scholarly journals Comparison of Liquid Desiccants for Air Cooling Systems Using Wetted Wall Column

2019 ◽  
Vol 9 (2) ◽  
pp. 691-698
Author(s):  
S. Shanmuga Priya et al., S. Shanmuga Priya et al., ◽  
Keyword(s):  
Air Cooling ◽  
Cooling Systems ◽  
Wetted Wall Column

Thermal Performance Evaluation of Friction Stir Welded Flat Plate Heat Sink Using CFD Analysis

2015 ◽  
Vol 787 ◽  
pp. 505-509
Author(s):  
A.K. Lakshminarayanan ◽  
M. Suresh
Keyword(s):  
Flat Plate ◽  
Heat Sink ◽  
High Efficiency ◽  
Base Plate ◽  
Software Tool ◽  
Cover Plate ◽  
Air Cooling ◽  
Cooling Systems ◽  
Plate Heat ◽  
Friction Stir

In an era of compact cooling requirements, where air cooling systems seem to be ineffective and consistently, being replaced by liquid cooled systems, with greater watt density heat energy dissipation. Such cooling systems must work with good quality enabling high efficiency. Hence, an attempt is made to fabricate an aluminum alloy based flat plate heat sink with cover and base plate using friction stir welding. The base plate is machined to obtain channels for fluid flow and the cover plate is fitted in the base plate and welded. Two such configurations of these heat sinks were fabricated with varying channel lengths and number of channels. The flow characteristics of the model for these configurations were analyzed numerically using computational fluid dynamics (CFD) software tool, ANSYS fluent 14.

Inlet Air Cooling Applied to Combined Cycle Power Plants: Influence of Site Climate and Thermal Storage Systems

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Nicola Palestra ◽  
Giovanna Barigozzi ◽  
Antonio Perdichizzi
Keyword(s):  
Power Output ◽  
Parametric Analysis ◽  
Power Plants ◽  
Cooling System ◽  
Thermal Storage ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Air Cooling ◽  
Ambient Conditions ◽  
Cooling Systems

The paper presents the results of an investigation on inlet air cooling systems based on cool thermal storage, applied to combined cycle power plants. Such systems provide a significant increase of electric energy production in the peak hours; the charge of the cool thermal storage is performed instead during the night time. The inlet air cooling system also allows the plant to reduce power output dependence on ambient conditions. A 127MW combined cycle power plant operating in the Italian scenario is the object of this investigation. Two different technologies for cool thermal storage have been considered: ice harvester and stratified chilled water. To evaluate the performance of the combined cycle under different operating conditions, inlet cooling systems have been simulated with an in-house developed computational code. An economical analysis has been then performed. Different plant location sites have been considered, with the purpose to weigh up the influence of climatic conditions. Finally, a parametric analysis has been carried out in order to investigate how a variation of the thermal storage size affects the combined cycle performances and the investment profitability. It was found that both cool thermal storage technologies considered perform similarly in terms of gross extra production of energy. Despite this, the ice harvester shows higher parasitic load due to chillers consumptions. Warmer climates of the plant site resulted in a greater increase in the amount of operational hours than power output augmentation; investment profitability is different as well. Results of parametric analysis showed how important the size of inlet cooling storage may be for economical results.

scholarly journals Study on Outside Air Cooling Systems Used in Data Processing Facilities

2012 ◽  
Vol 11 (1) ◽  
pp. 219-223 ◽  
Author(s):  
Iwao Yamaguchi ◽  
Makoto Koganei ◽  
Tomonobu Goto ◽  
Masataka Tsushima
Keyword(s):  
Data Processing ◽  
Air Cooling ◽  
Cooling Systems

Numerical simulations of flow induced noise from a dual rotor cooling fan used in electronic cooling systems

2021 ◽  
Vol 263 (5) ◽  
pp. 1308-1319
Author(s):  
Sahan Wasala ◽  
Yutong Xue ◽  
Lon Stevens ◽  
Ted Wiegandt ◽  
Tim Persoons
Keyword(s):  
Noise Exposure ◽  
Acoustic Noise ◽  
High Capacity ◽  
Disk Drive ◽  
Air Cooling ◽  
Noise Sources ◽  
Cooling Systems ◽  
Cooling Fan ◽  
Flow Induced Noise ◽  
High Level

