scholarly journals IR detection of the methane halides fluid-like state at ambient conditions

2021 ◽  
pp. 48-48
Author(s):  
Iosif Grinvald ◽  
Rostislav Kapustin
Keyword(s):  
Variable Thickness ◽  
Phase State ◽  
Thermodynamic Characteristics ◽  
Dual Phase ◽  
Vapor Compression ◽  
Ambient Conditions ◽  
Reversible Transition ◽  
Ir Detection ◽  
Ir Study

The paper presents the IR-study of the fluid-like state generated at ambient conditions for methane halides (iodomethane, tetrachloromethane, tri-chloromethane, and dichloromethane). It was shown that at vapor compression-extension procedure realized in variable thickness spectral cell (VTOC), the dual phase state exhibiting both gas and liquid properties arises. A reversible transition from a gas-like to a liquid-like shape, independent on the thermodynamic characteristics of the studied methane halides, was revealed.

Achieving Ultra-Low Energy Consumption in Data Center Mechanical Systems Through Indirect Airside Economization

2016 ◽  
Author(s):  
Dan Comperchio ◽  
Sameer Behere
Keyword(s):  
Information Technology ◽  
Energy Consumption ◽  
Data Center ◽  
Energy Use ◽  
Data Centers ◽  
Mechanical Systems ◽  
Electrical Energy ◽  
Vapor Compression ◽  
Ambient Conditions ◽  
Air Temperatures

Data center cooling systems have long been burdened by high levels of redundancy requirements, resulting in inefficient system designs to satisfy a risk-adverse operating environment. As attitudes, technologies, and sustainability awareness change within the industry, data centers are beginning to realize higher levels of energy efficiency without sacrificing operational security. By exploiting the increased temperature and humidity tolerances of the information technology equipment (ITE), data center mechanical systems can leverage ambient conditions to operate in economization mode for increased times during the year. Economization provides one of the largest methodologies for data centers to reduce their energy consumption and carbon footprint. As outside air temperatures and conditions become more favorable for cooling the data center, mechanical cooling through vapor-compression cycles is reduced or entirely eliminated. One favorable method for utilizing low outside air temperatures without sacrificing indoor air quality is through deploying rotary heat wheels to transfer heat between the data center return air and outside air without introducing outside air into the white space. A metal corrugated wheel is rotated through two opposing airstreams with varying thermal gradients to provide a net cooling effect at significantly reduced electrical energy over traditional mechanical cooling topologies. To further extend the impacts of economization, data centers are also able to significantly raise operating temperatures beyond what is traditionally found in comfort cooling applications. The increase in the dry bulb temperature provided to the inlet of the information technology equipment, as well as an elevated temperature rise across the equipment significantly reduces the energy use within a data center.

scholarly journals Influence of composition on the external quantum efficiency of reduced graphene oxide/carbon nanoparticle based photodetector used for human body IR detection

RSC Advances ◽  
2019 ◽  
Vol 9 (33) ◽  
pp. 18996-19005 ◽  
Author(s):  
Mohammad Sahabul Alam ◽  
Monny Akter Boby ◽  
Farzana Aktar Chowdhury ◽  
Hamad Albrithen ◽  
Mohammad Abul Hossain
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Human Body ◽  
Carbon Nanoparticles ◽  
Ambient Conditions ◽  
Ir Detector ◽  
Ir Radiation ◽  
Carbon Nanoparticle ◽  
Reduced Graphene ◽  
Ir Detection

We report an efficient infrared (IR) detector comprising reduced graphene oxide (RGO) and carbon nanoparticles (CNPs) for detecting human body IR radiation under ambient conditions.

scholarly journals Ultra-broad spectral photo-response in FePS3 air-stable devices

