would be viable with improved heat exchanger efficiency and adequate shower use, which depends on the user and the amount of people using the shower. The main issue with increased heat transfer efficiency is the greater risk of contamination between the incoming cold drinking water and the outgoing dirty drainage water.
5
Rajdlík, Lukáš. "Návrh vytápění rekreačního domku." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-399563.
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This master’s thesis deals with design of different variants of heating and warming of hot service water for holiday building (year-round weekend house, made of bricks). After calculations of the design heat load and heat requirement for heating and warming of hot service water for different types of operations the suitable heat sources are chosen. For heat sources the general design of heating is made. In the end the thesis includes economical analysis for each variant in view of investment and operating costs. The most suitable heat source is chosen from the results of analysis.
6
Böhme, Florén Simon. "Solel och solvärme ur LCC-perspektiv för ett passiv-flerbostadshus." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-162430.
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This master’s degree project concerns the combination of a multi dwelling passive house with solar energy for the generation of electricity and domestic hot water (DHW). Different alternatives with either solar thermal systems or photovoltaic (PV) systems are compared with two reference alternatives producing DHW from electricity or district heating. The economical comparison uses a life cycle cost (LCC) perspective based on the present value of expenditures for investment, energy and annual operating and maintenance. The energy yields from the solar energy systems were calculated by hand and with simulation software. Calculation and dimensioning of PV systems were carried out with a software called PVSYST. Solar thermal systems were calculated by hand and with the software Winsun Villa Education. Both softwares use hourly weather data for the calculations. The LCCs are lower for the two reference alternatives than for the solar energy alternatives. The reference alternative with district heating generates the lowest LCC. The alternatives with solar thermal energy replace more energy and have significantly lower LCCs than the PV alternatives. The study also shows the importance of using cheap and environmentally friendly backup energy for producing DHW. When aiming for a quantitative energy use target, the DHW-circulation losses ought to be taken into account as these can be extensive.
7
Palkovič, Peter. "Možnosti snížení nákladů za energie pro RD." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231826.
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Thesis deals with the possibility of reducing the energy costs of a typical family house located in Brno. In the first part is a detailed calculation of heat loss of the building, considering heat gain and subsequent quantification of costs for heating, hot water and total annual costs. In other sections provide specific calculation of the economics for the partial implementations of planned procedures leading to a reduction in heating costs (replacing windows, doors, facades and floor ceiling). A calculation for changing the heating method and compared to the existing boiler. A possible reduction in the energy required when using energy from the Sun. In the penultimate section briefly review the options for what you get a subsidy from the grant program "New Green Savings Programme" and reduce the initial investment. Finally the comprehensive proposals of different options exchanges boiler insulation, replacing windows and doors, and the subsequent evaluation of the best solution when investing 350 000 CZK.
8
Kingdon, Lorraine B. "Hot Water Issues." College of Agriculture, University of Arizona (Tucson, AZ), 1988. http://hdl.handle.net/10150/295533.
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Dvouletý, Tomáš. "Využití odpadního tepla pro vytápění a ohřev TV." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230347.
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The thesis aims to design a device for utilization of waste heat for heating and hot water in NETME Centre in area of FSI VUT in Brno. First of all there is summary of available sources of waste heat and evaluation of serviceability. Next there is design of a device for utilization of waste heat. Design incluades calculation of heat exchangers and selection of particular heat exchangers. It also incluades design of duct system which anables transportation of heated water from heat exchangers to machine room. In machine room is situated storage tank for accumulation of gained waste heat. This storage tank is conected to heating system and to consumption of hot water which anables utilization of waste heat. Finally there is economic evaluation based on amount of gained waste heat, consumption of heat and costs.
10
Eriksson, Mimmi. "Corrosion and microfluidics in hot water microsystems." Thesis, Uppsala universitet, Mikrosystemteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-207573.
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This thesis addresses some important issues when designing microfluidic systems for hot pressurized water. The properties and behavior of water at elevated temperatures and in micro scale is briefly reviewed, and opportunities and possible problems of using hot pressurized water in microfluidic devices are brought up. Experimental work was focused on corrosion resistance for commonly used microsystem materials in hot pressurized water, and the microfluidic behavior for hot pressurized water. An experiment system was successfully designed, assembled and used for corrosion resistance experiments in hot pressurized water. Corrosion resistance tests were performed for some common materials used in microfluidic and microsystems (silicon, stainless steel grade 304, silicon carbide, aluminum nitride, aluminum oxide, soda-lime glass and borosilicate glass) in deionized water and in low concentration HCl (0.1 mM) at two different temperatures (180oC and 270oC). All of the tested materials, except soda-lime glass, showed a good overall performance in the low temperature range. In the high temperature range, all materials showed signs of corrosion to some extent. Severe damages and high corrosion rates were observed for silicon and the two glasses, and stainless steel 304 showed signs of pitting corrosion. A microfluidic study identified some major issues needed to be overcome to make future microfluidic studies with hot pressurized water possible. Important observations included the importance of a short traveling distance for a hot micro flow to avoid rapid cooling, and to choose a suitable dye to avoid particles clogging thin capillaries and micro channels.
11
Harris, Jeff 1959. "A practical method for setting water rates." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23334.
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The thesis synthesises current water utility practice, and economic theory, through the development of a practical water rate based on marginal cost pricing. The suggested water rate is a three part tariff consisting of volumetric, connection and access charges. The volumetric charges recover the long run marginal costs associated with water demand, and include peak and off-peak prices. They are calculated using an extension to the Turvey concept of long run marginal cost. The connection charges represent the marginal costs associated with connecting to the system, rather than those associated with water demand. They are of two types: those related to the local distribution network, and those related to annual operating costs. An access charge is also suggested as a means of recovering residual common costs associated with economies of scale related to production. The proposed water rate, while based primarily on possible welfare improvements, also promises gains in simplicity in use and rate stability over time, compared to current practice.
12
Záboj, Jakub. "Návrh vytápění a ohřevu teplé vody v rodinném domě." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229674.
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The thesis aims to propose a system for heating and hot water for a family house, according to drawings supplied by the building architect. At the request of the investor as the primary object will be considered a variant of underfloor heating. For comparing the heat loss, economic and possibly to State subsidies system selected will be processed by an alternative option to the ventilation air heating. Underfloor heating and hot air are among the low-temperature heating system, which can use low temperature heat sources, such as heat pumps. This assumption corresponds to investor requests, the source of heat in a family house with a heat pump and gas boiler. For hot water will be used as an alternative to a fireplace in the living room. To use the results of the thesis is to calculate the heat loss and heat, according to current standards include design and hot-water heating system including hot-drawing documentation. Finally, the economic evaluation of different alternatives in terms of investment and operating costs.
13
Cohen, R. R. "Thermal energy accumulation in stratified hot water stores." Thesis, Cranfield University, 1986. http://hdl.handle.net/1826/4195.
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Hot water thermal energy stores have the potential to improve and
extend the performance of many kinds of energy system. Waperature
stratification in the store is likely to affect the system's
efficiency. A basic but accurate computer model of the hot water
store under various inlet flow conditions is a requisite means of
assesiing promising applications of hot water storage by system
computer simulation techniques.
A microprocessor-controlled test facility has been constructed to
evaluate the performance of a 3m
3
hot water store under a wide range
of inlet flow conditions, using a temperature step input approach.
Three types of inlet/outlet ports have been examined: horizontal,
vertical and distributors. The results show that two distinct
regions evolve within the store: a fully-mixed region adjacent to
the inlet port and a region of smooth 'plug-flow' in the remaining
volume of the store. The performance of the store is shown to be
defined by the initial depth of the fully-mixed region which in turn
is seen to be closely related to the buoyancy and momentum fluxes of
the inlet flow.
The behAviour of the store and the evident correlations have enabled
a one-dimensional computer model of the store to be developed, taking
into account the turbulent mixing, vertical heat conduction and heat
losses to the surrounding areas. The model has been successfully
validated against the results from the step input experiments.
The model has been integrated into a computer simulated central
heating system which incorporates a hot water store. Predictions have
been made, using the simulation, of the energy savings which may be
achieved with the use of storage in comparison to a conventional
system, and an assessment has been made of the economic viability of
the application.
14
Mote, R. T. "Heat exchanger design in a hot-water store." Thesis, Cranfield University, 1991. http://dspace.lib.cranfield.ac.uk/handle/1826/10999.
