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1
Tabassum, Salim Abid. "Solar refrigeration: evaluation of technical options and design of a solar-generator-adsorber for a novel adsorption refrigerator." Thesis, Cranfield University, 1989. http://hdl.handle.net/1826/4213.
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Various technical options for developing a solar operated
refrigerator have been discussed. Their suitability for being used
as a vaccine store for the conditions specified by the World Health
(EPI)
Organization Expanded Programme on Immunization
4have been evaluated.
A model to predict the performance of a photovoltaic refrigerator
have been developed and used to identify factors which influence its
performance. It was concluded that it can be more competitive in
areas where insolation is high and sunshine hours are long. It has
been proposed that ice-lined refrigerators, which would run during
the day, may be more economical and eliminate the need for a battery
storage.
The option of operating an 'Electrolux' absorption refrigerator with
evacuated tube heat pipe collectors has been assessed. It was
concluded that the operation was not possible without a major
re-design of the commercially available models. However, it was
proposed that coordination of the EPI with other development
programmes may be useful. It is proposed to build, with this
coordinated effort, biogas plants. Biogas can then fuel the modified
burner of the kerosene fueled absorption refrigerators. This may
well prove to be a cheaper option.
Characterization of various adsorption pairs has been done using the
experimental rig developed for the purpose. The influence of various
properties of adsorption pairs on the performance of an adsorption refrigeration cycle has been studied. It was observed that the
generation temperature in an adsorption refrigeration cycle (or a
bivariant absorption system), for a specified operating regime, was
only a function of the refrigerant.
A relationship between the refrigerant properties and the generating
temperature for specified operating conditions was developed. Using
this relationship it was established that ammonia and methanol
cannot be generated at temperatures below 1200C for WHO/EPI
specified operating conditions, if the condenser was air-cooled.
A novel idea of direct absorption of solar radiation into the
activated carbon bed is put forward to combat the temperature
differential of 214°C, in a conventional design of SGA, between the
carbon and the metal container. The idea was practically implemented
by replacing the top of the metal box by transparent glass sheet.
The seal between the metal container and glass imposed practical
difficulties in that design but the tests proved that the idea had
potential. A new tubular design of the SGA is proposed finally which
is hoped to bring improvement to the performance of activated carbon
adsorption refrigerators.
2
Tabassum, Alim Abid. "Solar refrigeration : evaluation of technical options and design of a solar-generator-adsorber for a novel adsorption refrigerator." Thesis, Cranfield University, 1989. http://dspace.lib.cranfield.ac.uk/handle/1826/4213.
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Various technical options for developing a solar operated refrigerator have been discussed. Their suitability for being used as a vaccine store for the conditions specified by the World Health (EPI) Organization Expanded Programme on Immunization 4have been evaluated. A model to predict the performance of a photovoltaic refrigerator have been developed and used to identify factors which influence its performance. It was concluded that it can be more competitive in areas where insolation is high and sunshine hours are long. It has been proposed that ice-lined refrigerators, which would run during the day, may be more economical and eliminate the need for a battery storage. The option of operating an 'Electrolux' absorption refrigerator with evacuated tube heat pipe collectors has been assessed. It was concluded that the operation was not possible without a major re-design of the commercially available models. However, it was proposed that coordination of the EPI with other development programmes may be useful. It is proposed to build, with this coordinated effort, biogas plants. Biogas can then fuel the modified burner of the kerosene fueled absorption refrigerators. This may well prove to be a cheaper option. Characterization of various adsorption pairs has been done using the experimental rig developed for the purpose. The influence of various properties of adsorption pairs on the performance of an adsorption refrigeration cycle has been studied. It was observed that the generation temperature in an adsorption refrigeration cycle (or a bivariant absorption system), for a specified operating regime, was only a function of the refrigerant. A relationship between the refrigerant properties and the generating temperature for specified operating conditions was developed. Using this relationship it was established that ammonia and methanol cannot be generated at temperatures below 1200C for WHO/EPI specified operating conditions, if the condenser was air-cooled. A novel idea of direct absorption of solar radiation into the activated carbon bed is put forward to combat the temperature differential of 214°C, in a conventional design of SGA, between the carbon and the metal container. The idea was practically implemented by replacing the top of the metal box by transparent glass sheet. The seal between the metal container and glass imposed practical difficulties in that design but the tests proved that the idea had potential. A new tubular design of the SGA is proposed finally which is hoped to bring improvement to the performance of activated carbon adsorption refrigerators.
3
Périer-Muzet, Maxime. "Modélisation et simulation dynamique d’une machine de réfrigération thermoacoustique solaire." Thesis, Pau, 2012. http://www.theses.fr/2012PAUU3028/document.
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La réfrigération solaire est une alternative à la production de froid à partir de machines à compression mécanique de vapeur dont l’alimentation est électrique. Parmi les technologies envisageables, le couplage d’une machine de réfrigération thermoacoustique avec un concentrateur solaire et un stockage frigorifique par chaleur latente apparait comme une option intéressante. Cette thèse introduit la problématique du sujet et présente les différentes technologies envisageables pour la conception d’un réfrigérateur thermoacoustique solaire. Ensuite, pour répondre au problème, le prototype expérimental qui a été conçu et fabriqué est présenté. Une méthode de modélisation transitoire au niveau système du prototype est proposée. Enfin les résultats obtenus par les simulations dynamiques sont discutés à travers l’analyse du comportement transitoire de l’ensemble du procédé et des performances associéesSolar refrigeration is an alternative to electrically driven vapor compression cycle for refrigeration. Among the solar refrigeration technologies, the coupling of a heat driven thermoacoustic refrigerator with a solar concentrator and a cold latent energy storage system seems to be a promising technology. This thesis introduces the issue of the subject and analyzes the different available technologies to design a solar driven thermoacoustic refrigerator. Then, to address the problem, the prototype that has been designed and built, is presented. A lumped model is introduced to describe the transient behavior of the prototype. Finally, simulation results are presented and discussed in terms of dynamic behavior and performance analysis
4
Karki, Bipin. "Experimental and Life Cycle Analysis of a Solar Thermal Adsorption Refrigeration (STAR) Using Ethanol - Activated Carbon." University of Dayton / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1524583058600568.
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de, Groot Martijn. "Development of a Plug and Play Solution for Commercial Off-grid Solar Refrigeration : Presenting a Battery Supported System Providing the AC Power Required to run a Coolfinity 300L Commercial Refrigerator." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-302991.
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In this report the design and testing of a plug and play system to run Coolfinity’s Icevolt 300 refrigerator on solar panels is discussed. Such a system will be able to provide adequate cooling for food & beverages in area’s with unreliable or no electricity available. Currently such systems are only available for small chest refrigerators, while the Icevolt 300 is a large standing commercial refrigerator with a glass door. This is ideal for shops, cafés restaurants and smaller distribution centres. The system contains a solar charge controller, a battery and an inverter. First the component specifications and required solar panels are calculated. From those calculations system components are evaluated. A custom casing is designed to fit the components. An OEM is chosen and the chosen Inverter is tested extensively. The tests show that the inverter does not have any problems starting the Icevolt 300 compressor at a reduced voltage. Many battery manufacturers are evaluated and samples from three different manufacturers are obtained and tested. Samples of one of the manufacturers match specifications and have no issues with the high start up power of the compressor. A full system test proofs that the system works, but also indicates that the original refrigerator consumption estimate was too low. This means more PV panels are needed than originally estimated. With the information from the tests a new model is build that estimates the performance more accurate. A program is written to estimate the performance and decide the PV panels required. The pilot series of the case showed a lot of improvements are needed in the case design, especially on cost. A test is prepared in Mali but no test data is obtained yet. Based on the work done it would be recommend to investigate DC direct refrigerators instead of continuing the path of PV to AC systems.I denna rapport diskuteras design och testning av ett plug and play - system för att köra Coolfinity’s Icevolt 300 -kylskåp på solpaneler. Ett sådant system kommer att kunna tillhandahålla tillräcklig kylning för mat och dryck i områden med opålitlig eller ingen tillgänglig el. För närvarande är sådana system endast tillgängliga för små kylboxar, medan Icevolt 300 är ett stort stående kommersiellt kylskåp med en glasdörr. Detta är idealiskt för butiker, kaféer och mindre distributionscentra. Systemet innehåller en laddningsregulator för solpaneler, ett batteri och en växelriktare. Först beräknas komponentspecifikationerna och nödvändiga solpaneler. Utifrån dessa beräkningar utvärderas systemkomponenter. Ett anpassat hölje är utformat för att passa komponenterna. En OEM väljs och den valda växelriktaren testas utförligt. Testerna visar att växelriktaren inte har några problem att starta Icevolt 300 -kompressorn med reducerad spänning. Många batteritillverkare utvärderas och prover från tre olika tillverkare erhålls och testas. Prover från en av tillverkarna matchar specifikationerna och har inga problem med kompressorns höga starteffekt. Ett fullständigt systemtest bevisar att systemet fungerar, men indikerar också att den ursprungliga uppskattningen av kylförbrukningen var för låg. Det betyder att fler PV -paneler behövs än vad som ursprungligen beräknades. Med informationen från testerna byggs en ny modell som uppskattar prestandan mer exakt. Ett program skrivs för att uppskatta prestanda och bestämma vilka PV -paneler som krävs. Pilotserien för höljet visade att många förbättringar behöver göras vad beträffar höljets design, särskilt vad gäller kostnaden. Ett test förbereds i Mali men inga testdata har erhållits ännu. Baserat på det utförda arbetet skulle det rekommenderas att undersöka direkta DC -kylskåp istället för att fortsätta vägen för PV till AC-system.
6
Cavalcanti, Vladyr Yuri Soares de Lima. "Simulação computacional de um tomógrafo capacitivo elétrico paralelo aplicado ao processo adsortivo." Universidade Federal da Paraíba, 2009. http://tede.biblioteca.ufpb.br:8080/handle/tede/5391.
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Previous issue date: 2009-04-30Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
This thesis aims to computationally simulate the electronic transducer for a parallel electrical capacitance tomography, can generate a voltage level used for image reconstruction of the adsorption phenomenon occurred in the adsorptive bed. This simulation was performed using a computer program like SPICE (Simulation Program with Integrated Circuit Emphasis) for the purpose of defining the parameters for its construction, dedicated to the application of the adsorptive bed bench in a glass case studies of the adsorptive process. This technique uses capacitive sensors coupled to an electronic transducer that will generate a voltage signal associated with the distribution of dielectric permittivity of the medium. The simulation is developed to simulate the main circuit, a differentiator, fitted with high frequency OPA 2690. The simulated model is a simple circuit with a transmitter and a receiver. The results show the technical feasibility of the project being proposed for future work to implement a prototype of the electronic transducer of electrical capacitance tomography applied to the study of the adsorption process.
