scholarly journals Numerical Analysis of Concentrated Solar Heaters for Segmented Heat Accumulators

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4350
Author(s):  
Martin Beer ◽  
Radim Rybár ◽  
Jana Rybárová ◽  
Andrea Seňová ◽  
Vojtech Ferencz

This presented paper focuses on the design and evaluation of the concept of concentrated solar heaters for segmental heat accumulators, which are designed to cover the energy needs of selected communities in terms of food preparation without the need for fossil fuels, which have a negative impact not only on the climate but especially on health. The proposed device is based on the traditional method of food preparation in the so-called earth oven; however, the fire-heated stones are replaced with heat accumulators heated by solar radiation. This approach eliminates the need to change common and long-term habits of food preparation for selected communities. The device connects solar vacuum heat pipes, a solar radiation concentrator, and heat accumulators. The concept was evaluated based on computational fluid dynamics (CFD) analysis with the use of a transient simulation of selected operating situations in three geographical locations. The results showed a significant temperature increase of the heat accumulators, where in the most effective case the temperature increased up to 227.23 °C. The concept was also evaluated based on a calorimetric analysis of the system consisting of heat accumulators and food. The resulting temperature in the considered case reached the pasteurization temperature necessary for safe and healthy food preparation.

2018 ◽  
Vol 34 (4) ◽  
pp. 503-528 ◽  
Author(s):  
Farihahusnah Hussin ◽  
Gulnaziya Issabayeva ◽  
Mohamed Kheireddine Aroua

Abstract The heavy reliance on fossil fuels, given their inevitable depletion and serious negative impact on the environment, has led to intensive scientific research to produce solutions which will ensure sustainable supply of energy based on renewable sources. Solar radiation is one of the major sources of clean and renewable energy with the potential to provide ample power for the growing human population in the long term. The current energy crisis is aggravated by the escalating concerns over the water quality especially in developing countries. There is great potential for utilisation of solar energy through solar photovoltaic systems throughout the world for electricity generation as well as water and wastewater treatment. Innovations in this area have opened new prospects to improve the quality of life for people as a whole. Hence, the focus of this review paper is to provide the reader with a brief history of solar photovoltaic systems, the various types of solar photovoltaic materials available and the solar cell efficiencies attained with the current solar photovoltaic technologies. Furthermore, applications of photovoltaic systems are discussed in terms of their societal economic and environmental effects.


Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5151
Author(s):  
Aleksandra Komorowska

In recent years, numerous countries have introduced or considered capacity markets as remuneration mechanisms for long-term capacity adequacy. Since adequacy is frequently linked with thermal power generation, there is an ongoing debate as to whether this instrument could impact decarbonisation. In this context, the paper presents a quantitative assessment of the consequences of introducing a capacity market on decarbonisation pathways. The Polish power system is taken as an example due to its heavy dependence on fossil fuels. To this end, a computable model of the Polish power system is developed and applied to the study of two research scenarios. The first scenario presents the power system without introducing a capacity market, while the latter considers the system with a capacity market in place. The analysis shows that the introduction of a capacity market delays the decarbonisation of the power system and has a negative impact on carbon neutrality. Even though coal-fired units are phased out, they are mainly replaced by natural gas. The method and model developed within this study can be applied to countries where a capacity market is being discussed, and fossil fuels continue to play a dominant role.


foresight ◽  
2017 ◽  
Vol 19 (2) ◽  
pp. 174-197 ◽  
Author(s):  
Ilya Kuzminov ◽  
Alexey Bereznoy ◽  
Pavel Bakhtin

