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Schematic Diagram of Solar Chimney 

Schematic Diagram of Solar Chimney 

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Solar energy is receiving attention in applying technologies and energy systems in recent years. Solar technologies for buildings relying on both passive and active systems are developed. Passive solar refers to those that absorb, store and distribute the sun’s energy without relying on mechanical devices, while active systems are those where heat...

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... storage wall combines the functions of solar collector and storage into a single unit. Heat is transferred from the wall to the room air and to the air between glazing and wall, by radiation and natural convection. Reducing indoor air temperature swings is one of its principal functions ( Figure 12) (Quesada et al. , 2012). A solar chimney is a structure that consists mainly of one heat-absorbing glazed surface and it is constructed on the wall facing the direction of the sun. When solar energy heats the chimney and the air within it, it produces an updraft of air in the chimney. The natural aspiration created at the chimney’s base can be used to ventilate the building (Figure 13) (Quesada et al. , 2012). As a simple and practical bioclimatic design methodology, solar chimneys are receiving considerable attention for reducing heat gain and inducing natural cooling or heating in both commercial and residential buildings because of their potential bene fi ts in terms of operational cost, energy requirement and carbon dioxide emission. In practical civil buildings, solar chimneys can be installed on the walls and roofs. For the purpose of improving natural ventilation performance and achieving better indoor thermal comfort, solar chimneys are always applied in the form of integrated con fi gurations. Solar chimneys can also be used to combine with natural cooling systems so as to enhance the cooling effect inside buildings. Besides, active solar systems may be utilized to enhance the ventilation performance of solar chimneys (Zhai et al. , 2011). Figure 14 shows solar chimney configurations (Harris and Helwig, 2007). Solar XXI building is a low energy of fi ce building with 1500 m 2 of gross fl oor area located in Lisbon, Portugal (38° 46’ N, 9° 11’ W) (Marta et al. , 2011). It is a low energy office building where passive and active solar strategies have been applied to reduce the use of energy for heating, cooling and lighting, combining also an extensive photovoltaic façade for electricity production. Solar XXI opened in 2006, is considered as a high efficient building, close to a net zero energy building (NZEB), where the difference between the energy consumed and that produced is 1/10 th of the energy consumed by a Portuguese standard new office building. Its design includes many energy efficiency concepts, such as a high insulated envelope, south sun exposure, windows external shading, photovoltaic panels heat recovery, ground- cooling system, daylighting, stack effect and cross ventilation. Some solar technologies for buildings are presented: passive solar systems which refer to those that absorb, store and distribute the sun’s energy without relying on mechanical devices, and active systems where heat is transferred mechanically by the use of a working fluid such as air or a fluid that is typically water, or water based. Building-integrated energy systems are also presented. Here, renewable technologies are integrated into the fabric of buildings. Today solar architecture is undergoing a true revolution through the integration of renewable technologies into the fabric of buildings. Such systems are designed for heating, ventilation, thermal isolation, shading, electricity generation and lighting of ...

