<p>Water has been heated with the sun has almost as long as there have been humans, but itis not until recently that more advanced and effective solar water heating systems havebecome common, and they are still gaining ground. Through the years new systems andnew solar collectors have been developed. In Kosovo, however, not much attention hasbeen paid to replace fossil fuels with renewable energy sources and solar water heatingsystems is a new concept.The United Nations Development Programme (UNDP) in Kosovo is working on a projecton sustainable development in Dragash Municipality in southern Kosovo. A solar waterheating system has recently been installed at the hospital in Dragash, as part of the UNDPproject. The system is a pilot project, to see how well solar energy can be used in thisarea.The existing solar water heating system at the hospital in Dragash was examined andevaluated. The possibilities of using the fundamental principle of the solar water heatingsystem at the hospital on residential houses in Dragash were looked into. Six prototypesof average residential houses in the village of Brod and Dragash Town were created. Thesolar collector size and storage needed to meet the demands for the six house prototypeswere calculated. Information on the incoming solar irradiation for each hour of a year wasobtained from the online service SoDa Solar Radiation Data. The total annual incomingsolar radiation for one square meter was calculated.The environmental, social and economic effects of solar water heating in Dragash wereconsidered and discussed. Rough economic calculations were made on the effects ofinstallation of solar water heating systems.The solar water heating system at the hospital in Dragash is a good pilot project, and islikely to work satisfyingly. The annual output effect of the system is approximately 7 400kWh. The fundamental principle needs to be altered to work on residential houses. Thesolar collector needs to be of a cheaper kind, and the collector and storage tank can be ofsmaller dimensions.Solar water heating can contribute to Kosovo’s work toward sustainable environmental,social and economic development focusing on hot water supply. Kosovo has sufficientsolar radiation for solar water heating systems to work in a satisfactory way. The outputeffect for a solar water heating system in Dragash is around 390 kWh/(m2∙year) with atotal efficiency for the system of 30%. If the solar water heating system replaces heatingby electricity the annual savings can be 31 €/m2 solar collector. The biggest obstacles forthe use of solar energy are the public’s lack of knowledge on solar water heating andenvironmental problems connected to energy, as well as economy.The work done in this thesis is a good foundation for future research on solar energy inKosovo. It can be extended and elaborated with more thorough economic calculations,since economy is an important factor in the future for solar energy. Only roughcalculations were made in this thesis, since it has a technical approach. More extensiveresearch could also be done to evaluate the possibilities of using solar water heating forspace heating.</p> / <p>Varmvatten har värmts med hjälp av solen nästan så länge det funnits människor, men detär inte förrän nyligen som mer avancerade och effektivare solvärmesystem har blivitvanliga, och de blir allt vanligare. Genom åren har nya system och nya solfångareutvecklats. I Kosovo däremot har inte mycket uppmärksamhet ägnats åt att ersätta fossilabränslen med förnyelsebara energikällor, och solvärme är ett nytt koncept.FN:s utvecklingsprogram (UNDP) i Kosovo arbetar med ett projekt med målet hållbarutveckling i Dragash kommun i södra Kosovo. Ett solvärmesystem har nyligeninstallerats på sjukhuset i Dragash, som en del av UNDP:s projekt. Systemet är ettpilotprojekt för att se hur bra solenergi fungerar i det här området.Det befintliga solvärmesystemet på sjukhuset i Dragash undersöktes och utvärderades.Möjligheterna att använda grundprincipen för solvärmesystemet på sjukhuset påbostadshus i Dragash undersöktes. Sex prototyper för genomsnittliga hus i byn Brod och iDragash centrum togs fram. Solfångararean och ackumulatortanksvolymen som krävs föratt klara behoven för de sex husprototyperna beräknades. Information om solinstrålningenför varje hus erhölls från SoDa Solar Radiation Data. Den totala solinstrålningen på enkvadratmeter beräknades.De miljömässiga, sociala och ekonomiska effekterna av solvärme i Dragash diskuterades.Ekonomiska överslagsberäkningar gjordes på effekterna av installation av solvärme.Solvärmesystemet på sjukhuset i Dragash är ett bra pilotprojekt, och är sannolikt attfungera tillfredsställande. Den årliga energi som systemet kan ge kommer att vara ungefär7 400 kWh. Grundprincipen behöver ändras för att fungera på