Existence of Solutions for a System of Integral Equations Using a Generalization of Darbo’s Fixed Point Theorem

In this paper, an extension of Darbo’s fixed point theorem via θ -F-contractions in a Banach space has been presented. Measure of noncompactness approach is the main tool in the presentation of our proofs. As an application, we study the existence of solutions for a system of integral equations. Finally, we present a concrete example to support the effectiveness of our results.The authors are grateful to the Basque Government by the support of this work through Grant IT1207-19

Politics of ethnic participation during Khatami's presidency in Iran (1997-2004)

Political participation is considered the most effective instrument for preserving citizens' freedom and rights in modern governments. Moreover, Political participation, as one of the aspects of social participation plays undoubtedly a prominent role in decreasing discrimination against minorities in the contemporary democratic societies. The reformist administration which governed Iran for eight years (1997-2004) and was established on (ex) president Khatami’s ideas and was headed by him, managed some steps toward promoting democracy in Iran. Beside its nation-wide efforts, the administration had its specific ethnic diversity management which encouraged the ethnic groups’ social as well as political participation. Through analysing the data collected by several in-depth interviews with the Iranian elites, this research minds to explore Khatami’s administration policies in the field of promoting ethnic groups participation. Collected data emphasizes on relative success of the administration achieving its aims

Performance Analysis of an R744 Supermarket Refrigeration System Integrated with an Organic Rankine Cycle

The energy and economic performance of a transcritical R744 booster supermarket refrigeration system with and without parallel compression and integrated with an organic Rankine cycle (ORC) was investigated. The results obtained were compared with those of a transcritical R744 booster supermarket refrigeration system with and without parallel compression and those of a conventional R404A direct expansion (DX) system. Nine different locations, namely Copenhagen (Denmark), Paris (France), Athens (Greece), New Delhi (India), Phoenix and Miami (US), Madrid (Spain), Bangkok (Thailand) and Riyadh (Saudi Arabia), were considered. It was discovered that the ORC is effective only at ambient temperatures higher than 27 °C when operating without parallel compression and 28 °C when operating with parallel compression. By using the heat recovered from the gas cooler to fuel the ORC, the latter was found to be capable of covering between 4% and 24% of the electricity demand of the R744 system in warm and hot climates (without parallel compression). The simple payback period of the additional investment associated with the ORC was found to be between 1.4 and 2.5 years in warm climate locations, while the same was found to be less than about 0.5 years in locations experiencing hot climatic conditions

Performance of integrated R744 packs part 2 : ejectors performance, a comparison of data-driven model from onsite measurements with rom model predictions

Rising concerns for climate change impacts along with the new legislation aimed at lowering emissions indicates the inevitable transition in the cooling/heating industry towards a more energy-efficient solution with minimal environmental impact. Integrated refrigeration, air condition and heat recovery solutions by CO2 (R744) packs are efficient solutions to high energy demanding building (supermarkets and hotels). Proven performance enhancement of Multi Ejector SolutionTM makes the R744 systems more energy efficient, especially in warm climates, compared to the most conventional synthetic refrigerant systems in food retail applications. Pilot installation in the frame of MultiPack, an EU funded project(Horizon 2020), provided a wide range of data, offering the possibility of evaluating the real performance of each ejector group: high pressure (HP), low pressure (LP), and liquid ejector(LE), by running the system in different operating modes. Analysis of the data indicated performance improvement of a system with ejector, on average a 35% lower energy consumption compared to baseline parallel compression R744 system without ejectors. The availability of mass flow measurement from 5 Coriolis mass flow meters on this pilot, enabled the possibility of comparison of mass flow rate in different evaporation temperatures. Data-driven models were used to estimate the performance of ejectors (Entrainment ratio) using onsite data from various operating modes and compare them with the simulated performance from CFD and lab measurements. Careful data pre-processing allows the data-driven model to predict the ejector performance using compressor mass flow rate models trained based on no ejector mode data derived from onsite measurements and compare with models validated by highly accurate lab experiments.acceptedVersio

