scholarly journals Development of software for the thermohydraulic analysis of air coolers

2003 ◽  
Vol 57 (4) ◽  
pp. 151-158 ◽  
Author(s):  
Slobodan Serbanovic ◽  
Dejan Milosevic ◽  
Emila Djordjevic ◽  
Aleksandar Tasic ◽  
Bojan Djordjevic
Keyword(s):  
Rational Design ◽  
Ambient Air ◽  
Graphical Form ◽  
Outlet Temperature ◽  
Software Module ◽  
Thermohydraulic Calculation ◽  
Air Cooler ◽  
Optimal Values ◽  
Reliable Methods ◽  
Additional Reason

Air coolers consume much more energy compared to other heat exchangers due to the large fan power required. This is an additional reason to establish reliable methods for the rational design and thermohydraulic analysis of these devices. The optimal values of the outlet temperature and air flow rate are of particular importance. The paper presents a methodology for the thermohydraulic calculation of air cooler performances, which is incorporated in the "Air Cooler" software module. The module covers two options: cooling and/or condensation of process fluids by ambient air. The calculated results can be given in various ways ie. in the tabular and graphical form.

scholarly journals ПІДВИЩЕННЯ ЕФЕКТИВНОСТІ СИСТЕМ КОНДИЦІЮВАННЯ ПОВІТРЯ ШЛЯХОМ РОЗПОДІЛУ ТЕПЛОВОГО НАВАНТАЖЕННЯ ЗА СТУПЕНЕВИМ ПРИНЦИПОМ

2019 ◽  
pp. 49-53
Author(s):  
Євген Іванович Трушляков ◽  
Микола Іванович Радченко ◽  
Андрій Миколайович Радченко ◽  
Сергій Георгійович Фордуй ◽  
Сергій Анатолійович Кантор ◽  
...  
Keyword(s):  
Thermal Load ◽  
Air Conditioning ◽  
Rational Design ◽  
Ambient Air ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Outlet Temperature ◽  
Thermal Loads ◽  
Air Conditioning System ◽  
Air Conditioning Systems

Maintaining the operation of refrigeration compressors in nominal or close modes by selecting a rational design thermal load and distributing it in response to the behavior of the current thermal load according to the current climatic conditions is one of the promising reserves for improving the energy efficiency of air conditioning systems, which implementation ensures maximum or close to it in the annual cooling production according to air conditioning duties. In general case, the total range of current thermal loads of any air-conditioning system includes a range of unstable loads caused by precooling of ambient air with significant fluctuations in the cooling capacity according to current climatic conditions, and a range of relatively stable cooling capacity expended for further lowering the air temperature from a certain threshold temperature to the final outlet temperature. If a range of stable thermal load can be provided within operating a conventional compressor in a mode close to nominal, then precooling the ambient air with significant fluctuations in thermal load requires adjusting the cooling capacity by using a variable speed compressor or using the excess of heat accumulated at reduced load. Such a stage principle of cooling ensures the operation of refrigerating machines matching the behavior of current thermal loads of any air-conditioning system, whether the central air conditioning system with ambient air procession in the central air conditioner or its combination with the local indoors recirculation air conditioning systems in the air-conditioning system. in essence, as combinations of subsystems – precooling of ambient air with the regulation of cooling capacity and subsequent cooling air to the mouth of the set point temperature under relatively stable thermal load.

Pinch Point Analysis of Air Cooler in sCO2 Brayton Cycle Operating Over Ambient Temperature Range

2019 ◽  
Author(s):  
Ankur Deshmukh ◽  
Jayanta Kapat
Keyword(s):  
Water Discharge ◽  
Ambient Air ◽  
Operating Conditions ◽  
Brayton Cycle ◽  
Pinch Point ◽  
Power Cycle ◽  
Point Analysis ◽  
Air Cooler ◽  
Set Up ◽  
Cycle Efficiency

