Compressor Selection Research Articles

Data-driven compressor performance maps and cost correlations for small-scale heat-pumping applications

The performance of vapour-compression heat pumps depends crucially upon compressor selection and design. In this work, a unified modelling framework is developed to enable technoeconomic comparisons of compressors intended for small-scale heating applications (<30 kWth). Published information on 120 commercially available compressors is analysed and used to develop performance maps that predict isentropic efficiency over a wide range of working conditions. Additionally, cost correlations are established to predict price as a function of nominal compressor inlet volumetric flowrate. When rotary-vane compressors are an available option (i.e., for inlet volumetric flowrates up to 5 ∙ 10−3 m3/s), they consistently achieve a high isentropic efficiency (∼70 %) for the investigated pressure ratios (1.5–9.5). Scroll compressors have an even higher isentropic efficiency (∼75 %) at pressure ratios below 5.5, but this drops to 50 % at higher pressure ratios, while the isentropic efficiency of reciprocating-piston compressors is best (∼75 %) at higher pressure ratios (5.5–7.5). Utilising an air-source heat pump model, the compressor types are compared for countries with different weather characteristics and electricity prices. Rotary-vane compressors are associated with the lowest levelised cost of heat, but the comparison largely depends on location and heating requirements.

Efficient Lossless Compression of Integer Astronomical Data

Each new generation of telescope produces increasingly larger astronomical data volumes, which are expected to reach the order of exabytes in the next decade. Effective and fast data compression methods are paramount to help the scientific community contain storage costs and improve transmission times. Astronomical data differs significantly from natural and Earth-observation images, asking for specifically tailored compression approaches. This paper presents a novel lossless compression technique that employs the discrete Haar wavelet transform within the JPEG 2000 standard. Its performance is compared to that of a comprehensive selection of compressors, including fpack, the most common technique in astronomical observatories, as well as other algorithms highly competitive for other types of data. Experiments are performed on a large data set of 16 bit integer images, produced by telescopes around the world and representative of a wide variety of astronomical scenarios. The proposed technique has two modes. The first mode outperforms all the other tested techniques in terms of compression performance. It surpasses the most competitive configuration of fpack by, respectively, 5.3% (about 0.3 bits per sample), having also 4.5% lower compression and decompression times. The second mode is the fastest among all tested techniques. Its compression and decompression times are 2.5 and 3.5 times faster than the fastest configuration of fpack, while also yielding a 2.4% better compression performance (0.15 bits per sample).

Synthesis of refinery hydrogen network considering compressor selection and interstage suction/discharge

In refinery hydrogen networks, the optimal arrangement of hydrogen compressors is important to hydrogen reuse and cost reduction. The share of hydrogen compressors can not only reduce the number of compressors, but also provide the economy of scale. However, the previous studies only consider the whole share of compressors and mostly treat the compressor model as reciprocating compressors by default, which limits the optimization of hydrogen networks and does not correspond well with the practice. This paper presents a novel method for hydrogen network synthesis considering the hydrogen compressor type selection and the interstage suction/discharge of multi-stage compressors. In the developed superstructure, hydrogen sources are allowed to be suctioned and discharged via all possible stages of multi-stage compressors. Meanwhile, hydrogen sources can select centrifugal compressors or reciprocating compressors according to the working ranges. A mixed integer nonlinear programming model is developed to minimize the total annualized cost. The proposed method is suitable for both retrofit problems and new design problems, which is demonstrated by a refinery case and a literature case. For the refinery case, the zero-investment retrofit based on the existing compressors can reduce the fresh hydrogen demand by 1.73%, and the new hydrogen network design requires fewer compressors. In terms of the literature case, the hydrogen network design obtained in this paper can reduce the number of compressors by 5 or 3 through interstage suction/discharge of multi-stage compressors.