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The behaviour of natural convective buoyancy-driven flows within
a hot-water store due to the forced passage of colder water
through the heat-exchanger's pipe are reviewed in the light of
recent advances in experimental
throughout the literature. The
exchanger designs, for natural
unworkable for the engineer
complication arises because the
heat exchanger are sensitive to
and numerical studies, reported
empirical development of heat
convection problems, are often
with a specification. The
heat transfer performance of the
the initial boundary conditions
of the problem, ranging from the initial charged temperature of
the water in the insulated tank of a fixed
dimensíon, to the
physical properties of the heat-exchanger's pipe. It was
concluded that an improvement in the heat transfer performance
can be derived by determining the optium length and the
orientation of the
heat-exchanger's arrangement. Further benefits
are derived by correlating the thermal convective behaviour,
within the hot-water store, with the forced passage of colder
water through the heat exchanger's pipe. A convective flow model,
based upon the experimental results, is described to advance the
heat
exchanger design principles in the situation of transient
natural convection. Assumptions employed in the experimental work
confirm that realistic and reasonable results can be obtained
from the thermal analysis of the vertical cylindrícal store in
two-dimensions.
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Kronholm, Juhani. "Utilization of pressurized hot water and supercritical water in the treatment of polluted water and soil." Helsinki : University of Helsinki, 2002. http://ethesis.helsinki.fi/julkaisut/mat/kemia/vk/kronholm/.
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Catherine, Quinton Shaun. "Effective geyser management through intelligent hot water usage profiling." Thesis, Cape Peninsula University of Technology, 2009. http://hdl.handle.net/20.500.11838/1094.
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Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2009This study presents an intelligent Hot Water Cylinder (HWC) usage profiling system to provide peak demand side management and improve HWC efficiency in a typical household. In this research HWCs will be referred to as geysers. Research was done into various techniques available to improve energy efficiency in South Africa, as well as the different sectors South Africa's electricity supplier, Eskom, has highlighted where improvements in energy efficiency can be made. From this it was decided to refine the scope of the project to the residential sector, and more importantly geyser. A typical geysers operation and power consumption was researched and analysed to determine where efficiency improvements could be made. A system was required that would reduce the amount of energy consumed by the geyser, and provide the consumer with hot water at the same time. Based on the research it was decided to design a profile based geyser controller. The profiling system comprised of a PIC microcontroller, four digital temperature sensors and a time keeper used to determine individually based hot water usage profiles for the home. The profile was based on three parameters, namely the frequency (repetitiveness) of hot water being drawn, the length of the draw period, and the time of day when the water was drawn. Once the profile had reached a 90% accuracy, the profile implemented itself. Based on the profile, the controller then regulated the temperature of the geyser according to the demand of the household, without manual intervention. If the household's routine were changed, the profile would adapt itself accordingly. The controller is therefore fully intelligent and continues to refine the profile on a day to day basis. By introducing the profile based controller, the monthly average geyser temperature was reduced, reducing the amount of standing losses, which in torn reduced the total amount of energy consumed by the geyser. The profile controller was designed to aid in the reduction of the energy demand of geysers on the power grid. This will benefit both the consumer as well as Eskom, as Eskom will have a reduced power load, and the consumer will have a reduced electricity bill. The results of the experiments are shown, as well as a comparison between calculated versus measured results, to justify the accuracy of the calculations.
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Bjorn, Andrew. "Enhanced removal of residual DNAPL with hot water injection." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0017/MQ53369.pdf.
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Kwan, F. S.-Y. "Deadleg losses from a simulated domestic hot water system." Thesis, University of Canterbury. Mechanical Engineering, 1985. http://hdl.handle.net/10092/8080.
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This report considers the factors determining the deadleg losses of horizontal 'supply' hot water copper pipes, in a dynamic simulation rig of a domestic hot water system in the laboratory of the Mechanical Engineering Department at the University of Canterbury.
In order to simulate the calculated system daily deadleg losses for a real house for which the ambient te1nperature was low* and the room temperature was l8°C, an air-conditioning unit was used to supply cool air blowing through the five sections of 75 mm ID PVC air 'tunnels' which were built over the horizontal 'supply' hot water copper pipes [photo 1].
Thus the effect of deadleg losses due to natural-convection heat transfer in an ordinary domestic house was simulated experimentally by using forced-convection heat transfer in the rig.
Quantitative values of deadleg losses at different usage patterns and tank temperatures are tabulated.
*5.7°C as ambient temperature was being used in this project. It was the most severe daily average temperature of Christchurch in July (1960-1969) - data from Meteorological Office at the airport of Christchurch, New Zealand.
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Salazar, Navalón Pablo. "EVALUATION OF HEAT LOSSES FROM ADOMESTIC HOT WATER CIRCULATIONSYSTEM." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-20044.
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Heat losses are an important problem in domestic hot water circulation systems. Therefore, toreduce these losses becomes an issue of utmost importance both economically andenvironmentally. Nevertheless, it has not been until recent years when these losses have beenstudied further. Commonly studies have focused on the heat space system operation or radiatorsystem. This study focuses on heat losses in the domestic hot water circulation through thepiping system in a building at a school located in Gävle (Sweden) using non-destructive flowand temperature reading devices. The heat used by the school is provided by the district heatingnetwork that feeds several heat exchangers. The heat losses, at the same time, will be comparedwith simulation and theoretical procedures to corroborate them. The domestic hot water pipingsystem of this study consists on more than 1200 meters of insulated copper pipes with differentdiameters and different insulation thickness. The system was measured for one week (April 26,2015 to May 3, 2015) when there are working days and nonworking days. A 5% of the annualdistrict heating consumption in the school was calculated as heat losses in the domestic hotwater circulation system in the building studied. Finally, improvements in insulation system andchanges in the domestic hot water temperature have been simulated and they demonstrate thatsavings of up to 35% of the heat losses can be achieved and produce significant energy savings.
20
Altorkmany, Lobna. "Energy Efficient Eradication of Legionella in Hot Water Systems." Licentiate thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-67514.
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Disease related to unsafe water, poor sanitation, and lack of hygiene is some of the most common causes of illness and death all around the world. Since the first detection of Legionella in Philadelphia 1976, Legionella is recognized to cause Legionellosis which is associated with two distinct forms: Legionnaires’ disease and Pontiac fever. The fact that vaccination against Legionella disease is not efficacious enhances the effort towards developing the existence disinfection methods and inventing new technologies. Re-colonization of Legionella in hot water systems may occur within a few days or weeks after disinfection since conventional disinfection methods significantly reduce but do not eliminate pathogens. Understanding the conditions favoring Legionella occurrence in hot and cold systems will aid in developing new treatment technologies that minimize or eliminate human exposure to legionella pathogens. The work introduces the Anti-Bact Heat Exchanger (ABHE) system as a new innovative system inspired by nature. Compared to conventional disinfection methods, the ABHE system proposed to achieve continuous thermal disinfection of bacteria in hot water systems and in simultaneously saving energy and reducing the required costs. Thermodynamic analysis, experimental test and simulation validation of the ABHE by the Engineering Equation Solver (EES)-based model were achieved to define the thermal performance of the ABHE system at given operation conditions. The experimental test shows high potential of recovering heat and thus saving energy by the ABHE system. In addition, pumping power (PP) was relatively small compared to the recovered heat which implies that less energy was required compared to the recovered heat. The effect of working parameters such as temperatures and flow rate on the thermal performance of the ABHE system was furthermore investigated. The study shows that supplied water temperature has similar effects as the disinfection temperature. Namely, increasing supplied water temperature enhances the regeneration ratio (RR) but it requires a large plate heat exchanger (PHE) area and PP. On the contrary, increasing the temperature in use results in a reduced PHE area and PP. Flow rate has the greatest influence on the thermal performance of the ABHE system. Increasing flow rate leads to an increase in the required area of the PHE. The EES-based model investigated the effect of the length and the width of the plates used in the PHE on the RR and the required area of the PHE. Then, the EES-based model was used to optimize the ABHE system in which the PHE area is minimized or the RR of the ABHE system is maximized.
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Bush, David B., and William E. Martin. "An Empirical Evaluation of the Costs of Groundwater Overdraft." Arizona-Nevada Academy of Science, 1985. http://hdl.handle.net/10150/296385.
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From the Proceedings of the 1985 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 27, 1985, Las Vegas, NevadaEstimates of the variable costs for groundwater pumping and overdraft in Central Arizona are compared to the price of water delivered via the Central Arizona Project (CAP). The respective marginal costs of supplying irrigation water through each of the two alternative sources are compared to the marginal demand for water by farmers. Finally, the relative cost competitiveness of groundwater versus CAP water is evaluated against a number of alternative rates of energy cost escalation and groundwater decline.
