Model-based Design of a Solar Driven Hybrid System for Space Heating and DHW Preparation of a Multifamily House☆

Abstract Following the most recent European Directives on Energy Performance of Buildings and Energy Efficiency, new solutions for DHW production, space heating and cooling have to be developed and applied to reduce the primary energy consumption of residential buildings. Due to the complexity of installation and control, H&C hybrid systems exploiting a mix of conventional fuels and RES are not yet widespread although they can bring important savings to the yearly building energy consumptions. This work summarizes the parametric analysis used as part of the design process of a hybrid system for the retrofit of a multifamily house located in Madrid, and shows how heating, cooling and DHW demands of multifamily houses can be covered by a heat pump plus solar systems, integrating a high share of RES. The design of the system has taken into account energy savings, economics and architectural aspects

5th generation district heating and cooling systems: A review of existing cases in Europe

Abstract This article investigates 40 thermal networks in operation in Europe that are able to cover both the heating and cooling demands of buildings by means of distributed heat pumps installed at the customer substations. The technology of thermal networks that work at a temperature close to the ground, can strongly contribute to the decarbonisation of the heating and cooling sector and furthermore exploit a multitude of low temperature heat sources. Nevertheless, the nomenclature used in literature shows that misinterpretations could easily result when comparing the different concepts of thermal networks that operate at a temperature level lower than traditional district heating. The scope of this work is to revise the definitions encountered and to introduce an unambiguous definition of Fifth-Generation District Heating and Cooling networks. A drawback-benefit analysis is presented to identify the pros and cons of such technology. The survey on the current networks shows that on average three Fifth-Generation District Heating and Cooling systems per year have entered the heating and cooling market in the last decade. Pioneer countries in such technology are Germany and Switzerland. For some networks, the assessed Linear Heating Power Demand Density results are lower than the feasibility threshold adopted in traditional district heating. High performances and low non-renewable primary energy factors are achieved in systems that exploit a very high share of renewable or urban excess heat sources. With respect to traditional district heating, the surveyed pumping energy consumptions result one order of magnitude higher, whereas the implemented control strategies can be completely different, leading the network temperature to float freely

Adaptive-predictive control strategy for HVAC systems in smart buildings – A review

Abstract High share of energy consumption in buildings and subsequent increase in greenhouse gas emissions along with stricter legislations have motivated researchers to look for sustainable solutions in order to reduce energy consumption by using alternative renewable energy resources and improving the efficiency in this sector. Today, the smart building and socially resilient city concepts have been introduced where building automation technologies are implemented to manage and control the energy generation/consumption/storage. Building automation and control systems can be roughly classified into traditional and advanced control strategies. Traditional strategies are not a viable choice for more sophisticated features required in smart buildings. The main focus of this paper is to review advanced control strategies and their impact on buildings and technical systems with respect to energy/cost saving. These strategies should be predictive/responsive/adaptive against weather, user, grid and thermal mass. In this context, special attention is paid to model predictive control and adaptive control strategies. Although model predictive control is the most common type used in buildings, it is not well suited for systems consisting of uncertainties and unpredictable data. Thus, adaptive predictive control strategies are being developed to address these shortcomings. Despite great progress in this field, the quantified results of these strategies reported in literature showed a high level of inconsistency. This is due to the application of different control modes, various boundary conditions, hypotheses, fields of application, and type of energy consumption in different studies. Thus, this review assesses the implementations and configurations of advanced control solutions and highlights research gaps in this field that need further investigations

On the development of a façade-integrated solar water storage

The integration of active solar thermal technologies into building envelopes has recently received a rising attention, promoted within international projects as IEA Task 56 or Cost Action 1403. Although the façade integration of solar thermal collectors is a long debated topic, less attention is paid to the building integration of solar water storages. The scope of the paper is to highlight the main barriers experienced in the development of a façade-integrated solar water storage. This activity is a part of the SunRise project that aims to develop new unitized curtain wall element for tertiary office buildings. The façade element integrates a complete solar thermal system consisting of a solar collector, a hot water storage, a radiant panel and all the required operation components. A mock-up of the solar facade is manufactured to identify practical constructive issues. The thermal behaviour of the tank is analysed through FEM simulations and laboratory tests

Quality for Solar Cooling on Component Level

Within IEA-SHC Task 48 “Quality assurance and support measures for Solar Cooling” the most crucial components of solar thermal cooling plants have been analyzed in detail aiming at improving their quality. Test procedures for characterizing continuous and discontinuous chillers have been developed; market available heat rejection devices have been investigated, rating their performance through monitoring data and comparing them; pump efficiency has been also investigated and design guidelines for pump selection and hydraulic configuration are now available; a detailed and updated database of medium temperature collectors has been built

Levels of vibration transmitted to the operator of the tractor equipped with front axle suspension