Selection of a Ship Compressor Using Statistical Data Processing

INTRODUCTION: Compressors are essential for supplying compressed air at various pressures and flow rates to the ships power systems, and to the ship as a whole. An appropriate choice of the compressor is essential for the proper operation of water transport infrastructure. Hence, it is necessary to consider this issue in detail. If all variables, the compressor selection parameters to be considered, were measured in the same scales and units, it would be possible to suggest adding up all values, but this approach is very crude. The solution is to normalize the values of the variables and then calculate a final criterion based on them.&#x0D; AIM: Finding a formal criterion by which the selection of a particular compressor will be made.&#x0D; MATERIAL AND METHODS: The process of selecting a compressor for starting the ships engines and for the general operation of the ship is discussed based on exponential and linear rationing methods. Certain parameters of compressors from domestic and foreign manufacturers are offered for statistical processing. Subsequently, data processing was carried out using maximum likelihood estimation and logistic regression.&#x0D; RESULTS: The result of the study is a single formal criterion, the final rating, instead of several qualitative parameters. A set of characteristics has been determined that describes the optimal compressor based on the above calculations and data processing. A simulation of the probability of assigning a compressor, with a certain set of characteristics, to a positive or negative class has been performed. The training of the model was done using the available training data.&#x0D; CONCLUSION: Statistical methods of data processing can be applied to an object such as a compressor. Given a set of desired compressor characteristics, it is possible to teach the machine to determine the optimal compressor.

Design and experimental study on precooled MR JT cryocooler for LNG recondensation purposes

The paper presents a preliminary experimental study of the precooled MR JT cryocooler, which was designed for LNG recondensation and potentially liquefaction purposes. The paper also includes the most vital aspects of the design: compressor selection and limitations, selection and size of expansion devices, effect of MR composition on the stability of the load temperature, and minimum approach during recuperation. In addition, a detailed description of the features of the test stand is provided. A series of experimental tests has been performed with varied heat load, suction pressure, discharge pressure, and precooling temperature. The cryocooler provided cooling power of 270 W at a temperature of −158 °C, which is the largest MR JT cryocooler reported in the literature. Experiments indicate an optimum precooling temperature similar to that derived from the theoretical study (approximately −35 °C).

A Low Power High Speed Accuracy Controllable Approximate Multiplier Design

Abstract: For energy effective and high performance design, the low power VLSI circuit is used. Multiplier is an essential part of low power VLSI design, since the effectiveness of the digital signal processor depends upon the multiplier. In multiplier circuit, utmost of the power is dissipated across in full adder circuits. Multiplication is one of the important process in microprocessor and there will be a lot of delay because of array multiplier, which can be compressed with the help of the column compressor approach. It uses a selection of half adders, full adders and compressors to sum the partial products in stages until two numbers are left. An 8 * 8 and 16 * 16 bit multiplier design is executed by assigning the adder and compressor. Partial product totality is the speed limiting operation in multiplication due to the propagation detention in adder networks. In order to reduce the propagation detention, compressors are introduced. Compressors calculate the sum and carry at each position concurrently. The attendant carry is added with a advanced significant sum bit in the coming stage. This is continued until the final product is generated. The partial product tree of the multiplier is estimated by the proposed tree compressor ( High Speed Compressor, Dual Stage Compressor, Exact Compressor). Keywords: Partial Products, Half Adder, Full Adder, High Speed Compressor, Dual Stage Compressor, Exact Compressor.

Atmospheric and Turbocharged Experimental Investigation of Heavy Vehicle Compressor Air Inlet Line

Reciprocating compressors, which come from the past to the present and whose development is parallel to internal combustion engine technolo-gies, find themselves a large share in this field in line with the innovative studies on it. The stored compressed air demanded in the heavy vehicle segment, where almost all diesel engines are used, is serviced for two main tasks such as brake and suspension system. Therefore, the engine to be used during the compressor selection; efficiency, performance and service maintenance period are very important while meeting the de-mands and what applications are used such as long-distance vehicle, construction site vehicle, transport vehicle, garbage truck, coach.In this paper, experimental studies were carried out on a Scania brand diesel vehicle by feeding the air brake compressor from the engine tur-bocharger intercooler with an improved interconnection and convention-al atmospheric feeding. Temperature and pressure values obtained via sensors from the data collection system, performance information ob-tained from the vehicle CAN module and exhaust emission measurement results measured by opacimeter for both cases are presented.