22
Palmer, Reed Characklis Gregory W. "Reducing the costs of meeting regional water supply reliability goals through risk-based water transfer agreements." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2006. http://dc.lib.unc.edu/u?/etd,537.
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Thesis (M.S.)--University of North Carolina at Chapel Hill, 2006.Title from electronic title page (viewed Oct. 10, 2007). "... in partial fulfillment of the requirements for the degree of Master of Science in the Department of Environmental Sciences and Engineering." Discipline: Environmental Sciences and Engineering; Department/School: Public Health.
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Jones, Sophia Christina Acle. "Micro-cogeneration optimal design for service hot water thermal loads." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/16016.
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Liu, Chun. "Modeling of water and lubricant sprays in hot metal working." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1196091214.
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JAYASINGHE, B. T. D. "ENERGY SAVING METHODS IN HOT WATER SUPPLY FOR HOSPITALITY INDUSTRY." Thesis, KTH, Energiteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-190810.
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Hotel Industry in Sri Lanka is becoming a vital sector in the economic development in the after the cessation of ethnic conflict that existed in almost 30 years. This has resulted in high demand for energy for enhanced activities in the hotel industry. The prime objective of the hospitality industry is to provide maximum comfort and facilities to its customers. Hence, Hotels utilize more energy to satisfy its visitors which will benefit the hotel as well as the income generated through foreign exchange to the country. Electrical energy is used in this industry for lighting, air conditioning (cooling), water purification, hot water and steam for washing, cleaning and cooking purposes etc. In Sri Lanka, electricity is generated mainly from fossil fuels. Furnace oil is used in boilers for heating of water and supply of steam for laundry, kitchen and washing for guest rooms. If thermal power generation with the use of fossil fuels is to be dominated in meeting energy demand, it will be a heavy burden to the country since Sri Lanka being a developing country lacks much needed foreign exchange. Burning of Fossil fuel will also affect the environment by releasing green house gases to the atmosphere as well. Therefore, it has to explore alternative sources of energy in order to meet the demand for energy in the hotel sector as much as possible. Further, sustainable use of energy is very vital for sustained development of the country at large. In this project, a comprehensive study was carried to identify the opportunities to minimize the energy utilized in hospitality institutes. It has been identified that around 22% of the total energy consumption in a hotel is for hot water generation, which is higher than energy used for cooling and lighting. Hence the amount of energy utilized for hot water production in a selected beach hotel was evaluated and alternative source of energy such as solar hot water system was studied, which could be utilized in order to minimize energy consumption though burning fossil fuel. A comprehensive study in designing the total solution in solar hot water system was undertaken with the available data with the selected hotel. A simulation was carried out to test the validity of solution with software packages Polysun , Kolektor 2.2 , SAM2010 and RETScrean. The proposed system of solar hot water is expected to save SLR 781,200. (Approximately 5,400.00 USD) per year and reduce emission of CO2 by 33 Tons per year.Hotellindustrin i Sri Lanka är en viktig del av den ekonomiska återhämtningen efter den 30-åriga krigsperioden i landet. Detta har resulterat i en stor efterfråga för energi för att kunna tillgodose en hög standard till turisterna. Hotellens ökade energianvändning tillfredsställer besökarna i en större grad som i sin tur leder till högre vinster. Elenergi används inom denna industri för belysning, luftkonditionering, vattenrening, tappvärmevatten och ånga för tvättning, städning osv. Eltillförseln i Sri Lanka är i huvud sak fossilbaserad. Fossilolja förbränns i pannor för olika varmvattenändamål. Om termisk kraftgenerering med fossila bränslen fortsätter att utnyttjas i så stora skala kommer Sri Lanka att drabbas ännu mer ekonomisk i framtiden på grund av oljeimporten. Miljön också påverkas negativt genom ökade utsläpp av växthusgaser. Därmed behöver man undersöka alternativa energikällor för att möta energibehoven i hotellsektorn. Dessutom bidrar förnybara energikällor till landets hållbar utveckling. Detta projekt omfattar en övergripande studie för att identifiera möjligheter för energibesparingar i Sri Lankas hotellindustri. Undersökningen visar att cirka 22% av hotellens energianvändning går åt varmvatten, vilken är en högre andel än energibehoven för komfortkyla och belysning. Varmvattenanvändning i ett strandhotell utvärderades och alternativa energikällor som solvärme studerades. Solvärmesystem designades i detalj med tillgängliga data. Simuleringar genomfördes med kommersiella mjukvaror som Polysun, Kolektor 2.2, SAM2010 och RETScreen. Det utvalda systemet förväntas leda till en årlig besparing på SLR 781,200 (circka 5,400 USD) och årlig CO2-minskning på 33 tonne.
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Herbstein, Tom Philip. "Insurance and the Anthropocene: like a frog in hot water." Doctoral thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/16571.
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Includes bibliographical referencesThis thesis explores the relationship between the commercial insurance industry, global environmental change (GEC) and what Beck (1992; 1999) termed the 'risk society'. In recent decades, there have been growing concerns that many of the risks impacting contemporary society have undergone fundamental changes. Many of these risks are increasingly being linked to the unintended consequences of humankind's remarkable progress in science and technology, and have been described as debounded, given that they so often transcend both geographical and temporal boundaries (Beck 1992). Within the risk society, the commercial insurance industry - which relies on statistical (actuarial) analysis to help it assess and manage its risk exposure - has been described as demarcating the frontier barrier between bounded (i.e. insurable) and debounded (i.e. uninsurable) risk. However, this claim has been a highly contested one, leading to calls for more empirical data to help clarify how commercial insurance is actually responding under conditions of uncertainty. Of all the debounded risks, GEC has emerged as one of the risk society's most recognisable. Now understood to be a result of the anthropogenic emission of greenhouse gasses, particularly since the onset of the industrial revolution, its impacts have risen so sharply in recent decades that it has prompted claims that Earth has moved away from the era of the Holocene and into the Anthropocene (Crutzen 2002). Given that at least 40% of the cost of environmental catastrophes is now borne by commercial insurance, GEC provides an excellent opportunity to gain a deeper understanding of how the industry is responding to debounded risk at the risk society's frontier barrier. Early commentators suggested that the commercial insurance industry would be well motivated to respond proactively to GEC, by taking a more mitigative approach to managing its drivers at both the global and local levels. However, the industry, so far, has been described as more adaptive of its own business activities than mitigative. This raises questions about whether such claims are true across all three of the insurance industry's activities - as risk carriers, risk managers and as investors, why they have responded in such ways, and what implications this has for broadening our understanding of the complex relationship between commercial insurance, debounded risk and the risk society's frontier barrier. To consider these questions, a collective case study was undertaken with a variety of commercial insurance companies, re-insurers, asset managers, clients, brokers, industry associations and regulators across South Africa, Germany, Switzerland, the United Kingdom and Belgium. The research identified how commercial insurers have indeed responded more by adaptation of their business activities than mitigation of the drivers of GEC. This is mainly through the use of defensive underwriting to help them manage their exposure. However, the research extends this analysis by highlighting some of the nuances of the industry's response. This includes its focus on centralisation, the influence of the existing paradigm framing its understanding of risk, and by highlighting the irony that the area of insurers' activities, initially believed to be most suited for responding to GEC (i.e. their investment portfolios), have, in practice, been the area recording the least response. In exploring why this is so, the study draws on understandings of the Anthropocene to argue that commercial insurers are finding their existing risk assessment tools progressively out-dated in a world where risk is no longer as predictable as it once was. This is further compounded by increasingly plural access to the risk society's science and technologies, which, in some instances, are undermining the role commercial insurance plays as society's primary financial risk manager. This raises questions around the role commercial insurance plays in demarcating the risk society's frontier barrier which, ultimately, has far broader implications for why so many of society's institutions are struggling to adapt to risk in the 21st Century.
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Pitarch, i. Mocholí Miquel. "High capacity heat pump development for sanitary hot water production." Doctoral thesis, Universitat Politècnica de València, 2017. http://hdl.handle.net/10251/81858.
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Heat pumps have been identified as an efficient alternative to traditional boilers for the production of sanitary hot water (SHW). The high water temperature lift (usually from 10ºC to 60ºC) involved in this application has conditioned the type of used solutions. On the one hand, transcritical cycles have been considered as one of the most suitable solutions to overcome the high water temperature lift. Nevertheless, the performance of the transcritical CO2 heat pump is quite dependent on the water inlet temperature, which in many cases is above 10ºC. Furthermore, performance highly depends on the rejection pressure, which needs to be controlled to work at the optimum point in any condition. On the other hand, for the subcritical systems, subcooling seems to be critical for the heat pump performance when working at high temperature lifts, but there is not any published work that optimizes subcooling in the SHW application for these systems. Therefore, the subcritical cycle should require a systematic study on the subcooling that optimizes COP depending on the external conditions, in the same way as it has been done for the rejection pressure in the transcritical cycle.