Hard Disk Drive (HDD) system enclosures in a data center require effective cooling systems to avoid HDD overheating. These systems often rely on air cooling because of their cost effciency and maintainability. Air cooling systems typically consist of an array of axial fans which push or pull the air through the system. These fans emit high level tonal noise particularly at high tip speed ratios. High-capacity HDDs, on the other hand, are sensitive to high acoustic noise, which consequently increases the risk of read/write error and deteriorates drive performance. Therefore, cooling fan noise adversely affects the function of the HDD enclosure systems which emphasizes the need to understand the noise sources and develop methods to mitigate HDD noise exposure.

The Use of Ejector Refrigeration Systems for Turbine Inlet Air Cooling: A Thermodynamic and CFD Study

2007 ◽  
Author(s):  
Hany A. Al-Ansary
Keyword(s):  
Power Consumption ◽  
Power Output ◽  
Waste Heat ◽  
Evaporative Cooling ◽  
Published Data ◽  
Air Cooling ◽  
Refrigeration System ◽  
Compressor Blades ◽  
Cooling Systems ◽  
Turbine Inlet

Cooling turbine inlet air is a proven method of increasing turbine power output, especially during peak summer demand. It is estimated that turbine power output can increase by as much as 0.7% for every 1°C drop in inlet air temperature. Two inlet air cooling systems are widely used: evaporative cooling systems and chiller systems. Evaporative cooling is economical and uncomplicated, but its efficiency can significantly drop if the relative humidity is high. There is also a potential for excessive wear of compressor blades if water droplets are carried into the compressor section. On the other hand, chiller systems have the advantage of being independent of humidity and do not have the potential to cause damage to compressor blades. However, chiller systems consume power and cause a larger pressure drop than evaporative coolers. In this work, the possibility of using an ejector refrigeration system to cool turbine inlet air is explored. These systems are low-maintenance, fluid-driven, heat-operated devices that can use part of the turbine exhaust flow as the heat source for running the cycle. These systems require only pump power to feed liquid refrigerant to the vapor generator, making the power consumption potentially lower than conventional chiller systems. Using thermodynamic analysis, this paper compares the performance of ejector refrigeration systems with that of chiller systems based primarily on their power consumption. Performance characteristics for the ejector system are obtained through a CFD model that uses a real-gas model for R-134a. Published data on the performance of a commercial gas turbine is also considered. The power consumption of ejector refrigeration systems is found to be significantly smaller than that of vapor compression systems, with savings ranging from 19% to 80%. Power consumption is also found to be small compared to the boost in turbine power that is obtained. The percentage of waste heat needed to operate the ejector refrigeration system is found to be generally less than 25%.

Assessments of High-Efficient Regenerative Evaporative Cooler Effects on Desiccant Air Cooling Systems

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Hakan Caliskan ◽  
Dae-Young Lee ◽  
Hiki Hong
Keyword(s):  
Cooling System ◽  
Dew Point ◽  
Air Cooling ◽  
Sensible Heat ◽  
Cooling Systems ◽  
High Efficient ◽  
Air Cooling System ◽  
Evaporative Cooler ◽  
Effectiveness And Efficiency ◽  
And Performance

Abstract In this paper, the effects of regenerative evaporative coolers on the dry desiccant air cooling system are assessed. Thermodynamic analysis is performed point by point on the unmodified (ɛ = 0.67) and modified (ɛ = 1) regenerative evaporative cooler supported systems. It is found that the effectiveness and efficiency of the system were significantly increased by modification. Effectiveness of the system increases from 0.95 to 2.16 for the wet bulb and from 0.63 to 1.43 for dew point effectivenesses, while the exergy efficiency increases from 18.40% to 41.93%. Exergy and energy performances of the system increase 1.28 times and 0.61 times, respectively. Finally, sustainability is increased by 40% with the modification of the regenerative evaporative cooler. Also, changing the regenerative evaporative cooler of the solid desiccant wheel with the effective one can increase the overall system efficiency and performance without changing the sensible heat and desiccant wheels.

Relative Cooling: Part II — Design Considerations and Efficiency

2001 ◽  
Author(s):  
Sandu Constantin ◽  
Dan Brasoveanu
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Cooling System ◽  
High Reliability ◽  
Difficult Problem ◽  
Turbine Engines ◽  
Air Cooling ◽  
Gas Turbine Engines ◽  
Coolant Pump ◽  
Cooling Systems

Abstract Cooling systems with liquid for gas turbine engines that use the relative motion of the engine stator with respect to the rotor for actuating the coolant pump can be encapsulated within the engine rotor. In this manner, the difficult problem of sealing stator/rotor interfaces at high temperature, pressure and relative velocity is circumvented. A first generation of such cooling systems could be manufactured using existing technologies and would boost the thermal efficiency of gas turbine engines by more than 2% compared to recent designs that use advanced air-cooling methods. Later, relative cooling systems could increase the thermal efficiency of gas turbine engines by 8%–11% by boosting the temperatures at turbine inlet to stoichiometric levels and recovering most of the heat extracted from turbine during cooling. The appreciated high reliability of this cooling system will allow widespread use for aerospace propulsion.

Relative Cooling With Liquid for Gas Turbines: Part I — A Solution for Exceeding 2000 K at Turbine Inlet

2001 ◽  
Author(s):  
Sandu Constantin ◽  
Dan Brasoveanu
Keyword(s):  
Thermal Efficiency ◽  
Gas Turbines ◽  
Cooling System ◽  
Turbine Blades ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Cooling Systems ◽  
Turbine Inlet ◽  
Cooling Methods ◽  
Current Operating

Abstract The thermal efficiency of gas turbines is critically dependent on the temperature of burnt gases at turbine inlet, the higher this temperature the higher the efficiency. Stochiometric combustion would provide maximum efficiency, but in the absence of an internal cooling system, turbine blades cannot tolerate gas temperatures that exceed 1300 K. Therefore, for this temperature, the thermal efficiency of turbine engine is 40% less than theoretical maximum. Conventional air-cooling techniques of turbine blades allow inlet temperatures of about 1500 K on current operating engines yielding thermal efficiency gains of about 6%. New designs, that incorporate advanced air-cooling methods allows inlet temperatures of 1750–1800 K, with a thermal efficiency gain of about 6% relative to current operating engines. This temperature is near the limit allowed by air-cooling systems. Turbine blades can be cooled with air taken from the compressor or with liquid. Cooling systems with air are easier to design but have a relatively low heat transfer capacity and reduce the efficiency of the engine. Some cooling systems with liquid rely on thermal gradients to promote re-circulation from the tip to the root of turbine blades. In this case, the flow and cooling of liquid are restricted. For best results, cooling systems with liquid should use a pump to re-circulate the coolant. In the past, designers tried to place this pump on the engine stator and therefore were unable to avoid high coolant losses because it is impossible to reliably seal the stator-rotor interface. Therefore it was assumed that cooling systems with liquid could not incorporate pumps. This is an unwarranted assumption as shown studying the system in a moving frame of reference that is linked to the rotor. Here is the crucial fact overlooked by previous designers. The relative motion of engine stator with respect to the rotor is sufficient to motivate a cooling pump. Both the pump and heat exchange system that is required to provide rapid cooling of liquid with cold ambient air, could be located within the rotor. Therefore, the entire cooling system can be encapsulated within the rotor and the sealing problem is circumvented. Compared to recent designs that use advanced air-cooling methods, such a liquid cooling system would increase the thermal efficiency by 8%–11% because the temperatures at turbine inlet can reach stoichiometric levels and most of the heat extracted from turbine during cooling is recuperated. The appreciated high reliability of the system will permit a large applicability in aerospace propulsion.

Sign in / Sign up

Export Citation Format

Share Document