Ensuring electricity availability and acquiring access of potable water during emergencies in remote areas are becoming a global challenge around the world. Utilizing solar energy electricity generation by photovoltaics and clean water production by solar distillation have shown its great potential to meet the world’s future energy and water demands. In this work, we fabricated a photovoltaic-membrane distillation-evaporative crystallizer device (PV-MD-EC), in which high electricity generation efficiency (~15%), clean water production rate (~2.66 kg/m2 h) and salt crystallization from seawater can be achieved in such an integrated system under one sun illumination. In addition, the solar cell operates in a much lower temperature at around 48 oC, which is much lower than previous work. The advanced performance is attributed to the utilization of a highly porous and thinner hydrophobic membrane. This design provides a new strategy to address the challenge of water-energy nexus.

Depuis quelques années, les exigences des occupants de bâtiments ont sensiblement changé. On observe en effet une demande de confort de plus en plus rigoureux en particulier en période estivale. Cette augmentation des besoins de climatisation induit un accroissement important de la consommation d'énergie électrique dans les bâtiments, dû à une utilisation majoritaire de climatiseurs à compression mécanique de vapeur. Dans ce contexte énergétique difficile, les systèmes de rafraîchissement solaire font partie des alternatives intéressantes aux systèmes de climatisation classiques, dans la mesure où l'énergie primaire est principalement consommée sous forme de chaleur et provenant du soleil donc gratuite. L'autre grand intérêt de ces procédés est que le besoin en rafraîchissement coïncide la plupart du temps avec la disponibilité du rayonnement solaire. La compréhension et le développement de cette technologie passent par une étude expérimentale avec la réalisation d'installations pilotes à échelle réelle dans le but d'acquérir une expérience concrète. C'est dans ce sens que notre laboratoire s'est proposé de mettre en place une plateforme expérimentale d'une puissance frigorifique de 30 kWf chargée de rafraîchir des locaux d'enseignement de l'Institut Universitaire Technologique de Saint Pierre à La Réunion. La première partie de ce manuscrit présente une analyse expérimentale de cette installation. Une seconde approche purement fondamentale a été envisagée avec l'élaboration de modèles numériques permettant de prédire le comportement de l'installation dans son ensemble. Ces modèles numériques décrits sous plusieurs niveaux de finesse, sont validés par les données expérimentales avant d'être utilisés, soit comme outils de pré‐dimensionnement pour les modèles à descriptions simplifiés, soit comme outil d'optimisation et d'analyse pour les modèles détaillés. Le modèle détaillé représentant notre plateforme expérimentale a permis de réaliser une optimisation du fonctionnement de l'installation et de proposer des améliorations pour réduire la consommation d'électricité et augmenter le coefficient de performance électrique global. / In the last few years, thermal comfort research in summer has significantly increased the electricity consumption in buildings. This is mainly due to the use of conventional air conditioning systems operating with mechanical vapor compression. Solar cooling systems applied to buildings is an interesting alternative for reducing energy consumption in traditional mechanical steam compression air conditioning systems. But the understanding of this technology has to be refined through experimental study by setting up pilot plants. This study is a practical method to gain experience by analyzing all the processes behind solar cooling technology. For that purpose, our laboratory decided to install a solar cooling absorption system implemented in Reunion Island, located in the southern hemisphere. The particularity of this project is to achieve an effective cooling of classrooms, by a solar cooling system without any backup systems (hot or cold). The first part of this work presents an experimental study of this installation. Moreover, the study of these systems should have a closely purely fundamental approach including the development of numerical models in order to predict the overall installation performance. The final objective is to estimate cooling capacity, power consumption, and overall installation performance with relation to outside factors (solar irradiation, outside temperature, building loads). These numerical models described in several levels of accuracy, are validated by experimental data before being used either as tools for pre‐sizing models with simplified descriptions, either as a tool for optimization and analysis for the detailed models. The detailed model describing our experimental platform is used to carry out an optimization of pilot plant operation and to propose improvements to reduce electricity consumption and increase the overall electrical performance coefficient.

