scholarly journals The effect of mean pressure on the performance of a single-stage heat-driven thermoacoustic cooler

2020 ◽  
Vol 15 (3) ◽  
pp. 471-476
Author(s):  
Irna Farikhah
Keyword(s):  
High Efficiency ◽  
Waste Heat ◽  
Heating Temperature ◽  
Acoustic Power ◽  
Environmental Issue ◽  
Thermoacoustic Engine ◽  
Limit Value ◽  
The World ◽  
Mean Pressure ◽  
Thermoacoustic Cooler

Abstract Waste heat is an environmental issue in the world. There are some technologies that can be used to recovery the waste heat, one of which is thermoacoustic cooler technology. Thermoacoustic technology can be divided into two parts: one is thermoacoustic engine and cooler. To design the cooler system having high efficiency and lower onset heating temperature, the effect of mean pressure is investigated. By increasing mean pressure from 0.5 to 3 MPa, the heating temperature generating acoustic power can be decreased from 831 to 580 K. Moreover, 15% of Thermodynamic upper limit value of the whole cooler system is achieved.

scholarly journals Numerical Study on the Effect of Mean Pressure and Loop's Radius to the Onset Temperature and Efficiency of Traveling Wave Termoacustic Engine

2020 ◽  
Vol 3 (3) ◽  
pp. 96-103
Author(s):  
Endang Dian Rokhmawati ◽  
Irna Farikhah ◽  
Ummi Kaltsum ◽  
Harto Nuroso ◽  
Aan Burhanudin ◽  
...  
Keyword(s):  
Traveling Wave ◽  
Waste Heat ◽  
Numerical Study ◽  
Heating Temperature ◽  
Heat Energy ◽  
Onset Temperature ◽  
Working Fluid ◽  
Air Conditioner ◽  
Mean Pressure ◽  
Stability Limits

The thermoacoustic engine can be a device to convert waste heat energy in the engine car become useful energy such as for charging battery in car or Air conditioner of the car. This work can be done by experimentally and numerically. There are some parameters that have an impact on the performance of the engine. They are geometry of the engines, working fluid, and mean pressure. The performance of the engine depends on the efficiency and the heating temperature. In the car, waste heat energy is not high enough. Therefore, we need to utilize the low heating temperature to be converted into useful energy. This study contributes to numerically the effect of mean pressure and loop’s radius of the regenerator on the onset temperature and the efficiency of traveling wave thermoacoustic engines. The application that is used to solve numerical problems is fortran95. There are two codings that are used in fortran95. They are stability limits and efficiency codes. The lowest onset temperature that achieved is 153˚C with efficiency up to 38.1% that can be reached when the mean pressure is 4.0 MPa and the loop's radius is 5 cm. This result indicated that we can use low heating temperatures from waste heat of engine car to turn on electronics equipment inside the car.

A TRAVELING WAVE THERMOACOUSTIC ENGINE - DESIGN AND TEST

2021 ◽  
pp. 1-9
Author(s):  
Mitchell McGaughy ◽  
Chengshi Wang ◽  
Eric Boessneck ◽  
Thomas Salem ◽  
John R Wagner
Keyword(s):  
Acoustic Wave ◽  
Traveling Wave ◽  
System Analysis ◽  
Waste Heat ◽  
Electrical Power ◽  
Performance Testing ◽  
Cost Effective ◽  
Acoustic Power ◽  
Consumer Products ◽  
Thermoacoustic Engine

Abstract The demand for clean, sustainable, and cost-effective energy continues to increase due to global population growth and corresponding use of consumer products. The provision of heat to a thermoacoustic prime mover results in the generation of an acoustic wave that can be converted into electrical power. Thermoacoustic devices offer highly reliable and transportable power generation with low environmental impact using a variety of fuel sources. This paper focuses on the design and testing of a single stage, traveling wave, thermoacoustic engine. The system configuration, component design, and integration of sensors will be described. Performance testing and system analysis shows that for a 300 W heat source, the thermoacoustic machine generates a 54 Hz acoustic wave with a thermal efficiency of 7.8%. The system's acoustic power output may be increased by 84% through improved heat exchanger design. Tuning of the acoustic system and optimization of the bi-directional turbine merit attention to realize an applicable waste heat energy harvesting system.

scholarly journals A Theoretical and Experimental Study of Moderate Temperature Alfa Type Stirling Engines

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1622 ◽  
Author(s):  
Jacek Kropiwnicki ◽  
Mariusz Furmanek
Keyword(s):  
High Efficiency ◽  
Waste Heat ◽  
Heating Temperature ◽  
Mechanical Energy ◽  
Stirling Engine ◽  
Moderate Temperature ◽  
Heat Sources ◽  
Stirling Engines ◽  
Charge Pressure ◽  
Further Development

The Stirling engine is a device that allows conversion of thermal energy into mechanical energy with relatively high efficiency. Existing commercial designs are mainly based on the usage of high temperature heat sources, whose availability from renewable or waste heat sources is significantly lower than that of moderate temperature sources. The paper presents the results of experimental research on a prototype alpha type Stirling engine powered by a moderate temperature source of heat. Obtained results enabled calibration of the evaluated theoretical model of the Stirling engine. The model of the engine has been subsequently used for the analysis of regenerator effectiveness influenced by the charge pressure and the heating temperature. Performed study allowed to determine further development directions of the prototype engine to improve its power and efficiency. As a result of optimization, worked out design will potentially increase the indicated efficiency up to 19.5% (5.5% prototype) and the indicated power up to 369 W (114 W prototype).

RESPONSABILIDADE AMBIENTAL DA PESQUISA MINERAL COM FINS ACADÊMICOS E CIENTÍFICOS

2020 ◽  
Vol 7 (2020) (2) ◽  
pp. 1-11
Author(s):  
Milson Xavier ◽  
Keyword(s):  
Extended Period ◽  
Environmental Issue ◽  
Legal Order ◽  
Environmental Legislation ◽  
Mineral Industry ◽  
Mineral Research ◽  
Legal Provisions ◽  
The World ◽  
Legal Security

he Coronavirus pandemic that spread around the world in the first half of 2020 brought impacts to society that will be registered for an extended period. In this paper, the effects showed an impossibility to maintain the progress of mineral research made by professionals in the academic and scientific areas. In an attempt to find justifications in the legal order of the mineral industry, to continue the work, it was faced with imposing environmental legislation that made a claim even more difficult. It was found that the Mining Code in place no longer regulates the activities of extraction of mineral specimens for museums, educational establishments and other scientific purposes. This left the legal security tied only to the interpretation of legal provisions in articles of the code and its regulation, as well as procedure manuals for environmental inspection bodies, and therefore, subject to the consequences of legal disputes with final decisions in higher courts, given the claim of superiority of the environmental issue over mining. Keywords: Coronavirus, pandemic, environmental legislation, mining code

scholarly journals The Main Progress of Perovskite Solar Cells in 2020–2021

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Tianhao Wu ◽  
Zhenzhen Qin ◽  
Yanbo Wang ◽  
Yongzhen Wu ◽  
Wei Chen ◽  
...  
Keyword(s):  
Solar Cells ◽  
High Efficiency ◽  
Perovskite Solar Cells ◽  
Lead Free ◽  
Manufacturing Cost ◽  
Practical Application ◽  
The World ◽  
Photovoltaic Technology

AbstractPerovskite solar cells (PSCs) emerging as a promising photovoltaic technology with high efficiency and low manufacturing cost have attracted the attention from all over the world. Both the efficiency and stability of PSCs have increased steadily in recent years, and the research on reducing lead leakage and developing eco-friendly lead-free perovskites pushes forward the commercialization of PSCs step by step. This review summarizes the main progress of PSCs in 2020 and 2021 from the aspects of efficiency, stability, perovskite-based tandem devices, and lead-free PSCs. Moreover, a brief discussion on the development of PSC modules and its challenges toward practical application is provided.

scholarly journals Research progress of viscoelastic surfactants for enhanced oil recovery

2021 ◽  
pp. 014459872098020
Author(s):  
Ruizhi Hu ◽  
Shanfa Tang ◽  
Musa Mpelwa ◽  
Zhaowen Jiang ◽  
Shuyun Feng
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
High Efficiency ◽  
Research Progress ◽  
Surfactant Flooding ◽  
Sweep Efficiency ◽  
The World ◽  
Washing Efficiency ◽  
Viscoelastic Surfactants ◽  
Viscoelastic Surfactant

Although new energy has been widely used in our lives, oil is still one of the main energy sources in the world. After the application of traditional oil recovery methods, there are still a large number of oil layers that have not been exploited, and there is still a need to further increase oil recovery to meet the urgent need for oil in the world economic development. Chemically enhanced oil recovery (CEOR) is considered to be a kind of effective enhanced oil recovery technology, which has achieved good results in the field, but these technologies cannot simultaneously effectively improve oil sweep efficiency, oil washing efficiency, good injectability, and reservoir environment adaptability. Viscoelastic surfactants (VES) have unique micelle structure and aggregation behavior, high efficiency in reducing the interfacial tension of oil and water, and the most important and unique viscoelasticity, etc., which has attracted the attention of academics and field experts and introduced into the technical research of enhanced oil recovery. In this paper, the mechanism and research status of viscoelastic surfactant flooding are discussed in detail and focused, and the results of viscoelastic surfactant flooding experiments under different conditions are summarized. Finally, the problems to be solved by viscoelastic surfactant flooding are introduced, and the countermeasures to solve the problems are put forward. This overview presents extensive information about viscoelastic surfactant flooding used for EOR, and is intended to help researchers and professionals in this field understand the current situation.

scholarly journals Effect of Green Construction on a Building’s Carbon Emission and Its Price at Materialization

2021 ◽  
Vol 13 (2) ◽  
pp. 642
Author(s):  
Shuangxi Zhou ◽  
Zhenzhen Guo ◽  
Yang Ding ◽  
Jingliang Dong ◽  
Jianming Le ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Emission Reduction ◽  
Carbon Emission ◽  
High Efficiency ◽  
Carbon Price ◽  
Carbon Trading ◽  
Construction Companies ◽  
Green Construction ◽  
The World ◽  
Total Price

Buildings consume many resources and generate greenhouse gases during construction. One of the main sources of greenhouse gases is carbon emission associated with buildings. This research is based on the computing rule of carbon emission at the materialization stage. By taking the features of green construction into consideration, quantitative analysis on construction carbon emission was undertaken via Life Cycle Assessment (LCA). Making use of Vensim (a system dynamics software package), we analyzed the amount of carbon emission at the materialization stage and determined the major subsystems affecting the carbon emission, then took into comprehensive consideration the differences of each subsystem’s carbon emission under different construction technologies. Under the mechanism of carbon trade at the materialization stage, the total price of carbon trades remains unchanged, while the trading price of each subsystem is adjusted. Under these conditions, a coefficient for step-wise increases in carbon price was proposed. By establishing such a system of gradient prices, construction companies are encouraged to adopt high-efficiency emission reduction technologies. Meanwhile, the system also provides a reference for the formulation of price-based policies about buildings’ carbon trading, and accelerates the process of energy conservation and emission reduction in China and the world at large.

Hybrid direct carbon fuel cell-thermoradiative systems for high-efficiency waste-heat recovery

2019 ◽  
Vol 198 ◽  
pp. 111842
Author(s):  
Xin Zhang ◽  
Jianying Du ◽  
Yee Sin Ang ◽  
Jincan Chen ◽  
Lay Kee Ang
Keyword(s):  
Fuel Cell ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
High Efficiency ◽  
Waste Heat ◽  
Direct Carbon Fuel Cell

Climate change in the Cameroonian press: An analysis of its representations

2020 ◽  
pp. 096366252097601
Author(s):  
Nicole Kay ◽  
Sandrine Gaymard
Keyword(s):  
Climate Change ◽  
Media Coverage ◽  
Psychological Distance ◽  
Environmental Issue ◽  
Social Psychological ◽  
Global Environmental Issue ◽  
Global Environmental ◽  
The World ◽  
The Relationship ◽  
Opening Up

Climate change is a global environmental issue and its outcome will affect societies around the world. In recent years, we have seen a growing literature on media coverage of climate change, but, to date, no study has assessed the situation in Cameroon, although it is considered to be one of the world’s most affected and vulnerable regions. This study attempted to address this deficit by analysing how climate change is represented in the Cameroonian media. A similarity analysis was performed on three newspapers published in 2013–2016. Results showed that climate coverage focused on politics and international involvement. It seems disconnected from local realities, potentially opening up a spatial and social psychological distance. The relationship between the representation of climate change and that of poverty is an area for further exploration.

Sign in / Sign up

Export Citation Format

Share Document