Exergoeconomic analysis of solar organic rankine cycle for geothermal air conditioned net zero energy buildings

This study is an attempt at achieving Net Zero Energy Building (NZEB) using a solar Organic Rankine Cycle (ORC) based on exergetic and economic measures. The working fluid, working conditions of the cycle, cycle configuration, and solar collector type are considered the optimization parameters for the solar ORC system. In the first section, a procedure is developed to compare ORC working fluids based on their molecular components, temperature-entropy diagram and fluid effects on the thermal efficiency, net power generated, vapor expansion ratio, and exergy efficiency of the Rankine cycle. Fluids with the best cycle performance are recognized in two different temperature levels within two different categories of fluids: refrigerants and non-refrigerants. Important factors that could lead to irreversibility reduction of the solar ORC are also investigated in this study. In the next section, the system requirements needed to maintain the electricity demand of a geothermal air-conditioned commercial building located in Pensacola of Florida is considered as the criteria to select the optimal components and optimal working condition of the system. The solar collector loop, building, and geothermal air conditioning system are modeled using TRNSYS. Available electricity bills of the building and the 3-week monitoring data on the performance of the geothermal system are employed to calibrate the simulation. The simulation is repeated for Miami and Houston in order to evaluate the effect of the different solar radiations on the system requirements. The final section discusses the exergoeconomic analysis of the ORC system with the optimum performance. Exergoeconomics rests on the philosophy that exergy is the only rational basis for assigning monetary costs to a system���s interactions with its surroundings and to the sources of thermodynamic inefficiencies within it. Exergoeconomic analysis of the optimal ORC system shows that the ratio Rex of the annual exergy loss to the capital cost can be considered a key parameter in optimizing a solar ORC system from the thermodynamic and economic point of view. It also shows that there is a systematic correlation between the exergy loss and capital cost for the investigated solar ORC system.

Labour and Low Energy Buildings: the energy performance gap as Social Practice

Buildings are responsible for approximately 30% of EU end-use emissions (Bettgenh��user , et al, 2009) and are at the forefront of efforts to meet emissions targets arising from their design, construction and operation. For the first time in its history, construction industry outputs must meet specific energy targets if planned reductions in greenhouse gas emissions are to be achieved through nearly zero energy buildings (nZEB) (EC, 2010) supported by on-site renewable heat and power. Where individual UK dwellings have been tested before occupation to assess whether they meet energy design criteria, the results indicate what is described as an ���energy performance gap���, that is, energy use is almost always more than that specified. This leads to the conclusion that the performance gap is, inter alia, a function of the labour process and thus a function of social practice. Social practice theory, based on Schatzki���s model (2002), is utilised to explore the performance gap as a result of the changes demanded in the social practice of building initiated by new energy efficiency rules. The paper aims to open a discussion where failure in technical performance is addressed as a social phenomenon.

Post-occupancy analysis of a Zero Energy Hojme (ZEH)

Zero energy buildings (ZEB) and zero energy homes (ZEH) are a current hot topic globally for policy makers (what are the benefits and costs), designers (how do we design them), the construction industry (can we build them), marketing (will consumers buy them) and researchers (do they work and what are the implications). This paper presents initial findings from actual measured data from a 9 star (as built), off-ground detached family home constructed in south-east Queensland in 2008. The integrated systems approach to the design of the house is analysed in each of its three main goals: maximising the thermal performance of the building envelope, minimising energy demand whilst maintaining energy service levels, and implementing a multi-pronged low carbon approach to energy supply. The performance outcomes of each of these stages are evaluated against definitions of Net Zero Carbon / Net Zero Emissions (Site and Source) and Net Zero Energy (onsite generation v primary energy imports). The paper will conclude with a summary of the multiple benefits of combining very high efficiency building envelopes with diverse energy management strategies: a robustness, resilience, affordability and autonomy not generally seen in housing.