bostadshus. Solfångarnabehöver vara av en billigare typ, och storleken på solfångare och ackumulatortankbehöver vara mindre.Solvärme kan bidra till Kosovos arbete mot hållbar miljömässig, social och ekonomiskutveckling med fokus på varmvattenbehov. Kosovo har tillräcklig solinstrålning för attsolvärmesystem ska fungera tillfredsställande. Med en totalverkningsgrad på 30 % för ettsolvärmesystem kan systemet ge ungefär 390 kWh/(m2∙year). Om systemet ersätteruppvärmning med el kan de årliga besparingarna bli ungefär 31 €/m2 solfångare. Destörsta hindren för användning av solenergi är allmänhetens brist på kunskap om solvärmeoch miljöproblem kopplade till energi, samt ekonomi.Arbetet i detta examensarbete är en bra grund för fortsatta studier om solenergi i Kosovo.Arbetet kan vidgas och utvecklas med mer ingående ekonomiska beräkningar, eftersomekonomi är en viktig faktor i framtiden för solenergi. Endast överslagsberäkningar gjordesi detta examensarbete, eftersom det har ett tekniskt förhållningssätt. Mer omfattandestudier kan också göras för att utvärdera möjligheterna ätt använda solvärme föruppvärmning av bostäder.</p>

Water has been heated with the sun has almost as long as there have been humans, but itis not until recently that more advanced and effective solar water heating systems havebecome common, and they are still gaining ground. Through the years new systems andnew solar collectors have been developed. In Kosovo, however, not much attention hasbeen paid to replace fossil fuels with renewable energy sources and solar water heatingsystems is a new concept.The United Nations Development Programme (UNDP) in Kosovo is working on a projecton sustainable development in Dragash Municipality in southern Kosovo. A solar waterheating system has recently been installed at the hospital in Dragash, as part of the UNDPproject. The system is a pilot project, to see how well solar energy can be used in thisarea.The existing solar water heating system at the hospital in Dragash was examined andevaluated. The possibilities of using the fundamental principle of the solar water heatingsystem at the hospital on residential houses in Dragash were looked into. Six prototypesof average residential houses in the village of Brod and Dragash Town were created. Thesolar collector size and storage needed to meet the demands for the six house prototypeswere calculated. Information on the incoming solar irradiation for each hour of a year wasobtained from the online service SoDa Solar Radiation Data. The total annual incomingsolar radiation for one square meter was calculated.The environmental, social and economic effects of solar water heating in Dragash wereconsidered and discussed. Rough economic calculations were made on the effects ofinstallation of solar water heating systems.The solar water heating system at the hospital in Dragash is a good pilot project, and islikely to work satisfyingly. The annual output effect of the system is approximately 7 400kWh. The fundamental principle needs to be altered to work on residential houses. Thesolar collector needs to be of a cheaper kind, and the collector and storage tank can be ofsmaller dimensions.Solar water heating can contribute to Kosovo’s work toward sustainable environmental,social and economic development focusing on hot water supply. Kosovo has sufficientsolar radiation for solar water heating systems to work in a satisfactory way. The outputeffect for a solar water heating system in Dragash is around 390 kWh/(m2∙year) with atotal efficiency for the system of 30%. If the solar water heating system replaces heatingby electricity the annual savings can be 31 €/m2 solar collector. The biggest obstacles forthe use of solar energy are the public’s lack of knowledge on solar water heating andenvironmental problems connected to energy, as well as economy.The work done in this thesis is a good foundation for future research on solar energy inKosovo. It can be extended and elaborated with more thorough economic calculations,since economy is an important factor in the future for solar energy. Only roughcalculations were made in this thesis, since it has a technical approach. More extensiveresearch could also be done to evaluate the possibilities of using solar water heating forspace heating. / Varmvatten har värmts med hjälp av solen nästan så länge det funnits människor, men detär inte förrän nyligen som mer avancerade och effektivare solvärmesystem har blivitvanliga, och de blir allt vanligare. Genom åren har nya system och nya solfångareutvecklats. I Kosovo däremot har inte mycket uppmärksamhet ägnats åt att ersätta fossilabränslen med förnyelsebara energikällor, och solvärme är ett nytt koncept.FN:s utvecklingsprogram (UNDP) i Kosovo arbetar med ett projekt med målet hållbarutveckling i Dragash kommun i södra