Esta dissertação tem como objetivo simular computacionalmente o transdutor eletrônico para um tomógrafo capacitivo elétrico paralelo capaz de gerar um nível de tensão utilizado para a reconstrução da imagem do fenômeno de adsorção ocorrido no leito adsortivo. Esta simulação foi realizada em um programa computacional do tipo SPICE (Programa de Simulação com Ênfase em Circuito Integrado) com a finalidade de definir os parâmetros para a sua construção, voltado para a aplicação no leito adsortivo de uma bancada em vidro para estudos do processo adsortivo. Esta técnica utiliza sensores capacitivos acoplados a um transdutor eletrônico que vão gerar um sinal de tensão associado à distribuição da permissividade dielétrica do meio. A simulação desenvolvida consiste em simular o circuito principal, um diferenciador, montado com OPA 2690 de alta freqüência. Simulou-se de um modelo de circuito simples, com um transmissor e um receptor. Os resultados apresentados mostram a viabilidade técnica do projeto, sendo proposto para trabalhos futuros a implementação de um protótipo do transdutor eletrônico do tomógrafo capacitivo elétrico aplicado ao estudo do processo de adsorção.
7
Eltom, Osman Mirghani Mohamed. "Solar refrigeration applications in the Sudan." Thesis, University of Reading, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332819.
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8
Zeiny, Aimen Rashad Noor. "Nanofluids for solar absorption refrigeration systems." Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/22416/.
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Vapour absorption refrigeration systems (VARSs), which utilise eco-friendly refrigerants (water), can work based on low-grade thermal energy, such as the solar energy. Using solar energy can relief the high electrical load on many national grids around the world as the peak load almost coincides with the high solar intensities time during summer. However, high initial cost, big specific size and low coefficient of performance are the main challenges that face the VARSs. Therefore, improving the efficiencies of the components of a solar refrigeration system, such as the solar collector, generator and absorber, is crucial to improve the overall efficiency of that system and to reduce its size and the cost. To improve the efficiency of a solar VARS, nanofluids are proposed in this work through direct and indirect ways. The direct way is seeding functional nanoparticles in the aqueous solution of a VARS. The expectations are that refrigerant (steam) can be generated efficiently via direct volumetric absorption of the solar energy at the generator and can be absorbed effectively via the Brownian motion of the nanoparticles at the absorber. While, the indirect way is; using aqueous nanofluids in direct solar collectors can harvest the solar energy in an efficient way, saving it in a storage tank. This stored energy is used later to generate the steam in the generator of the VARS. This work aims to investigate fundamentally the applicability of utilising nanofluids for solar absorption refrigeration systems through performing three main studies: Firstly, a comparative study of gold, copper oxide, gold and copper oxide hybrids, and carbon black nanofluids has been conducted to investigate the photo-thermal conversion efficiency. The results have shown that gold nanofluids are not feasible for solar application due to the high cost and low performance comparing to the carbon black nanofluids. Moreover, this study has demonstrated that blending different nanofluids of different narrow spectral absorption peaks can really broaden the effective spectral absorption peak but reduces its value due to the accompanied dilution of the blended nanofluids as the overall volume unavoidably increases. Secondly, a comparative study of solar steam generation among gold nanofluids, carbon black nanofluids and a thin carbon-based porous medium has been conducted. The results have also shown the infeasibility of using gold nanofluids comparing with the carbon black nanofluids due to the high cost and low absorptivity. Furthermore, this study has shown the superiority of using a thin, carbon-based porous medium in producing steam due to its capability to absorb most the solar energy in micro-sized thickness. While, very high nanoparticles concentration is required to trap and absorb the solar energy in such a thin layer, which consequently leads to an instability, high viscosity and high-cost issues. Finally, a study of the steam absorption by and generation from aqueous lithium bromide solutions seeded with carbon black and carbon nanotubes has been conducted. The results have demonstrated that a very low concentration of carbon black nanoparticles can reduce the transparency of the solutions to zero. However, seeding nanoparticles in the solutions has shown the negligible effect on the steam absorption rate, which demonstrated that the Brownian motion of the nanoparticles has a negligible effect on the steam absorption. Although the experiments conducted in this project showed negligible enhancement in the steam absorption, obvious enhancements in the photo-thermal conversion efficiency and steam generation were achieved by using nanofluids. Recommendations are suggested for future work to study other affecting aspects of seeding nanoparticles in aqueous solutions.
9
Swart, JC. "Solar refrigeration using the Peltier Effect." Thesis, Cape Technikon, 1996. http://hdl.handle.net/20.500.11838/1153.
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Thesis (Master Diploma (Electrical Engineering))--Cape Technikon, Cape Town,1996In order to design a coolerbox, utilising Thermo-electric technology as a heat pump, it was necessary to determine if this type of technology would be suitable for a coolerbox heat pump application. A detailed TEC (Thermo Electric Cooler) sizing estimation was done, using formulas supplied by the manufacturer, and using thermo-electric themy formulas to calculate the absolute theoretical performance parameters for a suitable TEe The correct heat pumping capability is important since.it is possible to obtain TEes with different input currents, voltages and heat pumping capabilities. Using the TEC as a heat pump, it was decided to use water cooling due to the extremely high cost of a suitable air cooled heatsink. It should be noted that to cool the hot side of theTEe a vel}' efficient heat exchanger should be used. A simulator was constructed to simulate, under variable operating temperatures and input powers, the cooling capacity of the TEC heat exchanger. The cooling characteristics were then used to determine if the theol}' and manufacturers claims correspond with the cooling characteristics of the coolerbox. It might be possible that the performance of the TEC would be drastically influenced, since installation con~itions may not be ideal when installed; and, that the manufacturers performance claims are done when the TEC is operated under ideal conditions. This would ensure optimum results because, should an under sized TEC be used, the result would be poor cooling characteristics; or, if the TEC is over sized, the coolerbox would consume too much power, resulting in an inefficient system.
10
Al, Juma Marwan. "Solar absorption cycle for cooling/refrigeration." Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/67695/.
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The purpose of this thesis is to critically highlight the development of solar absorption refrigeration technologies through time. The factors that have prompted the urgent need to reconsider this area of engineering will also be analyzed in depth. The relevant research in the area of solar absorption to date will be shown with specific emphasis on its contribution to industrial and domestic cooling systems. The Middle East may be awash with oil in the present circumstances with 48% of the known oil reserves in the world but challenges exist owing to fossil fuel being a finite resource and its exploitation fraught with environmental problems. Therefore developing solar cooling systems appears to be an essential and inevitable requisite for harnessing solar energy in order to make a lasting contribution to the development of the region, as well as the world Targeting the coefficient of performance (COP) of the solar absorption refrigeration systems was considered to be the fundamental part of this research. By investigating the absorber chamber in an absorption refrigeration system, it was found that enhancing the quality of the spray of the absorber fluid could raise the COP. Using a Phase Doppler Anemometry (PDA), a detailed analysis of the spray characteristics was achievable; this helped in targeting parameters which will have influence on the spray characteristics. These include the nozzle geometry, for instance, the size of orifice, as well as the internal forces of the liquid such as viscosity and surface tension. Operating parameters were also considered to influence the spray quality. The main operating parameter is to create a partial vacuum to simulate the absorber chamber working condition. Results revealed that high viscosity of the fluid and the vacuum had negative effects towards spray quality. But when combining these with a surfactant such as 2-ethyl-1-hexanol, the spray quality increases in terms of droplet diameter, which in turn decreases and thereby causes an increase in the surface area to volume ratio, resulting in the enhancement of COP.
11
Barbosa, Gerson. "Modelagem e simulação de um refrigerador solar por adsorção fisica." [s.n.], 1993. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254521.
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Orientador: Jose Antonio Dermengi RiosDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Descreve-se a elaboração de um modelo matemático simplificado e sua validação através da simulação em regime transiente de um ciclo real, realizado com um refrigerador solar por adsorção física utilizando um par carvão ativo / metanol. A diferença em relação aos resultados obtidos no ciclo real foi 4% para a massa ciciada de metanol, 2,2% para a temperatura máxima do coletor, e 3xl0-3 para o Coeficiente de Performance Teórico do Ciclo - CO.P.T.C. Simulações adicionais do mesmo ciclo mostraram a possibilidade de se aumentar a massa de metanol ciciada em cerca de 150%, utilizando-se de parâmetros da equação Dubinin - Astakov correspondentes a diferentes tipos e quantidades maiores de carvão ativo.
Abstract: This study describes the construction of a simple mathematical model and its validation through the simulation in transient state of a real cycle performed by a solar refrigerator based on physical adsorption using an activated carbon / methanol pair. The deviation from experimental results was 4% for the cycled mass of methanol, 2.2 % for maximum collector average temperature, and 3xl0-3 for the theoretical cycle coefficient of performance. Additional simulations of the same cycle inputting values representing different types and larger amounts of activated carbon showed the possibility of increasing the cycled methanol mass up to about 150 %.
Mestrado
Mestre em Engenharia de Alimentos
12
Fitó, de la Cruz Jaume. "Solar-driven hybrid refrigeration systems based on thermochemical processes." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/461061.
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Aquesta tesi doctoral proposa dos sistemes híbrids de refrigeració basats en energia solar en els quals l'element comú és un procés termoquímic: un sistema híbrid per absorció / termoquímic activat amb energia solar tèrmica de baixa temperatura (< 120 ºC), i un sistema híbrid per compressió / termoquímic activat amb energia solar fotovoltaica i calor residual.
El sistema per absorció / termoquímic és presentat en la seva configuració més simple i els seus components i condicions són discutits. Les prestacions del cicle són estimades de forma preliminar amb alguns parells de treball basats en amoníac, essent NH3/NaSCN i el NH3/BaCl2 dos d'interessants. La simulació preliminar del sistema híbrid mostra que aquest augmenta la fracció solar.
El sistema per compressió / termoquímic és definit i simulat en la fase d'acumulació de refrigerant assistida amb compressió. Un model de reacció quasi-estacionari de doble front, que pren en compte les limitacions de transferència de massa i de calor, és utilitzat per estudiar de forma preliminar la influència d'algunes condicions d'operació i paràmetres de disseny sobre la corba de reacció amb el parell amoníac / clorur de bari.
S'ha construit un dispositiu experimental per a obtenir dades experimentals de la fase d'acumulació de refrigerant assistida amb compressió, i confrontar aquestes dades amb les prediccions obtingudes del model de reacció de doble front, amb l'objectiu d'ajustar alguns dels paràmetres del model. Es conclou que el model ajustat prediu la corba de reacció amb una exactitud acceptable per a gairebé tots els experiments, amb petites discrepàncies.
