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Plants and Equipment
Published in Carl Bozzuto, Boiler Operator's Handbook, 2021
Unless otherwise indicated, the capacity of a compressor is always described in standard cubic feet per minute (scfm). The standard is equal to air at 60°F, 0% relative humidity, and one atmospheric pressure. The actual cfm that may be flowing in a system is often referred to as acfm. This can cause some confusion. The scfm can also be called atmospheric cfm, also abbreviated acfm. Be careful as to what is meant for any particular application. Take a burner application using an air atomizer. The burner manufacturer’s table indicates that 30 cfm of air at 80 psig is required. Call that 30 acfm. It is actually 190 scfm for a compressor (30×95÷15=190), assuming that the air is at the same temperature. If the compressor manufacturer listed the capacity as atmospheric cfm, or acfm, the wrong sized compressor might be selected. Again, be sure to read and understand the manufacturer’s information.
* , and Process Energy Management
Published in Barney L. Capehart, Wayne C. Turner, William J. Kennedy, Guide to Energy Management, 2020
Barney L. Capehart, Wayne C. Turner, William J. Kennedy
The vast majority of industrial compressors are of the rotary screw variety, but double acting reciprocating or centrifugal compressors are also available for specific applications. The diverse types of air compressors have various pros and cons associated with their use. The major design differentiation is the method of how the air is compressed, by either positive displacement or dynamically. Positive displacement compressors work by trapping a set amount of air in a compression chamber and mechanically reducing the volume, thereby causing a corresponding increase in pressure. Dynamic compressors operate by a rapidly spinning impeller which increases the air velocity, which in turn is changed into higher air pressure by the design of the impeller discharge and discharge diffusers.
*, and Process Energy Management
Published in Barney L. Capehart, William J. Kennedy, Wayne C. Turner, Guide to Energy Management, 2020
Barney L. Capehart, William J. Kennedy, Wayne C. Turner
The vast majority of industrial compressors are of the rotary screw variety, but double acting reciprocating or centrifugal compressors are also available for specific applications. The diverse types of air compressors have various pros and cons associated with their use. The major design differentiation is the method of how the air is compressed, by either positive displacement or dynamically. Positive displacement compressors work by trapping a set amount of air in a compression chamber and mechanically reducing the volume, thereby causing a corresponding increase in pressure. Dynamic compressors operate by a rapidly spinning impeller which increases the air velocity, which in turn is changed into higher air pressure by the design of the impeller discharge and discharge diffusers.
Review on performance analysis in diffusion absorption refrigeration system (DARS) using different working fluids
Published in International Journal of Ambient Energy, 2023
Sreenesh Valiyandi, Gireeshkumaran Thampi
In a compression-type refrigeration system, there are mainly certain demerits such as compressor leakage or failure, problems in the evaporator and condenser, motor cooling, and liquid line restriction. Compressor leakage or failure occurs due to overheating, slugging and clogging, and some lubrication problems and such demerits make the compressor fail (Pachbhai et al. 2017). Problems in Condenser and Evaporator increase the pressure in the compressor. This may happen because the evaporator and condenser tubes are dirty or without cleaning. Motor cooling mainly occurs in the vapour compression cycle. The efficiency of drops can cause a cooling problem. Some other problems are dirty air passages, blocked air filters, or changes in voltages. Liquid line restriction occurs due to the release of discharge at high temperature, low current, high temperature, low condensing pressures, or bubbles in the glass tubes. This affects the total unit and encounters the low-pressure evaporator. It leads to reducing the cooling capacity in the refrigeration system. Vapour absorption techniques use low-grade energy like heat and thus consist of the only pump as moving parts. It makes the process easy in conditions. Lower evaporator pressure can work on the system without affecting the coefficient of performance. Figure 1 shows the vapour absorption techniques of the refrigeration system.
Finite-time adaptive sliding mode control for compressor surge with uncertain characteristic in the presence of disturbance
Published in Systems Science & Control Engineering, 2021
Li Fu, Xiuwei Fu, Masoud Taleb Ziabari
Two frequently used compressors are the centrifugal and axial flow. According to Boyce (2011), the centrifugal compressor is more efficient in high pressure, low flow rate applications, while the axial one is preferred for higher flow rate and higher speed machinery. The compressor systems commonly face two major instabilities, surge and stall, which limit their operational range. As the mass flow through the compressor drops down to a critical point, the surge occurs reflected by an unstable flow pattern. The ‘surge point’ separates the stable and unstable regions in the compressor’s characteristic curve. Likewise, the ‘surge line’ connects the surge points on the characteristic curves obtained at various compressor speeds. Surge instability can impact the entire compression system, and as a limit cycle, it is characterized by extreme fluctuations in the compressor’s pressure and flow, leading to a substantial loss in the efficiency and performance of the system.
Design of a robust LMI-based model predictive control method for surge instability in interconnected compressor systems in the presence of uncertainty and disturbance
Published in Systems Science & Control Engineering, 2021
Cong Xie, Hashem Imani Marrani
A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. Centrifugal compressors, sometimes called radial compressors, are a subclass of dynamic turbo-machinery and achieve a pressure rise by adding kinetic energy/velocity to a continuous flow of fluid through the rotor or impeller (Brun & Kurz, 2018; Tibrewala et al., 2014). The most important applications of centrifugal compressors are in oil refineries, natural-gas processing, petrochemical, chemical plants, air-conditioning and refrigeration and HVAC, in industry and manufacturing to supply compressed air for all types of pneumatic tools and in air separation plants to manufacture purified and product gases (Bloch & Soares, 1998).