Interest in utilizing solar-driven refrigeration systems for air-conditioning or refrigeration purposes has grown continuously. Solar cooling is com-prised of many attractive features and is one path towards a more sus-tainable energy system. Compared to solar heating, the cooling load, par-ticularly for air-conditioning applications, is generally in phase with solar radiation. The objective of this thesis is to establish a fundamental basis for further research and development within the field of solar cooling. In this thesis, an overview of possible systems for solar powered refrigeration and air-conditioning systems will be presented. The concept of the ‘Solar Cool-ing Path’ is introduced, including a discussion of the energy source to the collector, and choice of cooling cycle to match cooling load. Brief infor-mation and comparisons of different refrigeration cycles are also pre-sented. The performance of solar cooling systems is strongly dependent on local conditions. The performance of a solar divan air-conditioning system in different locations will therefore be compared in this thesis. Solar cooling systems can be efficiently operated in locations where sufficient solar ra-diation and good heat sink are available. A solar-driven ejector refrigeration system has been selected as a case study for a further detailed investigation. A low temperature heat source can be used to drive the ejector refrigeration cycle, making the system suitable for integration with the solar thermal collector. Analysis of the solar driven ejector system is initiated by steady state analysis. System performance depends on the choice of working fluid (refrigerant), oper-ating conditions and ejector geometry. Results show that various kinds of refrigerants can be used. Also, thermodynamic characteristics of the re-frigerant strongly influence the performance of the cycle. An ejector re-frigeration cycle using natural working fluids generates good perform-ance and lower environmental impact, since traditional working fluids, CFC’s and HFC’s are strong climate gases. Further on, exergy analysis is used as a tool in identifying optimum operating conditions and investi-gating losses in the system. Exergy analysis illustrates that the distribu-tion of the irrervsibilities in the cycle between components depends strongly on the working temperatures. The most significant losses in the system are in the solar collector and ejector. Losses in the ejector pre-dominate over total losses within the system. In practice, the cooling load characteristic and solar radiation are not constant. Therefore, a dynamic analysis is useful for determining the characteristics of the system during the entire year, and dimensioning the important components of the solar collector subsystem, such as storage tanks. The final section of the thesis will deal with the ejector, the key compo-nent of the ejector refrigeration cycle. Characteristics of the actual ejector are shown to be quite complicated and its performance difficult to de-termine solely through theoretical analysis. Suggested design procedures and empirical equations for an ejector are offered in this thesis. Prelimi-nary test results for one fixed ejector dimension using R134a as the re-frigerant are also included. / QC 20100916

This report shows the study performed at Taipei National University of Technology in Taipei to evaluate the performance of a solar air conditioning system. The performance is evaluated under Taiwan climate conditions. The research is performed under summer weather conditions. No influence is done on these conditions. A solar air conditioning system currently available on the market is used. No changes are made to the system. The work to be done is divided into different phases in order to guide the process. First, a literature research is done to find similar research done on this topic and to gain a basic understanding of the topic. Then several measurement plans are made to investigate different parts of the system.. Measurements are done. It is tried to developing a computer model in order to be able to simulate the system performance. The overall objective was to gain knowledge about a solar assisted air-conditioning system and develop a model to simulate the system. Initially a list of research questions was made in order to quantify ‘gaining knowledge’ about the system. The plan was to answer them by using measurement data and creating a model to perform simulations. There are measurements done in this report, however due to too many ‘unknowns’* it is difficult to draw conclusions from them. A lot of research questions are still open and they are also not included in this report. It is also not succeeded to make a working model of a solar assisted air conditioner. It is succeeded in making a model to predict the performance of the evaporator. This model is currently within 11% accurate.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2006. / A small scale steam jet ejector experimental setup was designed and manufactured. This ejector setup is of an open loop configuration and the boiler can operate in the temperature range of Tb = 85 °C to 140 °C. The typical evaporator liquid temperatures range from Te = 5 °C t o 10 °C while the typical water cooled condenser presure ranges from Pc = 1 . 70 kPa t o 5. 63 kPa (Tc = 15 °C to 35 °C). The boiler is powered by by two 4kW electric elements, while a 3kW electric element simulates the cooling load in the evaporator. The electric elements are controlled by means of variacs. The function ... / Centre for Renewable and Sustainable Energy Studies

Solar DEC (Desiccant and Evaporative Cooling) air-conditioning is a renewable technological approach to the future air-conditioning of buildings driven with solar-thermal heat. The principal acceptance of solar airconditioning has led to system prototypes mainly across Europe, however the diffusion of this innovative technology is proceeding slowly due to little field testing experience. In climates with coexisting heating demand particularly, a multivalent system approach that utilizes solar-heat not only for air-conditioning but also for hot water preparation and heating has potential as a feasible concept. However, previous research focused on systems using solar heat exclusively for the DEC-process. This research contributes to the advancement of the solar DEC-technology with multivalent use of solar thermal heat. The investigation consists of an initial detailed in-situ monitoring analysis of a system prototype operated in an industrial environment, followed by the development of optimised system concepts and a climate-specific analysis of the solar DEC-technology. The monitoring provided in-depth knowledge about the system operation, revealing the reasons for the insufficient refrigeration capacity achieved in practice. A detailed simulation model for an entire multivalent solar DEC-system including the heat sinks, DEC-system, heating and hot-water preparation was developed and a DEC-control strategy has been formulated. A new optimised control strategy for multivalent systems with simultaneous sink supply concept was devised. A sensitivity analysis was carried out to investigate the key design parameters for the dimensioning of multivalent solar DEC-systems. The research concluded that the auxiliary primary energy consumption of the optimised system was lower by one third compared to the initial system. Finally, a methodological zoning approach was developed, to systematically produce design-specific outline data for the application of the solar DEC-technology at climatically different sites.