Kosovo. Ett solvärmesystem har nyligeninstallerats på sjukhuset i Dragash, som en del av UNDP:s projekt. Systemet är ettpilotprojekt för att se hur bra solenergi fungerar i det här området.Det befintliga solvärmesystemet på sjukhuset i Dragash undersöktes och utvärderades.Möjligheterna att använda grundprincipen för solvärmesystemet på sjukhuset påbostadshus i Dragash undersöktes. Sex prototyper för genomsnittliga hus i byn Brod och iDragash centrum togs fram. Solfångararean och ackumulatortanksvolymen som krävs föratt klara behoven för de sex husprototyperna beräknades. Information om solinstrålningenför varje hus erhölls från SoDa Solar Radiation Data. Den totala solinstrålningen på enkvadratmeter beräknades.De miljömässiga, sociala och ekonomiska effekterna av solvärme i Dragash diskuterades.Ekonomiska överslagsberäkningar gjordes på effekterna av installation av solvärme.Solvärmesystemet på sjukhuset i Dragash är ett bra pilotprojekt, och är sannolikt attfungera tillfredsställande. Den årliga energi som systemet kan ge kommer att vara ungefär7 400 kWh. Grundprincipen behöver ändras för att fungera på bostadshus. Solfångarnabehöver vara av en billigare typ, och storleken på solfångare och ackumulatortankbehöver vara mindre.Solvärme kan bidra till Kosovos arbete mot hållbar miljömässig, social och ekonomiskutveckling med fokus på varmvattenbehov. Kosovo har tillräcklig solinstrålning för attsolvärmesystem ska fungera tillfredsställande. Med en totalverkningsgrad på 30 % för ettsolvärmesystem kan systemet ge ungefär 390 kWh/(m2∙year). Om systemet ersätteruppvärmning med el kan de årliga besparingarna bli ungefär 31 €/m2 solfångare. Destörsta hindren för användning av solenergi är allmänhetens brist på kunskap om solvärmeoch miljöproblem kopplade till energi, samt ekonomi.Arbetet i detta examensarbete är en bra grund för fortsatta studier om solenergi i Kosovo.Arbetet kan vidgas och utvecklas med mer ingående ekonomiska beräkningar, eftersomekonomi är en viktig faktor i framtiden för solenergi. Endast överslagsberäkningar gjordesi detta examensarbete, eftersom det har ett tekniskt förhållningssätt. Mer omfattandestudier kan också göras för att utvärdera möjligheterna ätt använda solvärme föruppvärmning av bostäder.

This thesis is a study of an indirect heat pump assisted solar domestic hot water (I-HPASDHW) system, where the investigated configuration is called the Dual Side I-HPASDHW system. The study outlines the development of an Experimental Test Unit (ETU), and focuses on the experimental validation of TRNSYS models. Shortcomings of the system design realized throughout the validation process, as well as weaknesses in the control schemes used to operate the system are also provided. A description of the Dual Side I-HPASDHW system is provided along with the design intent of the system. The corresponding ETU is presented in detail to provide a comprehensive understanding of the ETU’s simulation capabilities. Components of the ETU, such as the heat pump, heat exchanger, and domestic hot water (DHW) tank are characterized in order to provide input data for built-in TRNSYS models, and to develop custom TRNSYS models for the heat pump and heat exchanger. Heat exchanger performance is modelled with a linear correlation, while the heat pump performance is mapped by applying experimental data to three-dimensional surface fitting software. For the purpose of validation, the ETU is used to simulate the performance of the Dual Side I-HPASDHW system under a realistic control scheme. Four full day tests are conducted using data from a fall, winter, and summer day. The full day summer test is repeated with and without electrical backup heating. The TRNSYS model of the Dual Side system is tuned in order to provide the closest match possible between the computer simulation and the measured performance of the ETU. Experimental tests were compared with TRNSYS simulations to reveal some disparity in the results. The majority of simulation error was attributed to inaccuracy in modeling DHW tank temperatures and water circulation patterns. The disparity created by the DHW tank model only resulted in substantial performance deviation when inaccurate DHW temperatures were used directly for vital control decisions. Conclusions were drawn suggesting that the TRNSYS model of the ETU was valid for a majority of operating conditions, often matching experimental tests well within experimental uncertainty. Caution was recommended towards the use of the developed TRNSYS model, where techniques were recommended for tracking and minimizing substantial simulation errors. Several key performance issues affecting the Dual Side I-HPASDHW system were targeted with recommendations for design and control alterations, along with future improvement and optimization studies.

