Design and analysis of reflectivity for Mylar-coated solar dish

Energy is the key driver of the economy but energy crisis is a problem for the present-day source of energy. The concentrated solar power systems make use of different reflector configurations to convert the solar energy into high-temperature heat energy. Parabolic dish system is considered as the best suitable system for achieving high temperature and so it is opted for the study. Here, a solar dish is designed with an open diameter of 1.8?m (which is 2.5?m² in area), and reflective film is being used to reflect the solar irradiance and concentrated it in the focal point. A receiver of 1?mm thickness and 10?cm diameter is used at the receiver end to measure the temperature of the focal point. The setup has made to attain a maximum temperature of 940°C and average temperature of 850°C in the focal point at clear sky in a sunny day.     

A comprehensive review of solar cooker with sensible and latent heat storage materials

Solar energy is available freely and does not create any pollution to the environment. Hence, researchers from all around the world are always working on solar energy applications with enhancement technologies. The solar cooker is one of the largest solar energy application, which is used to cook the food. However, because the solar energy is available only during the daytime, it is not widely used for industry as well as household application. To store the heat during the day, energy storage materials are used. Hence, this study presents a review of sensible and latent heat storage materials used to store the heat during daytime and use for other than daytime hours.     

An estimate of the time-varying temperature field of the main reflector and subreflector of the Shanghai 65 m radio telescope under solar illumination

The time-dependent temperature fields of the reflectors of the Shanghai 65 m radio telescope are investigated numerically, taking account of the non-uniform heating of the reflector surfaces due to solar illumination and the constantly changing ambient air temperature. This paper utilizes a ray casting algorithm to calculate the borderline separating the reflector areas in shadow and in sunshine, aiming to provide an accurate calculation of the solar energy absorbed. Then a ray tracing algorithm is utilized to calculate the total solar energy that is reflected by the main reflector area and received by the subreflector surface area. Finally, the solar energy is used as the main thermal load on the reflector surface to numerically examine the temperature distribution on both the main reflector and the subreflector. The results illustrate that the time-varying temperature fields of the reflectors of a radio telescope due to asymmetric solar illumination can be accurately simulated utilizing the ray casting algorithm and the ray tracing algorithm. The occurring periods and avoidance zones of the overheating of the subreflector are identified, among which the maximum temperature of the subreflector reaches 144.9°C. These dangerous observation zones should be avoided during the operation of the radio telescope.     

Investigation and performance analysis of Scheffler reflector solar cooking system integrated with sensible and latent heat storage materials

ABSTRACT

In this present research work, Scheffler reflector is taken to supply heat to specially designed cooker having sensible and latent heat storage materials. Here, three different types of sensible heat storage materials like sand, pebbles and iron balls and acetamide as latent heat storage materials. Experiments have conducted with sensible and latent heat storage materials during the month of March and April 2018. For cooking purpose, rice and water have been used. After series of experiments, it has been found that the solar cooking with the sand–acetamide and pebbles–acetamide pair of sensible and latent heat storage found productive as compared with iron balls–acetamide pair for evening cooking and rice found adequately in it. Also, sand–acetamide and pebbles–acetamide pair found 3 to 3.5 times more heat compared with Iron balls–acetamide pair.     

Determination of the optimum tilt angle of solar collectors for building applications

Solar energy technologies offer a clean, renewable and domestic energy source, and are essential components of a sustainable energy future. This paper deals with the determination of the optimum tilt angle of solar collectors for building applications. The optimum angle is calculated by searching for the values for which the total radiation on the collector surface is a maximum for a particular day or a specific period. An application of the model is done using the experimental data measured for Izmir in Turkey. The best orientation for solar collectors in Izmir is due south. For increasing the utilization efficiency of solar collectors, it is recommended that, if it is possible, the solar collector should be mounted at the monthly average tilt angle and the slope adjusted once a month.     

A review on compound parabolic solar concentrator for sustainable development

A compound parabolic concentrator (CPC) is defined as a non-imaging-type concentrating collector where incident solar radiations, after reflection from the reflector, are not concentrated at a point or line, but simply together on the absorber apparent which does not produce an image of the light source. It is an ideal solar energy collector which collects and focuses a larger area of sunlight onto a smaller area with minimum loss. This review paper presents a comprehensive review on CPCs carried out by various researchers from all around the world. Different factors affecting the performance of CPCs have been studied in the present paper.     

太阳能与建筑一体化的产业化推广之路

太阳能是建筑节能的最佳选择：中国是世界上太阳能光热利用最大的国家,但是目前使用领域还不够广泛。文章通过太阳能在住宅领域的应用,阐述太阳能与建筑一体化的可能性和可行性。     

Estimation of direct solar irradiance intercepted by a solar concentrator in different modes of tracking (case study: Algeria)

While reasonably accurate knowledge of solar radiation data at the location of interest is necessary for the design of any solar energy conversion system, the use of concentrating solar collectors implies that these systems only work with the direct solar irradiance. In the present study, by using a methodology based on simple equations, the total hourly, daily, monthly and annual direct radiations incident on four different oriented solar concentrators were calculated only from the recorded data of monthly mean daily global and diffuse horizontal solar irradiance for three different Algerian sites, in order to choose the best mode of tracking for concentrating solar thermal power systems and concentrating solar photovoltaic power systems applications. The model predictions were found to be consistent with ground measurements and prior studies of Kalogirou. It was found that the greatest energy gains were achieved by using full tracking. Furthermore, the model can be included for application to other Algerian and worldwide locations for estimating direct solar irradiance intercepted by a solar concentrator in different modes of tracking.     