Au cours des dernières années, l'utilisation des systèmes de climatisation classiques a connu une augmentation importante qui directement augmente la consommation d'électricité dans différents types de bâtiments.Par conséquent, le développement du système de climatisation solaire appliqué aux bâtiments est la nouvelle technologie qui pourrait remplacer le système conventionnel à compresseur. De cette façon, il est nécessaire de comprendre et d’évaluer cette solution alternative. À cet effet, notre Institut de recherche en énergie solaire et en énergies renouvelables (IRESEN) a financé un projet appelé «Refroidissement solaire au Maroc» basé sur la technologie d'absorption, afin de réaliser des études de faisabilité sur ce type de systèmes afin de les intégrer dans la nouvelle génération du bâtiment.Dans ce but, cette thèse a traité un système de refroidissement solaire en utilisant la machine à absorption comme la technologie de production de froid dans différentes conditions et climats. Tout d'abord, cette thèse commence par une étude bibliographique ou elle analyse et critique plusieurs travaux traitant les systèmes de refroidissement solaire, ainsi que les diffèrent technologie de capteur solaire. Deuxième point de cette thèse focalise sur la machine à absorption où elle présente un modèle mathématique d'une machine à absorption à simple effet, afin de comprendre le comportement dynamique de ce type de machine face à une variation des conditions extérieures telles que (rayonnement solaire, température extérieure, charges climatique internes). En plus, l'analyse du système de refroidissement solaire devrait prendre en compte une approche énergétique et financière qui permette de prévoir toutes les performances énergétiques (fraction solaire, coefficient de performance, efficacité thermique et efficacité exergétique…) et d'optimiser la taille des composants les plus importants, qui sont la surface du capteur solaire et le volume du ballon de stockage. Une évaluation détaillée de ces deux paramètres est examinée dans les six zones climatiques du Maroc, puis généralisée à neuf capitales africaines afin de fournir un outil numérique pour le dimensionnement et l'optimisation du système de refroidissement solaire non seulement au Maroc mais également dans l'ensemble des régions africaines. / In the last few years, the use of conventional air conditioning system has known an important increase, which directly increase the electricity consumption in different type of building.Therefore, the development of solar cooling system applied to buildings is the new technology that could replace the conventional system of air conditioning. That way, there is a need to understand and evaluate this alternative solution. For that purpose, our Institute of Research in Solar energy and renewable energies (SPCM) has finance a project called Solar cooling in Morocco based on the absorption technology, in order to have a feasibility studies on this kind of systems, in the scope of implementing them in the new generation of buildings. Thus, this thesis treats the solar cooling system using an absorption chiller as the technology of cooling under different conditions and climates. Firstly, it presents a mathematical model of a single effect absorption chiller, in order to understand the dynamic behavior of this kind of machine when they are confronted to a variation in the external conditions such as (solar radiation, external temperature, cooling loads).Moreover, the analysis of the solar cooling system should take into account an energetic and a financial approach to predict all the energetic performances (solar fraction, coefficient of performance, thermal efficiency and exergetic efficiency…) and to optimize the size of the most important component which are the solar collector surface and the storage tank volume. A detailed assessment of these two parameters is investigated in the six climatic zones of Morocco and then it is generalized to nine African capitals in order to give a numerical tool to pre-sizing and optimizing the solar cooling system not only in Morocco but also in all Africa.