The aim of this thesis is to investigate the role of subcooling in the performance of a Propane water-to-water heat pump for SHW production, in the application of heat recovery from any water source. Two different approaches to overcome the high degree of subcooling were designed and built to test them in the laboratory:
1) Subcooling is made at the condenser: The active refrigerant charge of the system is controlled by a throttling valve. Subcooling is controlled independently at any external condition.
2) Subcooling is made in a separate heat exchanger, the subcooler. Subcooling is not controlled, it depends on the external condition and the heat transfer at the subcooler.
The heat pumps were tested at different water temperatures at the evaporator inlet (10ºC to 35ºC) and condenser inlet (10ºC to 55ºC), while the water production temperature was usually fixed to 60¿C. The obtained results have shown that COP depends strongly on subcooling. In the nominal condition (20¿C/15¿C for the inlet/outlet water temperature at the evaporator and 10ºC/60ºC for the inlet/outlet water temperature in the heat sink), the optimum subcooling was about 43 K with a heating COP of 5.61, which is about 31% higher than the same cycle working without subcooling. Furthermore, the system with subcooling has been proved experimentally as being capable of producing water up to 90¿C and has shown a higher COP than some CO2 commercial products (catalog data reference).Las bombas de calor han sido identificadas como una alternativa eficaz a las calderas tradicionales para la producción de agua caliente sanitaria (ACS). El elevado salto de temperatura del agua que normalmente tiene lugar en esta aplicación (por lo general de 10ºC a 60ºC) ha condicionado el tipo de soluciones que se utilizan. Por un lado, los ciclos transcríticos han sido considerados como una de las mejores soluciones para trabajar con los elevados saltos de temperatura del agua. Sin embargo, el rendimiento de la bomba de calor transcrítica con CO2 es bastante dependiente de la temperatura de entrada del agua, que en muchos casos está por encima de los 10¿C. Además, el rendimiento depende en gran medida de la presión de descarga, la cual necesita ser controlada con el fin de trabajar en el punto óptimo en cualquier condición externa. Por otra parte, para los sistemas subcríticos, el subenfriamiento parece ser crítico para el buen funcionamiento de la bomba de calor cuando se trabaja con elevados saltos de temperatura del agua, pero no hay ningún trabajo publicado en el que optimicen el subenfriamiento para la aplicación de ACS en estos sistemas. Por lo tanto, los sistemas subcríticos requieren de un estudio sistemático para buscar el subcooling óptimo y maximizar el COP en función de las condiciones externas, de la misma forma que se ha hecho para la presión de descarga en los ciclos transcríticos. El objetivo de esta tesis es investigar el papel del subenfriamiento en el rendimiento de una bomba de calor trabajando con Propano para la producción de ACS, en la aplicación de recuperación de calor de cualquier fuente de agua (agua- agua). Dos enfoques diferentes para superar el alto grado de subenfriamiento fueron diseñados y construidos para ponerlos a prueba en el laboratorio: 1) El subenfriamiento se hace en el condensador: La carga activa de refrigerante del sistema se controla con una válvula de estrangulación. De esta manera, el subenfriamiento puede ser controlado de forma independiente a cualquier condición externa. 2) El subenfriamiento se hace en un intercambiador de calor separado, el subenfriadador. El subenfriamiento no se controla, este depende de la condición externa y de la transferencia de calor en el subenfriadador. Las bombas de calor se ensayaron a diferentes temperaturas del agua a la entrada del evaporador (10ºC a 35ºC) y entrada del condensador (10ºC a 55ºC), mientras que la temperatura de producción de agua, normalmente, se fija a 60¿C. Los resultados obtenidos han demostrado que el COP depende mucho del subenfriamiento. En las condiciones nominales (20ºC/15ºC para la temperatura del agua de entrada/salida en el evaporador y 10ºC/60ºC para la temperatura del agua de entrada/salida en el condensador), el subenfriamiento óptimo fue aproximadamente de 43 K con un COP de calentamiento de 5,61, que es alrededor del 31% más alto que el mismo ciclo trabajando sin subenfriamiento. Además, el sistema con subenfriamiento ha probado de forma experimental, que es capaz de producir agua hasta los 90ºC, y ha mostrado un COP más alto que algunos productos comerciales que trabajan con CO2 (datos de referencia del catálogo).
Les bombes de calor han estat identificades com una alternativa eficaç a les calderes tradicionals per a la producció d'aigua calenta sanitària (ACS). L'elevat salt de temperatura de l'aigua que normalment té lloc en aquesta aplicació (en general de 10ºC a 60ºC) ha condicionat el tipus de solucions que s'utilitzen. Per una banda, els cicles transcrítics s'han considerat com una de les millors solucions per tal de treballar amb els elevats salts de temperatura de l'aigua. No obstant això, el rendiment de la bomba de calor transcrítica amb CO2 és bastant dependent de la temperatura d'entrada de l'aigua, que en molts casos està per damunt de 10¿C. A més, el rendiment depèn en gran mesura de la pressió de descarrega, la qual necessita ser controlada per tal de treballar en el punt òptim a qualsevol condició externa. Per altra banda, per als sistemes subcrítics, el sub-refredament sembla ser crític per al funcionament de la bomba de calor quan es treballa amb elevats salts de temperatura de l'aigua, però no hi ha cap treball publicat en el qual optimitzen el sub-refredament per a l'aplicació d'ACS en aquests sistemes. Per tant, els sistemes subcrítics requereixen d'un estudi sistemàtic per tal de buscar el subcooling òptim i maximitzar el COP en funció de les condicions externes, en la mateixa forma que s'ha fet per la pressió de descarrega en els cicles transcrítics. L'objectiu d'aquesta tesi és investigar el paper del sub-refredament en el rendiment d'una bomba de calor treballant amb Propà per a la producció d'ACS, en l'aplicació de recuperació de calor de qualsevol font d'aigua (aigua-aigua). Dos enfocaments diferents per tal de superar l'alt grau de sub-refredament van ser dissenyats i construïts per posar-los a prova en el laboratori: 1) El sub-refredament es fa en el condensador: La càrrega activa de refrigerant del sistema es controla amb una vàlvula d'estrangulació. D'aquesta manera, el sub-refredament pot ser controlat de forma independent en qualsevol condició externa. 2) El sub-refredament es fa en un intercanviador de calor separat, el sub-refredador. El sub-refredament no es controla, este depèn de la condició externa i de la transferència de calor al sub-refredador. Les bombes de calor es van assajar a diferents temperatures de l'aigua a l'entrada de l'evaporador (10ºC a 35ºC) i a l'entrada del condensador (10ºC a 55ºC), mentre que la temperatura de producció d'aigua, normalment, es fixa a 60¿C. Els resultats obtinguts han demostrat que el COP depèn molt del sub-refredament. En les condicions nominals (20ºC/15ºC per a la temperatura de l'aigua d'entrada/eixida a l'evaporador i 10ºC/60ºC per a la temperatura de l'aigua d'entrada/eixida en el condensador), el sub-refredament òptim és aproximadament de 43 K amb un COP d'escalfament de 5,61, que és al voltant del 31% més alt que el mateix cicle treballant sense sub-refredament. A més, el sistema amb sub-refredament ha provat de forma experimental, que és capaç de produir aigua fins als 90ºC, i ha mostrat un COP més alt que alguns productes comercials que treballen amb CO2 (dades de referència del catàleg).
Pitarch I Mocholí, M. (2017). High capacity heat pump development for sanitary hot water production [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/81858
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Cataldi, Francesco. "Management Optimization of Energy Consumption Reduction for Residential Hot Water." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2995.
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The objective of this thesis is to create an automatic water management system capable of optimizing the usage of warm water stored in two water tanks to reduce the monthly energy consumption of the instant water heater installed in a residential house. This system is called Water Mixing System (WMS). The two heat sources considered are: PV-T system and heat rejected by the air condition system. The PV-T system is a new technology that allows transformation of the sun radiation into both electricity and warm water, increasing the efficiency of the panel compared to either a common photovoltaic panel or solar collector. The air-conditioning heat source, instead, recovers the heat rejected by the condenser to the environment by employing a heat exchanger that stores the heat collected in the water tank.