Net energy analysis of a solar combi system with Seasonal Thermal Energy Store

EU targets require nearly zero energy buildings (NZEB) by 2020. However few monitored examples exist of how NZEB has been achieved in practise in individual residential buildings. This paper provides an example of how a low-energy building (built in 2006), has achieved nearly zero energy heating through the addition of a solar domestic hot water and space heating system (���combi system���) with a Seasonal Thermal Energy Store (STES). The paper also presents a cumulative life cycle energy and cumulative life cycle carbon analysis for the installation based on the recorded DHW and space heating demand in addition to energy payback periods and net energy ratios. In addition, the carbon and energy analysis is carried out for four other heating system scenarios including hybrid solar thermal/PV systems in order to obtain the optimal system from a carbon efficiency perspective.

Development of new vocational training modules on sustainable buildings maintenance and refurbishment

This article presents the methodology and main results obtained in Spain within the FORMAR project, a European-funded project under the Leonardo Da Vinci scheme (Lifelong Learning Programme), whose main goal is to jointly develop training resources and modules to improve the skills on sustainability issues of buildings maintenance and refurbishment workers, in three different European countries: Spain, Portugal (Project Coordinator) and France. The Units of Short-term Training (UST) developed within this project are focused on the VET of carpenters, painters, bricklayers, building technicians and installers of solar panels, and a transversal unit containing basic concepts on sustainable construction and nearly Zero Energy Buildings (n-ZEB) is also developed. In parallel, clients��� guides for the aforementioned professionals are also implemented to improve the information provided to clients and owners in order to support the procurement decisions regarding building products and materials. Therefore, the project provides an opportunity to exchange experiences between organizations of these three European countries, as the UST will be developed simultaneously in each of them, exploring opportunities for training, guidance and exchange of experience. Even though the UST will have a common structure and contents, they will be slightly different in each country to adapt them to the different specific training needs and regulations of Spain, Portugal and France. This paper details, as a case study, the development process of the UST for carpenters and building technicians in Spain, including the analysis of needs and existing training materials, the main contents developed and the evaluation and testing process of the UST, which involves the active participation of several stakeholders of this sector as well as a classroom testing to obtain the students��� feedback.

NZEB e os novos revestimentos

Disserta����o de natureza cient��fica para obten����o do grau de Mestre em Engenharia Civil na ��rea de Especializa����o de Edifica����es

Projecto integrado de AVAC e outras especialidades para um edif��cio com necessidades quase nulas de energia

Trabalho Final de Mestrado para obten����o do grau de Mestre em Engenharia Mec��nica

A sustentabilidade e o ciclo de vida dos edif��cios

A crescente preocupa����o que envolve as quest��es ambientais a n��vel mundial, cada vez mais agravadas pelo comportamento irrespons��vel do Homem, conduziu �� cria����o de m��todos de avalia����o dos impactes ambientais provocados por produtos e sistemas. Sendo o sector da constru����o respons��vel por grande parte desses impactes, �� evidente a necessidade de aplica����o de medidas que visem mitigar ou, no m��nimo, reduzir at�� valores aceit��veis, essas agress��es ao meio ambiente. Nesse ��mbito, �� natural que tenha surgido a ideia de aplicar uma metodologia t��o precisa e rigorosa como a LCA ao sector da constru����o. No entanto, nos dias de hoje, as preocupa����es alargaram-se ��s vertentes social e econ��mica que, juntamente com a vertente ambiental, formam o tri��ngulo de equil��brio do desenvolvimento sustent��vel. �� precisamente essa avalia����o tripartida que esta Disserta����o pretende abordar, tentando aprofundar conhecimentos e fornecer alternativas, atrav��s da an��lise cr��tica, que possam contribuir para a melhoria cont��nua desta metodologia.