Atualmente, o processamento de dados é uma operação vital para os negócios de qualquer companhia, indústria ou prestador de serviços. Entretanto, os servidores em operação, dissipam energia térmica, aquecendo o ambiente, podendo ocasionar problemas operacionais, como funcionamento inadequado, paradas operacionais e até incêndios. Por isso, é necessário um sistema de condicionamento de ar para controlar de temperatura e umidade ambiental, entretanto o consumo de energia elétrica deste sistema aumenta o custo operacional da instalação, sendo necessário minimizá-lo. Baseado neste fato, esta tese avalia a aplicação de 2 tipos de sistemas de resfriamento solar, absorção térmica solar e fotovoltaico, para reduzir o consumo do tradicional sistema elétrico com unidades de resfriamento elétricas operadas por compressão de vapor, apresentando economias, disponibilidade diária e vantagens em uma sala de missão crítica localiza genericamente, em São Paulo, Abu Dhabi, Los Angeles e Nova York. Além disto, analisa a contribuição de sistemas de resfriamento natural e seus efeitos sobre carga e consumo. As densidades de carga propostas foram de 0,5 kW?m-², 1,0 kW?m-², 2,0 kW?m-², 4,0 kW?m-² e 8,0 kW/m. Os índices locais de irradiação e temperaturas anuais baseiam-se nos dados apresentados no banco de dados da ASHRAE para as localidades. Os resultados, válidos para um ano típico e são comparados com (1) Sala de missão crítica acionada por um sistema convencional, (2) combinação de métodos de resfriamento solar, (3) combinação de técnicas solares e resfriamento natural. Por meio de estimativas anuais, calculando as contribuições dos métodos de resfriamento solar e natural, concluiu- maioria dos casos o método de absorção solar apresenta maiores vantagens de economia de energia e retorno de investimento que o método fotovoltaico, especialmente quando associado ao resfriamento natural indireto. Ao final, conclui-se que a utilização de resfriamento solar, pode atingir a 50% de economia na conta de energia e um TIR de 25%. Quando associado a sistemas de resfriamento natural, a economia pode atingir valores de 68% de economia e um TIR de 134%. Para tal deverá ser observado a carga aplicada, o valor de investimento e a curva característica da unidade de resfriamento que irá complementar a carga. / Nowadays, data processing is a fundamental operation for modern business such as banks, technology companies, and factories, among others. However, computers dissipate non-negligible amounts of heat and as the operating temperature increases, these machines cannot operate properly or, under extreme conditions, can come to a stop by overheating. Consequently, it is necessary air conditioning systems to keep the proper operating temperature as well as the room temperature itself. On the other hand, a data center air conditioning system drains a large amount of electrical energy in the installation. Based on this, this thesis evaluates two types of solar cooling system, an absorption thermal system, and a photovoltaic system, to support the traditional electric chiller system showing the energy saving, advantage over conventional cooling and day availability for this system. In addition, it analyzed free cooling system contribution and his effects on consumption. A case study is analyzed in a generic data center located in the city of São Paulo, Abu Dhabi, Los Angeles, and New York. At first, the electrical power density simulated by the computers is 0.5 kW/m², 1.0 kW/m² 2.0 kW/m², 4.0 kW/m² and 8 kW/m², that would occur in half loads or in high loads computer installations. Local solar irradiation and temperature indexes are based on the ASHRAE database. The results are valid for a typical year and are compared to (1) a conventional data center; (2) the event combination of solar cooling; (3) the event combination of solar cooling and free cooling. In conclusion, the energy savings, payback and internal rate of return for 10 years are presented. In the main cases, the solar absorption takes advantage than photovoltaic cooling, However, It must be observed the load replicated and the influence on the work curve of the chiller and the beginning investment. In conclusion, the solar cooling, especially solar absorption can achieve great advantage to installation, resulting in 50% on savings in the electric bill a return internal rate for 10 years of 25%. When it is associated with free cooling this savings can achieve 68% and return rate of 134%.

