scholarly journals Enabling thermal efficiency improvement and waste heat recovery using liquid air harnessed from offshore renewable energy sources

2020 ◽  
Vol 275 ◽  
pp. 115351 ◽  
Author(s):  
Julian D. Osorio ◽  
Mayank Panwar ◽  
Alejandro Rivera-Alvarez ◽  
Chrys Chryssostomidis ◽  
Rob Hovsapian ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Thermal Efficiency ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Renewable Energy Sources ◽  
Energy Sources ◽  
Efficiency Improvement

scholarly journals Design analysis methods for Stirling engines

2008 ◽  
Vol 19 (3) ◽  
pp. 4-19 ◽  
Author(s):  
H. Snyman ◽  
T.M. Harms ◽  
J.M. Strauss
Keyword(s):  
Renewable Energy ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Renewable Energy Sources ◽  
Design Analysis ◽  
Energy Sources ◽  
Simple Analysis ◽  
Methods Of Analysis ◽  
Stirling Engines

Worldwide attempts are being made to increase the use of our renewable energy sources as well as to use our current fossil fuel energy sources more effi-ciently. Waste heat recovery forms a substantial part of the latter and is the focus of this project. Stirling technology finds application in both the renewable energy sector and in waste heat recovery. Investigating the applicability of Stirling engines in the above-mentioned fields is relevant to develop more efficient external combustion units as well as to utilize our renewable energy sources. Developing a design analysis and synthesis tool capable of opti-mizing Stirling powered units forms the main objec-tive of this project. The methodology followed to achieve this, involved the application of three differ-ent methods of analysis, namely the method of Schmidt, the adiabatic analysis and the simple analysis based on a five volume approach. The Schmidt analysis is used to obtain the internal engine pressure which is a required input for the adiabatic analysis while the simple analysis intro-duces pumping losses and regenerator inefficien-cies. These methodologies are discussed briefly in this paper. Experimental verification of the analyti-cal data was carried out on a Heinrici Stirling engine and both the analytical data and the experi-mental data are presented here. Shortcomings of these methods of analysis are highlighted and an alternative approach to solve particular shortcom-ings is presented.

scholarly journals The IRC-PD Tool: A Code to Design Steam and Organic Waste Heat Recovery Units

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5611
Author(s):  
Youcef Redjeb ◽  
Khatima Kaabeche-Djerafi ◽  
Anna Stoppato ◽  
Alberto Benato
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Renewable Energy Sources ◽  
Safety Information ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Industrial Processes ◽  
Working Fluid ◽  
Energy Sources

The Algerian economy and electricity generation sector are strongly dependent on fossil fuels. Over 93% of Algerian exports are hydrocarbons, and approximately 90% of the generated electricity comes from natural gas power plants. However, Algeria is also a country with huge potential in terms of both renewable energy sources and industrial processes waste heat recovery. For these reasons, the government launched an ambitious program to foster renewable energy sources and industrial energy efficiency. In this context, steam and organic Rankine cycles could play a crucial role; however, there is a need for reliable and time-efficient optimization tools that take into account technical, economic, environmental, and safety aspects. For this purpose, the authors built a mathematical tool able to optimize both steam and organic Rankine units. The tool, called Improved Rankine Cycle Plant Designer, was developed in MATLAB environment, uses the Genetic Algorithm toolbox, acquires the fluids thermophysical properties from CoolProp and REFPROP databases, while the safety information is derived from the ASHRAE database. The tool, designed to support the development of both RES and industrial processes waste heat recovery, could perform single or multi-objective optimizations of the steam Rankine cycle layout and of a multiple set of organic Rankine cycle configurations, including the ones which adopt a water or an oil thermal loop. In the case of the ORC unit, the working fluid is selected among more than 120 pure fluids and their mixtures. The turbines’ design parameters and the adoption of a water- or an air-cooled condenser are also optimization results. To facilitate the plant layout and working fluid selection, the economic analysis is performed to better evaluate the plant economic feasibility after the thermodynamic optimization of the cycle. Considering the willingness of moving from a fossil to a RES-based economy, there is a need for adopting plants using low environmental impact working fluids. However, because ORC fluids are subjected to environmental and safety issues, as well as phase out, the code also computes the Total Equivalent Warming Impact, provides safety information using the ASHRAE database, and displays an alert if the organic substance is phased out or is going to be banned. To show the tool’s potentialities and improve the knowledge on waste heat recovery in bio-gas plants, the authors selected an in-operation facility in which the waste heat is released by a 1 MWel internal combustion engine as the test case. The optimization outcomes reveal that the technical, economic, environmental, and safety performance can be achieved adopting the organic Rankine cycle recuperative configuration. The unit, which adopts Benzene as working fluid, needs to be decoupled from the heat source by means of an oil thermal loop. This optimized solution guarantees to boost the electricity production of the bio-gas facility up to 15%.

