scholarly journals Air Cooling in Steam Plant Condenser Using Refrigeration System for Improving Vacuum Pump Performance

2020 ◽  
Author(s):  
Ahmed Hegazy ◽  
Abraham Engeda
Keyword(s):  
Vacuum Pump ◽  
Air Cooling ◽  
Refrigeration System ◽  
Pump Performance ◽  
Steam Plant

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%.

Analysis and Design of Multistage Electrostatically-Actuated Micro Vacuum Pumps

2002 ◽  
Author(s):  
Aaron Astle ◽  
Anthony Paige ◽  
Luis P. Bernal ◽  
Jennifer Munfakh ◽  
Hanseup Kim ◽  
...  
Keyword(s):  
Thermodynamic Model ◽  
Volume Ratio ◽  
High Volume ◽  
Fixed Number ◽  
Vacuum Pump ◽  
Pump Performance ◽  
Analysis And Design ◽  
Electrostatically Actuated ◽  
Flow Through ◽  
Low Volume

A new concept for a MEMS-fabricated micro vacuum pump is proposed. The pump is designed to operate in air and can be easily integrated into MEMS-fabricated micro fluidic systems. The pump consists of a series of pumping cavities with electrostatically actuated membranes interconnected by electrostatically actuated microvalves. A thermodynamic model of the micropump has been developed and used to determine the pump performance. It is shown that volume ratio plays an important role in the operation of the pump. For a fixed number of stages, at high volume ratio, pumping action is uniformly distributed among the stages. In contrast, at low volume ratio most of the pumping takes place in the latter stages of the pump. Detailed calculations of the flow through key components of the micropump are also reported. In particular the flow through a checkerboard microvalve and electrode perforations is discussed, and new correlations for the pressure loss in these components are proposed.

scholarly journals System for measuring vacuum-pump performance using the standard throughput method

ACTA IMEKO ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 65
Author(s):  
Sheng-Jui Chen
Keyword(s):  
Flow Rate ◽  
Volume Flow Rate ◽  
Test Chamber ◽  
Vacuum Pump ◽  
Volume Flow ◽  
Vacuum System ◽  
Main Method ◽  
Pump Performance ◽  
Two Parameters ◽  
Performance Results

Ultimate pressure of a vacuum system is determined by two parameters, namely the total gas load of vacuum system and the pumping speed (volume flow rate) of vacuum pump.  After the total gas load of a system is estimated, the required pumping speed can be set.  In this study, we constructed a system for measuring the pumping speed of vacuum pump according to ISO 21360-1:2012, in which three methods are described, i.e. the throughput method, the orifice method and the pump-down method.  The vacuum pump under test is designed to be used in low vacuum range for evacuating a chamber at high pumping speed.  For this reason, the throughput method was selected as the main method.  The system consists of pressure gauges, thermometers, a flow meter and a test chamber.  The system was used to measure the pumping speed at the inlet of the vacuum pump at several pressure points.  We present the system setup, uncertainty evaluation and vacuum-pump performance results of this work.

The application of dynamic modelling technique on the pipeline drying operation during pre-commissioning

2020 ◽  
Vol 60 (2) ◽  
pp. 606
Author(s):  
Diwu Chen ◽  
Andrew Duff ◽  
John Willcocks
Keyword(s):  
Gas Injection ◽  
Vacuum Pump ◽  
Vacuum Drying ◽  
Residual Water ◽  
Drying Method ◽  
Pump Performance ◽  
Dry Air ◽  
Simultaneous Operations ◽  
Pipeline Networks ◽  
Drying Efficiency

The objective of pipeline drying during pre-commissioning is to remove residual water left in the pipeline after dewatering and desalination operations. Removing the residual water mitigates corrosion and hydrate formation and aids quicker delivery of product to required dryness. The common pipeline drying methods are vacuum drying and convection drying. The convection drying method blows dry air through the pipeline to remove the residual water. Its disadvantages are an inability to adequately dry complex-shaped pipeline networks, significant equipment footprint and expelling air noise during the convection drying operation. The vacuum drying method can achieve low dewpoints particularly for complex-shaped pipeline networks and the equipment footprint can also be smaller than for the convection drying method. Therefore, it is advantageous when facing space restrictions for equipment. This paper introduces a dynamic integrated model to simulate the pipeline drying operation. This model considers vacuum pump performance and gas saturation condition in the pipeline during the drying operation. The modelling results can be used to determine the vacuum drying suitability, predict the drying operation duration and identify opportunities to improve the pipeline drying efficiency, such as vacuum pump performance, dry gas injection and convection dry air flow rate. It also demonstrates where vacuum drying is unlikely to be feasible, i.e. low ambient temperature conditions, and methods for identifying such. An optimisation case study is also presented. The drying duration can be reduced significantly by integrating vacuum drying with dry gas injection. This combined methodology can thus significantly improve the pipeline vacuum drying efficiency, which reduces the project cost and improves and de-risks scheduled and simultaneous operations.

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