S'espera que els sistemes híbrids proposats operin amb energia solar, siguin relativament compactes, emmagatzemin energia en menys volum d'emmagatzemament, i tinguin un petit grau d'autonomia (algunes hores dins d'un cicle d'operació diari). Aquests sistemes són interessants per a futurs estudis.Esta tesis doctoral propone dos sistemas híbridos de refrigeración basados en energía solar donde el elemento común es un proceso termoquímico: un sistema híbrido absorción / termoquímico activado con energía solar térmica de baja temperatura (< 120 ºC), y un sistema híbrido compresión / termoquímico activado con energía solar fotovoltaica y calor residual. El sistema absorción / termoquímico es presentado en su configuración más simple y sus componentes y condiciones de operación discutidas. El desempeño del ciclo es estimado preliminarmente con algunos pares de trabajo con amoníaco, con NH3/NaSCN y NH3/BaCl2 como pares interesantes. La simulación preliminar del sistema híbrido muestra que este aumenta la fracción solar. El sistema compresión / termoquímico es definido y simulado en la fase de acumulación de refrigerante asistida con compresión. Un modelo de reacción cuasi-estacionario de doble frente, que tiene en cuenta limitaciones de transferencia de masa y de calor, es usado para estudiar preliminarmente la influencia de algunas condiciones de operación y parámetros de diseño sobre la curva de reacción con el par amoníaco / cloruro de bario. Se ha construido un dispositivo experimental para obtener datos experimentales de la fase de acumulación de refrigerante asistida con compresor, y confrontar estos datos con las predicciones obtenidas del modelo de reacción de doble frente, con el objetivo de ajustar algunos parámetros del modelo. Se concluye que el modelo ajustado predice la curva de reacción con exactitud aceptable para casi todos los experimentos, con pequeñas discrepancias. Se espera que los sistemas híbridos propuestos operen con energía solar, sean relativamente compactos, almacenen energía en menor volumen, y tengan un pequeño grado de autonomía (unas pocas horas en un ciclo de operación diario). Estos sistemas son interesantes para futuros estudios.
This doctoral thesis proposes two solar-based hybrid refrigeration systems where the central piece is a thermochemical process: an absorption / thermochemical hybrid system driven by low-grade solar thermal energy (< 120 ºC), and a compression / thermochemical hybrid refrigeration system driven by solar-PV energy and waste heat. The absorption / thermochemical hybrid system is presented in its most simple configuration, and its components and operating conditions discussed. A preliminary performance estimation is carried out with some ammonia-based working pairs finding the NH3/NaSCN and NH3/BaCl2 as interesting working pairs. A preliminary simulation of the hybrid system shows that it increases the solar coverage. The compression / thermochemical hybrid system is also defined and simulated in its refrigerant storage phase assisted with compression. A 2-front quasi-steady reaction model which accounts for heat and mass transfer limitations is used to preliminarily study the influence of some operating conditions and design parameters on the system’s reaction curve with the NH3/BaCl2 working pair. An experimental setup has been built to obtain experimental data from the compression-assisted refrigerant storage phase, and confront this data with the predictions obtained from the 2-front reaction model, with the objective of adjusting some parametres of the model. It is concluded that the adjusted model predicts the reaction curve with acceptable accuracy for almost all experiments, with small discrepancies. The proposed hybrid systems are expected to operate with solar energy, be relatively compact, store energy with reduced storage volume, and have a small degree of autonomy (a few hours within a daily operating cycle). These systems are promising for further study.
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Nguyẽ̂n, Minh. "The development of a passive solar-powered refrigeration system." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297766.
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Merino, Jose Carlos Alvarez, and Kazuo Hatakeyama. "Technology surveillance of the solar refrigeration by absorption/adsorption." Institute of Electrical and Electronics Engineers Inc, 2016. http://hdl.handle.net/10757/622310.
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PICMET 2016 - Portland International Conference on Management of Engineering and Technology: Technology Management For Social Innovation, Proceedings4 January 2017, Article number 7806767, Pages 1976-19822016 Portland International Conference on Management of Engineering and Technology, PICMET 2016; Honolulu; United States; 4 September 2016 through 8 September 2016; Category numberCFP16766-ART;
Code 125891In order to establish networks of cooperation looking for not to duplicate research and even to make use of existing research in a remote form, it is necessary to identify and classify (around the world) the researchers and laboratories, that are researching in the topic of solar refrigeration by absorption/adsorption. The methodology consists in: i) the technology's classification, ii) technological trajectory Identification, iii) a thematic bibliographic review, and iv) patent's analysis. In this way, with the previous determination of keywords, will be identified main authors and their respective institutions. With the same keywords, are determined the licensed patents (in certain span of time). In addition, the analysis of publications, patents, and commercial products give us an opportunity to establish comparisons between prototypes and tests (in several conditions). The larger results implicate the use of actor's network and the remote access to the data and tests, for a collaborative research, overcoming the lack of laboratory resource and accelerating the knowledge acquisition
Revisión por pares
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Escobedo, João Francisco. "Refrigeração com uso de energia solar." Universidade de São Paulo, 1987. http://www.teses.usp.br/teses/disponiveis/54/54132/tde-28052009-094024/.
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Uma simulação numérica do ciclo de refrigeração a adsorção é realizada para os pares zeólita-água e carvão ativo AC-35 metanol, justificando a escolha do par bem como do sistema de captação a serem utilizados no protótipo. O protótipo construído compreende um concentrador cilíndrico-parabólico com rastreamento solar, um tubo de calor e uma unidade frigorífica (com zeólita-água). Aspectos tecnológicos como válvulas, soldas e carregamento do par na máquina são analisados. Os resultados dos testes de desempenho são apresentados, discutidos e comparados com a literatura. Uma análise de custos é feita. Paralelamente, construímos termo pilhas pelo método da evaporação. Estas termopilhas foram utilizadas na construção do piranômetro e do pireliômetro. Os instrumentos são caracterizados em termos de sensibilidade, constante de tempo, linearidade, efeitos de temperatura e convecção natural. Os resultados desta caracterização são discutidos e comparados com um modelo fabricado pela Eppley. Finalmente, no apêndice I, testamos o desempenho de um coletor plano utilizando no absorvedor o revestimento seletivo de óxido de alumínio recentemente desenvolvido no IFQSC. As melhores condições para obtenção do revestimento seletivo em placas de grande porte são estudadas.A numerical simulation of the adsorption refrigeration cycle was made for zeolite/water and activated carbon(AC-35)/ methanol pairs, to select the pair and the solar collector in the prototype. The fabricated prototype consists of a cylindrical paraolic concentrator with solar trackins, a heat pipe and the refrigeration unit (with the zeolite/water pair). The technical aspects of values, welds and out-gassing are analyzed. The results of the performance tests are presented, discussed and compared with the literature. An analysis of costs is made. In parallel thermopiles were constructed using the evaporation method. These thermopiles were used in the construction of the piranometer and the pirheliometer. The instruments were characterized in terms of: sensitivity, stability with time, linearity, effects of temperature and natural convenction. The results of this characterization are discussed and compared with a model made by Eppley. Finally, in Apendix I, we tested the performance of a flat plate collector using a selective coating of aluminium oxide (developed in IFQSC) as absorber. The Best conditions for obtaining the seletive coating on big size plates are discussed.
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You, Ying 1962. "A solar adsorption refrigeration system operating at near atmospheric pressure." Monash University, Gippsland School of Engineering, 2001. http://arrow.monash.edu.au/hdl/1959.1/8740.
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Pridasawas, Wimolsiri. "Solar-driven refrigeration systems with focus on the ejector cycle." Doctoral thesis, Stockholm : Department of Energy Technology, Royal Institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4151.
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Babawale, Z. A. "Theoretical study of an absorption refrigeration system powered by CPC solar collectors for applications at near equatorial latitudes." Thesis, City University London, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383805.
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Silva, Ricardo Filipe Alves da. "Análise comparativa de um sistema de refrigeração solar." Master's thesis, Universidade de Évora, 2016. http://hdl.handle.net/10174/18572.
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Nesta dissertação são comparadas duas tecnologias de refrigeração. Uma tecnolo-gia é um sistema que usa a energia elétrica para fazer funcionar um ciclo de com-pressão de vapor, sistema comum em instalações de refrigeração. A outra solução é um sistema de absorção, em que a energia necessária para o funcionamento do sistema é energia térmica obtida através de coletores solares térmicos.
Estas tecnologias são estudadas e comparadas para a refrigeração de um arma-zém de produtos agrícolas à temperatura constante de 5ºC para a região de Alque-va, região onde estão a ser desenvolvidos projetos hortofrutícolas a que estão as-sociadas necessidades de preservação dos produtos que envolvem refrigeração e em que a acessibilidade à rede elétrica é reduzida.
É mostrado que a tecnologia do sistema de absorção com os coletores se apresenta a médio prazo mais vantajosa em termos económicos e ambientais; Abstract:
Comparative analysis of a solar refrigeration system
In this dissertation two refrigeration technologies are compared when used for the same objective. One is a technology using the electric energy to operate a vapour compression cycle, commonly used in refrigerated installations. The alternative technology is an absorption system driven by thermal energy, provided by solar thermal collectors.
Both technologies are studied and compared for the refrigeration of an agricultural products warehouse at a constant temperature of 5ºC in the Alqueva region, where horticultural projects are being developed with associated needs of preservation of the products involving refrigeration, and where accessibility to the electrical grid is reduced.
In the referred conditions it was shown that the absorption technology with collec-tors in the medium term surpasses the usual compression system, both from eco-nomic and environmental viewpoints.
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AraÃjo, Maria Elieneide. "ValidaÃÃo experimental de um resfriador de Ãgua operando em ciclo de adsorÃÃo com aquecimento solar indireto." Universidade Federal do CearÃ, 2009. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=3400.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorApresenta a validaÃÃo experimental de um novo refrigerador solar por adsorÃÃo com aquecimento indireto. Os componentes do refrigerador sÃo: adsorvedor, condensador, evaporador e coletor solar. A escolha do par adsorbato / adsorvente, Ãgua e sÃlica gel tipo RD, respectivamente, levou em consideraÃÃo as temperaturas alcanÃadas pelos coletores e disponÃveis para a dessorÃÃo do fluÃdo refrigerante (Ãgua) das cavidades do material adsorvente (sÃlido poroso). Devido à coexistÃncia das etapas de aquecimento e resfriamento no adsorvedor, foi definida uma geometria para este componente capaz de permitir uma melhor dissipaÃÃo de calor no material adsorvente na fase de resfriamento, e a conservaÃÃo de energia tÃrmica durante a fase de aquecimento. Os resultados experimentais comprovaram o funcionamento do refrigerador, visto que foram atingidas temperaturas de 140ÂC na entrada do adsorvedor, 80ÂC no leito adsortivo e de 4,4ÂC no evaporador, possibilitando sua aplicaÃÃo em sistemas de condicionamento de ar
This work presents the experimental validation of a new adsorption solar refrigeration with indirect heating. The components of the refrigerator are: an adsorber, a condenser, an evaporator, and a solar collector. The choice of the adsorbate / adsorbent pair, water and silica gel type RD, respectively, took into consideration the temperatures reached by the solar collectors and available for the desorption of the refrigerant fluid (water) from the cavities of the adsorbent material (a porous solid). Due to the co-existence of the heating and cooling phases in the adsorber, a specific geometry for this component was defined so as to allow a good heat dissipation in the adsorbent material in the cooling phase, and the conservation of thermal energy in the heating phase. The experimental results validate the operation of the refrigerator, as temperature valves of 140ÂC at the inlet of the adsorber, of 80ÂC in the adsorber bed, and of 4,4ÂC in the evaporator were reached, allowing its application in air conditioning systems
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Marcos, Carla Abregú, Abraham Sopla Maslucán, Miguel Cano Lengua, and José C. Alvarez. "Co-authors Networks in Adsorption Refrigeration and Air-Conditioning with Solar Energy." Universidad Peruana de Ciencias Aplicadas (UPC), 2021. http://hdl.handle.net/10757/653778.