Abstract Supercritical CO2 Brayton Power cycle is getting commercially attractive for power generation due to its numerous advantages like zero water discharge, compactness, low environmental emission and potential to reach high thermal efficiency. A typical recuperated sCO2 closed cycle consists of three heat exchangers (main heat exchanger, cooler and recuperator) and two turbomachinery (sCO2 turbine and sCO2 compressor). The cooler using ambient air for cooling is the focus of this study. Steady state air cooler model is set up to study the effect of air cooler size on cycle efficiency. The effect of change in ambient air temperature on air cooler pinch point for different air cooler sizes is analyzed using transient air cooler model. The simulation is setup for design of approximately 100MWe sCO2 cycle with operating temperature of 700° C and pressure of 250 barA. Transient calculations are done using LMS AMESim. LMS AMESim is Siemens PLM commercially available software. This work thus serves as a framework to develop a design basis for air cooler in sCO2 cycle as a function of transient operating conditions.

scholarly journals Gas turbine unite inlet air cooling by using an excessive refrigeration capacity of absorption-ejector chiller in booster air cooler

2018 ◽  
Vol 70 ◽  
pp. 03012 ◽  
Author(s):  
Roman Radchenko ◽  
Andrii Radchenko ◽  
Serhiy Serbin ◽  
Serhiy Kantor ◽  
Bohdan Portnoi
Keyword(s):  
Gas Turbine ◽  
Cooling System ◽  
Ambient Air ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Air Cooling ◽  
Two Stage ◽  
Air Cooler ◽  
Refrigeration Capacity ◽  
Heat Loads

Two-stage Gas turbine unite (GTU) inlet air cooling by absorption lithium-bromide chiller (ACh) to the temperature 15 °C and by refrigerant ejector chiller (ECh) to 10 °C through utilizing the turbine exhaust gas heat for changeable ambient air temperatures and corresponding heat loads on the air coolers for the south Ukraine climatic conditions is analysed. An excessive refrigeration capacity of combined absorption-ejector chiller (AECh) exceeding the current heat loads and generated at decreased heat loads on the air coolers at the inlet of GTU can be used for covering increased heat loads to reduce the refrigeration capacity of AECh. The GTU inlet air cooling system with an ambient air precooling booster stage and a base two-stage cooling air to the temperature 10 °C by AECh is proposed. The AECh excessive cooling capacity generated during decreased heat loads on the GTU inlet air coolers is conserved in the thermal accumulator and used for GTU inlet air precooling in a booster stage of air cooler during increased heat loads. There is AECh cooling capacity reduction by 50% due to the use of a booster stage for precooling GTU inlet ambient air at the expense of an excessive cooling capacity accumulated in the thermal storage.

CFD Application on Ventilation System of Hydro-Generator

2011 ◽  
Vol 383-390 ◽  
pp. 3561-3565
Author(s):  
Qun Feng Zhang ◽  
Jin Li Yan ◽  
Min Wang ◽  
Zhi Xiang Chen
Keyword(s):  
Pressure Loss ◽  
Rational Design ◽  
Ventilation System ◽  
Local Pressure ◽  
Porous Media Model ◽  
Air Cooler ◽  
Frame Method ◽  
Flow Flux ◽  
Icem Cfd ◽  
Different Parts

Averaged 3D N-S equations and RNG k-ε equations were solved with parallel computing CFD code on the flow field of dual radial ventilation system without fan for a hydro-generator. The MRF(multiple implicit rotating frame) method was used to simulated the rotating motion of the generator and porous media model were used to simulate the pressure loss of air cooler. Rational tactics were selected to generate calculation grids to compromise with calculation CPU time and result accuracy and the grids of different parts were generated with ICEM-CFD. The flow characteristic of different parts was analyzed and flow flux of different section was obtained. The research indicated that the flow from leakage gap between poles and stators formed "air wall", which generated a recirculation zone and made the bar cooling bad. The local pressure loss of stator entrance is dominant. There are leeward and windward areas for the air flowing with circumferential velocity component. Rational design of stator ducts entrance with some diversion effect, can reduce the pressure loss of the stator ventilation and improve the cooling of leeward area in stator ducts.

scholarly journals Rational Development and Characterization of a Ubiquitin Variant with Selectivity for Ubiquitin C-Terminal Hydrolase L3