Converg��ncia para NZEB de um edif��cio de servi��os em Faro

Disserta����o para obten����o do grau de Mestre em Engenharia Civil

Estrategias para el dise��o bioclim��tico de edificios nZEB en climas des��rticos c��lidos aplicando el modelo de confort adaptativo : el caso particular de las costas de las Islas Canarias

Programas de doctorado: Restauraci��n y rehabilitaci��n arquitet��nica.-- Construcci��n arquitect��nica, Tradici��n constructiva versus innovaci��n tecnol��gica actual. La fecha de publicaci��n es la fecha de lectura

Teoria e pratica dell'architettura solare - Morfologia, rendimento, strategia progettuale

La recente Direttiva 31/2010 dell���Unione Europea impone agli stati membri di riorganizzare il quadro legislativo nazionale in materia di prestazione energetica degli edifici, affinch�� tutte le nuove costruzioni presentino dal 1�� gennaio 2021 un bilancio energetico tendente allo zero; termine peraltro anticipato al 1�� gennaio 2019 per gli edifici pubblici. La concezione di edifici a energia ���quasi��� zero (nZEB) parte dal presupposto di un involucro energeticamente di standard passivo per arrivare a compensare, attraverso la produzione preferibilmente in sito di energia da fonti rinnovabili, gli esigui consumi richiesti su base annuale. In quest���ottica la riconsiderazione delle potenzialit�� dell���architettura solare individua degli strumenti concreti e delle valide metodologie per supportare la progettazione di involucri sempre pi�� performanti che sfruttino pienamente una risorsa inesauribile, diffusa e alla portata di tutti come quella solare. Tutto ci�� in considerazione anche della non pi�� procrastinabile necessit�� di ridurre il carico energetico imputabile agli edifici, responsabili come noto di oltre il 40% dei consumi mondiali e del 24% delle emissioni di gas climalteranti. Secondo queste premesse la ricerca pone come centrale il tema dell���integrazione dei sistemi di guadagno termico, cosiddetti passivi, e di produzione energetica, cosiddetti attivi, da fonte solare nell���involucro architettonico. Il percorso sia analitico che operativo effettuato si �� posto la finalit�� di fornire degli strumenti metodologici e pratici al progetto dell���architettura, bisognoso di un nuovo approccio integrato mirato al raggiungimento degli obiettivi di risparmio energetico. Attraverso una ricognizione generale del concetto di architettura solare e dei presupposti teorici e terminologici che stanno alla base della stessa, la ricerca ha prefigurato tre tipologie di esito finale: una codificazione delle morfologie ricorrenti nelle realizzazioni solari, un���analisi comparata del rendimento solare nelle principali aggregazioni tipologiche edilizie e una parte importante di verifica progettuale dove sono stati applicati gli assunti delle categorie precedenti

Almacenamiento de energ��a t��rmica por calor latente en los edificios: bases para la optimizaci��n de aplicaciones pasivas, opacas y trasl��cidas