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El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.The refrigeration and air conditioning systems by adsorption with solar energy are a very interesting option to replace the conventional compression systems because they save energy, are noiseless and use non-aggressive ozone layer refrigerants; however, there are scarcities of studies at this topic. The acquisition of knowledge and positioning in research on this topic by new research groups could be facilitated by knowing the context, trends, and collaborations that emerge in the subject. A map of collaborative co-authors between the greatest authors on the subject was drawn up, the same one that is done using Gephi software. From the analysis of these maps, the centrality degree and collaboration between the authors were determined.
Revisión por pares
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Dalichaouch, Mahieddine. "A theoretical and experimental investigation of an absorption refrigeration system for application with solar energy units." Thesis, University of Newcastle Upon Tyne, 1989. http://hdl.handle.net/10443/331.
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Application of the second law of thermodynamics to refrigeration systems is useful in identifying the thermodynamic losses and in finding out where improvements might be made. Theoretical absorption refrigeration cycles are analysed using the first law-based equations of energy balances and the second law-based concept of lost work. A thermodynamic efficiency, defined and formulated from the lost work approach, is used to examine a lithium bromide -water absorption cooling cycle with hot water as the heat source and cooling water as the heat sink. The cycle parameters are varied over applicable operating ranges in order to find their effect on the cycle thermodynamic efficiency. To accomplish this objective and to make a parameteric analysis for the L iBr -water absorption cycle under steady-state conditions, two computer programmes are written. The results indicate the system might be improved by better design. The efficiency variation is compared to variations of coefficient of performance found in the literature. A LiBT -water absorption refrigeration system for low hot water temperature applications has been proposed and detailed design aspects have been considered. Fabrication and testing of a laboratory model of the absorption refrigeration system have been described. As new design methodologies of solar energy applications have been developed recently, a study of solar thermal systems for absorption refrigeration has been presented. This includes the classification, description and modelling of solar systems. Types of design procedures of solar systems for absorption refrigeration are discussed and a computer programme has been implemented which prints out the yearly solar fraction of a solar thermal system with daily storage for supplying heat to an absorption cooling cycle. Numerical performance tests are carried out and the results show that the phibar-f chart design method is a simple and convenient mean of predicting the thermal performance of solar systems.
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Alkilani, Fouad M. "A solar assisted high temperature refrigeration system for postharvest pre-storage fruit cooling." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2557.
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Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2017.Agriculture has emerged as a major economic activity in the African continent. Therefore, fruits and vegetables are considered as essential source of vitamins, minerals and proteins. However, fruits and vegetables are perishing rapidly. Thus, the adequate handling starts from the field, by applying appropriate method of storage and preservation in order to reduce post-harvest losses and extend its shelf life. Preservation by removing heat from the products is the most common method of preservation. In rural areas, the access to the grid is expensive or in some cases impossible. Therefore, researchers have been paying more attention to find alternative sources of power to run the cooling units. This study provides proof of a concept for the use of solar energy to cool down harvested fruits and vegetables at the farm level to an adequate farm storage temperature. The target storage temperature range is between 5 and 15 oC. A model refrigerator was designed and constructed in the mechanical engineering workshop of Cape Peninsula University of Technology. It was installed and tested in outdoor conditions to get the effect of different weather conditions. The model consists of a typical vapour compression system powered by a 12 V solar PV system. A DC compressor was used, and therefore, there is no inverter. The model was first tested without a product and then with 20 kg batches of different fruits for a period of two weeks in April 2016. Wind speed, ambient temperature and solar radiation intensity data were monitored and collected from a Campbell Scientific weather station mounted on the roof adjacent to the model. By monitoring the temperatures and compressor current hourly, the refrigeration effect, power consumption and coefficient of performance were determined. The overall COP based on input solar energy was 2.8. It was thus proved that a suitably sized PV system could be designed and implemented at farm level to cool harvested fruits from ambient to storage temperature without the use of an inverter. This could go some way to helping retard deterioration of fruits and vegetables before delivery to a marketplace or to storage.
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Bahman, Ammar. "Modeling of Solar-Powered Single-Effect Absorption Cooling System and Supermarket Refrigeration/HVAC System." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/2993.
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This thesis consists of two different research problems. In the first one, the aim is to model and simulate a solar-powered, single-effect, absorption refrigeration system using a flat-plate solar collector and LiBr-H2O mixture as the working fluid. The cooling capacity and the coefficient of performance of the system are analyzed by varying all independent parameters, namely: evaporator pressure, condenser pressure, mass flow rate, LiBr concentration, and inlet generator temperature. The cooling performance of the system is compared with conventional vapor-compression systems for different refrigerants (R-134a, R-32, and R-22). The cooling performance is also assessed for a typical year in Tampa, Florida. Higher COP values are obtained for a lower LiBr concentration in the solution. The effects of evaporator and condenser pressures on the cooling capacity and cooling performance are found to be negligible. The LiBr-H2O solution shows higher cooling performance compared to other mixtures under the same absorption cooling cycle conditions. For typical year in Tampa, Florida, the model shows a constant coefficient of performance of 0.94.
In the second problem, a numerical model is developed for a typical food retail store refrigeration/HVAC system to study the effects of indoor space conditions on supermarket energy consumption. Refrigerated display cases are normally rated at a store environment of 24ºC (75ºF) and a relative humidity of 55%. If the store can be maintained at lower relative humidity, significant quantities of refrigeration energy, defrost energy and anti-sweat heater energy can be saved. The numerical simulation is performed for a typical day in a standard store for each month of the year using the climate data for Tampa, Florida. This results in a 24 hour variation in the store relative humidity. Using these calculated hourly values of relative humidity for a typical 24 hour day, the store relative humidity distribution is calculated for a full year. The annual average supermarket relative humidity is found to be 51.1%. It is shown that for a 5% reduction in store relative humidity that the display case refrigeration load is reduced by 9.25%, and that results in total store energy load reduction of 4.84%. The results show good agreement with available experimental data.
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Adegoke, C. O. "Evaluation of a refrigerant/absorbent combination for vapour absorption refrigeration systems utilising solar heat." Thesis, King's College London (University of London), 1987. https://kclpure.kcl.ac.uk/portal/en/theses/evaluation-of-a-refrigerantabsorbent-combination-for-vapour-absorption-refrigeration-systems-utilising-solar-heat(5c32f1a2-b5f9-41ba-b671-0bbb4fbcf578).html.
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Silveira, Júnior Vivaldo 1962. "Montagem e teste de desempenho de um refrigerador solar por absorção fisica com produção de gelo." [s.n.], 1990. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254518.
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Orientador: Jose Antonio Dermengi RiosDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-07-14T04:00:41Z (GMT). No. of bitstreams: 1 SilveiraJunior_Vivaldo_M.pdf: 5221008 bytes, checksum: d902006076cd6c717e576317410006d7 (MD5) Previous issue date: 1990
Resumo: Este trabalho descreve com detalhes a, construção, montagem, instrumentação, e testes de estanqueidade do protótipo experimental de um refrigerador solar por adsorção física, que usa o par carvão ativado / metanol. São analisados quatro testes de desempenho do equipamento. Os dados experimentais utilizados foram: energia solar incidente, temperatura e pressão do reator, temperaturas ambiente, do gabinete e da água estocada no reservatório. Este protótipo produziu 3.0 kg de gelo num ciclo de 24 horas com um Coeficiente de performance solar de 0.042, usando um coletor solar plano multitubular contendo 9.9 kg de adsorvente. Os parâmetros (Wo e D) da equação de Dubinin Raduskevich foram calculados com os dados experimentais para o par carvão ativado (Deion) e metanol. A faixa ótima da temperatura máxima do coletor foi estimada entre 90 e 100° C . Este conhecimento será útil para futuros estudos de otimização do sistema
Abstract: This study details the construction, instrumentation, and leak tests of an experimental prototype of a solar refrigerator by physical adsorption, using an activated carbon / methanol pair. Four performance tests of the equipment are analyzed. The experimental data utilized are solar energy temperature and pression of the reator, ambient temperature, temperature of the gabinet and temperature of water stornaged. The prototype produced 3,0 kg of ice in a 24 h cycle with a C.O.P.solar of 0,042 using a multipipe ftat-plate solar colletor containing 9,9 kg of adsorvent. The Dubinin-Raduskevich's equation parameters (Wo and D) are calculated with the experimental data for activated carbon (Deian) / methanol pair. The optimum temperature range for the colletor was predicted between 90 and 100°C. This knowledge will be useful to future studies to optimize the system
Mestrado
Mestre em Engenharia de Alimentos
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Zingano, Bernard Wilson. "Effects of solar radiation on buildings and thermal comfort." Thesis, University of Hertfordshire, 2003. http://hdl.handle.net/2299/14151.
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This work was undertaken to investigate the perceived problem of Thermal Discomfort in Malawi. One observable effect of thermal discomfort was the amount of foreign exchange that was spent to import air conditioning devices. The purpose of the work was to find out, and quantify the problem of thermal discomfort and outline its effects to the people and country. In order to investigate the problem of thermal discomfort in depth in a place where the necessary data hardly existed a lot of work had to be done. The work has been outlined in four stages of research, analysis and documentation and these are as follows 1 Literature Review The subject of Thermal Comfort appears to be location specific, but the general principles are universal. In that context it was necessary to read widely on both historical and contemporary current work. The problem of thermal comfort in general was being discussed as early as 1758 and still remains a big area of research and discussion today. A considerable number of literature that specifically relate to the problem of thermal comfort in the tropics has been reviewed. The problem of scales for thermal comfort measurement has been discussed in detail. It is still not possible to quote a scale that is satisfactory. However, the recent approach of Adaptive Thermal Comfort Model seems to be closer to the answer than the others 2 Analysing Existing Relevant Information And Data In Malawi In the course of this work it was found out that quite a large amount of useful data existed in Malawi. However, this data was not standardised. Most of this data had to be cleaned and updated. Some of the old formulae are quoted in their original formats in order not to confuse the referencing. The data that exists in Malawi has been recorded on three types of instruments; namely the Gunn Bellum Spherical Pyranometer, the Camp Bell Stoke Sunshine Recorder and the Eppley Pyranometer. Most of the data was recorded using the Camp Bell Stokes Sunshine Recorder. The data recorded on the Gunn Bellum Spherical Pyranometer had to be related to that from the Camp Bell Stokes Sunshine Recorder. The former gave data that was more accurate as was found out when a comparison was made with data recorded on an Eppley Pyranometer. A paper on this subject was accepted for publication in the Renewable Energy Journal of WREN. Wind speeds, air temperatures, and humidity have been analysed to investigate the severity of thermal discomfort relative to locations in Malawi. This has resulted in the identification of three climatic zones. A tool for testing Thermal Discomfort severity of a location by calculating number Degree Days (D. d) if the altitude (AL) has been developed; as D. d = -575.994 In AL + 4226.6 3 Field Measurements In order to investigate some of the issues that came out of this work, it was felt simpler to conduct field measurements. For example it would have been possible to build typical experimental houses, and extract performance data on Thermal Comfort from these buildings. However, this approach would have been very expensive. On the other hand it was felt that it was possible to find in the field that were representative of typical buildings and could be prepared and tested to extract performance data for use in the work. The latter approach was adopted and has proved to be more realistic than the former. 4 Field Surveys There were certain areas where the only way to find information was not to conduct experiments but to conduct field conduct surveys. This was done once to find the Preferred Bath Water Temperature (PBWT) and deduce the Neutral Temperature Range for Malawi. This yielded very useful results. The first published paper on this work was in this area (copy of this publication is attached). The second area of field survey was to survey traditional buildings in seven selected districts stretching from latitude 9°S to 17°S; covering a terrestrial distance of over 1000 km; over altitudes from 52 to over 1600 metres above mean sea level (m. a. m. s. l). This again yielded very useful environmental data that explained why traditional buildings have certain structural elements as functions of the environment and the need to achieve Thermal Comfort. A number of useful equations have been developed. From that sub routine of this research of PBWT survey an equation was developed that related the bath temperature (h) to the air temperature (tab) as; tb =0.3772 tab + 36.4401. Part of this work was also published separately in 2001. From this equation the Thermal Comfort Temperature Range for Malawi was deduced as 22-27°C. From the survey of the traditional buildings, a number of structural elements were that are functions of Thermal Comfort were identified as derivatives of the desire to have Thermal Comfort in the buildings. A regression equation that can give values of irradiation of the locality in MJm 1 Day' was developed. Lastly the results have been extracted as recommendations directed at policy makers, and both Architects and Engineers to use this data and the results in their design work. It is also further recommended that the national buildings regulations could be updated and revised to incorporate some of the findings. It is strongly believed that some of the findings will be incorporated to update the two main Laws that regulate Public Health in Malawi. These are the Public Health Act; Cap. 34.01, and the Health and Safety at Work Act, 1977; of the Malawi Laws. All data that has been cleaned up or measured specifically for this work has been organised and tabulated into ready-to-use tables and are included.