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Maria Ramos ◽  
Felix Carrascoso ◽  
Riccardo Frisenda ◽  
Patricia Gant ◽  
Samuel Mañas-Valero ◽  
...  
Keyword(s):  
Light Exposure ◽  
High Refractive Index ◽  
Ultraviolet Region ◽  
Narrow Gap ◽  
Ambient Conditions ◽  
Near Ir ◽  
Type Semiconductor ◽  
Photo Response ◽  
Ir Detection ◽  
P Type

AbstractVan der Waals materials with narrow energy gaps and efficient response over a broadband optical spectral range are key to widen the energy window of nanoscale optoelectronic devices. Here, we characterize FePS3 as an appealing narrow-gap p-type semiconductor with an efficient broadband photo-response, a high refractive index, and a remarkable resilience against air and light exposure. To enable fast prototyping, we provide a straightforward guideline to determine the thickness of few-layered FePS3 nanosheets extracted from the optical transmission characteristics of several flakes. The analysis of the electrical photo-response of FePS3 devices as a function of the excitation energy confirms a narrow gap suitable for near IR detection (1.23 eV) and, more interestingly, reveals a broad spectral responsivity up to the ultraviolet region. The experimental estimate for the gap energy is corroborated by ab-initio calculations. An analysis of photocurrent as a function of gate voltage and incident power reveals a photo-response dominated by photogating effects. Finally, aging studies of FePS3 nanosheets under ambient conditions show a limited reactivity of the outermost layers of flakes in long exposures to air.

Experimental and simulation study of the performance of a desiccant loop cooling system

2021 ◽  
pp. 095765092110105
Author(s):  
R Venkatesh ◽  
Madhu Ganesh ◽  
S Suriyaprakash ◽  
SE Deva Surya ◽  
L Ashok Kumar ◽  
...  
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Cooling System ◽  
Vapor Compression ◽  
Ambient Conditions ◽  
Experimental Conditions ◽  
Vapor Compression System ◽  
Reduced Power Consumption ◽  
Indian Cities

The paper presents experimental data and results from a prediction tool for the performance of a desiccant loop cooling system. The experiments are performed under a variety of high humidity and hot ambient conditions and the system performance is described. One of the experimental conditions is typical of many Indian cities and the systems appropriate for those cities are established. A simulation program that can predict the performance of the desiccant loop is developed. The simulation results show that this system can work as effectively as vapor compression air-conditioning for certain ambient conditions whereas it can function as a pre-cooler to a vapor compression system under more severe conditions, resulting in a reduced power consumption. The results presented in the paper give a guideline to practicing engineers as to when a desiccant loop cooling system would be useful. A simple payback analysis and a lifecycle cost analysis shows that a desiccant cooling system with a waste heat recovery recuperator is an economically viable investment.

Aqua Absorption Turbine Inlet Cooler

2003 ◽  
Author(s):  
Donald C. Erickson ◽  
Icksoo Kyung ◽  
G. Anand ◽  
E. E. Makar
Keyword(s):  
Los Angeles ◽  
Waste Heat ◽  
Operating Cost ◽  
Air Cooling ◽  
Vapor Compression ◽  
Absorption Refrigeration ◽  
Ambient Conditions ◽  
Distributed Energy ◽  
Vapor Compression Refrigeration ◽  
Ammonia Absorption

The emerging Distributed Energy Resources (DER) program envisions extensive use of small to midsize turbines for on-site power production. Their output decreases substantially at warm ambient conditions when it is most needed. Therefore inlet air cooling had received much scrutiny as a way to avoid this degradation. This study examines three approaches to inlet air cooling: evaporative cooling; mechanical vapor compression refrigeration; and waste heat powered absorption refrigeration. The benefits and limitations of each process were documented. Ammonia absorption refrigeration is shown to deliver the greatest benefit to continuosly operating turbines at very favorable installed and operating cost. The most economical process identified included an ammonia refrigeration cycle integrated directly into the combustion turbine cycle. This cycle was designed and modeled, and analyzed with ambient temperature conditions for six geographic areas (Boston, Atlanta, Los Angeles, Honolulu, Phoenix, and Chicago). Annual benefits for each area are detailed.

