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Desempenho de sistemas de condicionamento de ar com utilização de energia solar em edifícios de escritórios.; Performance of solar air conditioning systems in office buildings.

Ara, Paulo José Schiavon
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 14/12/2010 PT
Relevância na Pesquisa
56.38%
A preocupação energética tem impulsionado a humanidade a buscar alternativas sustentáveis de energia. Neste contexto, os edifícios de escritórios têm um papel importante, em especial, devido ao elevado consumo de energia dos sistemas de condicionamento de ar. Para esses sistemas, a possibilidade de utilização de energia solar é uma alternativa tecnicamente possível e interessante de ser considerada, principalmente porque, quando a carga térmica do edifício é mais elevada, a radiação solar também é mais elevada. Dentre os sistemas de condicionamento de ar solar, o sistema térmico - que associa coletores solares térmicos com chiller de absorção - é o mais disseminado, na atualidade. Entretanto, dependendo do caso, outras tecnologias podem ser vantajosas. Uma opção, por exemplo, no caso de edifícios de escritórios, é o sistema elétrico - que associa painéis fotovoltaicos ao chiller convencional de compressão de vapor. Neste trabalho, para um edifício de escritórios de 20 pavimentos e 1000 m2 por pavimento, na cidade de São Paulo, no Brasil, duas alternativas de ar condicionado solar tiveram seus desempenhos energéticos analisados: o sistema térmico - com coletores solares térmicos somente na cobertura e o sistema elétrico - com painéis FV somente nas superfícies opacas das fachadas. Para isso...

Life cycle assessment of solar thermal systems

Fernandes, V.; Mateus, Ricardo; Bragança, L.; Silva, Sandra Monteiro; Almeida, Manuela Guedes de
Fonte: ITeCons Publicador: ITeCons
Tipo: Conferência ou Objeto de Conferência
Publicado em /12/2014 ENG
Relevância na Pesquisa
66.19%
The better understanding of cost-benefit, economic and environmental performances of solar thermal systems (STSs) is crucial for designers to be able to take a conscious and weighted decision about the installation of these systems. Therefore the goal of this research was to create a methodology for designers to support decision-making in the selection of the most adequate STS for a project and as result to contribute to a more sustainable built environment. This methodology allows the calculation of the potential environmental impacts, such as the global warming potential, acidification, eutrophication, ozone depletion, embodied energy, amongst others, together with the life-cycle costs resulting from the implementation of STSs in buildings. The system boundary includes the production of the various parts of the solar thermal system, such as the solar collector and the hot water tank, the assembly process, the maintenance stage, the auxiliary energy consumption and the end of life of this system. In the economic analysis, both initial and maintenance costs are considered together with the cost of the auxiliary energy. At the end, it is possible to quantify carbon, energy and cost payback periods. One practical application of the methodology will be carried out in the end of this work...

On the sustainable development of solar thermal obligations in buildings in the framework of the Portuguese case

Prates, Manuel João Lopes; Costa, J. Cruz; Mendes, J. Farinha; Carvalho, M. J.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em 07/10/2008 ENG
Relevância na Pesquisa
66.34%
This paper starts remembering the steps given in Portugal to prepare the introduction of a solar thermal obligation. Next, it presents a description of the present legislation related to the Solar Thermal Obligation (STO) and to other incentive measures for growth of the solar thermal market in Portugal. The main problems with implementation of the new regulation are analysed and systematized. Based on the acquired knowledge, further actions are presented to guarantee the success of Solar Thermal Obligation, namely proposals for updating the obligation in conformity with best practice for solar thermal installations and taking into account the new realities upcoming from the actual solar thermal

The contribution of Portuguese solar thermal program on the country energy efficiency

Salgueiro, Andreia; Mendes, J. Farinha
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /09/2010 ENG
Relevância na Pesquisa
66.12%
The solar radiation available all over the year is a strong reason to promote the utilization of this resource and during the year 2009, a new program based on a 50% subside, was promoted by the Portuguese government. As expected, a significant number of new installations were realized. In 2009 the state program provided the installation of more than 50,000 systems. The program can be considered a success on the Portuguese solar thermal collector market.