Purpose This paper aims to study the ongoing and emerging technological changes in the global energy sector from the frequently neglected perspective of their potential destructive impact on the Russian economy. Design/methodology/approach Having reviewed existing global energy forecasts made by reputable multilateral and national government agencies, major energy corporations and specialised consulting firms, the authors noticed that most of them are by and large based on the extrapolation of conventional long-term trends depicting gradual growth of fossil fuels’ demand and catching-up supply. Unlike this approach, the paper focuses on the possible cases when conventional trends are broken, supply–demand imbalances become huge and the situation in the global energy markets is rapidly and dramatically changing with severe consequences for the Russian economy, seriously dependent on fossil fuels exports. Revealing these stress scenarios and major drivers leading to their realisation are in the focus of the research. Based on the Social, Technological, Economic, Environmental, Political, Values (analytical framework) (STEEPV) approach, the authors start from analysing various combinations of factors capable to launch stress scenarios for the Russian economy. Formulating concrete stress scenarios and assessing their negative impact on the Russian economy constitute the next step of the analysis. In conclusion, the paper underlines the urgency to integrate stress analysis related to global energy trends into the Russian national systems of technology foresight and strategic planning, which are now in the early stages of development. Findings The analysis of global energy market trends and various combinations of related economic, political, technological and ecological factors allowed to formulate four stress scenarios particularly painful for the Russian economy. They include the currently developing scenario “Collapse of oil prices”, and three potential ones: “Gas abundance”, “Radical de-carbonisation” and “Hydrogen economy”. One of the most important conclusions of the paper is that technology-related drivers are playing the leading role in stress scenario realisation, but it is usually a specific combination of other drivers (interlacing with technology-related factors) that could trigger the launch a particular scenario. Research limitations/implications This study’s approach is based on the assumption that Russia’s dependence on hydrocarbons exports as one of the main structural characteristics of the Russian economy will remain intact. However, for the long-term perspective, this assumption might not hold true. So, new research will be needed to review the stress scenarios within the context of radical diversification of the Russian economy. Practical implications This paper suggests a number of practical steps aimed at introducing stress analysis as one of the key functions within the energy-related sectoral components of the Russian national systems of technology forecasting and strategic planning. Originality/value The novelty of this paper is determined both by the subject of the analysis and approach taken to reveal it. In contrast to most of research in this area, the main focus has been moved from the opportunities and potential benefits of contemporary technology-related global energy shifts to their possible negative impact on the national economy. Another important original feature of the approach is that existing global energy forecasts are used only as a background for core analysis centred around the cases when conventional energy trends are broken.


2021 ◽  
Vol 11 (1) ◽  
pp. 221-236
Author(s):  
Minh Quang Chau ◽  
Van Vang Le ◽  
Tri Hieu Le ◽  
Van Tam Bui

Today, most of the essential energy needs of humans and production are met by fossil fuels that are expected to be exhausted in the next century. Furthermore, fossil fuels are not renewable and sensitive to the environment. In particular, there is growing concerned about the negative impact of internal combustion engine emissions on climate change and global environmental pollution. Fuel and alcohol-based additives are being considered as good candidates for sustainable alternative fuels used on compression ignition engines. In this review, the different key production pathways and properties of each of the five alcohol additive candidates were discussed. Besides, their effects on the emission characteristics of diesel engines when alcohol additives are added to diesel fuel are also carefully considered. Five candidates including methanol, ethanol, propanol, butanol, and pentanol have been shown to control pollutants from combustion engines while using alcohol-based additives. This is of great significance in the strategy of coping with the threats of pollution and climate change caused by the operation of transport vehicles


2021 ◽  
Vol 03 (06) ◽  
pp. 381-390
Author(s):  
Frias Fadhil MAHDI ◽  
Ismeal Abbass HURAT

The electric power sector is considered as the most important active economic sector in public life aspects including industrial, agricultural, service and recreational ones. It is known that traditional energy (fossil fuels) causes climate problems. Such problems have negative impact on the atmosphere, due to the increase in air pollution and the emergence of global sources such as solar energy as it is clean and renewable energy. As the southern Badia of Iraq has a high solar energy, it is possible to invest it in the production of electric energy and then employing it in the developmental fields in those cities (mentioned above) and even remote ones. Thus, this will lead to reducing the quantities of fossil energy consumption as well as reducing its polluting emissions to the atmosphere and its negative effects on nature, man in particular. The main objective of this study is to discover the potentials of the study area of solar radiation energy evaluating and choosing the optimal sites for the construction of the aforementioned power stations. In processing its data, the study used statistical methods to calculate the amount of solar energy reaching the surface of the study cities in the southern Badia of Iraq according to the following equation: Solar Energy = the amount of solar energy (Kilo Watt/ M2/ day) = the total solar radiation (calorie/C2/day) *constant, where the constant equals (0.0116) The study reached the most important results: Some of the study stations recorded the best optimal sites for constructing solar power stations. These are the stations of As Safawi, Busayyah, As-Salman, Al-Ma'aniya, Al-Shabajah, Al-Samawah, Najaf, Al-Nukhayb, and Al-Rutba. On the other hand, the Basra and Zubair stations recorded the lowest values for solar energy; therefore they are not ideal sites compared to other stati.


