This research is aimed to study the system performance for a large solar hot water system constructed by connecting a series of small domestic natural circulation systems. There are few studies on this type of large solar hot water system available. The major concern is that when circulation pump is on, there forms a short flow between inlet and outlet of each storage tank of natural circulation solar hot water unit. Therefore, water does not have chance to flow though the collector by thermosyphon and system performance can be lowered down drastically. This thesis presents the numerical simulation study for the control and system operating parameters effects on the system performance to provide important information both for users and system designers.

Thesis (MTech(Electrical Engineering)) -- Cape Peninsula University of Technology, 2014 / Today the building energy modeling industry is facing a number of challenges, the advanced programs or methods developed for building energy modeling, are very technical and complex to be used, especially for earlier designs, and the easy programs or methods are not accurate. Moreover, more than a hundred programs developed for energy modeling, have been used in the same building, but most of the time the results differed by about 30%. That is why this thesis has developed a new building energy model in System Modeling Language (SysML), in order to meet, at the same time, the accuracy and the simplicity to be used for future and existing buildings. In this thesis, SysML has been used to develop an energy model and to set up an automation system to the existing building. SysML can do more than simulations, but this thesis is limited to only the simulations steps by using easy applications of SysML and fewer diagrams which could develop in a complete building energy model. SysML is the extension of Unified modeling Language (UML), which uses fewer diagrams than UML. SysML is simple, open and more flexible to be used in any Engineering System. The previous chapter describes SysML and gives the overview and the platform of SysML. The simulations of SysML in this project have been developed through Enterprise Architect and Mat lab software. The inputs used to simulate the program are the parameters of the existing building chosen for modeling that is a student residential building complex located in Stellenbosch, Western Cape in South Africa. Automation system program used in this thesis was based on the norms and building standards of South Africa, renewable energy and the requirements of the buildings’ occupants, in order to meet energy efficiency and safety of the occupants.

Submitted by CRISTIANO PANSANATO null (pansanato.cristiano@gmail.com) on 2017-01-12T21:03:45Z No. of bitstreams: 1 Cristiano Pansanato - Dissertação de Mestrado - 2016.pdf: 4251034 bytes, checksum: f23b5995e15e89e575b69d4b742fb372 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-01-16T18:33:30Z (GMT) No. of bitstreams: 1 pansanato_c_me_bauru.pdf: 4251034 bytes, checksum: f23b5995e15e89e575b69d4b742fb372 (MD5) / Made available in DSpace on 2017-01-16T18:33:30Z (GMT). No. of bitstreams: 1 pansanato_c_me_bauru.pdf: 4251034 bytes, checksum: f23b5995e15e89e575b69d4b742fb372 (MD5) Previous issue date: 2016-12-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A busca mundial for fontes de energia que garantam um crescimento sustentável tem marcado o século XXI. Nesse cenário, o Brasil é beneficiado, com diversas fontes de energias viáveis nas condições atuais e outras promissoras num cenário de médio e longo prazo. A utilização da energia solar convertida em energia térmica ou elétrica apresenta-se como uma destas alternativas. Explorar a energia solar de forma viável economicamente e melhorar a eficiência de captação e transformação são os grandes desafios que se apresentam. Neste contexto, este estudo se propôs a analisar experimentalmente o desempenho de um Sistema Acoplado, composto por coletores planos com e sem cobertura. O objetivo é reduzir o custo de implantação de um sistema de aquecimento, uma vez que o os coletores sem cobertura são mais baratos. Além disso, dependendo das características de implantação, é ainda possível aumentar a eficiência global do sistema através de um pré-aquecimento da água no coletor sem cobertura, aproveitando a maior eficiência térmica para temperaturas de operação próximas a do ambiente. Para estudo do Sistema Acoplado, um outro sistema composto apenas por coletores com cobertura foi montado e denominado Sistema Simples. Desta forma, com os dois aparatos montados e devidamente instrumentados foi possível obter resultados para as mesmas condições ambientais de teste. Assim, diversos esquemas de controle também puderam ser testados e analisados tanto na operação do Sistema Acoplado como do Sistema Simples. Resultados comparativos avaliando as condições de saída, energia útil e armazenada e eficiências térmicas foram apresentados e comparados para os dois sistemas. / The global search for energy sources that ensure sustainable growth has marked the 21st century. In this scenario, Brazil is benefited, with several viable sources of energy under current conditions and other promising sources in a medium and long-term scenario. The use of solar energy converted into thermal or electric ones presents itself as one of these alternatives. Using solar energy in a cost-effective way and improving the performance for capturing and transforming are the major challenges nowadays. In this context, this study proposed to analyze experimentally the performance of a Coupled System, composed by glazed and unglazed flat collectors. The purpose of this system is to reduce the installation costs of a heating system, since the unglazed collectors are less expensive. In addition, depending on its implementation characteristics, it is possible to increase the overall efficiency of the system by preheating the water in an unglazed collector, taking advantage of its higher thermal efficiency at nearby operating and ambient temperatures. For analysis of Coupled System, another system composed only of glazed collectors was assembled and denominated as Simple System. In this way, with the two devices mounted and instrumented some results can be obtained for the same environmental test conditions. Thus, several control schemes could also be tested and analyzed in the operation of both systems. Comparative results evaluating the output conditions, useful and stored energy and thermal performances are presented and compared for the systems.