La principal motivaci��n para la elecci��n del tema de la tesis es nuestra realidad energ��tica y ambiental. Y m��s espec��ficamente, la necesidad urgente de dar una respuesta a esta realidad desde el sector de la edificaci��n. Por lo que, el trabajo parte de la b��squeda de soluciones pasivas que ayuden a la reducci��n del consumo energ��tico y de las emisiones de C02 de los edificios, tanto nuevos como existentes. El objeto de estudio son aplicaciones innovadoras, basadas en el uso de materiales reactivos, con un efecto t��rmico de memoria bidireccional. La energ��a es un elemento imprescindible para el desarrollo. Sin embargo, el modelo energ��tico predominante, basado principalmente en la utilizaci��n de combustibles de origen f��sil, es uno de los importantes responsables del deterioro ambiental que sufre el planeta. Adem��s, sus reservas son limitadas y est��n concentradas en unas pocas regiones del mundo, lo que genera problemas de dependencia, competitividad y de seguridad de suministro. Dado el gran potencial de ahorro energ��tico del sector de la edificaci��n, la Uni��n Europea en sus directivas enfatiza la necesidad de mejorar la eficiencia energ��tica de los edificios. A��adiendo, adem��s, la obligatoriedad de desarrollar edificios ���energ��a casi nula���, cuyo prerrequisito es tener un muy alto rendimiento energ��tico. En Espa��a, los edificios son responsables del 31% del consumo de energ��a primaria. La mayor parte de este consumo se relaciona a la utilizaci��n de sistemas activos de acondicionamiento. Una medida efectiva para reducir la demanda es mejorar la envolvente. Sin embargo, hay que buscar estrategias adicionales para aumentar a��n m��s la eficiencia de los edificios nuevos y existentes. Para los climas de Espa��a, el uso de la inercia t��rmica ha probado ser una estrategia v��lida. Sin embargo, su funcionamiento est�� vinculado al peso y al volumen de los materiales utilizados. Esto limita sus posibilidades en la rehabilitaci��n energ��tica y en los nuevos edificios basados en la construcci��n ligera. Una alternativa es el uso de aplicaciones de almacenamiento t��rmico por calor latente, utilizando materiales de cambio de fase (PCM). Los PCM son sustancias con un muy alto calor de fusi��n, capaces de almacenar una gran cantidad de energ��a t��rmica sin requerir aumentos significativos de peso o volumen. Estas caracter��sticas los hacen id��neos para reducir el consumo relacionado con el acondicionamiento t��rmico, en edificios nuevos y existentes. En la parte preliminar de la investigaci��n, se encontr�� que para lograr un aprovechamiento ��ptimo de las aplicaciones con PCM es necesario tener un conocimiento profundo de su funcionamiento y de las variables del sistema. De ah�� que el objetivo principal de la presente tesis sea: establecer las bases para la optimizati��n integral de las aplicaciones con almacenamiento de energ��a t��rmica por calor latente, identificando y validando sus variables m��s relevantes. La investigaci��n consta de tres partes. La primera, documental, sistematizando y jerarquizando la informaci��n cient��fica publicada; la segunda, num��rica, basada en un an��lisis param��trico de una aplicaci��n con PCM, utilizando simulaciones t��rmicas; y la tercera, experimental, monitorizando el funcionamiento t��rmico y energ��tico de diferentes aplicaciones con PCM en m��dulos a escala real. Los resultados brindan un m��s profundo entendimiento del funcionamiento de las aplicaciones evaluadas. Han permitido identificar sus variables relevantes, cuantificar su influencia, y determinar condiciones ��ptimas para su utilizaci��n as�� como situaciones en las que ser��a muy dif��cil justificar su uso. En el proceso, se realiz�� la caracterizaci��n t��rmica y energ��tica de aplicaciones con PCM, tanto opacas como trasl��cidas. Adem��s, se ha encontrado que las aplicaciones con PCM son capaces de aumentar la eficiencia energ��tica inclusive en recintos con dise��os optimizados, demostrando ser una de las estrategias adecuadas para lograr el muy alto desempe��o energ��tico requerido en los edificios energ��a nula. ABSTRACT The main motivation for choosing the theme of the thesis is our energy and environmental reality. And more specifically, the urgent need to respond to this reality from the building sector. This is why, the work start with the search of passive solutions that help reduce energy consumption and C02 emissions of buildings, in both new and existing ones. The object of study is innovative applications based on the use of responsive materials, with bidirectional thermal memory. Energy is an essential element for development. However, the predominant energy model, based primarily on the use of fossil fuels, is one of the major responsible for the environmental deterioration of the planet, the cause of most of the CO2 emissions. Furthermore, reserves of fossil fuels are limited and are concentrated in a few regions of the world, which creates issues related to dependency, competitiveness, and security of supply. Given the large potential for energy savings in the building sector, the European Union in its directives emphasizes the need to improve energy efficiency in buildings. Also, adding the obligation to develop "nearly zero energy" buildings, whose first prerequisite is to achieve a very high energy efficiency. In Spain, buildings are responsible for 31% of primary energy consumption and most of this consumption is related to the used of HVAC systems. One of the most effective measures to reduce demand is to improve the envelope. However, it is necessary to look for additional strategies to further increase the efficiency of new and existing buildings. For the predominant climates in Spain, use of the thermal inertia may be a valid strategy. Nevertheless, its operation is linked to weight and volume of the materials used. This limits their possibilities in the existing buildings energy retrofitting and in the new buildings based on lightweight construction. An alternative is the use of latent heat thermal energy storage applications (LHTES), using phase change materials (PCM). PCM are substances with a high heat of fusion, capable of storing a large amount of thermal energy without requiring significant increases in weight or volume. These features make them ideal for reducing energy consumption associated with thermal conditioning in both new and existing buildings. In the preliminary part of the investigation, it was found that to get optimum utilization of the PCM applications is needed to have a deep understanding of its operation and, in particular, how the system variables affect its performance. Hence, the main objective of this thesis is: to establish the basis for the integral optimization of applications with latent heat thermal energy storage, identifying and validating the most relevant variables. The research comprises of three parts. The first, documentary, systematizing and prioritizing published scientific information. The second, numeric, based on a parametric analysis of an application PCM using thermal simulations. The third, experimental, monitoring the thermal and energy performance of different applications with PCM on real scale test cells. The results provide a complete understanding of the functioning of the evaluated LHTES application. They have allowed to identify their relevant variables, quantify their influence and determine optimum conditions for use as well as situations where it would be very difficult to justify its use. In the process, it was carried out the power and thermal characterization of various opaque and translucent PCM applications. Furthermore, it has been found that applications with PCM can increase the energy efficiency, even in buildings with optimized designs; proving to be one of the appropriate measures to achieve the high energy performance required in zero energy buildings.