2019 ◽  
Vol 17 (3) ◽  
Author(s):  
Lamhot P. Manalu

Crop drying is essential for preservation in agricultural applications. It is performed either using fossil fuels in an artificial mechanical drying process or by placing the crop under the open sun. The first method is costly and has a negative impact on the environment, while the second method is totally dependent on the weather. The drying process requires a lot of energy in relation to the amount of water that must be evaporated from the product. It is estimated that 12% of the total energy used by the food industries and agriculture absorbed in this process. Due to the limitation of energy resources, it is important to keep researching and developing of diversification and optimization of energy This study aims to assess the use of energy for cocoa drying using solar energy dryer and bin-type dryer, as well as to determine the drying efficiency of each type of dryer. The results showed that the efficiency of the solar dryer drying system ranges between 36% to 46%, while the tub-type dryers between 21.7% to 33.1%. The specific energy of solar dryer ranged from 6.17-7.87 MJ / kg, while the tub-type dryers 8.58-13.63 MJ / kg. Dryer efficiency is influenced by the level of solar irradiation and the amount of drying load, the higher the irradiation received and more cocoa beans are dried, the drying efficiency is also higher and the specific energy further down.Proses pengeringan memerlukan banyak energi sehubungan dengan banyaknya air yang harus diuapkan dari bahan yang dikeringkan. Pengeringan dapat dilakukan dengan menggunakan pengering mekanis berbahan bakar fosil atau dengan menempatkan produk di bawah matahari terbuka. Metode pertama adalah mahal dan memiliki dampak negatif pada lingkungan, sedangkan metode kedua sangat tergantung pada cuaca. Diperkirakan bahwa 12% dari total energi yang dipergunakan oleh industri pangan dan pertanian diserap untuk proses ini. Mengingat semakin terbatasnya sumber energi bahan bakar minyak maka usaha diversifikasi dan optimasi energi untuk pengeringan perlu terus diteliti dan dikembangkan. Salah satunya adalah pemanfaatan energi surya sebagai sumber energi terbarukan. Penelitian ini bertujuan untuk mengkaji penggunaan energi untuk pengeringan kakao dengan memakai pengering energi surya dan pengering tipe bak, serta untuk mengetahui efisiensi pengeringan dari masing-masing tipe pengering. Hasil kajian menunjukkan bahwa efisiensi total sistem pengeringan alat pengering surya berkisar antara 36% dan 46%, sedangkan pengering tipe bak antara 21.7% dan 33.1%. Kebutuhan energi spesifik alat pengering surya berkisar antara 6.17-7.87 MJ/kg, sedangkan alat pengering tipe bak 8.58-13.63 MJ/kg. Efisiensi alat pengering dipengaruhi oleh tingkat iradiasi surya dan jumlah beban pengeringan, semakin tinggi iradiasi yang diterima pengering serta semakin banyak biji kakao yang dikeringkan, maka efisiensi pengeringan juga semakin tinggi dan kebutuhan energi spesifik semakin turun.Keywords: energy, efficiency, cocoa, solar dryer, bin-type dryer.


Author(s):  
David Mares

This chapter discusses the role of energy in economic development, the transformation of energy markets, trade in energy resources themselves, and the geopolitical dynamics that result. The transformation of energy markets and their expansion via trade can help or hinder development, depending on the processes behind them and how stakeholders interact. The availability of renewable, climate-friendly sources of energy, domestically and internationally, means that there is no inherent trade-off between economic growth and the use of fossil fuels. The existence of economic, political, social, and geopolitical adjustment costs means that the expansion of international energy markets to incorporate alternatives to oil and coal is a complex balance of environmental trade-offs with no solutions completely free of negative impact risk. An understanding of the supply of and demand for energy must incorporate the institutional context within which they occur, as well as the social and political dynamics of their setting.


2020 ◽  
Vol 4 (3) ◽  
pp. 1199-1207
Author(s):  
Amruta P. Kanakdande ◽  
Chandrahasya N. Khobragade ◽  
Rajaram S. Mane

The continuous rising demands and fluctuations in the prices of fossil fuels warrant searching for an alternative renewable energy source to manage the energy needs.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1109
Author(s):  
Robert Bock ◽  
Björn Kleinsteinberg ◽  
Bjørn Selnes-Volseth ◽  
Odne Stokke Burheim

For renewable energies to succeed in replacing fossil fuels, large-scale and affordable solutions are needed for short and long-term energy storage. A potentially inexpensive approach of storing large amounts of energy is through the use of a concentration flow cell that is based on cheap and abundant materials. Here, we propose to use aqueous iron chloride as a reacting solvent on carbon electrodes. We suggest to use it in a red-ox concentration flow cell with two compartments separated by a hydrocarbon-based membrane. In both compartments the red-ox couple of iron II and III reacts, oxidation at the anode and reduction at the cathode. When charging, a concentration difference between the two species grows. When discharging, this concentration difference between iron II and iron III is used to drive the reaction. In this respect it is a concentration driven flow cell redox battery using iron chloride in both solutions. Here, we investigate material combinations, power, and concentration relations.


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