scholarly journals Water-air regenerative heat exchanger with increased heat exchange efficiency

2021 ◽  
Vol 295 ◽  
pp. 04005
Author(s):  
Sergey Batukhtin ◽  
Andrey Batukhtin ◽  
Marina Baranovskaya

According to experts’ forecasts, by 2040 the global demand for energy will increase by 37%, and renewable energy sources in the next 20 years will become the fastest growing segment of the world energy, their share in the next decade will grow by about one and a half times. Solar energy is the fastest growing industry among all non-conventional energy sources and is gaining the highest rates of development in comparison with other renewable energy sources. In this article, the authors provide an overview of the technologies that increase the efficiency and productivity of solar panels, only the investigated methods are described that can speed up the process of introducing solar energy instead of traditional. All the methods described can increase the efficiency of systems that are based on the use of the sun as the main source of energy. The authors presented and described the scheme of a solar-air thermal power plant, which will improve energy efficiency through the use of a regenerative air solar collector with increased heat transfer efficiency. Strengthening will be achieved through the use of hemispherical depressions on the surface that receives solar radiation. A schematic diagram is given and the principle of operation of such a solar collector is described in detail. A comparative calculation of the intensification of the solar collector with the use of depressions and without the use as modernization was carried out, on the basis of which a conclusion was made about the efficiency of using this type of solar collector and the economic effect from the application of this method. A description of the method for calculating the solar collector is given, thanks to which this development can be used and implemented in existing heating and hot water supply systems.

Author(s):  
Yu. Selikhov ◽  
V. Kotsarenko ◽  
K. Gorbunov

Renewable energy sources (RES) are not limited by geologically accumulated reserves. Their use and consumption will not lead to the inevitable depletion of the Earth's reserves, and they do not pollute the environment. The main motive for the accelerated development of renewable energy in Europe, the United States and many other countries is concern for energy independence and environmental safety. Thus, the EU has adopted a program to achieve the contribution of renewable energy sources to the energy balance by 2020 up to 20%, and by 2040 – up to 40%. Renewable energy is characterized by versatility and diversity. In the list of tasks arising in the implementation of renewable energy (RE) projects (except technological and technical), there are issues of assessing the possibility and efficiency of using RES for energy supply to the regions. At the same time, it should be borne in mind that often the user is interested in comprehensive assessments for various types of energy sources. In specific regions, the most effective can be either the use of hybrid power plants, or the creation of thermal power plants using various types of renewable energy. In connection with the complexity of this problem, as well as the geographic “regionality” of renewable energy, the topic of this article becomes possible and relevant. A heat and power plant is proposed for supplying: electricity, hot water, hot air and heating, in which, together with a wind power generator, a double-circuit solar installation, a heat pump, electricity and heat accumulators are used. This installation allows to reduce the cost of heat energy by reducing material consumption and costs of equipment used, to save fossil fuel; produce electricity and supply the surplus to the state power grid; reduce heat load and environmental pollution.


2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Tomislav M. Pavlović ◽  
Ivana S. Radonjić ◽  
Dragoljub Lj. Mirjanić ◽  
Darko Divnić

The paper provides information on renewable energy sources (RES) and legislation related to the RES generated electricity in Serbia and the Republic of Srpska. In Serbia, hydropower, wind energy, solar energy, biomass and biogas are used for the RES generated electricity, whereas hydropower, solar energy, biomass and biogas are utilized in the Republic of Srpska. The paper gives an overview of the power of RES power plants and the percentage share of the thermal power plants and RES power plants in electricity production and the guaranteed (incentive) prices for RES generated electricity in Serbia and the Republic of Srpska. Furthermore, legal regulations related to the production of electricity from RES in Serbia and the Republic of Srpska are given. In the conclusion, it is pointed out that RES is increasingly used in Serbia and the Republic of Srpska for the production of electricity, that there are appropriate legal regulations and guarantees (incentive prices) for electricity generated by RES power plants.


Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8586
Author(s):  
Youngjin Choi ◽  
Hyun Bae Kim

Recently, the use of new and renewable energy sources to reduce carbon dioxide emissions and minimize global warming has attracted attention. Among the different renewable energy sources, solar energy is utilized for energy reduction in buildings because of its ease of use and excellent maintenance and repair. In this study, an air-based photovoltaic/thermal (PVT) system that improves solar energy utilization was developed, and its performance was experimentally compared with that of the existing photovoltaic (PV) system. The PVT system could increase the amount of generated power by decreasing the panel temperature raised by the air passing through the lower part of the panel. Moreover, it was possible to use the high-temperature air collected from the panel for heating or hot-water supply in the building. Based on the experimental results obtained for the PV and PVT panels subjected to the same weather conditions, the power generation efficiency of the PVT panel through which air was passed increased by approximately 10.1% compared to that of the PV panel. In addition, a heat collection efficiency of approximately 46.6% was generated by the temperature increase of the air passing through the PVT panel.


Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3860
Author(s):  
Priyanka Shinde ◽  
Ioannis Boukas ◽  
David Radu ◽  
Miguel Manuel de Manuel de Villena ◽  
Mikael Amelin

In recent years, the vast penetration of renewable energy sources has introduced a large degree of uncertainty into the power system, thus leading to increased trading activity in the continuous intra-day electricity market. In this paper, we propose an agent-based modeling framework to analyze the behavior and the interactions between renewable energy sources, consumers and thermal power plants in the European Continuous Intra-day (CID) market. Additionally, we propose a novel adaptive trading strategy that can be used by the agents that participate in CID market. The agents learn how to adapt their behavior according to the arrival of new information and how to react to changing market conditions by updating their willingness to trade. A comparative analysis was performed to study the behavior of agents when they adopt the proposed strategy as opposed to other benchmark strategies. The effects of unexpected outages and information asymmetry on the market evolution and the market liquidity were also investigated.


2014 ◽  
Vol 13 (1) ◽  
pp. 03
Author(s):  
E. Avallone ◽  
A. I. Sato ◽  
V. L. Scalon ◽  
A. Padilha

The need of renewable energy sources due to climate change and thus the search for clean energy sources, justify the growing investment on new types of solar collectors. The research has contributed to this expansion in the scope of solar concentrator collectors, with the efficiency as the main goal. Many works have been developed in order to optimize the thermal stratification of the fluid inside the tubes and heat reservoirs, as well as mathematical modeling considering the problem as transient heat flow as boundary condition. In this work is studied experimentally, the heating of the water by solar collector modified from the conventional evacuated tube, focusing on efficiency. With the help of CFD software, a theoretical analysis is done to visualize the phenomenon, assuming the same boundary conditions and geometric experimental problem. An important approach concerns the physical separation of the flows of both cold and hot water inside the evacuated tube. The system performance was analyzed using experimental tests performed outdoors with sunlight.


Author(s):  
Alexey Dragunov ◽  
Eugene Saltanov ◽  
Igor Pioro ◽  
Pavel Kirillov ◽  
Romney Duffey

It is well known that the electrical-power generation is the key factor for advances in any other industries, agriculture and level of living. In general, electrical energy can be generated by: 1) non-renewable-energy sources such as coal, natural gas, oil, and nuclear; and 2) renewable-energy sources such as hydro, wind, solar, biomass, geothermal and marine. However, the main sources for electrical-energy generation are: 1) thermal - primary coal and secondary natural gas; 2) “large” hydro and 3) nuclear. The rest of the energy sources might have visible impact just in some countries. Modern advanced thermal power plants have reached very high thermal efficiencies (55–62%). In spite of that they are still the largest emitters of carbon dioxide into atmosphere. Due to that, reliable non-fossil-fuel energy generation, such as nuclear power, becomes more and more attractive. However, current Nuclear Power Plants (NPPs) are way behind by thermal efficiency (30–42%) compared to that of advanced thermal power plants. Therefore, it is important to consider various ways to enhance thermal efficiency of NPPs. The paper presents comparison of thermodynamic cycles and layouts of modern NPPs and discusses ways to improve their thermal efficiencies.