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... On the other hand, the energy needs of buildings are electrical energy (lighting and air conditioning) and thermal energy (domestic hot water, swimming pool heating, space heating, and absorption cooling). Therefore, solar energy application in buildings has become one of the most important approaches to supply the building energy needs and reduces the environmental degradation caused by the fossil fuels [8][9][10]. ...
Article
Solar water heating is one of the most efficient solar technologies in the domestic sector. The most important component of the solar thermal systems is the solar collector, which converts solar radiation to useful thermal energy. There are many types of solar collectors, which are categorized based on the operating temperature (low, medium and high temperatures) or the working fluid (gas or liquid). One of the newest types of solar collectors is direct absorption solar collector in which solar radiation is absorbed through the working fluid, unlike other collectors that use the surface absorber or indirectly absorb the solar radiation. The common working fluid for DASC is the suspension of metal, metal oxide or carbon nanomaterials in solar common fluids (water, EG, PG and Therminol VP-1). In this review paper, the effect of design and operating parameters on the thermal performance of low-temperature direct absorption solar collector is summarized. Using the numerous studies done in this field, the efficiency enhancement of DASC by variation of the collector geometric properties, the flow properties (the flow rate and Reynolds number), the working fluid properties (the base fluid, the nanoparticle material and size, and the nanofluid concentration), and the collector design is identified. This paper also identifies the current challenges facing the direct absorption solar collectors and the future recommendations for developing and commercializing these collectors.
... In fact, the first station of the specific electricity consumption (excluding heating) of housing is the production of domestic cold. It represents a third of the worldwide energy consumption (approximately 1000 kWh/year) [1,2]. According to Djongyang et al. [2], the economic growth of developing countries will surely involve a growing need for cold. ...
... It represents a third of the worldwide energy consumption (approximately 1000 kWh/year) [1,2]. According to Djongyang et al. [2], the economic growth of developing countries will surely involve a growing need for cold. In the current energy crisis, solar energy can be an efficient solution [3]. ...
... Solar energy applications in different fields have been increasing gradually. Several studies showed that, cold production from this energy is possible [2]. In fact, PV system is the most appropriate system for small capacity refrigeration plants used for food or medical applications in areas far from conventional energy sources, where a high level of solar radiation is present [4,5]. ...
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This paper presents an assessment of a solar electric-vapor compression refrigeration (SE-VCR) system in a dry tropical area. The specific case of the city of Maroua (14.33°E, 10.58°N), located in the Sudano-Sahelian climatic region of Cameroon is considered. The overall evaluation of the hourly cooling loads and the performance of the system were done by the means of heat balance method. The results showed that, for an evaporating temperature of 0 o C, the effective power of the compressor varies between 5.33 kW and 6 kW, the capacity of the condenser varies between 24 and 28 kW, and the coefficient of performance varies from 3.28 to 3.74 while the efficiency of the installation varies between 17 % and 35 %. Regulations on new installations of air-conditioners require COP values of at least 3, so SE-VCR system could successfully be operated in dry tropical areas to improve thermal comfort in living environments.
... PV-panels are the next element to choose for the facility. The main part of on-ground mounted installations with crystalline silicon technologies have a market share of over 80% [29]. There are mono-crystalline modules with up to 14% efficiency and polycrystalline modules with approximately 12% efficiency on the market. ...
... and [4]: ...
Conference Paper
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In recent years building integration of solar thermal with PV modules has become more and more popular in different countries, where national support programs have accelerated the dissemination of grid connected PV systems. The installation of a (BIPV) systems have certain advantages compared to a traditional PV or thermal system mounted in a separate structure on the roofs. The main purpose of this project to evaluate the feasibility of using combined PV/T collectors in typical Syrian building installations, and to test this system as a optional solution for a public, governmental or service sector buildings, there are two main advantages for such systems, large area of the roofs are suitable for mounting such systems, and specially for periodic uses or where short term thermal and electrical energy outputs are needed. PV/T collectors being considered in this paper are collectors which can provide both electrical and thermal energy. An experimental model of PV/T air collector was designed and constructed on the roof of Faculty of Mechanical Engineering in University of Aleppo, then it was inspected. This model consisted of a conventional air solar thermal collector with PV cells. One of the main conclusions of this study is that the thermal linking between PV cells and absorber plate is very important for the thermal efficiency. The electrical efficiency is depend on the flow rate of the air which passes through the collector, because the PV cells are on the inlet, then the cool air will pick the heat generated from the PV cells, so it will become relatively warm after passing under the PV cells, and thus PV cells will have a higher electrical output. This results of the measurement show that the project will provide yearly saving for the building about: thermal energy 6133 S.P/year (2496kW/year) and electrical energy saving 1579 S.P/year (520kW/year).
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Environmental assessment methods have emerged to assess the environmental performance of buildings across the world. Accurate results obtained using these methods are considered highly important, especially when taking into account the global trend of being obligatory and the use of their results to compare the environmental performance of buildings creating a fair competition amongst them. They are used for assessing green buildings regarding issues such as energy, water …, etc. The indoor quality is one of these issues and human comfort is evaluated in those methods using a set of items to assess achieving the identified comfortable ranges by evaluating a number of factors influencing them. These items are using quantitative measurements, so the current assessing way is considered complex besides the consumption of time and effort without reaching significantly accurate results. Therefore the research problem appears in the lack of an appropriate mean in the current assessment methods to evaluate items linked with sensation and emotions. The research paper aims to propose a more credible and an accurate assessment approach to assess those items, and also helps evaluating another set of items which are linked to the psychological comfort. The previous type of comfort rarely appears in current assessment methods despite being one of the green architecture principles. The ‘Kano Model’ is the proposed way used for the application of questionnaires that are put through the information network and linked to assessment methods to get more accurate and creditable results when assessing human comfort items.
Article
A method to determine the photovoltaic (PV) series–parallel array configuration that provides the highest Global Maximum Power Point (GMPP) is proposed in this paper. Such a procedure was designed to only require measurements of voltage and current of each string, which avoids to perform experiments in each module. The ideal single-diode model parameters of each module in the string are obtained from the analysis of the voltage vs. current characteristics of the string. Using the estimated parameters, all feasible PV array configurations are evaluated to determine the array configuration that provides the highest GMPP. Finally, the proposed solution is validated using simulations and experimental data.
Article
In this paper a systematic approach suitable for modeling the behavior of a photovoltaic field operating in both uniform and mismatched conditions is shown. The proposed approach is intended for the evaluation of the long-term energetic performances of photovoltaic fields on a daily, monthly or yearly basis where a fast computation process must be achieved. Two aspects characterize the novel modeling approach: the first one is the evaluation in closed form of the inflection voltage points which represent, in mismatched conditions, the array voltages where the bypass diodes turn off. The second one is the identification of a new set of non-linear equations that describe the photovoltaic field in a simple way, thus speeding up the model solution and the evaluation of the operating voltage and current. The model employs a simple analytical formulation of the photovoltaic field characteristics, allowing a fast evaluation of the energetic performance of different configurations to select the most efficient one in a given irradiance and temperature conditions. The performance of the proposed solution was contrasted with a traditional model obtaining satisfactory results. Finally, numerical examples based on experimental irradiance measurements illustrate the usefulness of the model in the evaluation of photovoltaic field configurations.