This study is an examination of the (broadly envisioned) process that has led to the emerging use of solar water heaters in Oaxaca de Juárez, Mexico. In 2007, Mexico launched a major policy initiative designed to encourage the use of solar water heaters in the residential sector throughout the country. As this policy has been implemented, over one hundred thousand solar water heaters have been installed on new homes and many people are beginning to encounter this technology for the first time. This policy has been successful in placing solar water heaters on the rooftops of new homes, but problems with how some of them are functioning threaten the long-term prospects of diffusion of the technology. The study shows that while solar water heaters have the potential to carry positive environmental and economic benefits at the household level, there are also many potential and actual scenarios in which the technology can have detrimental effects. Drawing on literature from the Diffusion of Innovations, the Social Construction of Technology, Actor-Network Theory, the Multi-Level Perspective on Technological Transitions, and Ecological Modernization Theory, this paper also seeks to contribute to the literature concerning the overall processes of socio-technical transitions. / text

This thesis is a study of an indirect heat pump assisted solar domestic hot water (I-HPASDHW) system, where the investigated configuration is called the Dual Side I-HPASDHW system. The study outlines the development of an Experimental Test Unit (ETU), and focuses on the experimental validation of TRNSYS models. Shortcomings of the system design realized throughout the validation process, as well as weaknesses in the control schemes used to operate the system are also provided. A description of the Dual Side I-HPASDHW system is provided along with the design intent of the system. The corresponding ETU is presented in detail to provide a comprehensive understanding of the ETU’s simulation capabilities. Components of the ETU, such as the heat pump, heat exchanger, and domestic hot water (DHW) tank are characterized in order to provide input data for built-in TRNSYS models, and to develop custom TRNSYS models for the heat pump and heat exchanger. Heat exchanger performance is modelled with a linear correlation, while the heat pump performance is mapped by applying experimental data to three-dimensional surface fitting software. For the purpose of validation, the ETU is used to simulate the performance of the Dual Side I-HPASDHW system under a realistic control scheme. Four full day tests are conducted using data from a fall, winter, and summer day. The full day summer test is repeated with and without electrical backup heating. The TRNSYS model of the Dual Side system is tuned in order to provide the closest match possible between the computer simulation and the measured performance of the ETU. Experimental tests were compared with TRNSYS simulations to reveal some disparity in the results. The majority of simulation error was attributed to inaccuracy in modeling DHW tank temperatures and water circulation patterns. The disparity created by the DHW tank model only resulted in substantial performance deviation when inaccurate DHW temperatures were used directly for vital control decisions. Conclusions were drawn suggesting that the TRNSYS model of the ETU was valid for a majority of operating conditions, often matching experimental tests well within experimental uncertainty. Caution was recommended towards the use of the developed TRNSYS model, where techniques were recommended for tracking and minimizing substantial simulation errors. Several key performance issues affecting the Dual Side I-HPASDHW system were targeted with recommendations for design and control alterations, along with future improvement and optimization studies.

