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- A certificação de qualidade em sistemas solares para aquecimento de águaPublication . Costa, J. Cruz; Carvalho, Maria João; Mendes, J. Farinha; Prates, Manuel João LopesTendo em atenção a política nacional para o desenvolvimento do mercado da Energia Solar Térmica, motivada pela necessidade de uma maior utilização das Energias Endógenas (Resolução do Conselho de Ministros nº154/2001 de 27 de Setembro), descreve-se a situação actual na área dos Equipamentos Solares para Aquecimento de Água, no que diz respeito à Certificação de Produtos e à Certificação de Pessoas, como medidas necessárias para a Garantia de Qualidade nesta área.
- European round robin test on solar collectors and solar thermal systemsPublication . Fischer, S.; Carvalho, Maria João; Weißmüller, C.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.
- Heuristic algorithm for the piecewise linear segmentation of multiple time-series for solar thermal systems inverse modellingPublication . Lopes, Vitor V.; Ferro, Filipa; Carvalho, Maria João; Novais, Augusto Q.This paper presents a novel algorithm for the piecewise linear segmentation of multivariate time-series and proposes its application to the analysis of hot water thermal solar systems (TSS). The ISO 9459-5:2007 norm describes a non-intrusive dynamic test for the performance assessment of TSS. This allows to characterize the system heat losses and the thermal stratification properties, as well as to predict its long-term performance. The application of this norm requires an inverse modeling approach where the parameters of a simplified plug flow storage model, based on simulation runs, are determined through an optimization procedure aiming at the adjustment of the predicted results to those obtained by a predefined experimental test sequence (3-5 days). This paper proposes a new method to decrease the computation time required for the model simulation, which is based on the segmentation of the multivariate time-series into a piecewise linear approximation, where the number of segments is critically selected. An illustrative example is presented consisting in the simulation of a real 3-day experimental dataset with 26873 points and a 15 s sampling rate.
- Components of solar thermal systemsPublication . Mendes, J. Farinha; Carvalho, Maria João; Schossig, PeterThe 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.
- New test methodologies to analyse direct expansion solar assisted heat pumps for domestic hot waterPublication . Facão, Jorge; Carvalho, Maria JoãoSince there are not specific standards for testing direct expansion solar assisted heat pumps for domestic hot water, new testing methodologies are proposed supported by laboratory experiments. Two methodologies were developed for performance measurement: modified BIN method and long term performance prediction with a TRNSYS model validated with specific experimental conditions. The long term performance prediction is a methodology similar to the already obtained for solar thermal systems. A system was tested in Lisbon during one year, covering almost all possible local weather conditions. The hot water tapping test cycle used was in agreement with recent standards EN16147:2011 or EN15316-3-1:2007. The influence of average daily air temperature, dew point temperature and solar irradiation was analysed. The seasonal performance factor was calculated for two cities in Portugal (Lisbon and Porto) and for additional four cities in Europe (Davos, Athens, Helsinki and Strasburg). The establishment of a procedure to calculate the seasonal performance of this kind of systems is very important according to the directive 2009/28/EC of the European Parliament and of the Council.
- Sistema solar para aquecimento ambiente e aquecimento de piscinas: uma solução promissora para climas do Sul da EuropaPublication . Carvalho, Maria João; Neves, AnaA avaliação do sistema apresentado neste trabalho foi focada em sistemas que podem fornecer água quente, aquecimento ambiente e aquecimento de piscinas, e que são projectados para climas do Sul da Europa, especialmente para habitações uni-familiares. Pelas características climáticas do Sul da Europa, o aquecimento ambiente é apenas necessário para um curto período do ano, sendo para esta avaliação considerado um período de seis meses para aquecimento ambiente e um período de seis meses para aquecimento de piscinas. Estes sistemas são actualmente utilizados por um mercado reduzido de pessoas, que estão a construir as suas casas como habitações uni-familiares e que desejam também usufruir das condições climáticas dos seus países, para o uso da energia solar. É comum que a integração de uma piscina seja também projectada e construída. A avaliação apresentada foi realizada considerando como sistema de referência um sistema do tipo “kit” com uma área de colector de 4m 2 e um depósito de 300 l. O sistema em avaliação oferece um serviço extra aquecimento ambiente e de piscinas e é constituído por um campo de colectores e por um depósito combinado, capaz de fornecer águas quentes sanitárias e aquecimento ambiente no período de Inverno e também aquecimento de piscinas no período de Verão. A avaliação realizada mostra que nos climas do Sul da Europa este sistema irá fornecer um serviço extra em comparação com os sistemas solares térmicos tradicionais, podendo também ser economicamente interessante.
- Optical properties of solar absorbers : results on Round Robin and guidelinesPublication . Carvalho, Maria João; Páscoa, Soraia; Sallaberry, Fabienne; Wilson, Helen Rose; Fischer, S.; Loren, Anders; Bohren, Andreas; Nielsen, Jan ErikABSTRACT: The scope of the standard ISO 22975-3:2014 is the determination of the long term behavior and service life of selective solar absorbers for use in vented flat plate collectors used in typical solar domestic hot water systems or combisystems. With this scope, this standard can be the basis for the certification of solar absorbers in the framework of Solar Keymark European Certification Scheme. Measurements of optical properties are fundamental to support this certification. Six test laboratories participated in a Round Robin test for the measurement of solar absorptance and thermal emittance of different absorber coatings. The samples used were one PVD coating and two selective paint coatings all on aluminum substrates. The results were submitted anonymously and were analyzed according to standard ISO 13528:2015. The results obtained showed good agreement among the measurements made by the participants and allowed the preparation of guidelines to guarantee quality of the measurements of optical properties of solar absorbers. A proposal to include absorber coatings in the Solar Keymark certification scheme was prepared.
- Rede de laboratórios para a energia e geologiaPublication . Roseiro, J. Carlos; Trancoso, Maria Ascensão; Cunha Diamantino, Teresa; Carvalho, Maria João; Machado Leite, MárioRESUMO: O Laboratório Nacional de Energia e Geologia (LNEG), nas suas áreas de competências reuniu as competências de anteriores instituições com um histórico de trabalho em Laboratórios com acreditação desde os anos 80. No LNEG, estes Laboratórios focaram-se em atividades da área de energia e geologia, mantendo as suas acreditações mas sentiram a necessidade de trabalhar em rede.
- On an integrated DSM package associated to a solar thermal obligation. The ProSTO EU project and the Portuguese experiencePublication . Prates, Manuel João Lopes; Mendes, J. Farinha; Carvalho, Maria JoãoBased on the work that it is running within the ProSTO EU project (http://www.solarordinances.eu/), this paper presents a tentative approach to an integrated demand side measures (DSM) package that must be associated to a solar thermal obligation (STO) in a community. 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; planner, designer and installer certification; technical mandatory requirements in the regulations; mandatory guarantee (maintenance contract). All relevant documents of these quality items must be integrated in the Building Use Manual for easy management. Another kernel key point, this one with focus on overcoming barriers, is public awareness, throughout on-line information (lists of certified equipments, installers, technical description of the equipments, manual of good practices, scholar materials (class notes, computer codes, homework assignments, etc.), etc.), and the implementation of training courses for all
- On the sustainable development of solar thermal obligations in buildings in the framework of the Portuguese casePublication . Prates, Manuel João Lopes; Costa, J. Cruz; Mendes, J. Farinha; Carvalho, Maria JoãoThis 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
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