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Abebe, Yibekal Alemayehu. "Managing the soil water balance of hot pepper (Capsicum annuum L.) to improve water productivity." Thesis, University of Pretoria, 2010. http://hdl.handle.net/2263/25257.
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A series of field, rainshelter, growth cabinet and modelling studies were conducted to investigate hot pepper response to different irrigation regimes and row spacings; to generate crop-specific model parameters; and to calibrate and validate the Soil Water Balance (SWB) model. Soil, climate and management data of five hot pepper growing regions of Ethiopia were identified to develop irrigation calendars and estimate water requirements of hot pepper under different growing conditions. High irrigation regimes increased fresh and dry fruit yield, fruit number, harvest index and top dry matter production. Yield loss could be prevented by irrigating at 20-25% depletion of plant available water, confirming the sensitivity of the crop to mild soil water stress. High plant density markedly increased fresh and dry fruit yield, water-use efficiency and dry matter production. Average fruit mass, succulence and specific leaf area were neither affected by row spacing nor by irrigation regimes. There were marked differences among the cultivars in fruit yields despite comparable top dry mass production. Average dry fruit mass, fruit number per plant and succulence were significantly affected by cultivar differences. The absence of interaction effects among cultivar and irrigation regimes, cultivars and row spacing, and irrigation regimes and row spacing for most parameters suggest that appropriate irrigation regimes and row spacing that maximize productivity of hot pepper can be devised across cultivars. To facilitate irrigation scheduling, a simple canopy cover based procedure was used to determine FAO-type crop factors and growth periods for different growth stages of five hot pepper cultivars. Growth analysis was done to calculate crop-specific model parameters for the SWB model and the model was successfully calibrated and validated for five hot pepper cultivars under different irrigation regimes or row spacings. FAO basal crop coefficients (Kcb) and crop-specific model parameters for new hot pepper cultivars can now be estimated from the database, using canopy characteristics, day degrees to maturity and dry matter production. Growth cabinet studies were used to determine cardinal temperatures, namely the base, optimum and cut-off temperatures for various developmental stages. Hot pepper cultivars were observed to require different cardinal temperatures for various developmental stages. Data on thermal time requirement for flowering and maturity between plants in growth cabinet and open field experiments matched closely. Simulated water requirements for hot pepper cultivar Mareko Fana production ranged between 517 mm at Melkassa and 775 mm at Alemaya. The simulated irrigation interval ranged between 9 days at Alemaya and 6 days at Bako, and the average irrigation amount per irrigation ranged between 27.9 mm at Bako and 35.0 mm at Zeway.Thesis (PhD)--University of Pretoria, 2010.
Plant Production and Soil Science
unrestricted
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Cemo, Thomas A. Van Treuren Kenneth W. "Design and validation of a solar domestic hot water heating simulator." Waco, Tex. : Baylor University, 2009. http://hdl.handle.net/2104/5357.
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Jang, Won-Ik. "Costs of chronic disease and an alternative to reduce these costs: case study of End Stage Renal Disease (ESRD)." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1481.
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An improved understanding of the costs of diseases is obtained by conducting a case study of the costs associated with end stage renal disease (ESRD). In estimating the costs of ESRD, the costs incurred by both patients and their primary unpaid caregivers are calculated. Most economic studies of the costs of diseases ignore either the patients or unpaid caregiver side, focusing on one or the other. From a theoretical standpoint, it is shown unpaid caregiving lowers the costs of diseases to society. Unpaid caregiver lowers the cost, because for unpaid caregiving to occur, the net benefits of unpaid caregiving must be lower than the net benefits of hiring a paid caregiver.
Using patients and their primary caregivers at the Gambro Dialysis Center in College Station, Texas as a case study, estimated total ESRD costs range from $84,000 to $121,000 / year / case. The distribution of these costs is positively skewed. Of the total costs, approximately 2% to 25% can be attributed to unpaid caregiving. Excluding direct medical costs in total ESRD costs, unpaid caregiving is 14% to 65% of total ESRD costs. Consideration of unpaid caregiving costs is, therefore, an important component of the costs of diseases. These estimates are conservative as the costs associated with lifestyle changes and health effects are noted, but no monetary value is placed on them. Results also indicate the patients and caregivers perception of the quantity of caregiving varies.
An alternative water supply system to improve the efficiency of water supply systems taking into account water pricing, marketing, and treatment costs is proposed. This system treats and supplies water differently depending on the source of the water and if the end-use of the water is a potable or non-potable use, then may reduce treatment costs. Decreased treatment costs may make more stringent water standards more affordable. More stringent water standards may cause a decrease in the risk of water-related diseases including ESRD induced by water-borne toxins. Reducing the risk of ESRD will reduce societys costs associated with chronic illnesses. Possible benefits and costs of the proposed system are discussed, but not calculated.
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Deng, Yuming. "Present and expected economic costs of zebra mussel damages to water users with great lakes water intakes /." Connect to resource, 1996. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=osu1249669221.
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Deng, Yuming. "Present and expected economic costs of zebra mussel damages to water used with Great Lake water intakes." The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1249669221.
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Marlor, Kathryn Marie. "Examining the Economic Costs and Sources of Potable and Nonpotable Water in Northern Mexico." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4144.
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Water availability and the cost of different water sources have been studied at great length. However, information is still needed to determine the policy directions to be undertaken by nations that have not yet achieved universal coverage of an improved water source. To further examine differences in water availability and pricing in the context of the developing world, three communities in Northern Mexico were surveyed to determine the differences in water distribution schemes and associated costs between rural and urban centers. It was observed that rural communities without a piped water supply paid 13 percent more for potable water supplies and 39 percent more for nonpotable water supplies than urban communities with a piped water source. A relationship between access to piped water and the probability of contracting diarrhea was also observed, with households with access to piped water having a lower probability of contracting diarrhea than those households without, and experiencing a lower number of days per month with diarrhea, on average. This leads to the observation that rural communities, who typically are less likely to be able to afford a piped distribution system, are paying more for their water supplies than nearby urban centers, both in terms of the money spent each month for water resources, and the costs associated with contracting and treating diarrhea. Steps should be taken by Mexico and other developing nations to ensure that water is distributed equally and priced fairly, so that the more impoverished subsets of their populations are not paying higher prices for their water.
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Turaga, Rama Mohana Rao. "Spatial Resolution, Costs, and Equity in Air Toxics Regulation." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16236.
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Concern about environmental injustice has been driving the recent effort to characterize risks from exposures to air toxics at very fine spatial resolutions. However, few studies seek to understand the potential policy implications of regulating risks at increasingly finer spatial resolutions and the impact of resulting policies on distribution of risks. To address this gap, the broad question for this research is how could the choice of spatial resolution for regulation of risks from toxic air pollutants affect emission controls and the consequences thereof? This research develops a formal model of a hypothetical decision maker choosing emission controls within a risk-based regulatory framework. The model suggests that optimal controls on air toxics emissions vary depending on the spatial resolution chosen to regulate risks; net social costs are non-decreasing as one regulates at finer and finer spatial resolutions.
An empirical application of the model using air toxic emission data for Escambia and Santa Rosa Counties in Florida demonstrates the sensitivity of optimal emissions to spatial resolution chosen for regulation. The research then investigates the equity implications of regulating at different spatial resolutions with regard to the spatial distribution of cancer risks. The empirical results indicate that regulation at finer spatial resolutions could involve a tradeoff between costs and equitable distribution of risks. For example, at a threshold cancer risk of 100 in a million, regulating at census block level resolution could be twice as costly as regulating at census tract resolution while reducing the maximum individual risk by almost half. Further, regulation at finer spatial resolutions might not address environmental injustice by itself unless such concerns are more explicitly incorporated into emission control decisions. Finally, this research shows that spatial resolution at which air toxics risks are regulated could matter in predictable ways even after taking into account the uncertainties that the decision maker faces.
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Asim, Muhammad. "Experimental Analysis of Integrated System of Membrane Distillation for pure water with solar domestic hot water." Thesis, KTH, Energiteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-141141.