Power Cycles of Generation III and III+ Nuclear Power Plants

2014 ◽  
Author(s):  
Alexey Dragunov ◽  
Eugene Saltanov ◽  
Igor Pioro ◽  
Pavel Kirillov ◽  
Romney Duffey
Keyword(s):  
Renewable Energy ◽  
Natural Gas ◽  
Thermal Efficiency ◽  
Nuclear Power ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Thermal Power ◽  
Electrical Energy ◽  
Energy Sources ◽  
Thermal Power Plants

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.

scholarly journals Integrated Capacitive Deionization and Humidification-Dehumidification System for Brackish Water Desalination

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7641
Author(s):  
Sadam-Hussain Soomro ◽  
Yusufu Abeid Chande Jande ◽  
Salman Memon ◽  
Woo-Seung Kim ◽  
Young-Deuk Kim
Keyword(s):  
Renewable Energy ◽  
Salt Concentration ◽  
Brackish Water ◽  
Waste Heat ◽  
Renewable Energy Sources ◽  
Water Desalination ◽  
Energy Sources ◽  
Capacitive Deionization ◽  
Combined System ◽  
Flow Rates

A hybrid capacitive deionization and humidification-dehumidification (CDI–HDH) desalination system is theoretically investigated for the desalination of brackish water. The CDI system works with two basic operations: adsorption and regeneration. During adsorption, water is desalted, and during the regeneration process the ions from electrodes are detached and flow out as wastewater, which is higher in salt concentration. This wastewater still contains water but cannot be treated again via the CDI unit because CDI cannot treat higher-salinity waters. The discarding of wastewater from CDI is not a good option, since every drop of water is precious. Therefore, CDI wastewater is treated using waste heat in a process that is less sensitive to high salt concentrations, such as humidification-dehumidification (HDH) desalination. Therefore, in this study, CDI wastewater was treated using the HDH system. Using the combined system (CDI–HDH), this study theoretically investigated brackish water of various salt concentrations and flow rates at the CDI inlet. A maximum distillate of 1079 L/day was achieved from the combined system and the highest recovery rate achieved was 24.90% from the HDH unit. Additionally, two renewable energy sources with novel ideas are recommended to power the CDI–HDH system.

scholarly journals Energy benchmarking in educational buildings in the city of Kragujevac - possibilities for energy efficiency improvement

2021 ◽  
Vol 18 (1) ◽  
pp. 95-114
Author(s):  
Ana Radojevic ◽  
Danijela Nikolic ◽  
Jasna Radulovic ◽  
Jasmina Skerlic
Keyword(s):  
Energy Efficiency ◽  
Renewable Energy ◽  
Energy Consumption ◽  
Co2 Emissions ◽  
Renewable Energy Sources ◽  
Electricity Consumption ◽  
Energy Sources ◽  
Efficiency Improvement ◽  
Energy Efficiency Improvement ◽  
Energy Benchmarking

The implementation of energy efficiency measures and use of renewable energy sources in educational buildings can significantly contribute to reducing energy consumption, but also to CO2 emissions in the entire public sector. The paper shows the comparison of energy consumption indicators for 61 elementary school buildings which have previously been divided in 12 groups, according to the period of construction and size, based on the national typology called TABULA, as the first step of further study on how to use the renewable energy sources. The aim of this paper is to use the energy benchmarking process to select representative facilities which are suitable for applying renewable energy sources, for their further energy efficiency improvement. Indicators of annual specific electricity consumption and CO2 emissions per unit area [kWh/m2] and per user [kWh/user] were calculated. After that, from two groups (in which the highest electricity consumption and CO2 emissions are 68.37% and 74.53% of the total consumption/ emissions), one representative facility was selected.