On the Best Practice Implementation of Solar Thermal Obligations. The ProSTO EU Project and the Portuguese experience

Prates, Manuel João Lopes; Mendes, J. Farinha; Carvalho, M. J.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /11/2009 ENG
Relevância na Pesquisa
66.27%
Based on the work that it is running within the ProSTO EU project (http://www.solarordinances.eu/), this paper presents a tentative approach to the best way for a successful implementation of a solar thermal obligation (STO) in a community. The EU framework, and base line assessment – including success factors and performance indicators were presented by the ProSTO coordinator elsewhere [1]. The Portuguese case was presented elsewhere too [2]. Here, all the complete set of measures that must be taken to succeed, will be presented. The experience shows that it is necessary to get an integrated “policy package” in the way of “zero building emissions”, around the kernel key point of clear requirements, aiming energy savings, namely for energy demand limitation, and energy efficiency of thermal installations. A parent kernel key point of this “policy package” is quality: certification of thermal solar system and components – solar collectors, factory made systems, and custom built systems; planner, designer and installer certification; technical impositions in the regulations (supported by a very consistent manual of actual good practices for solar thermal applications, with a flexible method to follow new developments); guarantee impositions (maintenance contract). All relevant documents of these quality items must be integrated in the Building Use Manual for easy management. Another kernel key point...

Solar thermal collector yield: experimental validation of calculations based on steady-state and quasi-dynamic test methodologies

Horta, Pedro; Carvalho, M. J.; Fischer, S.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em 07/10/2008 ENG
Relevância na Pesquisa
66.24%
The characterization of collector efficiency is the fundamental tool for long term calculation of collector yield. It is, thus, one of the most important inputs in software tools aiming the design of solar thermal systems. Presently two test methodologies are available for characterization of the efficiency of glazed collectors: i) steady state test and ii) quasi-dynamic test, methodologies based in different model approaches to a solar collector, providing different collector efficiency curve parameters and, consequently, imposing different power calculation algorithms. Moreover, Horta et al (2008) demonstrated that the use of the collector efficiency curve derived from steady state test method is not enough for a thorough characterization of the long term performance of a collector. The present work takes into account the introduction of the above referred test methodologies in the European Test Standard for Solar Thermal Collectors, and aims at clarifying how each test results should be used in long term thermal performance calculations. The paper presents a synthesis of the different efficiency parameters provided by each test methodology and corresponding algorithms, applicable in the calculation of delivered power. Application of these algorithms to two days of measured data allows for a comparison of the results obtained with these different methodologies. For validation purposes...

Latest developments in the field of solar thermal standardisation

Fischer, S.; Carvalho, M. J.; Kovacs, P.; Malenkovic, I.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2011 ENG
Relevância na Pesquisa
66.26%
The European project QAiST-―Quality Assurance in Solar Thermal Heating and Cooling Technology‖ funded by the Intelligent Energy Europe program and by the participating countries, gathers 15 participating organizations including the European Solar Thermal Industry Federation ESTIF and major testing and research institutes in Europe. The objective of the project is to enhance the competitiveness of the European Solar thermal industry and further increase consumer confidence through improved standards and certification schemes, harmonization in testing and certification and a wide dissemination of the quality concept throughout Europe. Global harmonization in collector standards and certification is also on the QAiST agenda and has taken a large step forward through CEN/ISO cooperation and a strong European representation in the IEA SH&C task 43.

European round robin test on solar collectors and solar thermal systems

Fischer, S.; Carvalho, M. J.; Weißmüller, C.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2011 ENG
Relevância na Pesquisa
66.34%
Within the European project QAiST (Quality Assurance in Solar Thermal Heating and Cooling Technology)a Round Robin test on solar collectors and solar thermal systems is carried out in the years 2010 and 2011. For two different collector types, one flat plate collector and one evacuated tubular collector with CPC reflector, thermal performance tests according to EN 12975-2 (EN 12975, 2006) are carried out by 12 different test institutes throughout Europe. The two different solar thermal systems, one thermosiphon system and one system with forced circulation are subject to a thermal performance test according to EN 12976-2 (EN 12976, 2006) and are tested by 9 different test institutes.In order to finish the Round Robin test within two years despite of the high number of participants, the following procedure was applied: Each participant received in the year 2010 samples of the two different collector types and of the two solar thermal system types respectively. After testing, the samples have been sent to the next test institute to be tested within the year 2011. Thus all institutes are testing identical collectors and system types taken out of the same production batch, however each unique collector or system is only tested by two institutes. For the first time Round Robin tests on solar thermal products are evaluated by an independent institute (Institut für Eignungsprüfung) using the acknowledged procedures for the evaluation of proficiency tests.This paper presents some of the midterm results of the Round Robin test in an anonymous and standardised way.