Application of the nZEB methodology in the retrofitting of a typical Portuguese dwelling from the 60's.

Buildings and the whole built environment are in a key role when societies are mitigating climate change and adapting to its consequences. More than 50% of the existing residential buildings in EU-25 were built before 1970. Thus, these buildings are of significant importance in reducing energy consumption and CO2 emissions. The existence of more nearly zero energy buildings (nZEB) is a possible solution for this problem. This study aims to analyze the application of the nZEB methodology in the retrofitting of a typical Portuguese dwelling build in 1950. It was shown that the primary energy used can be reduced to a very low value (11,95 kWhep/m2.y) in comparison with the reference consumption (69,15 kWhep/m2.y), with the application of the best construction techniques together with the use of energy from on-site renewable sources.

Examining the potential for design and renewable energy to contribute to zero energy housing in Queensland

This was a comparative study of the possibility of a net zero energy house in Queensland, Australia. It examines the actual energy use and thermal comfort conditions of an occupied Brisbane home and compares performance with the 10 star scale rating scheme for Australian residential buildings. An adaptive comfort psychometric chart was developed for this analysis. The house's capacity for the use of the natural ventilation was studied by CFD modelling. This study showed that the house succeeded in achieving the definition of net zero energy on an annual and monthly basis for lighting, cooking and space heating / cooling and for 70% of days for lighting, hot water and cooking services.

Design a zero energy house in Brisbane, Australia

Due to the increasing energy demand and global warming effects, energy efficient buildings have become increasingly important in the modern construction industry. This research is conducted to evaluate the energy performance, financial feasibility and potential energy savings of zero energy houses. Through the use of building computer simulation technique, a 5 stars energy rated house was modelled and validated by comparing the energy performance of a base case scenario to a typical house in Brisbane. By integrating energy reduction strategies and utilizing onsite renewable energy such as solar energy, zero energy performance is achieved. It is found that approximately 66 % energy savings can be achieved in the household annual energy usage by focusing on maximizing the thermal performance of building envelope, minimizing the energy requirements and incorporating solar energy technologies.