In recent years the comfort and the preservation of the health of the operators became central issues in the evolution of agricultural machinery and led to the introduction of devices aimed at improving working conditions. Thereby, for instance, the presence of air conditioner, soundproof cab and driver seat suspension became normal on agricultural tractors. The vibrations are one of the most complex issues to deal with, being determined by the characteristics and interaction of elements such as tyres, axles, mainframe, cab and seat suspension. In this respect, manufacturers are trying to improve their products, even integrating these elements with new devices such as the suspension on the front axle of the tractor, aimed at reducing the level of vibrations during the transfers at high speed. One of these underwent tests at CRA-ING. Since its purpose is to reduce the level of vibration transmitted to the driver, their measurements in different points of the tractor and in different operating conditions, were compared in order to evaluate the effectiveness of the device, expressed as time of exposure. The suspension system of the front axle is designed to absorb the oscillations (especially pitching) determined by irregularities in the road surface, allowing an increased control of the vehicle at high speed, as demonstrated by the test results and confirmed by the driving impressions outlined by the operator. The action of the device under these conditions results in an increase of the exposure time, important fact because of the relevance of the road transfer operations of tractors with mounted implements or trailers to tow and of the tendency to increase the speed limit for the road tractors (in Germany were brought to 50 km h–1 for several years). The action just described is less evident with increasing irregularity of the road surface and with the decrease of the travel speed. Nevertheless, in such conditions, the device appears to positively work along the other directions, in particular in the Z-axis, improving the action of the suspension of the driver seat

Implantação de sistemas de bombeamento fotovoltaico em comunidades tradicionais : Questões a se considerar

Parte-se do princípio de que a tecnologia de bombeamento fotovoltaico está consolidada apresentando alto grau de confiabilidade. No entanto, muitas vezes, projetos de abastecimento de água à comunidades tradicionais com a tecnologia fotovoltaica ficam comprometidos por não serem levadas em consideração questões relativas a especificidades locais e a transferência da tecnologia. Este trabalho põe de manifesto que a concepção do projeto, a disponibilidade de água, o tipo de configuração do sistema, a determinação da demanda de água, o tipo de introdução da tecnologia e a forma de gestão podem ser decisivas para a longevidade dos projetos.Is well know that photovoltaic pumping technology is consolidated with high degree of reliability. However, many times, projects of water supply to the traditional communities with the photovoltaic technology are engaged for not being taken in account questions related to the local characteristics and the transference of the technology. This work puts of manifesto that the conception of the project, the water availability, the type of configuration of the system, the determination of the water demand, the type of introduction of the technology and the form of management can be decisive for the longevity of the projects.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Bombeamento de água no meio rural, análise econômica de duas configurações fotovoltaicas e uma elétrica convencional

Apesar do grande potencial de aplicação, a tecnologia de bombeamento fotovoltaico não está mais disseminada por requerer um grande aporte de investimento inicial, ainda que seus custos de operação sejam reduzidos por não depender da compra de combustível, como é o caso dos sistemas com energia fóssil, ou do pagamento de tarifa elétrica, como é o caso dos sistemas elétricos convencionais. Este trabalho apresenta uma avaliação econômica de duas configurações de sistemas fotovoltaicos de bombeamento e a respectiva comparação com a alternativa de atendimento com a rede elétrica convencional. Através dos resultados e premissas de um estudo de caso no estado de São Paulo, pôde-se constatar que para um único atendimento, nas potências necessárias, que são usualmente baixas, a opção fotovoltaica é mais competitiva para distâncias superiores a 1 km da rede.In spite of the great potential of application, the photovoltaic pumping technology is not more disseminated by requesting a great contribution of initial investment, although its operation costs are reduced for not depending of the purchase of fuel, as it is the case of the systems with fossil energy, or of the payment of electric tariff, as it is the case of the conventional electric systems. This work presents an economic evaluation of two configurations of photovoltaic pumping systems and the respective comparison with the attendance alternative with the conventional electric grid. Through the results and premises of a case study in the state of São Paulo, it could be verified that for an only attendance, in the necessary potencies, that they are usually low, the option photovoltaic is more competitive for distances higher than 1 km of the grid.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Bombeamento de água no meio rural, análise econômica de duas configurações fotovoltaicas e uma elétrica convencional

Apesar do grande potencial de aplicação, a tecnologia de bombeamento fotovoltaico não está mais disseminada por requerer um grande aporte de investimento inicial, ainda que seus custos de operação sejam reduzidos por não depender da compra de combustível, como é o caso dos sistemas com energia fóssil, ou do pagamento de tarifa elétrica, como é o caso dos sistemas elétricos convencionais. Este trabalho apresenta uma avaliação econômica de duas configurações de sistemas fotovoltaicos de bombeamento e a respectiva comparação com a alternativa de atendimento com a rede elétrica convencional. Através dos resultados e premissas de um estudo de caso no estado de São Paulo, pôde-se constatar que para um único atendimento, nas potências necessárias, que são usualmente baixas, a opção fotovoltaica é mais competitiva para distâncias superiores a 1 km da rede.In spite of the great potential of application, the photovoltaic pumping technology is not more disseminated by requesting a great contribution of initial investment, although its operation costs are reduced for not depending of the purchase of fuel, as it is the case of the systems with fossil energy, or of the payment of electric tariff, as it is the case of the conventional electric systems. This work presents an economic evaluation of two configurations of photovoltaic pumping systems and the respective comparison with the attendance alternative with the conventional electric grid. Through the results and premises of a case study in the state of São Paulo, it could be verified that for an only attendance, in the necessary potencies, that they are usually low, the option photovoltaic is more competitive for distances higher than 1 km of the grid.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES