Gas compressor

About: Gas compressor is a research topic. Over the lifetime, 91817 publications have been published within this topic receiving 552209 citations.

Variable capacity rotary compressor

Abstract: A variable capacity rotary compressor includes a hermetic casing, a housing installed in the hermetic casing to define therein first and second compression chambers having different capacities, and a compressing unit placed in the first and second compression chambers and operated to execute a compression operation in either the first or second compression chamber according to a rotating direction of a rotating shaft which drives the compressing unit. The compressor further includes a suction path controller, a high-pressure pipe, and a high-pressure path controller. The suction path controller controls a refrigerant suction path so that a refrigerant is delivered into an inlet port of the first or second compression chamber where the compression operation is executed. The high-pressure pipe couples an outlet side of the compressor to the suction path controller. The high-pressure path controller is provided at a predetermined portion of the suction path controller, and controls a high-pressure path so that the high-pressure pipe communicates with the inlet port of the first or second compression chamber where an idle operation is executed, according to variance of temperature when the refrigerant suction path is controlled by the suction path controller.

Centralized and Integrated Decentralized Compressed Air Energy Storage for Enhanced Grid Integration of Wind Power

Abstract: In this paper, we model the economic feasibility of compressed air energy storage (CAES) to improve wind power integration. The Base Case is a wind park with 100 MW of installed capacity and no storage facility. In Variant 1 we add a central CAES system with 90 MW of compressor and 180 MW of generation capacity. The compressed air is stored in a cavern. The CAES system is operated independently of the wind park such that profits from peak power sales at the spot market and reserve power market are maximized. Variant 2 is an integrated, decentralized CAES system, where each wind turbine is equipped with a compressor but no generator. The compressed air is stored in a cavern and converted into electricity by a turbine, again maximizing profit as a peak power plant. Both variants are modeled for conventional diabatic and the more advanced adiabatic systems.

Experimental and Theoretical Study of Surge in a Small Centrifugal Compressor

Abstract: Experimental results for deep surge in a small single-stage centrifugal compressor are compared to predictions based on the lumped parameter Greitzer model developed for axial compressors. Both negative and positive flow branches of the steady characteristic, being essential for the model, were measured. Predictions are in fair agreement with data when using a relaxation time smaller than the one proposed for axial compressors. The stability limit of the model equations have been studied for finite amplitude disturbances.

A Modular Code for Real Time Dynamic Simulation of Gas Turbines in Simulink

Abstract: A high-fidelity real-time simulation code based on a lumped, nonlinear representation of gas turbine components is presented. The code is a general-purpose simulation software environment useful for setting up and testing control equipments. The mathematical model and the numerical procedure are specially developed in order to efficiently solve the set of algebraic and ordinary differential equations that describe the dynamic behavior of gas turbine engines. For high-fidelity purposes, the mathematical model takes into account the actual composition of the working gases and the variation of the specific heats with the temperature, including a stage-by-stage model of the air-cooled expansion. The paper presents the model and the adopted solver procedure. The code, developed in Matlab-Simulink using an object-oriented approach, is flexible and can be easily adapted to any kind of plant configuration. Simulation tests of the transients after load rejection have been carried out for a single-shaft heavy-duty gas turbine and a double-shaft aero-derivative industrial engine. Time plots of the main variables that describe the gas turbine dynamic behavior are shown and the results regarding the computational time per time step are discussed.

Method of operating a transport refrigeration unit

Abstract: A method of operating a transport refrigeration system having a refrigerant compressor driven by an internal combustion engine. Microprocessor based electrical control maintains the temperature of a conditioned space at a desired set point via heating, cooling and null cycles, with the engine being started and stopped, as required. During the engine starting process, a suction line modulation valve, if used, is closed, engine pre-heat time is selected, including using engine temperature to access a look-up table, and current draw is checked during pre-heat. Excessive current terminates pre-heat. Control diagnostics checks the voltage level on both sides of a refrigerant high pressure switch, before initiating engine cranking. Prior to stopping the engine, a control option initiates a heating cycle for a short time when null is being entered from a cooling cycle, to warm the evaporator and prevent premature starting of the engine.