Abstract
In order for humans to meet their fundamental needs, energy is required. The main sources of natural energy are carbon-based fuels such as biomass and fossil fuels. These fuels made of carbon are scarce and harmful to the environment. Innovative, clean, and environmentally friendly energy solutions are desperately needed. Particularly in light of the global issues posed by population expansion, the environment, and economic growth, solar energy may be a workable alternative for sustainable development. The Scheffler is a unique kind of solar concentrator that can quickly attain a high temperature. By adding a heat storage unit, Scheffler's capacity to retain heat may be greatly boosted. This study compares the thermal and physical properties, such as density, thermal conductivity, and melting point, of various thermal storage materials that are used to store heat energy for a longer amount of time, such as bricks, concrete, water, phase change material (PCM), latent heat storage material (LHS), aluminum, iron, molten salts, silicon, etc.
TopIntroduction
The world's supply of fossil fuels is limited and will run out by 2088. A significant portion of the population in many countries still uses carbon fuels, such as wood, biomass, and other hydrocarbons (Patel, R. et al. 2022). A considerable amount of dangerous chemicals, including greenhouse gasses, are emitted during the burning of these carbon-based fuels. Since fossil fuels take millions of years to create, using them up rapidly might result in their depletion. Alternatives to these energy sources should be looked into in order to meet the basic energy demands of the population. Renewable energy (Kumar, A. et al. 2017) sources, especially solar energy, are clean and beneficial to the environment. Solar heaters, panels, concentrators, and their combinations are only a few of the devices and applications for solar energy. Solar concentrators are used for a variety of purposes, such as electricity generation, cooking, heating and cooling, and areas that need high temperatures. A Scheffler reflector (Reddy, D. S. et al. 2018) is a useful solar device that concentrates sunlight at a fixed focus (see image 1). It has to stay focused by tracking the daily and seasonal motions of the Sun. The tracking mechanism used by Scheffler to monitor the Sun's movement may be either automatic or human. Figure 1 shows the phases that a Scheffler goes through to operate. After striking the reflector, the sun's rays are concentrated on a fixed focus, or receiver (Hassan, F. et al. 2022), which transforms the incoming light into heat that may be used for a number of purposes. The receiver might be covered with a material that is good at retaining heat. Its primary usage is in cooking, while it may also be used in other high-heat operations (Ahmed, S. F. et al. 2022) including desalination, power generation, and cremation. Meals for a big group of people are prepared in community kitchens using it. Built by Brahma Kumari, the largest solar kitchen in the world can produce 38,500 meals a day. Because Scheffler runs on solar energy, it will not perform effectively on overcast or dreary days. This problem may be lessened by using heat-storage (Cárdenas, B. 2013) materials, which hold heat for extended periods of time and enable Scheffler to run for longer durations of time.
The way this research will be carried out is as follows: Part II compares the desired qualities of various heat storage (Chandel, S. S. et al. 2017) materials and covers the types of materials and their properties that are suitable for use in Scheffler reflectors. The challenges associated with producing heat using phase-change materials (Lingayat, A. B. et al. 2022) were discussed in Part III. The research's last portion addresses the topic's future and ongoing discussions.
Figure 1. Scheffler reflector used for desalination of water
Energy may be stored as heat in two different ways: by changing its phase, or by storing it without changing it. Phase shift (Leong, K. Y. et al. 2019) heat storage seems more attractive than other useful heat storage techniques since it can store more heat for a given unit volume and maintains a steady temperature throughout the transfer process. When heat is delivered to a material, its temperature increases, and thermal energy is just stored there. This energy may be gathered from the approved medium when the temperature fell. They can work at a range of temperatures and accommodate a large number of applications (Veeraiah, V. et al. 2023). A substance that changes phases has the following properties:
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As phases change, there shouldn't be a significant difference in volume.
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A large latent heat capacity is required of the material.
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It must not be corrosive or react with the container it is stored in.
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Its thermos-physical characteristics shouldn't be lost too quickly during phase transitions.
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There should be no damage to the ecosystem.
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The material should be inexpensive.
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It must be easy to access.
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When functioning at a greater temperature, it shouldn't catch fire.
Key Terms in this Chapter
Phase Change Materials: Phase change materials, or PCMs, are substances that, when they undergo a change in their physical state—that is, when they shift from a solid to a liquid and vice versa—absorb or release significant quantities of heat that is said to be “latent.”
Sustainable Development: Development that is sustainable is one which satisfies current demands without jeopardising the capacity of future generations to satisfy their own needs.
Sustainable Development Goals: The seventeen interconnected Sustainable Development Goals, also known as the Global Goals, are intended to act as a “shared blueprint for peace and prosperity for people and the planet, now and into the future.”
Scheffler: Since its introduction by Wolfgang Scheffler, fixed focus type Scheffler concentrators have found widespread usage in a variety of low- to medium-sized industrial process heat applications. The typical sizes of these Scheffler concentrators are 8 m2 and 16 m2.
Latent Heat Storage: Using the significant latent heat of phase shift during the melting of a solid into a liquid, latent heat storage involves storing heat in a phase-change substance. Heat is transformed into chemical bonds by thermochemical storage, which is advantageous for long-term storage applications and reversible.