Planar solar reflectors

A planar reflector is preferred to curved alternatives as a concentrating or augmenting device for a flat-plate solar collector. The performance characteristics of a reflector-augmented collector have previously been determined, and are reviewed in this paper. Particular emphasis is placed on the practical application of the principal results to single reflector and V-trough systems. The usefulness of highly reflective, horizontal diffuse surface to a tilted collector, and the comparative performance of a faceted reflector containing two planar segments are also discussed.     

Optimisation of solar and wind energy systems: a survey

In the last decade, the penetration of renewable energy sources (RESs) for energy generation has increased. Because of their several technical and environmental benefits, solar and wind energy systems are the major RESs that are being increasingly employed for different aims. In solar and wind energy systems, there are a variety of optimisation problems which are non-linear and non-convex in nature. Study of the literature shows that among the meta-heuristic techniques, genetic algorithm (GA) and particle swarm optimisation (PSO) are highly used to solve different optimisation problems of solar and wind energy systems. The main goal of this paper is to review different applications of GA and PSO in solar and wind energy systems. This review will enable the researchers to study the present status of different solar and wind optimisation problems and plan for future investigations.     

太阳能技术在建筑中应用的综合策略

太阳能利用是世界能源与可持续发展战略的重要组成部分,太阳能技术的应用能够缓解能源紧张、减少污染和CO2的排放。通过以太阳能的光热利用技术、光电利用技术以及自然光技术为分类方法,从应用原理、应用现状以及技术发展等方面对建筑中太阳能技术运用的综合策略进行总结。     

酒店热水与空调系统联合供应解决方案探讨

本文介绍酒店热水与空调系统联合供应的几个优化方案，涉及到太阳能和热泵技术的应用原理与系统，应用中充分考虑两者的结合，选择最优的方案，做到最大限度地节能。     

酒店热水与空调系统联合供应解决方案探讨

本文介绍酒店热水与空调系统联合供应的几个优化方案,涉及到太阳能和热泵技术的应用原理与系统,应用中充分考虑两者的结合,选择最优的方案,做到最大限度地节能。     

厦门大学2013国际太阳能十项全能竞赛作品节能体系

国际太阳能十项全能竞赛,倡导将太阳能利用与建筑节能先进技术紧密结合,设计、建造并运行一座功能完善、舒适、宜居、可持续性的太阳能居住空间。该文探讨了厦门大学参赛方案节能体系配置,重点介绍其太阳能光热与光电系统、围护结构材料、空调系统、相变通风及智能控制系统等方面的节能举措。国际太阳能十项全能竞赛设计作为一个系统工程,对太阳能利用与建筑节能进行一体化设计、协调配合才能使参赛方案取得预期的节能成效。     

Enhancement of surface temperature distribution of solar receiver tube using coil winding

ABSTRACT

This paper is a study of straight solar receiver tube wounded by a helical coil. Here, a 50?mm diameter and 2.2 m length stainless steel straight receiver tube is wounded by a helical coil made up of 6?mm diameter and 6.2 m length copper tube. While the straight solar receiver tube and the wounded copper tube are heated, oil is passed through both of the tubes. So, the oil flowing through the two tubes also gets heated and in case of the wounded copper tube, the fluid helps to pass the heat from lower part of the tube to the upper part, this helps to enhance the temperature distribution of the straight solar receiver tube and which in turn reduces the thermal strain. In the study, it has been found that the wounded solar receiver tube set up produces best results up to 220°C.     

太阳能热泵供热系统的应用及经济性分析

以0.7 MW的供热功率为评价标准,分别对太阳能热泵、燃油锅炉、燃气锅炉和电加热锅炉四种供热系统进行了初期投资、运行费用、燃料价格等因素的综合技术经济分析与评价,评价结果表明：太阳能热泵供热系统的综合效果最好,适合在青岛推广应用。     

A review on technology and promotional initiatives for concentrated solar power in world

Concentrated solar power (CSP) is a hopeful area of research for higher efficiency sun heat extraction. Due to this, it has attracted the attention of researchers and scientist in last few years. It can be operated in the clear sky condition for a good performance. However, it is difficult to operate in cloudy days and off sunshine hours. It cannot give energy in night hours except using thermal storage system. The temperature of a system is about to 300–550°C and the efficiency of the plant is 25–30% approximately. The biggest issue of CSP plant is to balance between the production and requirement if storage provision is not there. The primary concern is to improve the quality of reflector, collector, power production and thermal storage. This review paper will become reference material for the researchers and scientists who are working in this field of research.     

太阳能采暖技术及系统设计

太阳能采暖系统是一种满足住户采暖和热水供热需求的新型太阳能热水系统,是太阳能热利用技术的延伸。文中介绍了太阳能采暖系统的构成和设计方法,对太阳能采暖系统的成本和经济性进行了分析,并介绍一种新型太阳能采暖系统。