Efficiency Enhancement of Novel Photovoltaic-Thermal (PVT) Air Collector

2014 ◽  
Vol 494-495 ◽  
pp. 1845-1848 ◽  
Author(s):  
Huan Liang Tsai ◽  
Chieh Yen Hsu ◽  
Yung Chou Chen
Keyword(s):  
Solar Cells ◽  
Thermal Efficiency ◽  
Heat Sink ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Conduction Mechanism ◽  
Waste Heat ◽  
Operating Temperature ◽  
The Novel ◽  
Efficiency Enhancement

This paper presents the efficiency enhancement for a novel photovoltaic/thermal (PVT) air collector in which PV and thermal efficiency is simultaneously enhanced with a reciprocal aid. With the encapsulation of solar cells directly on a fin-type heat sink, the direct conduction mechanism and the convective area for the thermal transportation are effectively increased. Through a two-month experiment measurement, it is found that the thermal efficiency of PVT module is obviously enhanced up to over 50% in sunny days. In addition, the waste heat recovery decreases the operating temperature of solar cells and concurrently improves the PV efficiency. The results demonstrate the concurrent enhancement of the novel PVT module in PV electricity and solar thermal efficiency.

scholarly journals Thermodynamic Analysis of Supercritical Carbon Dioxide Cycle for Internal Combustion Engine Waste Heat Recovery

Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 216 ◽  
Author(s):  
Wan Yu ◽  
Qichao Gong ◽  
Dan Gao ◽  
Gang Wang ◽  
Huashan Su ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Thermal Efficiency ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Combustion Engine ◽  
Recovery Ratio ◽  
Split Flow ◽  
Exhaust Heat ◽  
Exhaust Heat Recovery

Waste heat recovery of the internal combustion engine (ICE) has attracted much attention, and the supercritical carbon dioxide (S-CO2) cycle was considered as a promising technology. In this paper, a comparison of four S-CO2 cycles for waste heat recovery from the ICE was presented. Improving the exhaust heat recovery ratio and cycle thermal efficiency were significant to the net output power. A discussion about four different cycles with different design parameters was conducted, along with a thermodynamic performance. The results showed that choosing an appropriate inlet pressure of the compressor could achieve the maximum exhaust heat recovery ratio, and the pressure increased with the rising of the turbine inlet pressure and compressor inlet temperature. The maximum exhaust heat recovery ratio for recuperation and pre-compression of the S-CO2 cycle were achieved at 7.65 Mpa and 5.8 MPa, respectively. For the split-flow recompression cycle, thermal efficiency first increased with the increasing of the split ratio (SR), then decreased with a further increase of the SR, but the exhaust heat recovery ratio showed a sustained downward trend with the increase of the SR. For the split-flow expansion cycle, the optimal SR was 0.43 when the thermal efficiency and exhaust heat recovery ratio achieved the maximum. The highest recovery ratio was 24.75% for the split-flow expansion cycle when the total output power, which is the sum of the ICE power output and turbine mechanical power output, increased 15.3%. The thermal performance of the split-flow expansion cycle was the best compared to the other three cycles.

scholarly journals Parametric Study of a Supercritical CO2 Power Cycle for Waste Heat Recovery with Variation in Cold Temperature and Heat Source Temperature

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6648
Author(s):  
Young-Min Kim ◽  
Young-Duk Lee ◽  
Kook-Young Ahn
Keyword(s):  
Heat Source ◽  
Thermal Efficiency ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Low Pressure ◽  
Power Cycle ◽  
Cooling Temperature ◽  
Source Temperature ◽  
Heat Source Temperature