Outsourcing in the Compressed Air Sector – Financial Opportunities in Industry

The compressed air sector is currently responsible for up to 10% world-wide overall industry electricity consumption, 30% of which ascribable to the compressor technology alone. Such a datum makes the saving potential from a proper compressor selection (30-35% overall consumption) as appealing as those associated with other energy measures and in line with the 20-20-20 timeline. Plus, every electricity saving on the compressor virtually corresponds to an income from selling Energy Saving Certificates (usually referenced as White Certificates) and CO2 quotas from avoided emissions on dedicated markets, which can eventually reduce the payback time of the additional investment. Outsourcing in the CAS is addressed as the most effective alternative to efficiency ownership and its development is supported by the common perception of the compressed air as a utility, analogously to electricity and thermal energy. An in-depth net present value analysis is performed on market compressors for industrial purposes, based on the environmental market model, the electricity cost and compressors market policy in the average European context. In addition to the financial advantage from White Certificates and Carbon markets, the outsourcing always benefits from the lower investment cost on the compressor and the higher compressors efficiency: this results in lower sale prices for the cubic meter of compressed air, with little or no difference among different machine types. The relative importance of energy and investment-related costs is assessed as well. The outsourcing allows a m3 cost reduction with respect to the purchase of new compressors in the 15-20% range, dependently on the machine size and operation regime.

Study on the output pressure amplitudes of the linear compressor based on the complex vector analysis method

The advent of high-performance linear compressor has promoted the rapid development of Stirling type cryocoolers due to its advantages of low vibration, long life and compactness. At present, most of the studies on the usage of the linear compressor are focus on the high efficiency and output acoustic power (pV power) for the cold head. However, besides the above two parameters, the high-performance operation of the cold head also requires enough input pressure amplitude, which can be defined as the quality of the required power. In this study, the output pressure amplitudes of the linear compressor were graphically investigated with the help of the complex vector method. Compared to harmonic oscillation analysis, the complex vector diagram of the piston stress and velocity can provide an easier understanding for analyzing the pressure amplitude output characteristics of the compressor. Equations for estimating the output maximum pressure amplitude and the pressure amplitude under the maximum pV power of a linear compressor were deduced based on the vector diagram, which can be used for the design and selection of linear compressors. Experiments were done to verify the theoretical analysis. Influences of different operating and structure parameters on the output pressure amplitudes of the linear compressor were calculated and compared. It shows that the frequency and piston area are the optimal parameters for improving the output pressure amplitudes, which also benefits the compactness of the compressor.

A mixed integer nonlinear programming model for optimizing a gas pipeline transmission linear network

The technical equipment developed and used in both installation and operation processes in refineries, oil and gas pipelines, and gas booster stations has always been expensive. Hence, managers at different organizational levels are keen to find methods to control and reduce these costs. Generally speaking, the operators in a gas booster station choose the operating devices without considering the related costs. This research presents a mixed integer nonlinear programming model designed to minimize the operational costs of gas booster stations in a main pipeline distribution network. The goal is to optimize the choice of operating devices in these stations to minimize costs while still meeting customer demands. Turbo compressors are chosen as the operating devices and the operational costs are fuel, maintenance, start-up, and penalty costs. However, the significance indexes of these costs are valued differently by the three expert managers: the executive officer, operating head, and the overhaul repairing director. Consequently, the analytical hierarchy process (AHP) method is used to calculate the overall weights of costs, and a gas transmission company in the north of Iran is considered as a case study. The model can minimize the total cost, when compared to the selections of ten experienced operators; however, the absolute weights of choosing measures and the essence of the objective function under study mean that an operator choice exists that would represent the optimum selection of turbo compressors.

