Eight-Ton Advanced GAX Cycle Prototype Results

2000 ◽  
Author(s):  
G. Anand ◽  
Donald C. Erickson

Abstract The advanced Vapor eXchange Generator Absorber heat eXchange (VX GAX) cycle has similar components as the basic GAX cycle but is a three-pressure cycle and makes more complete use of the GAX temperature overlap. Less external heat is supplied to the generator, and the cycle efficiency is increased. A breadboard prototype of a gas-fired heat pump using the VX GAX cycle has been developed and tested. A higher COP was achieved using reliable and cost effective components. This paper presents the VX GAX cycle breadboard design concept, the hardware realization, and the performance achieved. Several novel concepts were incorporated to achieve the design objectives of higher efficiency and capacity, lower cost, compactness, avoidance of code restrictions, and operability from 49°C (120°F) summer to −8°C (17°F) winter ambient conditions. The prototype results have confirmed the high performance capability of the advanced GAX cycle. At 35°C (95°F) ambient air-cooled conditions, a gas-cooling COP of 0.85 was achieved at design capacity. This is a 20% improvement relative to current basic GAX chillers. The eight-ton capacity is ideal for small-scale commercial applications and provides economy of scale. The wide ambient operating range is key to year-round operation and attractive payback in all climate zones. The demonstrated improvement in both system performance and cost is key to achieving nationwide mass-market status.

2018 ◽  
Vol 51 (4) ◽  
pp. 291-336 ◽  
Author(s):  
Antimo Graziano ◽  
Shaffiq Jaffer ◽  
Mohini Sain

Blends of polyethylene (PE) and polypropylene (PP) have always been the subject of intense reasearch for encouraging polymer waste recycling while producing new materials for specific applications in a sustainable way. However, being thermodynamically immiscible, these polyolefins form a binary system usually exhibiting lower performances compared with those of the homopolymers. Many studies have been carried out to better understand the PE/PP blend compatibilization for developing a high-performance and cost-effective product. Both nonreactive and reactive compatibilization promote the brittle to ductile transition for a PE/PP blend. However, the final product usually does not meet the requirements for high demanding commercial applications. Therefore, further PE/PP modification with a reinforcing filler, being either synthetic or natural, proved to be a good method for manufacturing high-performance reinforcend polymer blend composites, with superior and tailored properties. This review summarizes the recent progress in compatibilization techniques applied for enhancing the interfacial adhesion between PE and PP. Moreover, future perspectives on better understanding the influence of themodynamics on PE/PP synergy are discussed to introduce more effective compatibilization strategies, which will allow this blend to be used for innovative industrial applications.


2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Rohit Saraf ◽  
Hua Fan ◽  
Vivek Maheshwari

AbstractFlexible, large-area, and stable perovskite photodetectors have drawn increasing widespread research attention for next-generation wearable and portable optoelectronic devices. However, high mechanical durability coupled with large device area and enhanced environmental stability has not been demonstrated yet to attain practical viability. Herein, a highly bendable, stable, and large-area (3 cm2) flexible polystyrene incorporated perovskite photodetector is presented. Due to the formation of a porous polystyrene-perovskite composite film in a single step it allows unprecedented mechanical stability, maintaining 85% of its original photocurrent value after 10,000 bending cycles at a bending angle of 120°. Equally crucial, the solution-processed self-assembled Pt–Au nanochains were developed to provide a simple and fast method of patterning the conductive and flexible electrodes onto the filter substrate. The optimized polystyrene-perovskite photodetector exhibits a high responsivity up to 2.73 A W−1, a maximum specific detectivity of 6.2 × 1013 Jones, and a superior switching ratio of 1.0 × 104. In addition, the polystyrene-perovskite photodetector yields excellent stability under the combined stresses of moisture, ambient air, and room light, and retains 92% of its original performance for over 30 days. All these results demonstrate that this work provides a facile and cost-effective approach that paves the way to develop high-performance, stable, and highly flexible optoelectronic devices.


Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3126 ◽  
Author(s):  
Minjeong Park ◽  
Joohee Kim ◽  
Hanjung Song ◽  
Seonpil Kim ◽  
Minhyon Jeon

Ionic electroactive polymer (IEAP) actuators that are driven by electrical stimuli have been widely investigated for use in practical applications. However, conventional electrodes in IEAP actuators have a serious drawback of poor durability under long-term actuation in open air, mainly because of leakage of the inner electrolyte and hydrated cations through surface cracks on the metallic electrodes. To overcome this problem, a top priority is developing new high-performance ionic polymer actuators with graphene electrodes that have superior mechanical, electrical conductivity, and electromechanical properties. However, the task is made difficultby issues such as the low electrical conductivity of graphene (G). The percolation network of silver nanowires (Ag-NWs) is believed to enhance the conductivity of graphene, while poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), which exhibits excellent stability under ambient conditions, is expected to improve the actuation performance of IEAP actuators. In this study, we developed a very fast, stable, and durable IEAP actuator by employing electrodes made of a nanocomposite comprising PEDOT:PSS and graphene–Ag-NWs (P/(G–Ag)). The cost-effective P/(G–Ag) electrodes with high electrical conductivity displayed a smooth surface resulting from the PEDOT:PSS coating, which prevented oxidation of the surface upon exposure to air, and showedstrong bonding between the ionic polymer and the electrode surface. More interestingly, the proposed IEAP actuator based on the P/G–Ag electrode can be used in active biomedical devices, biomimetic robots, wearable electronics, and flexible soft electronics.


Author(s):  
Xihui Wu ◽  
Azim Eskandarian

Abstract This paper introduces a small-scale platform for Connected Autonomous Vehicle (CAV) research that outperforms currently available commercial options in several important benchmarks. The platform is built around a Radio-Control (RC) car utilizing high-performance brushless DC motors allowing the vehicle to reach a maximum speed of 70mph, expanding the possibilities for higher speed research applications. Furthermore, this platform (named after our lab, ASIMcar, for brevity in this article) is equipped with a robust sensor suite and features a state-of-the-art embedded GPU unit for onboard computation, allowing for real-time control over a wide range of challenging operations. For demonstration and comparison, lane keeping as an Advanced Driving Assistance System (ADAS) function was implemented and evaluated using the platform. The commercially available mobile robots are expensive, offer limited capabilities, are harder to modify for various research needs, are more difficult to interface with other robots (cars), and could have proprietary software/hardware features which render them less flexible and less adaptable to specific research needs. The developed ASIMcar overcomes these limitations and provides a highly flexible and cost-effective alternative for automated/autonomous and connected vehicle research and development projects. This paper provides an in-depth description for the development of this car and lists significant features which will assist other researchers to easily and rapidly duplicate them and create a similar platform for their research.


Author(s):  
William E. Simon ◽  
Terrence L. Chambers ◽  
John L. Guillory ◽  
Varaprasad Ventrapragada ◽  
Jeremy R. Angelle ◽  
...  

Until recently the cost of fuel cells for terrestrial applications was prohibitive. Recently, several companies have begun developing high-performance, long-life and cost-effective fuel cell systems, and commercial units are now becoming available for stationary power generation. These systems can often be operated in conjunction with other energy systems to increase overall operational efficiency. A recent technology demonstration project at the University of Louisiana at Lafayette involved the installation, operation and analysis of a fuel cell and a desiccant dehumidification system, which is considered a good combination for the hot, humid climate of the U.S. Gulf coast. The three-year project involved technology assessment, hardware selection and procurement, installation, and operation of the two systems, followed by a performance analysis. The results were reported in a regional symposium. This paper describes the project, focusing on system operation and the results obtained, and predicts future possibilities for integrated energy systems of this type.


Author(s):  
Tanvir Ahmed ◽  
Tanjid Zaman

Drying is an important agricultural process, particularly for crops, and shriveled products are used all over the world. The performance of drying green chili was also tested in this article, which created an alternate way of drying agricultural products. The goal of this study is to provide a solar biomass hybrid dryer with improved design, construction, and performance testing. During most hours of the trial, the temperature within the solar collector and dryer was sufficiently higher than the ambient temperature, according to the results obtained during the test period. The temperature of the ambient air at the collector intake ranged from 30 to 35 degrees Celsius. The temperature of the air at the collector's outlet ranged from 54 to 64 degrees Celsius, while the temperature of the drying chamber ranged from 51 to 60 degrees Celsius, making it suitable for drying green chili and a variety of other agricultural products. The collector was found to be 46.54 percent efficient. The findings revealed that the alteration of the collector, which produces turbulent air flow and improves chamber wall insulation, affects drying. Based on the results of this study, the created solar biomass hybrid drier is cost-effective for small-scale crop growers in rural areas of developing countries.


Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4793 ◽  
Author(s):  
Joanna K. Huertas ◽  
Lawrence Quipuzco ◽  
Amro Hassanein ◽  
Stephanie Lansing

Biological desulfurization of biogas from a field-scale anaerobic digester in Peru was tested using air injection (microaeration) in separate duplicate vessels and chemical desulfurization using duplicate iron filters to compare hydrogen sulfide (H2S) reduction, feasibility, and cost. Microaeration was tested after biogas retention times of 2 and 4 h after a single injection of ambient air at 2 L/min. The microaeration vessels contained digester sludge to seed sulfur-oxidizing bacteria and facilitate H2S removal. The average H2S removal efficiency using iron filters was 32.91%, with a maximum of 70.21%. The average H2S removal efficiency by iron filters was significantly lower than microaeration after 2 and 4 h retention times (91.5% and 99.8%, respectively). The longer retention time (4 h) resulted in a higher average removal efficiency (99.8%) compared to 2 h (91.5%). The sulfur concentration in the microaeration treatment vessel was 493% higher after 50 days of treatments, indicating that the bacterial community present in the liquid phase of the vessels effectively sequestered the sulfur compounds from the biogas. The H2S removal cost for microaeration (2 h: $29/m3 H2S removed; and 4 h: $27/m3 H2S removed) was an order of magnitude lower than for the iron filter ($382/m3 H2S removed). In the small-scale anaerobic digestion system in Peru, microaeration was more efficient and cost effective for desulfurizing the biogas than the use of iron filters.


Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 741
Author(s):  
Olga Dombrowski ◽  
Harrie-Jan Hendricks Franssen ◽  
Cosimo Brogi ◽  
Heye Reemt Bogena

Affordable and accurate weather monitoring systems are essential in low-income and developing countries and, more recently, are needed in small-scale research such as precision agriculture and urban climate studies. A variety of low-cost solutions are available on the market, but the use of non-standard technologies raises concerns for data quality. Research-grade all-in-one weather stations could present a reliable, cost effective solution while being robust and easy to use. This study evaluates the performance of the commercially available ATMOS41 all-in-one weather station. Three stations were deployed next to a high-performance reference station over a three-month period. The ATMOS41 stations showed good performance compared to the reference, and close agreement among the three stations for most standard weather variables. However, measured atmospheric pressure showed uncertainties >0.6 hPa and solar radiation was underestimated by 3%, which could be corrected with a locally obtained linear regression function. Furthermore, precipitation measurements showed considerable variability, with observed differences of ±7.5% compared to the reference gauge, which suggests relatively high susceptibility to wind-induced errors. Overall, the station is well suited for private user applications such as farming, while the use in research should consider the limitations of the station, especially regarding precise precipitation measurements.


TAPPI Journal ◽  
2018 ◽  
Vol 17 (09) ◽  
pp. 507-515 ◽  
Author(s):  
David Skuse ◽  
Mark Windebank ◽  
Tafadzwa Motsi ◽  
Guillaume Tellier

When pulp and minerals are co-processed in aqueous suspension, the mineral acts as a grinding aid, facilitating the cost-effective production of fibrils. Furthermore, this processing allows the utilization of robust industrial milling equipment. There are 40000 dry metric tons of mineral/microfbrillated (MFC) cellulose composite production capacity in operation across three continents. These mineral/MFC products have been cleared by the FDA for use as a dry and wet strength agent in coated and uncoated food contact paper and paperboard applications. We have previously reported that use of these mineral/MFC composite materials in fiber-based applications allows generally improved wet and dry mechanical properties with concomitant opportunities for cost savings, property improvements, or grade developments and that the materials can be prepared using a range of fibers and minerals. Here, we: (1) report the development of new products that offer improved performance, (2) compare the performance of these new materials with that of a range of other nanocellulosic material types, (3) illustrate the performance of these new materials in reinforcement (paper and board) and viscosification applications, and (4) discuss product form requirements for different applications.


2011 ◽  
Vol 39 (3) ◽  
pp. 193-209 ◽  
Author(s):  
H. Surendranath ◽  
M. Dunbar

Abstract Over the last few decades, finite element analysis has become an integral part of the overall tire design process. Engineers need to perform a number of different simulations to evaluate new designs and study the effect of proposed design changes. However, tires pose formidable simulation challenges due to the presence of highly nonlinear rubber compounds, embedded reinforcements, complex tread geometries, rolling contact, and large deformations. Accurate simulation requires careful consideration of these factors, resulting in the extensive turnaround time, often times prolonging the design cycle. Therefore, it is extremely critical to explore means to reduce the turnaround time while producing reliable results. Compute clusters have recently become a cost effective means to perform high performance computing (HPC). Distributed memory parallel solvers designed to take advantage of compute clusters have become increasingly popular. In this paper, we examine the use of HPC for various tire simulations and demonstrate how it can significantly reduce simulation turnaround time. Abaqus/Standard is used for routine tire simulations like footprint and steady state rolling. Abaqus/Explicit is used for transient rolling and hydroplaning simulations. The run times and scaling data corresponding to models of various sizes and complexity are presented.


Sign in / Sign up

Export Citation Format

Share Document