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In GCC countries, especially in UAE desalination of sea water is considered to be one of the most effective and strategic alternative for satisfying the current and future demand of water for domestic purposes. The depletion of ground water aquifers, rapid industrial development and increase of urban population in UAE lead to tremendous increase in fresh water demand during past decade. Although, desalinated fresh water is supplied to the consumers by local municipalities, people in the region rely mostly on bottled water for drinking purpose obtained through post desalination re-processing. Thousands of suppliers in UAE deliver bottled water to homes or offices thus leading to environmental unsustainability in the whole conversion chain from desalinated water to bottling, packaging and delivery. In fact, UAE is one of the leading countries in per capita bottle water consumption. Therefore, a need has been observed to provide safe drinking water for households in a sustainable way.In order to produce drinking water at homes, a concept of integrating Membrane Distillation (MD) based water purification with Solar Domestic Hot Water (SDHW) systems has been proposed and its feasibility has been evaluated in this research study. Present application is for a single family house/villa in UAE region that requires 20 l/day of drinkable water and 250 l/day of hot water for domestic purpose. An experimental pilot system has been installed at CSEM-uae for evaluating different operational parameters of such integrated system and also to determine overall thermal performance of the system. The study provides detailed design of experimental unit, procurement, installation and commissioning of the SDHW-MD integrated system along with estimated annual profiles of pure water and overall energy consumption.Experiments performed for one month during summer and distillate fluxes of around 4.5 – 12 l/m2/hour has been obtained with optimum MD hot and cold side flow rates of 6 and 3 l/min respectively and at hot side temperatures ranging from 50 - 70oC with cold side average temperature of 35oC. With recovery of cold side heat of MD unit, 25% of daily demand of DHW could be reduced and hence the estimated annual combined energy demand of 8220 kWh could be sufficiently fulfilled with either 8.5 m2 aperture area of Flat plate solar thermal collectors or with 7.5 m2 of Evacuated tubular collectors.
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Brazeau, Randi Hope. "Sustainability of Residential Hot Water Infrastructure: Public Health, Environmental Impacts, and Consumer Drivers." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/26537.
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Residential water heating is linked to the primary source of waterborne disease outbreaks in the United States, and accounts for greater energy demand than the combined water/wastewater utility sector. To date, there has been little research that can guide decision-making with regards to water heater selection and operation to minimize energy costs and the likelihood of waterborne disease.
We have outlined three types of systems that currently dominate the marketplace: 1) a standard hot water tank with no hot water recirculation (STAND), 2) a hot water tank with hot water recirculation (RECIRC), and 3) an on-demand tankless hot water system with no hot water recirculation (DEMAND).
Not only did the standard system outperform the hot water recirculation system with respect to temperature profile during flushing, but STAND also operated with 32 – 36% more energy efficiency. Although RECIRC did in fact save some water at the tap, when factoring in the energy efficiency reductions and associated water demand, RECIRC actually consumed up to 7 gpd more and cost consumers more money. DEMAND operated with virtually 100% energy efficiency, but cannot be used in many circumstances dependent on scaling and incoming water temperature, and may require expensive upgrades to home electrical systems.
RECIRC had greater volumes at risk for pathogen growth when set at the lower end of accepted temperature ranges, and lower volumes at risk when set at the higher end when compared to STAND. RECIRC also tended to have much lower levels of disinfectant residual (40 -850%), 4-6 times as much hydrogen, and 3-20 times more sediment compared to standard tanks without recirculation. DEMAND had very small volumes of water at risk and relatively high levels of disinfection.
A comparison study of optimized RECIRC conditions was compared to the baseline modes of operation. Optimization increased energy efficiency 5.5 – 60%, could save consumers 5 – 140% and increased the disinfectant residual up to 560% higher disinfectant residual as compared to the baseline RECIRC system. STAND systems were still between 3 – 55% more energy efficient and could save consumers between $19 - $158 annual on water and electrical costs. Thus, in the context of “green” design, RECIRC systems provide a convenience to consumers in the form of nearly instant hot water, at a cost of higher capital, operating and overall energy costs.Ph. D.
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Bierbrauer, Frank. "Mathematical modelling of water-droplet impact on hot galvanised steel surfaces." School of Mathematics and Applied Statistics - Faculty of Informatics, 2004. http://ro.uow.edu.au/theses/400.
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Hot-dip galvanising is commonly used in industry to increase the corrosion resistance of cold-rolled steel products for commercial use such as roofing and walling of buildings. Traditionally, the zinc coated steel surface is characterised by a relatively smooth surface with large spangle relief which is detrimental to corrosion resistance. One of the techniques to modify the surface appearance consists of a water-mist spray solution which allows for the creation of a large number of nucleation sites giving rise to micro rather than macro spangles, thereby producing a much smoother surface. In addition, controlling the spray parameters allows the hot, zinc coated, steel surface to be ‘roughened’ facilitating its bonding to concrete or for lamination. The proper control of water droplet impact parameters such as impact velocity, droplet diameter and crater size is essential for a successful implementation of this technique. Certain aspects of the second of these processes, the production of rough, non-skid galvanised steel sheet surfaces, has been addressed by this thesis.Although an experimental investigation of the effect of such water droplet parameters on the formation of zinc surface characteristics such as crater diameter and depth would provide a great deal of valuable data it is fraught with difficulties. The presence of hot metal surfaces exceeding 450oC and the boiling and evaporation of water droplets taking place at very small timescales (microseconds) all combine to make an experimental study difficult to implement not to say unsafe. On the other hand computer simulations with a properly constructed mathematical model are a valuable tool for the investigation of these parameters.A comprehensive modelling of the process would include the process of heat transfer: such as conduction through a vapour layer, internal droplet and vapour convection, radiation from the hot surface, solidification of the zinc liquid layer; as well as the fluid dynamical aspects: such as surface tension at the droplet-air, droplet-zinc and zinc-air interfaces, the droplet impact phenomena such as spreading and splashing and the formation of impact craters and wave propagation in a thin viscous zinc layer. As a first stage in the modelling exercise this thesis will concentrate on an investigation of single water droplet impact on a thin liquid zinc layer with a steel substrate which provides a simplified and computationally tractable model of the spraying process.The objectives of this thesis are twofold: firstly, the development and construction of an accurate, robust mathematical model and, secondly, the solution of the model for the impact of a single water droplet onto a thin liquid layer of zinc on a steel substrate. This model must be able to deal with rapidly deforming moving interfaces and maintain stability in the presence of very large density and viscosity ratios. This moving boundary problem requires the tracking of three fluid interfaces while also maintaining incompressibility. The Godunov-Marker-Particle Projection Scheme developed in this thesis is able to satisfy these requirements. Through a combination of approximate projection methods, Godunov convective differencing, Marker-Particle interface tracking and velocity filters the method is able to treat viscous, multi-fluid free surface flows. The modelling of free surface flows with more than two separate immiscible fluids, to the author’s knowledge not yet published in the literature, is a secondary aim of the thesis. A major part of the thesis deals with the thorough testing of each aspect of the combination of numerical methods used: firstly, the Poisson solver with discontinuous coefficients and homogeneous boundary conditions used in the approximate projection method, analytical solutions for the construction of an initial solenoidal velocity field, testing of the projection and velocity filters and kinematic tests of the Marker-Particle method for tracking of fluid interfaces; secondly, dynamical tests of the viscous incompressible Navier-Stokes equations for: an exact solution, the Lid-Driven Cavity and the Rayleigh-Taylor instability. The combined method is also successfully tested on the limited two-fluid droplet-solid and droplet-liquid impact problems before solving the thesis problem.It is shown that, for the impact of a single water droplet onto a thin liquid zinc layer, impact crater growth, diameter and depth, are linearly dependent on impact velocity. For a given impact velocity, crater diameter is not effected by increasing zinc layer depth although crater depth is linearly dependent. The time at which the droplet commences penetration of the zinc layer is inversely dependent on impact velocity and the maximum crater diameter and depth are nonlinearly dependent on impact velocity. The model shows that, within the convective timescale, droplet impact on thin liquid zinc layers can be approximately described by droplet spreading on a solid zinc surface. The droplet is shown to spread preferentially to the zinc layer splashing after completion of spreading. This shows that adjustment of the droplet impact velocity or zinc layer depth can vary the surface roughness appropriately.
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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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Salazar, Navalón Pablo. "Evaluation of heat losses from a domestic hot water circulation system." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-20042.
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Heat losses are an important problem in domestic hot water circulation systems. Therefore, to reduce these losses becomes an issue of utmost importance both economically and environmentally. Nevertheless, it has not been until recent years when these losses have been studied further. Commonly studies have focused on the heat space system operation or radiator system. This study focuses on heat losses in the domestic hot water circulation through the piping system in a building at a school located in Gävle (Sweden) using non-destructive flow and temperature reading devices. The heat used by the school is provided by the district heating network that feeds several heat exchangers. The heat losses, at the same time, will be compared with simulation and theoretical procedures to corroborate them. The domestic hot water piping system of this study consists on more than 1200 meters of insulated copper pipes with different diameters and different insulation thickness. The system was measured for one week (April 26, 2015 to May 3, 2015) when there are working days and nonworking days. A 5% of the annual district heating consumption in the school was calculated as heat losses in the domestic hot water circulation system in the building studied. Finally, improvements in insulation system and changes in the domestic hot water temperature have been simulated and they demonstrate that savings of up to 35% of the heat losses can be achieved and produce significant energy savings.