A comprehensive study of the effect of chemical impurities on selection and sizing of centrifugal machines for supercritical carbon dioxide transport pipelines

Compressors and booster pumps constitute the “heart” of the supercritical carbon dioxide transport pipeline network because they consume most of the required energy input. In other words, most of the operating expenditure for the transport pipeline goes to the running of compressors and pumps. The long-term economic feasibility of running such pipeline networks is achievable only if operating costs linked to the energy consumption of both machines can be kept as low as possible. Energy consumption can be kept as low as possible by sizing compressors and booster pumps optimally to ensure that power losses in both machines are minimized.In this study, a quasi-dimensional model based on the laws of conservation was developed, validated with available experimental data and then used for a detailed investigation of the effect of various impurities on the performance of a centrifugal machine handling supercritical carbon dioxide of varying purity. Results of the study show that discharge pressure, power requirement and efficiency of a centrifugal machine are strongly dependent on certain key parameters; namely, the size and speed of its impeller rotor as well as the composition of the impure CO2 stream. More importantly, this study also demonstrates that the quasi-dimensional model can be used as a tool for appropriate selection and sizing of centrifugal compressors and booster pumps installed on a supercritical carbon dioxide transport pipeline.

Compressed Air Supply and Distribution System for Aviation Laboratories and Wind Tunnels

Abstract The purpose of this text is to demonstrate an operation of a compressed air system designed for high air flow laboratories and wind tunnels. Development of such air system is a challenge due to unusual requirements (simultaneous supply of several users having different requirements and necessity to provide extremely high flows) which have to be address by means of adequate compressed air storage capacity and sophisticated control system. Each stage of the design process is going to be described, focusing on the selection of air compressors, air receivers and air dryers, followed by an insight into a development of the control system. The air system being described in this paper was successfully implemented at the Institute of Aviation in Warsaw improving the quality of the compressed air supply and simplifying the research planning.

Effect of Chemical Impurities on Centrifugal Machine Performance: Implications for Compressor Sizing In A CO2 Transport Pipeline

Several research studies have been published on CO2 pipeline transportation. Most of them focus on developing hydraulic models of entire CO2 pipeline networks. From these studies, a lot of original knowledge has been produced to understand the behaviour of CO2 pipeline networks under dense phase or supercritical conditions. The globalized modelling approach used in these studies are generally sufficient for carrying out an overall design and operation of an entire CO2 pipeline network. However, such models are too insufficiently detailed for use in optimizing the performance of a compressor in a CO2 transport pipeline. This is because in hydraulic models, compression is simulated with adiabatic or polytropic equations which do not account for the geometry and internal fluid flow processes within the compressor. Moreover, in energy requirement calculations involving these equations, compressor efficiency is assumed to be fixed, where as in reality, it varies with change in the purity of the CO2 stream being compressed. Given that compressors consume most of the energy needed to operate an entire CO2 pipeline network, it is vital that a detailed analysis of the effect of impurities on machine performance is done as a prerequisite for developing an optimal procedure for compressor sizing and selection. To this end, a quasi-dimensional model based on the laws of conservation was developed and validated for a detailed investigation of the effect of various impurities on the performance of a centrifugal machine handling supercritical carbon dioxide. Results of the study confirm that the power requirement of a compressor is affected by the impurities and provides an insight into the relationship between compressor size, work input and the pressure required to maintain the CO2 stream flowing in a transport pipeline network in supercritical state.

Selection of gas compressors: part 8.2

In this series, Eduardo Larrade and Rafael Ocampo look in detail at the state of the art of gas compressors. In order to illustrate the selection of compressors, two examples have been used. The discussion of the first example involving a reciprocating compressor was presented in the previous article1 and is completed here.

Selection of gas compressors: part 8.1

Selection of gas compressors: part 8.1

Effect of Various Parameters on Working Condition of Chiller

Abstract The present work aims to find out the effect of various parameters on evaporator, compressor and condenser in vapour compression cycle using “high performance tube manufacturer's software” for evaporator and condenser and using “compressor selection software of a reputed manufacturer” for compressor. The present work includes the effect of number of tubes, number of passes and fouling factor on saturated refrigerant temperature (SST), tube side velocity, pressure drop and temperature approach in evaporator and condenser. Effect of SST on power input to compressor, cooling capacity, condenser capacity and coefficient of performance (COP) and also effect of condensing temperature on power input to compressor, cooling capacity and condenser capacity is studied using software.