Components of solar thermal systems

Mendes, J. Farinha; Carvalho, M. J.; Schossig, Peter
Fonte: Springer-Verlag/Wien Publicador: Springer-Verlag/Wien
Tipo: Parte de Livro
Publicado em //2013 ENG
Relevância na Pesquisa
66.2%
The heat production sub-system is the part of the overall system which provides heat to a thermally driven air-conditioning system. With regards to the solar-driven equipment, the solar collector is the main component of the sub-system. A brief review on the present state-of-the-art with respect to performance characteristics and available certification schemes of solar collectors is given in the following chapter. Besides the solar collector field, the storage unit and the back-up heat source unit are also important components. An overview of these items and the identification of other relevant components of the solar thermal system are given in the following sections.

Application of chemical looping combustion for solar thermal energy storage

Jafarian, S.; Arjomandi, M.; Nathan, G.; Nasehi, S.
Fonte: The Combustion Institute; Australia Publicador: The Combustion Institute; Australia
Tipo: Conference paper
Publicado em //2011 EN
Relevância na Pesquisa
56.32%
In this paper a solar hybrid chemical looping combustion (CLC) system for solar thermal energy storage (TES) is proposed. For those combinations of fuels and metal oxides in CLC systems with an endothermic reaction, there is a potential to utilize solar thermal energy to drive the CLC reactions and so to allow the solar thermal energy to be stored as a reduced metal oxide. The application of oxygen carrier particles for solar thermal energy storage is also possible. A novel solar hybrid system is proposed and assessed, in generation cycles to enable base load generation from solar thermal energy. For this purpose three reservoirs are added to a CLC system to store the oxygen carrier particles and a cavity solar reactor is used as the fuel reactor. The ASPEN PLUS software is used to simulate the hybrid process. Basic validation of the model is performed using independent simulation result reported previously and the model is then used to calculate operating temperature, solar efficiency and solar fraction of the system. The results identify potential benefits from the solar hybridization of a CLC system.; S.M. Jafarian, M. Arjomandi, G. Nathan and S.M. Nasehi

A hybrid solar and chemical looping combustion system for solar thermal energy storage

Jafarian, S.; Arjomandi, M.; Nathan, G.
Fonte: Elsevier Sci Ltd Publicador: Elsevier Sci Ltd
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
Relevância na Pesquisa
56.3%
A novel hybrid of a solar thermal energy and a chemical looping combustion (CLC) system is proposed here, which employs the oxygen carrier particles in a CLC system to provide diurnal thermal energy storage for concentrated solar thermal energy. In taking advantage of the chemical and sensible energy storage systems that are an inherent part of a CLC system, this hybrid offers potential to achieve cost effective, base load power generation for solar energy. In the proposed system, three reservoirs have been added to a conventional CLC system to allow storage of the oxygen carrier particles, while a cavity solar receiver has been chosen for the fuel reactor. The performance of the system is evaluated using ASPEN PLUS software, with the model being validated using independent simulation result reported previously. Operating temperature, solar efficiency, solar fraction, exergy efficiency and the fraction of the solar thermal energy stored for a based load power generation application are reported.; Mehdi Jafarian , Maziar Arjomandi, Graham J. Nathan

Assessment of the use of solar thermal collectors for desalination

Horta, Pedro; Zaragoza, G.; Alarcon-Padilla, D.C.
Fonte: Taylor & Francis Publicador: Taylor & Francis
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.25%
The use of renewable energy in desalination is the only sustainable way to decrease the water deficit without aggravating the energy crisis. Solar desalination is usually presented as the most optimal solution for sustainable desalination since the water needs are usually larger in places with high solar radiation. Considering the potential use of desalination as means of producing water in small isolated communities, the focus of this study lies on the use of solar energy in thermal desalination systems of small–medium capacity and low maintenance requirements. Based on typical values for the thermal energy requirements of such systems and on characteristic performance parameters of commercially available low-temperature solar thermal technologies, different system layouts are assessed and optimal system dimensioning is studied, for different locations, in terms of estimated water production costs.