Biomolecules ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 62
Author(s):  
Chad S. Hewitt ◽  
Chittaranjan Das ◽  
Daniel P. Flaherty
Keyword(s):  
Rational Design ◽  
Deubiquitinating Enzyme ◽  
Triple Mutant ◽  
Cellular Assays ◽  
Rational Development ◽  
Alternative Approach ◽  
Covalent Adducts ◽  
Reliable Methods ◽  
Insight Into

There is currently a lack of reliable methods and strategies to probe the deubiquitinating enzyme UCHL3. Current small molecules reported for this purpose display reduced potency and selectivity in cellular assays. To bridge this gap and provide an alternative approach to probe UCHL3, our group has carried out the rational design of ubiquitin-variant activity-based probes with selectivity for UCHL3 over the closely related UCHL1 and other DUBs. The approach successfully produced a triple-mutant ubiquitin variant activity-based probe, UbVQ40V/T66K/V70F-PRG, that was ultimately 20,000-fold more selective for UCHL3 over UCHL1 when assessed by rate of inactivation assays. This same variant was shown to selectively form covalent adducts with UCHL3 in MDA-MB-231 breast cancer cells and no reactivity toward other DUBs expressed. Overall, this study demonstrates the feasibility of the approach and also provides insight into how this approach may be applied to other DUB targets.

scholarly journals Modeling of compositions and predicting properties of modified mixtures for rough thin-layer coatings

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Dmitriy Chernykh ◽  
Mihail Pakin
Keyword(s):  
Thin Layer ◽  
Building Materials ◽  
Physical And Mechanical Properties ◽  
Graphical Form ◽  
Operational Parameters ◽  
Mathematical Planning ◽  
Statistical Research ◽  
Second Stage ◽  
Optimal Values ◽  
Planning Of Experiments

In recent years, the approach to experimental and statistical research and optimization of complex multicomponent systems has changed radically. In various fields of scientific and technical research, methods of mathematical planning of experiments are successfully used. Their wide application significantly increases the effectiveness of research, as well as proves their universality and suitability in most studies of building materials. As a result, the authors present a method of mathematical planning of the experiment, which is used to optimize the composition and properties of modified mixtures for rough thin-layer coatings. This method allows a fairly complete and comprehensive assessment of the effect of components on the properties of modified mixtures and to obtain a mathematical model of the process in graphical form, as well as to obtain a theoretical model for evaluating and predicting the physical, mechanical and operational properties of the materials under study. In this article, the first stage of research was used to select the percentage of binder, hydrate lime and additives, and also studied the influence of the variation factor of these components on the physical and mechanical properties of the mixture. At the second stage, changes in response functions were investigated. The results of a complete three-factor experiment allowed us to establish rational ranges of values of the studied components in order to obtain mixtures for rough concolay coatings with optimal values of physical, mechanical and operational parameters.

scholarly journals Monitoring the efficiency of cooling air at the inlet of gas engine in integrated energy system

2020 ◽  
pp. 344-344
Author(s):  
Andrii Radchenko ◽  
Ionut-Cristian Scurtu ◽  
Mykola Radchenko ◽  
Serhiy Forduy ◽  
Anatoliy Zubarev
Keyword(s):  
Waste Heat ◽  
Cooling System ◽  
Ambient Air ◽  
Energy System ◽  
Air Conditioner ◽  
Absorption Chiller ◽  
Gas Engine ◽  
Chilled Water ◽  
Air Cooler ◽  
Cooling Air

The fuel efficiency of gas engines is effected by the temperature of intake air at the suction of turbocharger. The data on dependence of fuel consumption and engine electric power on the intake air temperature were monitored for Jenbacher gas engine JMS 420 GS-N.LC to evaluate its influence. A waste heat of engine is rejected for heating water to the temperature of about 90??. The heat received is used in absorption lithium-bromide chiller to produce a cold in the form of chilled water. A cooling capacity of absorption chiller firstly is spent for technological needs and then for feeding the central air conditioner for cooling the ambient air incoming the engine room, from where the air is sucked by the engine turbocharger. The monitoring data revealed the reserves to enhance the efficiency of traditional cooling system of intake air by absorption chiller through deeper cooling. This concept can be realized in two ways: by addition cooling a chilled water from absorption chiller to about 5-7?? for feeding engine intake air cooler or by two-stage cooling with precooling ambient air by chilled water from ACh in the first stage and subsequent deep cooling air to the temperatures 7-10?? in the second stage of intake air cooler by using a refrigerant as a coolant. In both cases the ejector chiller could be applied as the most simple in design.