2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
T. Pimonenko ◽  
O. Lyulyov ◽  
N. Letunovska ◽  
O. Lytvynenko ◽  
A. Nazarenko

The article aims to study current trends in the use of solar energy in Ukraine and the world as one of the main directions of decarbonization of the national economy. The authors systematize the prospects, advantages and disadvantages of the development of renewable energy sources. They conducted a comparative analysis of the "efficiency" of solar energy in some countries and Ukraine. The authors determined that the leading position in terms of the share of energy consumed from renewable sources is occupied by countries with developed economies due to the availability of effective motivational mechanisms. From the experience of EU countries, the authors concluded that renewable energy sources form a prerequisite for obtaining additional socio-economic and environmental effects. In the presence of favorable market conditions, renewable energy sources can increase the level of energy security in the country and its energy independence. The article analyzes the legislation of Ukraine on stimulating the development of alternative energy. The authors proposed two opposed ways of further developing solar energy in Ukraine. In particular, the country can implement methods of using alternative energy, which developed countries have successfully implemented. Another area involves increasing research and innovation in implementing, using, maintaining, and utilizing energy-generating devices from alternative energy sources. Despite the polarity of the proposed directions for further development of renewable energy, in both cases, the state policy on attracting investment and promoting the use of energy from alternative energy sources is crucial. In addition, the authors noted the benefits for society from the development and implementation of alternative energy sources. The scaling up and promotion of energy production technologies from alternative sources can reduce carbon emissions, which has been an urgent problem globally.


Author(s):  
N. V. Tsopa ◽  
A. E. Dikarev

in the article provides a comparative analysis of the development of solar energy in the world, in the European Union, in Russia and in Crimea; the advantages and disadvantages of the use of solar energy, the features of the use of renewable energy sources are considered, the use of solar energy in the Crimea is justified; describes the mechanism of a feasibility study for the use of autonomous power supply for low-rise buildings in Crimea.


2021 ◽  
Vol 5 (3) ◽  
pp. 56-61
Author(s):  
Ahmet Erhan AKAN

The decrease in fossil-based energy sources and increasing environmental problems increase the tendency to renewable energy sources day by day. The potential of renewable energy sources differs according to the region where the energy will be produced. For this reason, it is crucial to conduct a good feasibility study that deals with the selected systems from a technical and economic point of view before making an investment decision on energy conversion systems based on renewable energy sources. In this study, the most suitable equipment and capacities were investigated by examining the techno-economic analysis of a hybrid system created with wind-solar renewable energies for a detached house, which is considered off-grid, in a rural area of Tekirdağ province (40o58.7ı N, 27o30.7ı E). Investigations were carried out using the HOMER Pro (Hybrid Optimization Model for Electric Renewable) program. The wind and solar energy potential of Tekirdağ province were obtained from the NASA renewable energy resources database added to the HOMER Pro program. The daily electricity requirement of the sample house was chosen as 11.27 kWh, and the current peak electrical load was chosen as 2.39 kW. A wind turbine is connected to the AC busbars, solar collectors and battery group connected to the DC busbars, and a converter that converts energy between AC and DC busbars in the energy conversion system. In order to determine the optimum capacities of the system elements, 27486 different simulations were performed by HOMER Pro. The selection of the most suitable system among these was determined according to the lowest net present cost (NPC) value. In addition, the energy production capacities that will occur in the case of different wind speeds were also investigated. Accordingly, the system to be installed with a solar panel with a capacity of 6.25 kW, PV-MPPT with a capacity of 1 kW, 2 wind turbines with a capacity of 1 kW, 8 Lithium-ion batteries with a capacity of 6V-167 Ah, and a converter with a capacity of 2.5 kW has been determined will generate electrical energy of 5433 kWh per year. In addition, it has been determined that 61.8% of this produced energy will be obtained from solar energy and 38.2% from wind energy, and the simple payback period of the investment will be 14 years. It is thought that this study will provide valuable information to researchers and investors.


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