Experimental Investigation and Simulation of a Boeing 747 Auxiliary Power Unit

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Christos Skliros ◽  
Fakhre Ali ◽  
Ian Jennions
Keyword(s):  
Simulation Model ◽  
Rotational Speed ◽  
Failure Modes ◽  
Electrical Power ◽  
Thermodynamic Characteristics ◽  
Aircraft Engine ◽  
Ambient Conditions ◽  
Auxiliary Power ◽  
And Performance ◽  
Calibrated Simulation

Abstract Auxiliary power units (APUs) are a major driver of maintenance on civil aircraft. However, experimental data and performance simulations are rarely seen in public domain literature. While there is recourse to aircraft engine experience, this does not address the loading and the failure modes of an APU. This work aims to add to the literature, by experimentally investigating a Boeing 747 APU, collecting data under various power settings and ambient conditions, and using these data to calibrate a simple simulation model. This simulation model will subsequently be used to explore failure modes in the APU and hence what sensors may be needed for health monitoring purposes in future work. In this paper, a Boeing 747 APU rig development process and the testing strategy are presented. The rig is validated through a process that includes uncertainty analysis, repeatability tests, consistency tests, and comparison of the collected data with the calibrated simulation model. The results from the rig's validation indicate that the data collected from the APU is independent of its running time or the order of loading cycles imposed on it, i.e., the results are path independent. Changes in pneumatic and electrical power result in small changes in the rotational speed despite the fact that the rotational speed should remain constant. The rotational speed shows a slightly increasing trend when the extracted power rises, and this affects the APU thermodynamic characteristics. This work has resulted in a calibrated simulation model that will be further used in examining fault mode scenarios, as injecting these directly into the rig is seen as high risk.

Magnetic Dual-Phase State of Superparamagnetic Particles in the Field of Mechanical Stresses

2013 ◽  
Vol 683 ◽  
pp. 377-380 ◽  
Author(s):  
Leonid Afremov ◽  
Ilia Ilyushin
Keyword(s):  
Phase State ◽  
Mechanical Stresses ◽  
Dual Phase ◽  
Two Phase ◽  
Superparamagnetic Particles ◽  
Magnetic States

The set of equation has been worked out, allow to study the effect of mechanical stresses on distribution of two-phase superparamagnetic particles over equilibrium magnetic states. The method of analysis of mechanical stresses effect on metastability of magnetic states of superparamagnetic two-phase particles system has been developed.

scholarly journals Performance Assessment of a Hybrid Vapor Compression and Evaporative Cooling Fresh-Air-Handling Unit Operating in Hot Climates

Processes ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 872 ◽  
Author(s):  
Yousef Al Horr ◽  
Bourhan Tashtoush ◽  
Nelson Chilengwe ◽  
Mohamed Musthafa
Keyword(s):  
Cooling System ◽  
Evaporative Cooling ◽  
Climatic Conditions ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Direct Expansion ◽  
Ambient Conditions ◽  
Air Handling Unit ◽  
Mode Of Operation ◽  
Cooling Effects

Evaporative cooling can be integrated into fresh-air-handling units, to reduce cooling demand. This study considers a hybrid fresh-air-handling unit which incorporates a vapor-compression cooling cycle and indirect evaporative cooling to condition an ambient primary airstream to a desired supply air state. The cooling effects of using various modes (vapor compression only; direct expansion with mist; direct expansion with water shower; and direct expansion with mist and water shower) are compared when the fresh-air-handling unit operates in harsh (hot and humid) climatic conditions experienced in Qatar. Experimental analysis is based on actual ambient conditions measured from August 2018 to July 2019. It is found that the best-performing wet mode of operation saves more than 60% of the energy required by a conventional direct expansion cooling system operating under the same ambient conditions. In hot, dry conditions, the coefficient of performance of the fresh-air-handling unit when using the indirect evaporative mode of operation is double the coefficient of performance when operating with direct expansion mode only.

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