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Zurawlew, Michael. "Post-exercise hot water immersion : a novel approach to heat acclimation." Thesis, Bangor University, 2018. https://research.bangor.ac.uk/portal/en/theses/postexercise-hot-water-immersion(107af32f-9f52-4474-b47b-0d6344185b88).html.
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Hot environmental conditions can reduce work productivity/exercise performance and increase the incidence of exertional heat illness. In preparation for hot environments, individuals commonly complete heat acclimation protocols that initiate physiological and perceptual adaptations to reduce thermal strain and improve physical capabilities. However, conventional exercise-heat acclimation interventions can be costly and impractical, as they require access to an artificial hot environment and often require control of core temperature during exercise. As such, there is a demand for a flexible heat acclimation intervention that can be easily incorporated into the daily training of athletes and military/occupational personnel. Therefore, the aim of this thesis was to develop a novel and practical post-exercise hot water immersion heat acclimation protocol. Firstly, 6-days of submaximal exercise in temperate conditions followed by a hot water immersion induced hallmark heat acclimation adaptations during submaximal exercise in temperate and hot conditions and improved endurance exercise performance in the heat (Chapter 4). The initiated adaptations were also not specific to the clock-time of when heat exposures occurred (Chapter 5). Post-exercise hot water immersion also initiated hallmark heat acclimation adaptations in both endurance trained and recreationally active individuals (Chapter 6). In addition, the decay of the induced adaptations following post-exercise hot water immersion is slow, with no observable loss of heat acclimation two weeks following the cessation of the protocol (Chapter 7). The studies presented in this thesis demonstrate that the novel post-exercise hot water immersion intervention provides heat acclimation and reduces thermal strain during exercise in the heat. Future research is required to optimise this technique to improve its incorporation into different military/occupational or athlete scenarios and assess the impact of the intervention on the incidence of exertional heat illness.
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Armstrong, Peter Michael. "Enhancing the energy storage capability of electric domestic hot water tanks." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:af140a2c-aab4-4fc9-8709-6f9474079cd5.
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Electric hot water tanks play a pivotal role as demand response assets within the UK's energy system by storing heat when energy is inexpensive and delivering domestic hot water when it is required. This role will become increasingly important if non-dispatchable renewable energy sources are to play a bigger part in the energy mix. Historically, the design standards relating to hot water tanks have focused primarily on minimising heat losses. However, in addition to preserving energy, a hot water tank should preserve the availability of heat above a useful temperature for as long as possible to avoid energy usage during peak times when it is costly or carbon intensive. To do this, thermal stratification within hot water tanks must be promoted. Unfortunately, thermal stratification leads to conditions that are conducive to bacterial growth due to the hospitable temperatures that arise during operation. For this reason, question marks have arisen over the extent to which more flexible control strategies, designed to allow for increasing penetrations of intermittent renewable energy sources, might lead to the growth of pathogenic bacteria within hot water tanks. The objective of the work discussed in this thesis was to understand the extent to which there is a conflict between thermal stratification and bacterial growth in practice, whether this conflict can be resolved and the potential implications for electric hot water tanks operating on a time of use tariff. A small field study demonstrated that there is prolific bacterial growth within conventional electric cylinders and that this can be attributed to thermal stratification with a confidence of (P<0.01). Fitting a de-stratification pump, to enhance sanitary performance, resulted in a 19% decrease in the recovery of useable hot water above 43°C. Given that the tanks tested during the field study were made of copper, the consequences of alternative material choices on thermal performance were explored. It was found that the rate of useable hot water loss, due to de-stratification associated with thermal diffusion across the thermocline, could be reduced by a factor of 2.7 by making the tank liner wall from stainless steel instead of copper. Further numerical work indicated that this improvement in stratifying performance was most significant for small tanks with high aspect ratios. In addition to de-stratification that arises due to vertical conduction, de-stratification due to inlet mixing was reduced by up to 30% by installing a spiral diffuser into the base of a test cylinder. In addition, by lowering the immersion heating element to ensure there is sufficient heat transfer to the base of the cylinder, sterilising temperatures could be attained throughout the stored volume of water in the tank during heating. This showed that the conflict between thermal and sanitary performance within electric tanks could potentially be resolved. A bespoke tank, made from stainless steel and fitted with a diffuser, was built and subjected to typical draw cycles that reflect real world operation. These tests showed that more useable hot water could be delivered in comparison to a commercial off the shelf copper tank and consequently the utilisation of the Economy 7 time of use tariff would be enhanced.
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Karwa, Nitin. "Experimental Study of Water Jet Impingement Cooling of Hot Steel Plates." Phd thesis, tuprints, 2012. https://tuprints.ulb.tu-darmstadt.de/3041/1/PhD_Thesis_Karwa.pdf.
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Liquid jet impingement cooling is critical in many industrial applications. Principle applications include extracting large heat flux from metal parts, such as hot fuel bundle post-loss-of-coolant-accident in nuclear reactors, heat treatment of steel plates post-hot-processing, etc. The ability of liquid jets to extract high heat flux at controlled rates from metal parts, with temperatures as high as 800-1000 ºC, at moderate flow rates has made them indispensable in these applications. Due to the complexity of the process, the mechanism of flow boiling heat transfer during jet impingement cooling is not well understood. Resultantly, the presently used design approaches are based more on experience and rule of thumb than science. The principle challenge in the study of jet impingement cooling for these high temperature applications has been the lack of reliable instrumentation for measuring the cooling rates. To add to this, the conjugate nature of boiling heat transfer, especially on low conductivity metal like steel, makes this problem very complicated to understand. Thus, much of the state of art on this subject has been limited to experiments where either the conjugate problem has not been addressed or the tests have been performed at temperatures that are much lower than in the above mentioned applications.
The basic objective of the present work is to contribute to the understanding of the thermo-hydrodynamic phenomenon occurring during the cooling of a hot steel plate with an impinging water jet. This work also complements a parallel study being conducted at the Institute of Fluid Mechanics and Aerodynamics (Technische Universität Darmstadt), in which the complex transport processes are being treated theoretically and validated against the experimental results of this work.
To achieve the objective, transient cooling experiments have been performed on an instrumented stainless steel AISI-type 314 cylinder. To measure the temperature variation within the stainless steel cylinder during the transient cooling, fast-response thermocouples have been embedded within holes that are precisely drilled though its bottom flat face. The cylinder is induction heated to a homogeneous initial temperature of 900 ºC and is subsequently cooled by means of an axisymmetric subcooled free-surface water jet that impinges on its top flat face (impingement surface). During the cooling, each thermocouple output has been recorded at the rate of 100 samples per second. A two-dimensional axisymmetric inverse heat conduction analysis using these measured temperature data has been performed to estimate the temporospatial variation of temperature and heat flux on the impingement face. Both low and high speed images have been recorded to visualize the two-phase flow. These images and the estimated heat transfer distribution are used to understand the boiling mechanism. The effect of jet parameters, namely subcooling and impingement velocity, on the heat transfer process has been studied. Additionally, the effect of spent liquid accumulation over the impingement surface has been studied in few exploratory plunging jet experiments.
This study presents a systematic methodology for the measurement and estimation of the temporospatial variation of heat transfer on the impingement surface of a hot steel plate. Three distinct regions, with difference in the extent of liquid-wall contact, have been identified on the impingement surface from the recorded images.
i) A wetted region surrounds the jet stagnation region. Nucleate boiling is the principle heat transfer mode in this region. The outer periphery of this region is called the wetting front. No boiling activity has been observed in the high speed images, most likely because the bubbles were small and were unable to reach the liquid free-surface. The maximum heat flux position is determined to be within this region. As the wetted region grows in size with time, the maximum heat flux position also moves radially outwards. The wetting front and maximum heat flux position velocity reduce with increasing radial distance from the impingement point because the liquid velocity and subcooling reduce at the wetting front. Likewise, the wetting front velocity increases with jet velocity and subcooling.
ii) The liquid gets deflected at the wetting front due to the efflux of large vapor bubbles beyond the maximum heat flux position. A term ``wetting front region' has been coined in this thesis to describe this region. The width of this region could not be determined from the high speed images. Transition boiling within a thin superheated liquid film that is continuously replenished by the bulk flow is proposed to be the probable reason for the high heat flux in this region. Further, the radial heat conduction to the wetted region is also significant here.
iii) The impingement surface outside the wetting front region is dry. The dry surface slowly cools down due to film boiling and radial heat conduction to the wetting front region. The film boiling rate is very low in the impingement region. After deflecting away from the impingement surface in the wetting front region, the liquid film breaks into droplets over this region. Looking from the side, droplet deflection angle is observed to be small; still these droplets do not come into direct contact with the impingement surface, as has been confirmed by looking down from the top.