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Yeung, King-ho, and 楊景豪. "An optimization model for a solar hybrid water heating and adsorption ice-making system." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B29632432.
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AragÃo, Thales Silva Ximenes de. "AperfeiÃoamento Experimental de um Tubo de VÃrtice para Acionamento por Sistema Solar Fotovoltaico." Universidade Federal do CearÃ, 2016. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=19011.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorO presente trabalho buscou a determinaÃÃo de parÃmatros Ãtimos - como pressÃo e fraÃÃo de massa fria - para tubos de vÃrtice, visando o melhor desempnho termodinÃmico. As principais variÃveis de entrada estudadas fromas a pressÃo (1a 6 bar) e fraÃaà de massa fria, em torno de 40%, assim como o nÃmero de entradas da cÃmara de vÃrtice, com 4 e 6. As fraÃÃes de massa fria se apresentaram mais eficientes entre os valores de 40 e 50%. A anÃlise realizada usou um tube de vÃrtice que possibilitava um trabalho conjunto com um compressor de 7,5hp. Instrumentos de mediÃÃo foram utilizados para a obtenÃÃo dos dados experimentais. SÃo eles: um rotÃmatro com grande capacidade de mediÃÃo de fluxo de ar e uma sÃrie de termopares para mediÃÃes de temperaturas em diferentes pontos do circuito, como a entrada da cÃmara de vÃrtice e as saÃdas quente e fria do tubo. Os experimentos revelaram que o coeficiente de performance (definido como a razÃo entre o trabalho de compressÃo do ar e a variaÃÃo de entalpia deste entre a entrada do tubo e a saÃda fria) foi saifatÃrio, atingindo Ãndices de 0,12. A melhor configuraÃÃo apresentada foi com um tubo de vÃrtice trabalhando a pressÃo de 6 bar, com uma cÃmara de geraÃÃo de vÃrtice possuindo 4 entradas. A eficiÃncia em termos de energia - determinada como a razÃo entre a exergia das massas de ar na saÃda do tubo e a exergia da massa de ar na entrada deste - tambÃm foi estudadas e calculada, apresentando valores de 2% para os pontos mais eficientes. os valores desta eficiÃncia apresentaram pouca variaÃÃo em relaÃÃo à variaÃÃo de pressÃo. Nos trabalhos analÃticos, foram realizados o dimensionamento e a escolha de um arranjo fotovoltaico capaz de alimentar o sistema de geraÃÃo de energia, composto de 8 unidades de painÃis fotovoltaicos trabalhando em paralelo.
This work wanted to determine the optimum parameters - like pressure and cold mass fraction - to vortex pipes, in order to find out the best thermodynamic performance. The main inlet variables studied were the pressure - from 1 to 6 bar - and the cold mass fraction, around 40% as well as hte number of inlets on the vortex chamber, with 4 and 6 inlets. The cold mass fraction presented more efficient between 40 and 50%. This analysis used a vortex tube that enabled to work together with a 7,5hp compressor. Measurement instruments were used to obtain the experimental data. They are a rotameter capable of measure 400 standard cubic feet per hour and several termocouples, as in the inlet of the vortex chamber and the cold and hot outlet. The experiments revealed that the coefficient of performance (defined as the ratio between the air compression work and the enthalpy variation between the inlet of the chamber and the cold outlet) was satisfactory, reaching levels of 0,12. The best configuration presented used a vortex pipe working at 6 bar, with a vortex chamber with 4 inlets. The exergy efficiency - determined as the ratio between the exergy of tme mass in the both outlets and the exergy in the inlet - was also studied and calculated, resenting values of 2% in the most efficient points. The values of this efficiency presented little variation compared to the present variation. In the analytical works, it was done the dimensioning and the choice of a photovoltaic assemby, capable of feed the energy generation system, made of 8 units of photovoltaic panels working in parallel.
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Coca, Ortegón Adriana-Clemencia. "Estudio teórico-experimental de un refrigerador solar fotovoltaico con almacenamiento de frio mediante materiales de cambio de fase." Doctoral thesis, Universitat Rovira i Virgili, 2019. http://hdl.handle.net/10803/667651.
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Els refrigeradors solars fotovoltaics són una solució útil per a la conservació d'aliments i la gestió de la cadena de fred en aquelles regions sense subministrament d'electricitat, o on aquest subministrament no tingui prou fiabilitat. Actualment aquests refrigeradors tenen major viabilitat, ja que el cost dels mòduls fotovoltaics ha estat en descens durant els últims 30 anys.
Aquests refrigeradors normalment utilitzen bateries elèctriques basades en plom-àcid, per cobrir el desfasament entre la producció fotovoltaica i la demanda. Tanmateix, és possible també utilitzar altres opcions d'emmagatzematge energètic de menor impacte mediambiental, com l'emmagatzematge tèrmic en fred, mitjançant materials de canvi de fase (PCMs).
De tal manera, la present tesi es centra en l'estudi teòric-experimental, d'un refrigerador solar fotovoltaic, amb emmagatzematge tèrmic latent, de fred, mitjançant PCMs, per tal d'augmentar l'autonomia del refrigerador, millorar la seva integració amb el sistema fotovoltaic i reduir la mida de les bateries elèctriques. La integració dels materials de canvi de fase s'ha realitzat disposant-los encapsulats, en un panell, en contacte amb l'evaporador de paret.
Per analitzar els efectes del panell de PCMs al refrigerador, va ser implementat un model teòric, el qual inclou el sistema fotovoltaic, el sistema de refrigeració, el panell de PCM i la cel refrigerada. La validació del model del refrigerador amb el panell de PCM integrat, s'ha realitzat mitjançant un assaig experimental del refrigerador, dins d'una cambra climàtica realitzat segons la norma EN 62552.
La transferència de calor al PCM, utilitza un model de transferència de calor per conducció unidimensional i per resoldre l'equació diferencial del model, s'utilitza el mètode de diferències finites. Les simulacions finals realitzades per a tres emplaçaments tropicals indiquen que el sistema proposat és viable tècnica i econòmicament.Los refrigeradores solares fotovoltaicos son una solución útil para la conservación de alimentos y la gestión de la cadena de frío en aquellas regiones sin suministro de electricidad, o donde dicho suministro no tenga suficiente fiabilidad. Actualmente estos refrigeradores tienen mayor viabilidad, pues el coste de los módulos fotovoltaicos ha estado en descenso durante los últimos 30 años, por lo que se considera. Estos refrigeradores normalmente utilizan baterías eléctricas basadas en plomo-ácido, para cubrir el desfase entre la producción fotovoltaica y la demanda. No obstante, es posible también usar otras opciones de almacenamiento energético de menor impacto medioambiental, como el almacenamiento térmico en frío, mediante materiales de cambio de fase (PCMs). De tal manera, la presente tesis se centra en el estudio teórico-experimental, de un refrigerador solar fotovoltaico, con almacenamiento térmico latente, de frío, mediante PCMs, con el fin de aumentar la autonomía del refrigerador, mejorar su integración con el sistema fotovoltaico y reducir el tamaño de las baterías eléctricas. La integración de los materiales de cambio de fase se ha realizado disponiéndolos encapsulados, en un panel, en contacto con el evaporador de pared. Para analizar los efectos del panel de PCM en el refrigerador, fue implementado un modelado teórico, el cual incluye el sistema fotovoltaico, el sistema de refrigeración, el panel de PCM y la celda refrigerada. La validación del modelo del refrigerador con el panel de PCM integrado, se ha realizado mediante un ensayo experimental del refrigerador, dentro de una cámara climática realizado según la norma EN 62552. La transferencia de calor en el PCM, utiliza un modelo de transferencia de calor por conducción unidimensional y para resolver la ecuación diferencial del modelo, se utiliza el método de diferencias finitas. Las simulaciones finales realizadas para tres emplazamientos tropicales indican que el sistema propuesto es viable técnica y económicamente.
Solar powered refrigerators driven with photovoltaic panels are a useful solution for food preservation and cold chain management in those regions in which there is no electrical supply, or this supply is unreliable. Currently, these refrigerators have high feasibility, since the cost of photovoltaic panels has been in going down during the last 30 years. These refrigerators usually use of electrical lead-acid batteries to cover the gap between photovoltaic production and power load; however, it is also possible to use other energy storage options, with lower environmental effects, such us cold thermal storage, with phase change materials (PCMs). This thesis is focused on a theoretical-experimental study of a photovoltaic solar refrigerator, with cold latent thermal storage, using PCMs, in order to increase the autonomy time of the refrigerator, improve its integration with the photovoltaic system and reduce the size of conventional electrical batteries. The integration of the phase change materials has been carried out by installing a PCM slab, in contact with the evaporator-wall of the refrigerator. In order to analyze the effects of the PCM slab on the refrigerator, a theoretical model was implemented. This model includes the photovoltaic system, the refrigeration system, the PCM slab, and the refrigerated cell. The validation of the refrigerator model with the PCM slab was carried out by testing the refrigerator inside of a climatic chamber, according to EN 62552. The heat transfer in the PCM uses a one-dimensional conduction heat transfer model and to solve the differential equations of the model, the finite difference method was used. The final simulations carried out for three tropical locations indicate that the proposed system is technically and economically feasible.