This thesis evaluates domestic water heating systems in conjunction with energy saving technologies such as solar water heating, drain water heat recovery, and heat pump water heating. Five dynamic models are developed using Matlab Simulink® with a time-step of one minute. Using minute resolution hot water flow, hourly solar radiation data and ambient temperature, the performance of various configurations are assessed when operating in Victoria, Kamloops, and Williams Lake, B.C. Twelve different demand profiles on a summer day and winter day are simulated. Some specific metrics, such as conventional energy consumption, system energy factor, and equivalent CO2 emissions are used as the basis of evaluating the system efficiency. Results indicate the potential improvements in system performance over a conventional domestic water heating system in lower conventional energy consumption and lower CO2 emissions when applying any one of the three energy saving technologies mentioned above. For example, on a representative summer day (Day 228) in Victoria with a load profile of a low-use two-person family on a weekday, the system‟s energy factor can be improved from 0.50 to up to 2.84, and the corresponding conventional energy consumption and the CO2 emissions decrease from 9.86 kwh to 1.67 kwh, and 1.77 kg/day to 0.06 kg/day, respectively depending on which energy saving technology is applied. The modeling tool developed in this research can be used to guide the design of domestic water heating systems with various system configurations. / Graduate

Yes / Fresh water is crucial for life, supporting human civilizations and ecosystems, and its production is one of the global issues. To cope with this issue, we evaluated the performance and cost of a solar-powered direct contact membrane distillation (DCMD) unit for fresh water production in Karachi, Pakistan. The solar water heating system (SWHS) was evaluated with the help of a system advisor model (SAM) tool. The evaluation of the DCMD unit was performed by solving the DCMD mathematical model through a numerical iterative method in MATLAB software®. For the SWHS, the simulation results showed that the highest average temperature of 55.05 ◦C and lowest average temperature of 44.26 ◦C were achieved in May and December, respectively. The capacity factor and solar fraction of the SWHS were found to be 27.9% and 87%, respectively. An exponential increase from 11.4 kg/m2 ·h to 23.23 kg/m2 ·h in permeate flux was observed when increasing the hot water temperatures from 44 ◦C to 56 ◦C. In the proposed system, a maximum of 279.82 L/day fresh water was produced in May and a minimum of 146.83 L/day in January. On average, the solar-powered DCMD system produced 217.66 L/day with a levelized water cost of 23.01 USD/m3 / This research was funded by the Researcher’s Supporting Project Number (RSP-2021/269), King Saud University, Riyadh, Saudi Arabia.

O presente trabalho consiste em um estudo experimental sobre o efeito do controle de vazões em sistemas de aquecimento solar de água em instalações com grande número de coletores, onde o gradiente de temperatura não é suficiente para circular a água por termossifonagem. Foi avaliado o desempenho de todo o sistema sob diferentes condições de insolação, de vazão, de diferenciais de temperatura entre os coletores e o reservatório, em regime não permanente. Os resultados experimentais foram comparados com a equação de rendimento dos coletores, para condições de regime quase permanente, obtida segundo a norma da ABNT - NBR 10184/1988. Os ensaios foram realizados em duas baterias de testes, cada uma composta de dois coletores industrializados e um reservatório isolado termicamente. Em uma destas baterias, o fluxo de água entre os coletores e o reservatório ocorreu por termossifonagem, isto é, sem nenhuma restrição à vazão; na outra bateria, a vazão foi controlada por um registro e uma bomba hidráulica. Um sistema de automação coletou e processou os dados de forma a permitir a execução dos controles desejados, inclusive a simulação de consumo de água quente. O sistema com circulação natural, isto é, por termossifão, demonstrou ter uma grande habilidade de se adaptar à disponibilidade de energia com as temperaturas da água armazenada, por meio da otimização da velocidade da troca de calor. Foi desenvolvido, tomado como referência o escoamento por termossifão, um modelo de operação para sistemas diretos ativos que calcula a vazão com base no monitoramento das temperaturas das extremidades das tubulações que interligam o reservatório e os coletores, temperatura do ar, radiação solar disponível e vazão no instante anterior. O modelo foi testado experimentalmente e a operação do sistema ativo resultou em significativa melhora a eficiência. / The focus of this work is the experimental study of the effect of water control discharge in solar water-heating systems with a large number of collectors where the temperature gradient is not sufficient for thermosiphon water circulation. The performance of the system was evaluated under different conditions of solar radiation, flow rate, temperature differential between solar collectors and the storage tank and under transient conditions. The results were compared to a collector\'s performance equation of the quasi-steady-state model according to ABNT-NBR 10184/1988 standard. The tests were carried out on two systems each one constituted of two manufacturing collectors and one thermal tank. In one of these systems the flow between the collectors and storage occurred by thermosiphoning, i.e., by natural convection and without discharge restrictions. In the other, the flow control was done by means of a valve and a pump. In order to allow the execution of the desired controls, including hot water consumption, data were colleted and controlled through an automation system. The system of natural circulation shows a great ability to adaptation of disposal energy with water temperature stored, through velocity of heat exchange optimization. An operation model was developed, having thermosiphoning water circulation as reference, for active direct circulation systems that calculate the discharge taking into consideration the monitoring of the differential temperature between solar collectors and the storage tank, the air temperature, solar radiation available and the flow rate on previous time interval. This model was experimentally tested and resulted in a significant improvement in performance of the system operation.