Research on Movement Stability of Robotic Arm Driven by Antagonistic Pneumatic Artificial Muscle with Mechanical Properties

2013 ◽  
Vol 644 ◽  
pp. 235-238
Author(s):  
Jun Xian Zhu ◽  
Yu Wang ◽  
He Ting Tong
Keyword(s):  
Rational Design ◽  
Simulation Analysis ◽  
Artificial Muscle ◽  
Robotic Arm ◽  
Rotational Inertia ◽  
Artificial Muscles ◽  
Ideal System ◽  
Starting Point ◽  
Movement Stability ◽  
Optimal Values

This paper presents a method how to implement stable rotation of an 1D robotic arm driven by antagonistic pneumatic artificial muscles (PAM) based on SIMULINK platform. Through simulation analysis, the optimal values of the torque from tensile difference of PAM, damping coefficient and rotational inertia were determined to ensure that the robotic arm can smoothly turn from starting point to target one inside an limited interval of time. The results of the study provide a useful reference for the rational design of mechanical characteristics and structure features of the dynamic system. And they also provide more ideal system parameters for successive control of the system.

scholarly journals Experimental Study of the Slit Spacing and Bed Height on the Thermal Performance of Slit-Glazed Solar Air Heater

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Seyyed Mahdi Taheri Mousavi ◽  
Fuat Egelioglu
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Ambient Air ◽  
Solar Air Heater ◽  
Outlet Temperature ◽  
Flow Rates ◽  
Air Mass ◽  
Bed Height ◽  
Mass Flow Rates

The thermal performances of three slit-glazed solar air heaters (SGSAHs) were investigated experimentally. Three SGSAHs with different bed heights (7 cm, 5 cm, and 3 cm) were fabricated with multiple glass panes used for glazing. The length, width, and thickness of each pane were 154 cm, 6 cm, and 0.4 cm, respectively. Ambient air was continuously withdrawn through the gaps between the glass panes by fans. The experiments were conducted for four different gap distances between the glass panes (0.5 mm, 1 mm, 2 mm, and 3 mm) and the air mass flow rate was varied between 0.014 kg/s and 0.057 kg/s. The effects of air mass flux on the outlet temperature and thermal efficiency were studied. For the SGSAH with bed height of 7 cm and glass pane gap distance of 0.5 mm, the highest efficiency was obtained as 82% at a mass flow rate of 0.057 kg/s and the air temperature difference between the inlet and the outlet (∆T) was maximum (27°C) when the mass flow rate was least. The results demonstrate that for lower mass flow rates and larger gaps, the performance of SGSAH with a bed height of 3 cm was better compared to that of others. However, for higher mass flow rates, the SGSAH with 7 cm bed height performed better.

scholarly journals Impact of indirect evaporative air cooler type on the performance of desiccant systems

2018 ◽  
Vol 44 ◽  
pp. 00134 ◽  
Author(s):  
Anna Pacak ◽  
Aleksandra Cichoń ◽  
Demis Pandelidis ◽  
Sergey Anisimov
Keyword(s):  
Air Temperature ◽  
Cross Flow ◽  
Ambient Air ◽  
System Component ◽  
Air Humidity ◽  
Desiccant Wheel ◽  
System A ◽  
Air Cooler ◽  
Operational Factors ◽  
System Configurations

In this study, two different indirect evaporative coolers operating with a desiccant wheel are compared theoretically: System A with the regenerative Maisotsenko Cycle (M-Cycle) unit and System B with the cross-flow M-cycle unit. Each system component performance was simulated using the original ε-NTU model. The influence of selected operational factors, such as inlet air temperature, humidity and regeneration air temperature for two system configurations was analysed and compared. It was established, that System B obtains higher cooling capacities and is more sensitive on ambient air humidity changes than System A.

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