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Vieira, Herbert Melo. "Estudo teórico e experimental de coletor adsortivo." Universidade Federal da Paraíba, 2009. http://tede.biblioteca.ufpb.br:8080/handle/tede/5392.
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This paper presents simple and feasible alternatives that will help improve the performance of a refrigeration system by adsorption, which uses solar energy as a heat source to promote the raising of the temperature of the porous bed, thus occurring, the process of desorption, which is the separation of the adsorbent adsorbato. The studies were made in the modification of the geometry of the absorber plate for triangular tube, which caused an increase in the area provided between the plate and the adsorbent, which were analyzed by a computer program that simulates the cycle of a refrigeration system by adsorption . Another study proposed is the removal of a concentric screen, which aims to promote the flow of radial adsorbato during the processes of sorption, the withdrawal of this screen aims to verify whether the change in the flow of adsorbato of radial to the axial an increase in the concentration of adsorbato the porous bed and if the phenomenon occurs throughout the entire adsorptive column, thus enabling a constructive process of collecting tubular simple plan, this phase of work, is shown through experimental results, verifying the concentration and temperature in two adsorptive columns during the adsorption.
O presente trabalho apresenta alternativas viáveis e simples que venham contribuir para melhorar o desempenho de um sistema de refrigeração por adsorção, que utiliza a energia solar como fonte de calor para promover a elevação da temperatura do leito poroso, ocorrendo assim, o processo de dessorção, que é a separação do adsorbato do adsorvente. Os estudos feitos constituíram na modificação da geometria da placa absorvedora de tubular para triangular, o que ocasionou um aumento na área de contanto entre a placa e o adsorvente, que foram analisadas através de um programa computacional que simula o ciclo de um sistema de refrigeração por adsorção. Outro estudo proposto é a retirada de uma tela concêntrica, que tem como finalidade promover o fluxo radial do adsorbato durante os processos de adsorção/dessorção, a retirada desta tela tem como objetivo verificar se com a modificação do fluxo do adsorbato de radial para axial a um aumento na concentração de adsorbato no leito poroso e se ocorre o fenômeno adsortivo ao longo de toda coluna, possibilitando assim, um processo construtivo do coletor plano tubular mais simples, esta etapa do trabalho, é apresentada através de resultados experimentais, verificando a concentração e temperatura em duas colunas adsortivas durante o período de adsorção.
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Fenton, Ryan. "The study, development and experimental investigation of a novel, solar powered refrigeration system based on the jet-pump cycle." Thesis, London South Bank University, 2015. http://researchopen.lsbu.ac.uk/2072/.
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Every year, millions of people die from diseases that are preventable by vaccination. The lack of an effective cold-chain in developing countries means that many of the vaccinations intended for administration are spoiled and wasted. Poor energy infrastructure in these countries is often coupled with high solar irradiance values, providing a compelling reason for research into effective solar powered refrigeration systems. A number of studies have shown that a refrigeration system, thermally powered via a jet-pump circuit, as an alternative to an electrically driven compressor, could provide a working solution. Such a system could be powered largely by heat (i.e. solar energy) and would find application in developing countries with high solar availability. A comparative review of prior research into small scale jet-pump refrigeration systems highlighted a gap in existing knowledge as the performance of small scale units (< 500W) has not previously been investigated. A system specification was defined, based on current World Health Organisation (WHO) standards for solar-powered vaccine refrigerators. A jet-pump, rated to deliver 100 W evaporator cooling capacity using R134a as a working fluid, was developed and tested at the defined operating conditions (Te=6°C, Tg=90°C and Tc=42°C). The experimental study focused on the need for technology that is suited to off-grid applications and the use of secondary heat sinks (i.e. cooling water circuits) was avoided. Alternatives to an electrically powered refrigerant feed pump were investigated and a novel reservoir transfer system is presented and experimentally evaluated. In order to minimise moving parts, the use of natural convection heat transfer (i.e no fans) was also investigated for both the evaporator and condenser heat exchangers. Automated systems were used to control the apparatus and experimental data collected to evaluate the systems thermal coefficient of performance (COP). Experimental results showed that the system could achieve COPs of 0.06 - 0.12 and demonstrates the potential for small capacity jet-pump cooling systems using less than 50 W electrical power.
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Vieira, Herbert Melo. "Estudo experimental e teórico de um resfriador de água por adsorção usando energia solar." Universidade Federal da Paraíba, 2013. http://tede.biblioteca.ufpb.br:8080/handle/tede/5350.
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The respective thesis aims to develop a cooling system that uses an adsorptive chiller for cooling water and subsequent use of this cold water for air conditioning environment, theoretically and experimentally verifying the performance of adsorption refrigeration system, these devices have several advantages, among them, the use of clean energy such as solar. Brazil is a country with high rates of stroke, with an average capacity 16-20 MJ / year / h, so it becomes quite conducive to harnessing this energy, and to be contributing to the reduction of fossil fuel consumption and reduction of harmful gases to the environment. The proposed system consists of flat solar collectors, which are used to convert solar energy into thermal, being last transferred to a heat transfer fluid that circulates through the collector which is then stored in a boiler, or a thermal fluid, to be used whenever required for heating the bed adsorptive a chiller, which is composed of bed adsorptive the finned annular ducts involved with the adsorbent (silica gel). Many studies have been developed with the aim of increasing the performance of these systems, these studies have focused primarily on increasing the mass transfer and heat of adsorption beds and using systems which run continuously through the use of two adsorption beds which work in different phases. Experimental studies in porous beds featuring different configurations were performed, observing thus which present higher rates adsorbent, and subsequently applied this setting in the construction of the porous bed adsorptive chiller. A computational model was developed theoretically allowing you to check your system's performance.
O respectivo trabalho de tese visa desenvolver um sistema de refrigeração que utiliza um chiller adsortivo para resfriamento de água e posterior uso desta água fria para climatização de ambiente, verificando teoricamente e experimentalmente o desempenho do sistema de refrigeração por adsorção, estes dispositivos apresentam várias vantagens, entre elas, o uso de energia limpa, como a solar. O Brasil é um país que apresenta grande índice de insolação, com uma capacidade média de 16 a 20 MJ/ano/h, desta forma torna-se bastante propício o aproveitamento desta energia, além de estar contribuindo para a redução do consumo de combustíveis fósseis e redução de gases nocivos ao meio-ambiente. O sistema proposto é composto por coletores solares planos, que são usados para converter a energia solar em térmica, sendo está última transferida para um fluido térmico que circula pelo coletor que posteriormente é armazenado em um boiler, podendo este fluido térmico, ser usado sempre que necessário para o aquecimento do leito adsortivo de um chiller, sendo este leito adsortivo composto por dutos aletados na forma anular envolvidos com o adsorvente (sílica gel). Muitos trabalhos vem sendo desenvolvidos com o intuito de aumentar o desempenho destes sistemas, estes estudos estão concentrados basicamente no aumento da transferência de massa e calor dos leitos adsortivos e utilização de sistemas que funcione continuamente através do uso de dois leitos adsortivos que trabalham em fases diferentes. Ensaios experimentais com leitos porosos apresentando configurações diferentes foram realizados, observando deste modo, qual apresentaria maiores taxas adsortivas, sendo posteriormente aplicada esta configuração na construção do leito poroso do chiller adsortivo. Um modelo computacional foi desenvolvido permitindo verificar teoricamente o desempenho do sistema.
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Caglar, Ahmet. "Theoretical And Experimental Performance Analysis Of A Solar Assisted Heat Pump." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/3/12607898/index.pdf.
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In this thesis, performance of a heat pump aided by solar heating system with an evacuated tubular collector has been analyzed theoretically and experimentally. For this purpose, a domestic hot water heating system has been designed, constructed and tested. The evacuated tubular solar collector has been used to achieve higher collector efficiency in winter. The fraction of the solar energy utilized has been measured experimentally and estimated theoretically. Effects of various parameters have been investigated on the performance of the proposed system.
A mathematical model was developed to investigate the effects of different environmental, design and operational parameters on the solar heating system. In order to compare the obtained theoretical results with experimental ones, an experimental study has been carried out. For that, a number of experiments have been made at the solar house of the Mechanical Engineering Department of METU. An air-to-air heat pump was integrated with an evacuated tubular solar water heater unit (closed water circulation) and the performance of it has been studied experimentally. As a result of the experimental study, the maximum value of the coefficient of performance of the solar assisted heat pump used in this study was obtained as 4.85. The second law efficiency of the system was between 4.8-27.4 %.
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Hussen, Muaz Bedru. "STUDY OF A SMALL-SCALE COOLING SYSTEM BASED ON AN ICE-STORAGE AND A DC-POWERED VAPOUR COMPRESSION REFRIGERATION UNIT TO IMPLEMENT SOLAR ENERGY IN REMOTE AREAS." Doctoral thesis, Universitat Rovira i Virgili, 2020. http://hdl.handle.net/10803/670597.
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La refrigeració manté la qualitat sensorial del productes i minimitza la pèrdua en les cadenes de valor del fred. Les àrees remotes dels països en desenvolupament es caracteritzen principalment pels baixos nivells de tecnologia, accés limitat a la xarxa elèctrica i el predomini de les petites explotacions agrícoles com un desafiament.
El principal objectiu d'aquesta tesi és desenvolupar i caracteritzar un sistema de refrigeració modular multipropòsit basat en l'emmagatzematge de gel per a aplicacions de petita escala. El sistema d'emmagatzematge de gel va utilitzar un equip de refrigeració amb un compressor de corrent continu i velocitat variable. La càrrega de refrigerant i les dimensions de l'tub capil·lar es van optimitzar experimentalment per maximitzar el rendiment i evitar la caiguda de temperatura de la línia de succió. A més, es va avaluar experimentalment el rendiment de sistema sota diversos paràmetres.
Els usos de l'emmagatzematge de gel per a refrigeració de llet i aplicacions de càmeres frigorífiques també es van investigar experimentalment. Es van utilitzar deposits de llet convencionals en un bany de refredament aïllat, i en una cambra frigorífica dotada d'una unitat de fancoil amb els seus respectius sistemes experimentals.
En general, el treball de recerca realitzat en aquesta tesi aporta més coneixements sobre el desenvolupament de tecnologies de refrigeració baixes en carboni adequades per a països en desenvolupament.La refrigeración mantiene la calidad sensorial del producto y minimiza la pérdida en las cadenas de valor del frío. Las áreas remotas de los países en desarrollo se caracterizaron principalmente por bajos niveles de tecnología, acceso limitado a la red eléctrica y el predominio de las pequeñas explotaciones agrícolas como un desafío. El principal objetivo de esta tesis es desarrollar y caracterizar un sistema de refrigeración modular multipropósito basado en el almacenamiento de hielo para aplicaciones de pequeña escala. El sistema de almacenamiento de hielo utilizó un equipo de refrigeración con un compresor de corriente continua y velocidad variable. La carga de refrigerante y las dimensiones del tubo capilar se optimizaron experimentalmente para maximizar el rendimiento y evitar la caída de temperatura de la línea de succión. Además, se evaluó experimentalmente el rendimiento del sistema bajo diversos parámetros. Los usos del almacenamiento de hielo para refrigeración de leche y aplicaciones de cámaras frigoríficas también se investigaron experimentalmente. Se utilizaron cantaras de leche convencionales en un baño de enfriamiento aislado, y en una cámara frigorífica dotada de una unidad de fancoil con sus respectivos sistemas experimentales. En general, el trabajo de investigación realizado en esta tesis aporta más conocimientos sobre el desarrollo de tecnologías de refrigeración bajas en carbono adecuadas para países en desarrollo.