Atualmente, o processamento de dados é uma operação vital para os negócios de qualquer companhia, indústria ou prestador de serviços. Entretanto, os servidores em operação, dissipam energia térmica, aquecendo o ambiente, podendo ocasionar problemas operacionais, como funcionamento inadequado, paradas operacionais e até incêndios. Por isso, é necessário um sistema de condicionamento de ar para controlar de temperatura e umidade ambiental, entretanto o consumo de energia elétrica deste sistema aumenta o custo operacional da instalação, sendo necessário minimizá-lo. Baseado neste fato, esta tese avalia a aplicação de 2 tipos de sistemas de resfriamento solar, absorção térmica solar e fotovoltaico, para reduzir o consumo do tradicional sistema elétrico com unidades de resfriamento elétricas operadas por compressão de vapor, apresentando economias, disponibilidade diária e vantagens em uma sala de missão crítica localiza genericamente, em São Paulo, Abu Dhabi, Los Angeles e Nova York. Além disto, analisa a contribuição de sistemas de resfriamento natural e seus efeitos sobre carga e consumo. As densidades de carga propostas foram de 0,5 kW?m-², 1,0 kW?m-², 2,0 kW?m-², 4,0 kW?m-² e 8,0 kW/m. Os índices locais de irradiação e temperaturas anuais baseiam-se nos dados apresentados no banco de dados da ASHRAE para as localidades. Os resultados, válidos para um ano típico e são comparados com (1) Sala de missão crítica acionada por um sistema convencional, (2) combinação de métodos de resfriamento solar, (3) combinação de técnicas solares e resfriamento natural. Por meio de estimativas anuais, calculando as contribuições dos métodos de resfriamento solar e natural, concluiu- maioria dos casos o método de absorção solar apresenta maiores vantagens de economia de energia e retorno de investimento que o método fotovoltaico, especialmente quando associado ao resfriamento natural indireto. Ao final, conclui-se que a utilização de resfriamento solar, pode atingir a 50% de economia na conta de energia e um TIR de 25%. Quando associado a sistemas de resfriamento natural, a economia pode atingir valores de 68% de economia e um TIR de 134%. Para tal deverá ser observado a carga aplicada, o valor de investimento e a curva característica da unidade de resfriamento que irá complementar a carga. / Nowadays, data processing is a fundamental operation for modern business such as banks, technology companies, and factories, among others. However, computers dissipate non-negligible amounts of heat and as the operating temperature increases, these machines cannot operate properly or, under extreme conditions, can come to a stop by overheating. Consequently, it is necessary air conditioning systems to keep the proper operating temperature as well as the room temperature itself. On the other hand, a data center air conditioning system drains a large amount of electrical energy in the installation. Based on this, this thesis evaluates two types of solar cooling system, an absorption thermal system, and a photovoltaic system, to support the traditional electric chiller system showing the energy saving, advantage over conventional cooling and day availability for this system. In addition, it analyzed free cooling system contribution and his effects on consumption. A case study is analyzed in a generic data center located in the city of São Paulo, Abu Dhabi, Los Angeles, and New York. At first, the electrical power density simulated by the computers is 0.5 kW/m², 1.0 kW/m² 2.0 kW/m², 4.0 kW/m² and 8 kW/m², that would occur in half loads or in high loads computer installations. Local solar irradiation and temperature indexes are based on the ASHRAE database. The results are valid for a typical year and are compared to (1) a conventional data center; (2) the event combination of solar cooling; (3) the event combination of solar cooling and free cooling. In conclusion, the energy savings, payback and internal rate of return for 10 years are presented. In the main cases, the solar absorption takes advantage than photovoltaic cooling, However, It must be observed the load replicated and the influence on the work curve of the chiller and the beginning investment. In conclusion, the solar cooling, especially solar absorption can achieve great advantage to installation, resulting in 50% on savings in the electric bill a return internal rate for 10 years of 25%. When it is associated with free cooling this savings can achieve 68% and return rate of 134%.

The demand for cooling and air-conditioning of building is increasingly ever growing. This increase is mostly due to population and economic growth in developing countries, and also desire for a higher quality of thermal comfort. Increase in the use of conventional cooling systems results in larger carbon footprint and more greenhouse gases considering their higher electricity consumption, and it occasionally creates peaks in electricity demand from power supply grid. Solar energy as a renewable energy source is an alternative to drive the cooling machines since the cooling load is generally high when solar radiation is high. This thesis examines the performance of PV/T solar collector manufactured by Solarus company in a solar cooling system for an office building in Dubai, New Delhi, Los Angeles and Cape Town. The study is carried out by analyzing climate data and the requirements for thermal comfort in office buildings. Cooling systems strongly depend on weather conditions and local climate. Cooling load of buildings depend on many parameters such as ambient temperature, indoor comfort temperature, solar gain to the building and internal gains including; number of occupant and electrical devices. The simulations were carried out by selecting a suitable thermally driven chiller and modeling it with PV/T solar collector in Polysun software. Fractional primary energy saving and solar fraction were introduced as key figures of the project to evaluate the performance of cooling system. Several parametric studies and simulations were determined according to PV/T aperture area and hot water storage tank volume. The fractional primary energy saving analysis revealed that thermally driven chillers, particularly adsorption chillers are not suitable to be utilizing in small size of solar cooling systems in hot and tropic climates such as Dubai and New Delhi. Adsorption chillers require more thermal energy to meet the cooling load in hot and dry climates. The adsorption chillers operate in their full capacity and in higher coefficient of performance when they run in a moderate climate since they can properly reject the exhaust heat. The simulation results also indicated that PV/T solar collector have higher efficiency in warmer climates, however it requires a larger size of PV/T collectors to supply the thermally driven chillers for providing cooling in hot climates. Therefore using an electrical chiller as backup gives much better results in terms of primary energy savings, since PV/T electrical production also can be used for backup electrical chiller in a net metering mechanism.