The supercritical carbon dioxide (S-CO2) power cycle is a promising development for waste heat recovery (WHR) due to its high efficiency despite its simplicity and compactness compared with a steam bottoming cycle. A simple recuperated S-CO2 power cycle cannot fully utilize the waste heat due to the trade-off between the heat recovery and thermal efficiency of the cycle. A split cycle in which the working fluid is preheated by the recuperator and the heat source separately can be used to maximize the power output from a given waste heat source. In this study, the operating conditions of split S-CO2 power cycles for waste heat recovery from a gas turbine and an engine were studied to accommodate the temperature variation of the heat sink and the waste heat source. The results show that it is vital to increase the low pressure of the cycle along with a corresponding increase in the cooling temperature to maintain the low-compression work near the critical point. The net power decreases by 6 to 9% for every 5 °C rise in the cooling temperature from 20 to 50 °C due to the decrease in heat recovery and thermal efficiency of the cycle. The effect of the heat-source temperature on the optimal low-pressure side was negligible, and the optimal high pressure of the cycle increased with an increase in the heat-source temperature. As the heat-source temperature increased in steps of 50 °C from 300 to 400 °C, the system efficiency increased by approximately 2% (absolute efficiency), and the net power significantly increased by 30 to 40%.

scholarly journals ECONOMIC EFFICIENCY OF ENERGY AUTONOMY OF THE AIC DUE TO THE USE OF BIOFUELS

2019 ◽  
pp. 7-19 ◽  
Author(s):  
Inna HONCHARUK ◽  
Inna TOMASHUK
Keyword(s):  
Renewable Energy ◽  
Thermal Efficiency ◽  
Rural Areas ◽  
Energy Production ◽  
Alternative Energy ◽  
Renewable Energy Sources ◽  
Energy Sources ◽  
Agricultural Crops ◽  
Alternative Energy Sources ◽  
Live Stock

It has been substatiated in the article that renewable energy sources have recently become one of the important criteria for the sustainable development of rural areas. The emphasis is placed on the search for new and improved existing technologies for the production of alternative energy sources, expansion of their implementation areas. It is substantiated that the main reasons for such attention to the energy supply of rural territories are expected exhaustion of fossile fuels resourses, sharp increase in their prices, imperfections and low efficiency of their use technologies, harmful effects on the environment. It is shown that the situation of energy dependence can be changed by conducting the corresponding energy policy, improving the regulatory framework and attracting investment in the development of non-traditional and renewable energy sources. It is highlighted that Ukraine has sufficient opportunities to provide an adequate amount of biofuels, primarily through the use of biomass potential of agricultural crops and fast-growing energy crops. It is researched that in conditions of a complex socio-economic situation in Ukraine, a significant energy dependence on energy imports, the search for alternative energy sources is of particular relevance. It is estimated that Ukraine is among the dozens of countries - the largest consumers of energy resources, with a small share in the structure of the world's product. It is proved that energy saving today becomes one of the most important priorities of socio-economic development in the national and regional dimensions. The necessary condition for successful work in national and world agrarian markets is constant work on increasing the competitiveness of products, in particular, reducing its value by reducing the energy intensity of production. It is substantiated that agricultural producers are actively working on the issue of reducing energy consumption per unit of output. It is determined that the majority of these measures is aimed at increasing the productivity of agricultural crops, increasing productivity of the livestock sector, technical and technological re-equipment of the production process. It was emphasized that special attention should be paid to the branches of animal husbandry, because this industry is a serious source of alternative energy production. This applies not only the large live-stock producing agro-holdings but also the small households that operate in rural areas, for which live-stock production is subsidied by the state. Besides, it may become a source of energy supplies for their own needs as well. It was investigated that each year large livestock farms and poultry farms can receive environmentally friendly biofuels in an anaerobic way and significantly improve the quality of sewage. It is determined that thermal efficiency of cogeneration units of biogas production depends very much on equipment for electricity generation. For example, the use of gas-fired internal combustion engines has a thermal efficiency of 70% to 75%, while in the case of using gas turbines and boiler-wastes thermal efficiency can reach more than 90%. It is concluded that one of the ways to reduce the dependence on energy imports and to improve ecology in rural areas of Ukraine is to develop alternative energy generation in agro-industrial complex. Ukraine should create all opportunities for the development of innovative technologies for the implementation of renewable energy sources; to provide conditions for serial production and implementation of bioenergy facilities; to promote the formation of the equal competitive environment for different types of fuel. This will promote green energy production

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