Refrigeration and cooling maintains the sensory quality of the product and minimizes the loss in cold value chains. Remote areas of the developing countries were mainly characterized by low levels of technology, limited access to modern energy and dominance of small-holder farms as a challenge. Hence, the main objective of this thesis is to develop and characterize a modular-multipurpose cooling system based on an ice-storage for small-scale applications. As part of the experimental system, the ice storage with a variable speed DC-compressor was developed and fabricated. The refrigerant charge and the capillary tube dimensions were experimentally optimized to maximize performance and avoid suction line temperature drop. Moreover, performance of the system under varying parameters was evaluated. Uses of the ice storage for milk cooling and cold room applications were also experimentally investigated. Conventional milk-cans with insulated box and a heat simulated room with a FCU were utilized as respective experimental systems. Chilled water recirculation rates, ice-storage energy density, and air flow rate across FCU were varied as main experimental parameters. Improvement of the ice production technique and corresponding performance data obtained were among main contributions of this research. In general, the research work performed in this thesis contributes more knowledge on development of low-carbon cooling technologies suitable for developing countries. Therefore, piloting and field testing of the technology are among major recommendations for future work.
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Vodianitskaia, Paulo José. "Estudo teórico e experimental de um chiller a adsorção para sistemas de ar condicionado solar." Universidade Federal da Paraíba, 2016. http://tede.biblioteca.ufpb.br:8080/handle/tede/8957.
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Human society in general, and Brazil in particular, face severe scenarios, from restricted energy supply to climate change and other challenges for a sustainable future. Thus renewable energy alternatives offering lower environmental and social impacts such as solar energy are subjects of special interest. The present work refers to this challenging picture. As a way to apply renewable energy, solid adsorption air conditioning favors energy security and contributes to the mitigation of greenhouse gases due to the lower dependency in regard to primary energy. It allows to a reduction on demand peaks, and to a natural adjustment between supply and demand levels. Moreover, the materials used in such systems present low environmental impact, especially the refrigerant fluid: water, abundant in nature and non-toxic. The general objective of this work is the development of an experimental chiller using local technology, resulting in a state-of-the-art performance level. Specific objectives include the development of a representative model for the adsorber, the comparison of adsorption kinetics between two fractions of silica gel, the evaluate how specific heat and mass diffusion influence the chiller performance. The numerical model contributions are related to the use of specific heat of the adsorbed phase, and mass diffusion for cycle characterization. The model resulted representative of the experimental behavior. COP was found to be 0,53 and SCP is 68 W/kg for 2.0 mm beads. These values are comparable or higher to the ones reported in literature for silica gel in loose grains. The use of a crushed silica gel of smaller size (026 mm) resulted in lower level of performance, which is probably due to the reduction of porosity after crushing.
A humanidade em geral, e o Brasil em particular, enfrentam duros cenários de restrição de energia, mudanças climáticas e outros desafios para um futuro sustentável. Assim, alternativas de energia renovável, de menor impacto ambiental e social, como a energia solar, se tornam objeto de especial interesse. É dentro desse quadro desafiador que se insere o presente trabalho. Como aplicação de energia renovável, a climatização a adsorção se configura como fator de segurança energética e contribui para a mitigação das emissões de gases efeito estufa, ao reduzir a dependência de energia primária. Conduz à redução de picos de demanda, e apresenta um ajuste natural entre demanda e oferta. Além disso, os materiais utilizados são de baixo impacto ambiental, especialmente o refrigerante: a água, abundante na natureza e atóxica. O objetivo geral do presente trabalho é desenvolver um chiller experimental com tecnologia nacional que permita atingir níveis de desempenho comparáveis ao estado da arte. Os objetivos específicos são: desenvolver um modelo representativo para o reator adsortivo, comparar a cinética de adsorção em duas granulometrias de sílica gel, e estudar a influência do calor específico e da difusão de massa. O modelo numérico trouxe como contribuições originais considerar o calor específico da fase adsorvida e a difusão de massa para caracterização do ciclo. O modelo resultou representativo do comportamento verificado experimentalmente. Foram obtidos COP de 0,53 e SCP de 68 W/kg para partículas de adsorvente de 2,0 mm, valores comparáveis ou superiores aos registrados na literatura para sílica gel em grãos soltos. A fração de granulometria menor (0,26 mm) teve desempenho inferior, provavelmente devido à redução de porosidade após britagem.
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Forson, Francis Kofi. "Modelling and experimental investigation of a mixed-mode natural convection solar crop dryer (MNCSD)." Thesis, De Montfort University, 1999. http://hdl.handle.net/2086/4201.
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Meyer, Adriaan Jacobus. "Steam jet ejector cooling powered by low grade waste or solar heat." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/2012.
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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
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Alvares, Sergio Gontijo. "A Computer aided assessment study on the viability of a solar powered single stage aqua-ammonia absorption refrigeration system for milk cooling at remote Brazilian dairy farms /." [S.l.] : [s.n.], 1985. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=7717.
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Yen, Shih-Ming, and 顏仕銘. "Study of Independent Mobile Solar Refrigerator." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/71416004072669053936.
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碩士國立臺灣大學
機械工程學研究所
94
The main purpose of the research presented is designing an Independent Mobile Solar Refrigerator, which can operate independently without other electric power, easier to move and combine. System sizing is determined with local weather data, characteristic of load operation, and the efficiency of solar cell and lead-acid battery. In the research, design and make a 60 liter prototype, the combining process only needed 10 minutes, and the controller can change compressor speed to control refrigerator temperature in 1℃. In the sunny day, there is no probability to loss load, and in the cloudy day, the average power consumption less than 10W. If the battery capacity is 80% , the compressor can operate about 3 cloudy days.
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Hsieh, Yueh-Chou, and 謝岳洲. "A Study of the absorption refrigerator with solar thermal energy." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/99605067771977297310.
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碩士東南科技大學
機械工程研究所
103
In recent years, the government policy is to encourage low energy consumption industry, or the better the industry no any energy consumptionsuch asthe tourism industry,for conventional refrigeration and air conditioning industry must face the innovation and transformation. Comparing the conventional compressor type refrigerators,the absorption refrigerators are quiet, there are no annoying noises.Some superior tourist hotel considering housing quality to the customer, it is the first priority to use the absorption refrigerator.But conventional absorption refrigerator still need electric power to heat generator.For energy saving, combining the solar thermal energy with the absorption refrigeration cycle is a way to reduce electric power demand.In this article,the ammonia - water absorption refrigerator is used.The solar planar collector, the pastusing, is change to reflection centralized heating collectors, and the high specific heat capacity kerosene is used as a heat transfer medium. The experimental results show that the absorption refrigerator with solar thermal energy in this article is still low noise and it is energy saving.
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Nwamba, Khombomuni Jerry. "The design and evaluation of a solar-powered adsorption refrigerator for African conditions." Thesis, 2008. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000361.
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Thesis (MTech. degree in Mechanical Engineering)--Tshwane University of Technology, 2008.The sun is known to be the main source of energy to earth. It is further more outstanding since it is clean and comes to the earth with no costs. However, mankind does not utilize most of this precious energy effectively. In South Africa, emerging farmers need their agricultural products preserved in storage or in transit. Solar adsorption cooling machines would be of benefit to these farmers as they do not require any additional source of energy and are completely autonomous. This study presents a theoretical and experimental analysis of a solar assisted adsorption fridge, as well as the cost effectiveness when compared with the vapour compression method. The cooling machine was designed, developed and tested. It does not contain any moving part; nor consume any mechanical energy. The results show that the refrigerator can chill 25 litres of water from 35 to 5 °C per day. Vegetables and fruits with preservation temperatures in the range 4 -10 °C are within the scope of the present system. The best useful cooling obtained was 1785 kJ per day, and the best coefficient of performance was 0.058.
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Kandhway, Vikash. "Performance Analysis Of A Photovoltaic Powered Cold Store." Thesis, 1997. http://etd.iisc.ernet.in/handle/2005/2146.
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WU, MING-JIA, and 吳明家. "The Study of Thermoelectric Effect Refrigeration System with Solar Energy." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/81087306736274190472.
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碩士大葉大學
機械與自動化工程學系
104
This paper is meant to discuss the system configuration of the Thermoelectric Effect wafer in refrigeration system with solar energy and the effect of weather changes on Thermoelectric Effect refrigeration system. In this research, the Thermoelectric Effect wafer is put into the interlayer of a Styrofoam, with plastic-coated for insulation. The cold side of the wafer with Aluminum fins faces inside, and the hot side of the wafer is put outside with Aluminum fins, radiating with fans. The experimental configuration uses 54 solar panels connected in series with 12V75D lead-acid batteries and then connects to the Thermoelectric Effect wafers’ positive and negative, using the steady flow characteristic of lead-acid batteries to limit the solar power which changes a lot in voltage and current in a range that the thermoelectric element is effective in order to observe the impact of weather changes on the input power and the output power and the actual relationship between the battery voltage changes the capacitance changes. Dividing the total electric power by the total charging power to calculate the charging efficiency of 54 solar modules toward lead-acid batteries, the efficiency is between 6.93 percent to 8.47 percent, and the average efficiency is 7.42 percent. According to the data, when the lumen rises between 1.4 times to 3.87times, the input current rises between 1.45 times to 3.97 times, and the variation width of the input voltage, output voltage and output current change is between 1.03 times to 1.18times, the variation width of the input current and lumen changes are similar. In the experiment, the temperature difference in an hour is between 13.37 ℃ to 16.37 ℃, and the COP is between 0.20 to 0.28. In this experiment, the obtained electric power, output electric power, and the change in the voltage of the batteries are recorded. When the stored electricity of batteries is 88.66 percent, the difference is between 0.80 to o.91 percent; when the stored electricity of batteries is 95 percent, the difference is between 2.12 to 2.26 percent. Therefore, the more the differences approach to saturation, the greater the value of the differences are.
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Santos, Nelson de Sousa Pedro dos. "An investigation into the thermo-fluid design and technical feasibility of a practical solar absorption refrigeration cycle." Thesis, 2010. http://hdl.handle.net/10210/3077.