O presente trabalho consiste em um estudo experimental sobre o efeito do controle de vazões em sistemas de aquecimento solar de água em instalações com grande número de coletores, onde o gradiente de temperatura não é suficiente para circular a água por termossifonagem. Foi avaliado o desempenho de todo o sistema sob diferentes condições de insolação, de vazão, de diferenciais de temperatura entre os coletores e o reservatório, em regime não permanente. Os resultados experimentais foram comparados com a equação de rendimento dos coletores, para condições de regime quase permanente, obtida segundo a norma da ABNT - NBR 10184/1988. Os ensaios foram realizados em duas baterias de testes, cada uma composta de dois coletores industrializados e um reservatório isolado termicamente. Em uma destas baterias, o fluxo de água entre os coletores e o reservatório ocorreu por termossifonagem, isto é, sem nenhuma restrição à vazão; na outra bateria, a vazão foi controlada por um registro e uma bomba hidráulica. Um sistema de automação coletou e processou os dados de forma a permitir a execução dos controles desejados, inclusive a simulação de consumo de água quente. O sistema com circulação natural, isto é, por termossifão, demonstrou ter uma grande habilidade de se adaptar à disponibilidade de energia com as temperaturas da água armazenada, por meio da otimização da velocidade da troca de calor. Foi desenvolvido, tomado como referência o escoamento por termossifão, um modelo de operação para sistemas diretos ativos que calcula a vazão com base no monitoramento das temperaturas das extremidades das tubulações que interligam o reservatório e os coletores, temperatura do ar, radiação solar disponível e vazão no instante anterior. O modelo foi testado experimentalmente e a operação do sistema ativo resultou em significativa melhora a eficiência. / The focus of this work is the experimental study of the effect of water control discharge in solar water-heating systems with a large number of collectors where the temperature gradient is not sufficient for thermosiphon water circulation. The performance of the system was evaluated under different conditions of solar radiation, flow rate, temperature differential between solar collectors and the storage tank and under transient conditions. The results were compared to a collector\'s performance equation of the quasi-steady-state model according to ABNT-NBR 10184/1988 standard. The tests were carried out on two systems each one constituted of two manufacturing collectors and one thermal tank. In one of these systems the flow between the collectors and storage occurred by thermosiphoning, i.e., by natural convection and without discharge restrictions. In the other, the flow control was done by means of a valve and a pump. In order to allow the execution of the desired controls, including hot water consumption, data were colleted and controlled through an automation system. The system of natural circulation shows a great ability to adaptation of disposal energy with water temperature stored, through velocity of heat exchange optimization. An operation model was developed, having thermosiphoning water circulation as reference, for active direct circulation systems that calculate the discharge taking into consideration the monitoring of the differential temperature between solar collectors and the storage tank, the air temperature, solar radiation available and the flow rate on previous time interval. This model was experimentally tested and resulted in a significant improvement in performance of the system operation.

This work studies the performance of heat pipe solar collector for water heating. Experimental results are validated using numerical modeling. Homemade heat pipes with distilled water as a working fluid were used for experimental tests. Both natural and forced convective heat pipe condensing mechanisms are studied and their results are compared with conventional natural circulation solar water heating system. Cross flow and parallel flow heat exchanger were tested in forced type heat pipe condensing mechanism. Experimental and numerical results showed good agreement. Heat pipe solar collectors outperformed conventional solar collector because of their efficient heat transport method. Forced convective heat exchanger was found to give higher efficiency compared to natural convective heat pipe condensing system. However, natural convective heat pipe condensing is free from parasitic power and low system weight. It also showed appreciable system efficiency and can be further developed to be used in rural areas where grid electricity is scarce. Cross flow and parallel flow heat exchanger have been tested for forced convective heat pipe condensing mechanism and no appreciable difference was found due to higher fluid velocity in heat exchangers.