An integrated multi attribute decision model for energy efficiency processes in petrochemical industry applying fuzzy set theory

Energy efficient technologies offered by the market increases productivity. However, decision making for these technologies is usually obstructed in the firms and comes up with organizational barriers. Compressor selection in petrochemical industry requires assessment of several criteria such as ‘reliability, energy consumption, initial investment, capacity, pressure, and maintenance cost.’ Therefore, air compressor selection is a multi-attribute decision making (MADM) problem. The aim of this study is to select the most eligible compressor(s) so as to avoid the high energy consumption due to the capacity and maintenance costs. It is also aimed to avoid failures due to the reliability problems and high pressure.MADM usually takes place in a vague and imprecise environment. Soft computing techniques such as fuzzy sets and system can be used for decision making where vague and imprecise knowledge is available. In this study, an integrated fuzzy analytical hierarchy process (FAHP) and fuzzy technique for order performance by similarity to ideal solution (TOPSIS) methodologies are employed for the compressor selection. Fuzzy AHP was used to determine the weights of criteria and fuzzy TOPSIS was employed to order the scenarios according to their superiority. The total effect of all criteria was determined for all alternative scenarios to make an optimal decision. Moreover, the types of compressor, carbon emission, waste heat recovery and their capacities were analyzed and compared by statistical approaches. Six different scenarios were compared, scenario III was determined to be the best which has the highest closeness coefficient. In this scenario, the turbo compressors of active system reduces the total energy consumption due to low specific energy consumption (SEC) characteristics. Although the screw compressors have high maintenance costs, the heat recovery potential makes scenario III still preferable than the other 5 scenarios.

Selection of gas compressors: part 7

In this on-going series, Eduardo Larralde and Rafael Ocampo provide an in-depth survey of the state of the art concerning gas compressors. Following the specific directions for selection of a centrifugal compressor provided in the previous instalment, here they discuss a number of additional but important considerations.

Brayton cycle for internal combustion engine exhaust gas waste heat recovery

An average passenger car engine effectively uses about one-third of the fuel combustion energy, while the two-thirds are wasted through exhaust gases and engine cooling. It is of great interest to automotive industry to recover some of this wasted energy, thus increasing the engine efficiency and lowering fuel consumption and contamination. Waste heat recovery for internal combustion engine exhaust gases using Brayton cycle machine was investigated. The principle problems of application of such a system in a passenger car were considered: compressor and expander machine selection, machine size for packaging under the hood, efficiency of the cycle, and improvement of engine efficiency. Important parameters of machines design have been determined and analyzed. An average 2-L turbocharged gasoline engine’s New European Driving Cycle points were taken as inlet points for waste heat recovery system. It is theoretically estimated that the recuperated power of 1515 W can be achieved along with 5.7% improvement in engine efficiency, at the point where engine power is 26550 W.

Compressor selection methods for multi-stage re-liquefaction system of liquefied CO2 transport ship for CCS

Recently, CCS (carbon dioxide capture and sequestration) has been receiving considerable attention as a possible means of dealing with emissions of CO2, a greenhouse gas. To this end, EOR (enhanced oil recovery) and EGR (enhanced gas recovery) are regarded as being viable options for economically sequestrating large amounts of CO2. A feasible approach would involve capturing CO2 from large-scale CO2 emission sources such as power plants, and then transporting that captured gas to near-depleted oil and gas wells to maintain the reservoir pressure and enhance the oil/gas recovery rate. In the future, CO2 will be transported large distances from emission sources in developed countries to oil/gas producing regions by pipelines or ships. The long-distance ship-based transport of CO2 would require that the gas be compressed or liquefied (LCO2). Furthermore, an LCO2 transport ship would have to be capable of processing boil-off gas while at sea.In this study, the selection method of compressors for re-liquefaction system of dedicated LCO2 transport ship was investigated by computational method. The performance of same compression ratio (SCR) method exhibited low levels of efficiency and reliability as for coefficient of performance (COP) and compressor discharge temperature in terms of oil degradation compared to that of intermediate pressure optimization (IPO). Of these three methods, IPO produced the highest level of performance of all, but could not guarantee compressor reliability as like SCR, too. Intermediate pressure optimization with same discharge temperature (IPODT) method was found to be better in terms of reliability, with a decrease in performance of only 5% relative to that obtained by IPO. Consequently, we recommend the use of the IPODT method for the design of a multi-stage compression system for the re-liquefaction cycle of an LCO2 transport ship.