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M.Eng.The need and problem was originated from the trends of the earths dwindling energy resource. As time progresses humans are becoming more aware of need to use so called “alternative energy sources” to alleviate the main energy converters i.e. power stations. The student was tasked with investigating the thermal performance of a solar powered refrigeration cycle (prototype) that could: produce enough refrigeration effect that it replaces the standard home vapour compression unit, used for cooling or freezing of foods, heats up a geyser sufficiently to have hot water for a common house hold, has excess energy to heat or cool liquid or air based environments and has the potential to lower the electrical bill of a house. The introductory step was to obtain the thermo fluid properties of aqua ammonia solutions. A setback came about when determining the aqua ammonia properties. There were too many conflicting properties being yielded by six different authors. In an attempt to gain confidence in only one author a comparison table was prepared. The table compared the six authors to each other. By looking at all the values compared it brought great clarity to the problem. When continuing the research into the fundamental law approach of solving for the cycle new findings were made. Initially very little comprehensive studies were done which explained in fundamental laws to solve for the absorption cycle. After extensive reviewing of a detailed study on how to solve for absorption refrigeration cycles, then it was able to begin improving on the thermo – fluid design of the cycle. As cycle and component design began to progress the train of thought began to steer in a direction. Each component needed to be detail designed. The advantage of having each component specifically catered for in the cycle design was that it would increase the cycle efficiency. In this way it would ensure that during the concept generation phase the functioning of each component was clear, thereby enabling a clear understanding of how components would compliment each other in a cycle. A mode of solving for the cycle was to endeavour that all parameters could be calculated unambiguously, with the aid of computerisation. Testing was carried out on a real life commercial thermal siphoning machine in order to realistically understand how absorption refrigeration works and gain experience. At the end of the study the most important result is that the dissertation research shows strong evidence that it will be possible to create a device which can fulfil the four tasks listed above. Another result is a program which is a refined cycle design of the pump absorption type refrigeration. The program solves for points along the cycle. Lastly it was found that even though EES was the simpler program to use for aqua ammonia solution properties it was the only program which catered for sub cooling and super heating.
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Pais, Joana Isabel Pereira Malheiro. "Simulation and numerical optimization of diffusion-absorption refrigeration (DAR) cycle powered by solar energy." Dissertação, 2009. http://hdl.handle.net/10216/58030.
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Oliveira, João Filipe Morgado. "Conceção técnica e avaliação económica de um veículo solar para venda de produtos refrigerados." Master's thesis, 2015. http://hdl.handle.net/1822/39524.
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Dissertação de mestrado integrado em Engenharia MecânicaA presente dissertação aborda o estudo e desenvolvimento de um veículo parcialmente alimentado com o recurso a energia fotovoltaica, para venda de produtos refrigerados. Este projeto surgiu em parceria com a empresa Dst Solar S.A. no âmbito de um estágio curricular efetuado durante esta dissertação. O objetivo primário deste projeto é apresentar as potencialidades do uso da energia fotovoltaica com vista a incentivar o uso e a generalização desta tecnologia na sociedade. Esta dissertação foca-se essencialmente no módulo energético do sistema, o qual foram desenvolvidas cinco (5) soluções possíveis com tensões do sistema de 12V e 24V. Esta dissertação não se propõe a apresentar o projeto completo, mas a descrever os principais aspetos envolvidos, com destaque para o sistema de alimentação solar, composto por um módulo fotovoltaico, baterias e controlador de carga. Desta forma, a dissertação inicia-se com a descrição das principais caraterísticas dos módulos fotovoltaicos, das baterias e dos controladores de carga, com foco para os sistemas off-grid. São ainda abordados conceitos relativos ao cálculo de ganhos térmicos em sistemas de refrigeração, como forma de estimar os consumos inerentes ao funcionamento da arca frigorífica, para esta aplicação em particular. A metodologia de projeto aplicada visa a utilização de uma abordagem sistemática e objetiva, na qual são estabelecidos os objetivos, estrutura de funções e subfunções, as especificações e os requisito que o projeto deverá ter. A partir das especificações e objetivos previamente estabelecidos, procede-se a uma estudo da energia produzida pelo módulo fotovoltaico e do consumo que o equipamento de refrigeração deverá ter. Conclui-se que a energia produzida seria suficiente para alimentar o equipamento de refrigeração para os meses compreendidos entre Maio e Setembro durante o horário de funcionamento estabelecido. Seguidamente procede-se ao desenvolvimento das soluções para o sistema de alimentação solar, as quais são posteriormente alvo de uma avaliação com recurso a pontuações de “utilidade” em que, a cada critério (objetivo) é atribuído um peso relativo e uma pontuação. Conclui-se que a melhor solução será a solução com baterias de lítio que, apesar de um investimento inicial mais elevado, apresenta vantagens a nível de peso e tempo de vida útil, sendo esta a solução tecnologicamente mais evoluída.
The presente dissertation deals with the study and development of a vehicle partially powered with photovoltaic energy for sale of chilled products. This project was created in partnership with the company Dst Solar S.A. under an intership made during this dissertation. The primary objective of this project is to present the potencial use of photovoltaics in order to encourage their use and generalization of this technology on society. This dissertation focuses on the energy system module, which were developed five (5) potential solutions with system voltages of 12V and 24V. This dissertation proposes not to submit the complete project, but to describe the main aspects involved, especially the solar power system, formed by a photovoltaic panel, batteries and charge controller. In this way, the thesis will describe the main characteristics of PV modules, batteries and charge controllers, focusing on off-grid systems. Additionally are discussed conceps relating to the calculation of thermal gains in refrigeration systems, as a way of comsumption estimation, inherent to the operation of the freezer. The design methodology applied uses a systematic and objective approach, which are estabilished the goals, functions and subfunctions structure, specifications and requirements that the project should obey. From that specifications and objectives previously established, its made a study of the energy produced by the PV module and consumption that refrigeration equipment should have, for this particular application. It is concluded that the energy produced would be enough to power the refrigeration equipment during the operation hours (between 9am and 6pm) for the months between May and September. Next, comes the development of the solutions for the power supply, and then its made an evalution based on scores of “utility” where each criterion (objetive/goal) is assigned a relative weight and a score. It is concluded that the best solution is the solution with lithium-ion battery that, despite having a higher initial investment, offers advantages in terms of weight and service life, being this the most technologically evolved solution. It is also made na economic feasibility analysis to assess whether the investment will be profitable concluiding that at first sight this is economically viable.
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Pais, Joana Isabel Pereira Malheiro. "Simulation and numerical optimization of diffusion-absorption refrigeration (DAR) cycle powered by solar energy." Master's thesis, 2009. http://hdl.handle.net/10216/58030.
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Kantole, Joseph Basakayi. "Modelling and design of a latent heat thermal storage system with reference to solar absorption refrigeration." Thesis, 2012. http://hdl.handle.net/10210/7883.
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M.Ing.The research in this thesis focuses on the theoretical thermal modelling and design of a Latent Heat Storage system (LHS) for an absorption refrigeration machine. A shell-and-tube latent heat storage exchanger retaining any excess solar thermal energy is selected. Here, solar thermal energy supplied by a collector is transferred to and stored by the LHS. During low insolation, stored thermal energy is transferred by a Heat Transfer Fluid (HTF) into the generator, a component of an Ammonia Absorption Refrigerator (AAAR), to ensure efficiency of the cooling cycle. The shell-and-tube LHS contains Phase Change Material (PCM) which fills space outside the tube heat exchangers. The HTF flowing through the tubes exchanges thermal energy with the PCM. The selection of a suitable PCM for a LHS is based on several factors. A primary criterion for an efficient, reliable storage unit is the correct melting point of the PCM at a desired operating temperature of the heating application. An analytical model describing both the freezing process in the PCM and increased HTF temperature in the tube heat exchangers is investigated. The model is developed using energy balance equations. It is solved in terms of dimensionless parameters. The thermal resistance of the tube heat exchangers is considered for this model. From the result of the analytical model, the design approach to size the LHS is provided and the different steps are given in order to determine the volume, mass, number of tube heat exchangers, inner and outer radius of the tube heat exchangers and other parameters of the LHS. The dimensions of LHS are given as a function of a storage period, PCM properties, HTF properties, inner and outer radius of the tube heat exchangers, material of construction of the tube heat exchangers and the nature of load on the heating process. Simulations from the analytical model developed are provided for the output thermal parameters of the storage system. These thermal parameters of the shell-and-tube latent exchanger are given in terms of the HTF outlet temperature, the front solidification of the PCM and the heat transfer rate during the solidification process of the PCM. A case study to demonstrate the application of the design approach with respect to the size shell-and-tube latent heat exchanger is provided.The integration of the tube heat exchangers thermal conductivity in the modelling of the LHS resulted in an increase of 2% in mass of the storage material compared to an analytical model neglecting the thermal conductivity of the tube heat exchangers. The results of the model developed compared well with the results obtained from other analytical models at similar operating conditions.
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Chien, Zi-Jie, and 簡子傑. "The Application Research of UsingRenewable Energy Source (Solar Energy andWind Force) in Refrigeration and Heat Pump." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/p8p32p.
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博士國立臺北科技大學
冷凍空調工程系所
102
The goal of this dissertation is to experimentally investigate the solar absorption refrigerator, the solar thermoelectric cooler, and the wind directly forced heat pump. The specific tasks of this study include the following issues. In emergency situations, the systems can be powered by solar energy when the grid power is lacked. In the evenings or rainy days, the systems can be powered by storage battery. The storage battery can be powered by the grid power supply when the supply is available and the battery can be full charged as a backup supply. This study conduct experimental explorations on cooling performance of the thermoelectric cooler being driven by solar cells, as well as comparison results to the performance being driven by fixed direct current. Solar energy is clear and limitless, and can be collected by solar cells. We use solar cells to drive thermoelectric cooler, where the cold side is connected to the water tank. This study proposes a new technique to directly adopt the wind force to drive heat pump systems, which can effectively reduce the energy conversion losses during the processes of wind force energy converting to electric energy and electric energy converting to kinetic energy. The operation of heat pump system transfers between the chiller and heat that is controlled by a four-way valve. In solar absorption refrigerator performance test, the alternation of solar irradiance 550 to 700w/m2 is adopted as solar energy source and 500ml of ambient temperature water is adopted as the cooling load. After 160 minutes, the proposed refrigerator can maintain the temperate at 5 to 8℃, the coefficient of performance (COP) of NH3-H2O absorption refrigerator system is about 0.25. In solar thermoelectric performance test, it is found that 250 ml water can be cooled from 18.5℃ to 13℃, where the corresponding coefficient of performance (COP) is change between 0.55 and 1.05, when the solar insolation is ranged between 450 W/m^2 and 1000 W/m^2. In wind directly forced heat pump performance test, the experimental results indicated that the average value for cool water producing efficiency of 54.38% in the outdoor temperature is 35ºC and the indoor temperature is 25ºC and the hot water producing efficiency of 52.25% in the outdoor temperature and the indoor temperature both are 10ºC. From our experimental results, an absorption refrigerator driven by solar cell can be expected to be used in remote areas or for refrigeration of food and beverages in outdoor environments or activities. The thermoelectric cooler driven by solar cell is feasible and effective for energy saving issues. Heat pump directly driven by wind energy can improve the efficiency of heat pump indirectly driven by wind energy.