Paving the Way for a Transformational Future : Lessons from Jawaharlal Nehru National Solar Mission Phase I

World Bank
Fonte: Washington, DC Publicador: Washington, DC
Tipo: Publications & Research :: ESMAP Paper; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
56.36%
Renewable energy, especially solar power, has been garnering a lot of interest from governments, international development organizations, civil society, and the private sector for the last few years. There has been a huge surge in the popularity of this important energy source from various stakeholders in India as well. On the other hand, solar power presents a formidable option for addressing pertinent issues being faced in international geopolitical and national macroeconomic arenas for the Government of India (GoI). Though the World Bank, India considers all market segments of solar power to be important; this report specifically looks at the utility-scale grid-connected segment of solar power in India. As one of the eight missions under India's National Action Plan for Climate Change (NAPCC), the Jawaharlal Nehru National Solar Mission (JNNSM) was launched in January 2010 with the aim of accelerating India's march toward grid parity in solar power. JNNSM envisages the achievement of grid parity through long-term and predictable policy...

Experimental Evaluation and Modeling of a Solar Liquid Desiccant Air Conditioner

Crofoot, LISA
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
56.31%
Air-conditioning systems driven by solar energy have can save primary energy and reduce peak power consumption, which is particularly important for utility providers in the summer months. Additionally solar cooling is a promising application of solar thermal technology since the cooling load is well correlated to the overall solar availability. Liquid desiccant air-conditioning, which uses a salt solution to dehumidify air, can be used in a thermally driven air-conditioning system and offers many benefits for solar applications including the ability to store solar energy in the form of concentrated liquid desiccant. The current work focuses on the Queen’s University Solar Liquid Desiccant Cooling Demonstration Project. In previous work, a pre-commercial Liquid Desiccant Air Conditioner (LDAC) was installed and experimentally characterized using a gas-fired boiler to provide heat. As part of the current study a 95m2 solar array was added as a heat source. The Solar LDAC was tested for 20 days in the summer of 2012 to evaluate performance. The solar LDAC was found to provide between 9.2kW and 17.2kW of cooling power with an overall thermal Coefficient of Performance (COP) of 0.40 and electrical COP of 2.43. The collector efficiency was 53%...

THE DEVELOPMENT AND APPLICATION OF A SIMPLIFIED THERMAL PERFORMANCE EQUATION FOR A SHEET-AND-TUBE PHOTOVOLTAIC THERMAL COMBI-PANEL

Carriere, JARRETT
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
56.34%
PV/Thermal technology is the combination of solar thermal and photovoltaics - two mature and widely understood technologies. Combining the two technologies complicates existing standardized rating procedures and performance modeling methods. Currently a standardized performance test method does not exist for PV/Thermal (PV/T) panels. Existing and developing PV/T panels are commonly tested using separate standardized solar thermal and photovoltaic test procedures. Solar thermal performance is rated in terms of temperature difference whereas photovoltaic performance is dependent on absolute temperature level. The thermal and electrical performance of a PV/T panel is, however, coupled so performance equations derived using traditional test methods may not accurately reflect the performance of a combined PV/T panel over a wide range of conditions. The purpose of this work was to develop an efficiency equation for a PV/T panel which can be derived from a minimal amount of empirical test data and still accurately predict its thermal and electrical performance over a wide range of conditions. To accomplish this, a quasi- 3-dimensional steady-state model of a sheet-and-tube PV/T collector was developed and used to generate a broad data set from which a simplified PV/T performance equation was developed. Using this numerically generated data set...

Preliminary Investigation into Solar Thermal Combi-system Performance

Lee, Elizabeth
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
66.4%
Solar thermal combi-systems use solar energy to provide thermal energy for space heating and domestic hot water. These systems come in many different designs and configurations, and their performance is dependent on many different factors such as location, solar collector type and orientation, and thermal storage size. In this study, two different combi-system configurations (a basic combi-system, and a single-tank combi-system) as well a stand-alone solar space heating system and a stand-alone solar domestic hot water system were investigated using TRNSYS models and simulations, and the thermal performances were compared using different combinations of solar collector and heat exchanger types, different locations, and a sensitivity analysis was performed using the basic solar combi-system. Using Toronto as the reference location, the performance of the solar stand-alone and combi-systems were compared using combinations of solar collector types (glazed vs. vacuum tube) and heat exchanger types (fixed effectiveness vs. natural convection). Each system combination was optimized for collector flow rate and tilt angle, and all systems were given the same solar collector area, thermal storage volume, and load profiles. This analysis revealed that the glazed type solar collector performed best when the heating load was continuous throughout the year...