The velocity of the splashed droplets has been determined by analyzing the high speed images. It has been found that the drop velocity is much lower than the liquid film velocity calculated at the wetting front position using single-phase flow relations suggested by Watson. It has been hypothesized that the liquid film in the wetted region is decelerated by the bubbles growing on the impingement surface. Further, measurements reveal that the drop velocity increases with decreasing subcooling, which means that the film and the droplet are accelerated in the radial outward direction by the vapor released in the wetting front region.
It has been shown that the rewetting temperature (analogous to the Leidenfrost temperature for a sessile droplet), which refers here to the temperature below which the direct liquid-wall contact is re-established and the heat flux increases, in both the impingement and radial flow regions is significantly higher than that reported in the literature for pool boiling. Removal of bubbles by the flowing liquid in the early stages of their growth and then their rapid condensation within the subcooled liquid avoids the buildup of vapor near the hot wall, which is the likely reason for the enhancement of the rewetting temperature. This observation confirms that high heat fluxes can be removed at large wall superheats by impinging liquid jets, as practiced in the industry.
The boiling curve shifts to higher heat flux and superheat with the increase in the jet velocity and subcooling. The maximum heat flux and surface temperature at maximum heat flux increase with both the jet velocity and subcooling. Area-weighted average boiling curves have been determined, which clearly show the enhancement in the heat transfer with jet velocity over the average surface superheat of 100 to 800 K. The enhancement in jet subcooling is, however, noticeable only in the wall superheat range of 300 to 700 K. The maximum heat flux and surface temperature at maximum heat flux decrease with radial distance from the stagnation point before reaching a constant value. The radial distribution of maximum heat flux condition has been classified into three regions based on the relative size of the hydrodynamic/thermal boundary layer and the liquid film.
In the plunging jet impingement studies, it has been found that the wetting front growth slightly slows down due to accumulation of the spent liquid over the impingement surface. Area-weighted average boiling curves show that the heat transfer reduces due to accumulation.
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Vorobieva, Ekaterina. "Valorization of grape pomace residues integrating hot compressed water with biotechnology." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10819.
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Hsin, Hsieh Chih, and 謝志新. "The Study of Cost Saving for the Hot Water Boiler System in Semiconductor Plant with Design of Experiment." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/11131710617101892438.
Full textAbstract:
碩士亞洲大學
資訊工程學系碩士在職專班
98
This study used the experimental design method (Design of Experiment, DOE), analysis of hot water boiler control factor in the more significant impact on the Programme fees important process parameters, and find out the correlation of various factors.Keywords: hot water boiler, experimental design, ANOVA. Two-stage study of Yi Yi experimental design model to establish the first stage is considered the hot water boiler of the factors to be included in the experimental range, find the optimal impact of significant water supply factor. The second phase of the significant factors on the hot water boiler, with two level factorial experimental design study for the effects of various experimental factors using Minitab to plan, aimed at the less derived from the experimental combination of reasonable and accurate results. In addition, using statistical analysis of variance (ANOVA) of experimental factors on the response (Response Value) and factors influence the interaction between the relationship between the research methods section of fees will be improved.
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Walker, Dustin Luke. "Experimental investigation of the effect of increasing the temperature on ASP flooding." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-12-4919.
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Chemical EOR processes such as polymer flooding and surfactant polymer flooding must be designed and implemented in an economically attractive manner to be perceived as viable oil recovery options. The primary expenses associated with these processes are chemical costs which are predominantly controlled by the crude oil properties of a reservoir. Crude oil viscosity dictates polymer concentration requirements for mobility control and can also negatively affect the rheological properties of a microemulsion when surfactant polymer flooding. High microemulsion viscosity can be reduced with the introduction of an alcohol co-solvent into the surfactant formulation, but this increases the cost of the formulation. Experimental research done as part of this study combined the process of hot water injection with ASP flooding as a solution to reduce both crude oil viscosity and microemulsion viscosity. The results of this investigation revealed that when action was taken to reduce microemulsion viscosity, residual oil recoveries were greater than 90%. Hot water flooding lowered required polymer concentrations by reducing oil viscosity and lowered microemulsion viscosity without co-solvent. Laboratory testing of viscous microemulsions in core floods proved to compromise surfactant performance and oil recovery by causing high surfactant retention, high pressure gradients that would be unsustainable in the field, high required polymer concentrations to maintain favorable mobility during chemical flooding, reduced sweep efficiency and stagnation of microemulsions due to high viscosity from flowing at low shear rates. Rough scale-up chemical cost estimations were performed using core flood performance data. Without reducing microemulsion viscosity, field chemical costs were as high as 26.15 dollars per incremental barrel of oil. The introduction of co-solvent reduced chemical costs to as low as 22.01 dollars per incremental barrel of oil. This reduction in cost is the combined result of increasing residual oil recovery and the added cost of an alcohol co-solvent. Heating the reservoir by hot water flooding resulted in combined chemical and heating costs of 13.94 dollars per incremental barrel of oil. The significant drop in cost when using hot water is due to increased residual oil recovery, reduction in polymer concentrations from reduced oil viscosity and reduction of microemulsion viscosity at a fraction of the cost of co-solvent.text
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詹仕榮. "Development of Parallel Hot Water Heater System forLarge Flow of Hot Water." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/v4au97.
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碩士建國科技大學
電機工程系暨研究所
107
Traditional water heaters are frequently found to be unable to provide sufficient water supply and maintain temperature instability. The thesis develops a high-volume water heater parallel system to cope with this problem. First, multiple cool water storage tanks are employed to store enough cool water. Next, the control valve is activated to heat cool water, when heated is to a setting temperature, the water is then transported to the hot water tank for storage. Finally, the needed heated water is delivered to the faucet or shower nozzle. To prevent instability of temperature and water output, this product employs three devices including an anti valve, a temperature sensor and an alarming lamp. The backflow barrier is employed to keep water backflow, the temperature sensor is adopted to detect temperature signal, and the alarming lamp shows the status of the heater. The empirically made water heater is credited with maintaining stability of water supply and temperature on the one hand, and interchangeability and life of the water heater on the other hand. Besides, the whole design can make us to understand the knowledge which related to physics, material science and electrical engineering.
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Wilken, Andries Stephan. "Customer-orientated hot water load management." Diss., 2001. http://hdl.handle.net/2263/26229.
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Please read the abstract in the section 00front of this documentDissertation (MEng (Electrical Engineering))--University of Pretoria, 2007.
Electrical, Electronic and Computer Engineering
MEng
unrestricted
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Muya, T. M. "Hot water consumption in South Africa." Thesis, 2012. http://hdl.handle.net/10210/7265.
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M.Ing.A one-year investigation on hot water consumption was conducted in South African developed and developing communities of Johannesburg to determine the personal and household average daily consumption of hot water as well as the average hourly (in summer and in winter) and monthly patterns. The motivation for this research project was to provide to engineers and water heaters manufacturers reliable experimental data on hot water consumption from various categories of dwellings. The existing sources of information in South Africa being extremely limited and results of estimations. The necessary information was collected from hourly and monthly measurements taken by monitoring hot water systems in different dwellings including, houses (300 units), traditional houses (90 units), shacks (200 units), apartments (123 units), townhouses (90 units). For the purpose of this study, the selected (not statistically) dwellings were classified into three categories, which are: high-density dwellings representing the developing communities, medium-density and low-density dwellings which represent the developed communities. The results of measurements show that, in general, people living in developed communities (low-density dwellings) use at least 1.4 times more hot water than those of developing communities (high-density dwellings). The patterns of hot water consumption have been determined for monthly and hourly consumption. The former is divided in four sections: summer weekdays, winter weekdays, summer weekends and winter weekends. The differences between sections are the specific times of peaks and the consumption. The results of this study should be of great assistance to engineers and water heaters designers in analysing existing systems for performance improvement, and in sizing more efficient and suitable systems to South African use.
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Schaefer, Paul Jeffery. "Modeling of solar domestic hot water systems." 1991. http://catalog.hathitrust.org/api/volumes/oclc/24232135.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1991.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 209-212).