Central Solar Heating Plants with Seasonal Storage for Residential Applications in Canada: A Case Study of the Drake Landing Solar Community

Wamboldt, JASON
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 4917997 bytes; application/pdf
EN; EN
Relevância na Pesquisa
56.3%
In Canada, 20% of greenhouse gas (GHG) emissions result from burning fossil fuels to heat homes, buildings, and water. Solar thermal technologies convert the sun’s energy into emission-free heat. The Drake Landing Solar Community (DLSC) in Okotoks, Alberta uses a Central Solar Heating Plant (CSHP) with Seasonal Storage to achieve an astounding annual reduction of 89 % in fossil fuel consumption and more than 5 tonnes in GHG emissions per home. This thesis examines: (1) the role for solar thermal technologies in Canada; and (2) what social, economical, and environmental factors are critical to the implementation and ultimate success of the DLSC. The former was examined through a literature review and the latter through a qualitative case study. Data was collected from published articles, media reports, conference proceedings, and in-person interviews in Okotoks. International markets have shown strong solar thermal growth, yet Canada lags significantly despite its powerful solar resources and readily available technology. Europe has demonstrated that strong policies with ambitious targets have a critical role in the implementation of solar technologies. A review of recent public opinion polls demonstrates Canadians value the environment and would favour such policy developments. The case study sought to understand the roles and motivations of the municipality...

Solar Thermal Energy Systems in Australia

Lovegrove, Keith; Dennis, Michael
Fonte: Taylor & Francis Group Publicador: Taylor & Francis Group
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.29%
Australia has developed world leading solar thermal technologies, with only very low national market penetration. Domestic solar water heating is the most common solar thermal instrument, with around 5% of homes using it and most of these systems are conv

Techno-Economic Analysis of a 10 MWe Solar Thermal Power Plant Using Ammonia-Based Thermochemical Energy Transfer

Luzzi, Andreas; Lovegrove, Keith; Fillipi, Ermanno; Fricker, Hans; Shmitz-Goeb, Manfred; Chandapillai, M; Kaneff, Steven
Fonte: Pergamon-Elsevier Ltd Publicador: Pergamon-Elsevier Ltd
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.21%
The production of solar thermal power on a continuous, 24-h basis is possible by applying thermochemical energy storage. An international group of industrial and academic partners is studying such a base-load solar power plant concept, where the reversible thermo-catalytic ammonia reaction serves as the energy vector between supply and demand. Early results confirm the technical soundness of the concept using conventional technology, equipment and materials, and indicate also the potential for economic viability. A first-of-a-kind, solar-only demonstration power plant with a net capacity of 10 MWe would require a capital investment of the order of AUD 180 million and operate with a net solar-to-electric conversion efficiency of 18% and a capacity factor of 80%. This would result in levelised electricity costs of less than AUD 0.25 per kWh.

System and component modelling of a low temperature solar thermal energy conversion cycle

Situmbeko,Shadreck M; Inambao,Freddie L
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2013 EN
Relevância na Pesquisa
66.29%
Solar thermal energy (STE) technology refers to the conversion of solar energy to readily usable energy forms. The most important component of a STE technology is the collectors; these absorb the shorter wavelength solar energy (400-700nm) and convert it into usable, longer wavelength (about 10 times as long) heat energy. Depending on the quality (temperature and intensity) of the resulting thermal energy, further conversions to other energy forms such as electrical power may follow. Currently some high temperature STE technologies for electricity production have attained technical maturity; technologies such as parabolic dish (commercially available), parabolic trough and power tower are only hindered by unfavourable market factors including high maintenance and operating costs. Low temperature STEs have so far been restricted to water and space heating; however, owing to their lower running costs and almost maintenance free operation, although operating at lower efficiencies, may hold a key to future wider usage of solar energy. Low temperature STE conversion technology typically uses flat plate and low concentrating collectors such as parabolic troughs to harness solar energy for conversion to mechanical and/or electrical energy. These collector systems are relatively cheaper...