Performance of integrated R744 packs part 2 : ejectors performance, a comparison of data-driven model from onsite measurements with rom model predictions

Rising concerns for climate change impacts along with the new legislation aimed at lowering emissions indicates the inevitable transition in the cooling/heating industry towards a more energy-efficient solution with minimal environmental impact. Integrated refrigeration, air condition and heat recovery solutions by CO2 (R744) packs are efficient solutions to high energy demanding building (supermarkets and hotels). Proven performance enhancement of Multi Ejector SolutionTM makes the R744 systems more energy efficient, especially in warm climates, compared to the most conventional synthetic refrigerant systems in food retail applications. Pilot installation in the frame of MultiPack, an EU funded project(Horizon 2020), provided a wide range of data, offering the possibility of evaluating the real performance of each ejector group: high pressure (HP), low pressure (LP), and liquid ejector(LE), by running the system in different operating modes. Analysis of the data indicated performance improvement of a system with ejector, on average a 35% lower energy consumption compared to baseline parallel compression R744 system without ejectors. The availability of mass flow measurement from 5 Coriolis mass flow meters on this pilot, enabled the possibility of comparison of mass flow rate in different evaporation temperatures. Data-driven models were used to estimate the performance of ejectors (Entrainment ratio) using onsite data from various operating modes and compare them with the simulated performance from CFD and lab measurements. Careful data pre-processing allows the data-driven model to predict the ejector performance using compressor mass flow rate models trained based on no ejector mode data derived from onsite measurements and compare with models validated by highly accurate lab experiments

Performance of integrated R744-packs part 1: compressor mass flow estimation based on data-driven models using analytical methods and actual field measurements

Rising concerns for climate change impacts along with the new legislation aimed at lowering emissions indicates the inevitable transition in the cooling/heating industry towards a more energy-efficient solution with minimal environmental impact. Integrated refrigeration, air condition and heat recovery solutions by CO2 (R744) packs are efficient solutions to high energy demanding building (supermarkets and hotels). Proven performance enhancement of Multi Ejector SolutionTM makes the R744 systems more energy efficient, especially in warm climates, compared to the most conventional synthetic refrigerant systems in food retail applications. Pilot installation in the frame of MultiPACK, an EU funded project (Horizon 2020), provided a wide range of data, offering the possibility of evaluating the real performance of each ejector group: high pressure (HP), low pressure (LP) and liquid ejector (LE), by running the system in different operating modes. Analysis of the data indicated performance improvement of a system with ejector, on average a 35% lower energy consumption compared to baseline parallel compression R744 system without ejectors. Availability of mass flow measurement, 5 Coriolis mass flow meters on this pilot, enabled the possibility of comparison of mass flow rate estimation based on data acquisition from compressors with actual measurement. Methods utilized include: Energy balance, volumetric displacement, manufacturer polynomials, and data-driven method. The comparison reveals the importance of compressor suction and discharge parameters for obtaining reliable results based on energy balance, volumetric displacement, manufacturer polynomials methods. The current study shows data-driven method performs well after enough training time with error bounded to 3% and 10 % on low and medium temperature level compressors, respectively.acceptedVersio

The Performance Analysis of an Integrated CO2 Refrigeration System with Multi-Ejectors Installed in a Supermarket

The field data from an integrated CO2 refrigeration system installed in a supermarket located north of the capital of Lisbon was analyzed. The goal was to demonstrate the effect and performance of multi-ejectors on a refrigeration system operating in a warm climate. The measurement results for the system with and without activating ejectors were compared. It was observed that the system with a multi-ejector operation had considerable performance superiority. The ejectors improved the cooling capacity of the medium temperature stage of the system by 17.4%. The system with active ejectors had 7.5% less total power consumption compared to the ejector off mode of the same system

The Performance Analysis of an Integrated CO₂ Refrigeration System with Multi-Ejectors Installed in a Supermarket

The field data from an integrated CO2 refrigeration system installed in a supermarket located north of the capital of Lisbon was analyzed. The goal was to demonstrate the effect and performance of multi-ejectors on a refrigeration system operating in a warm climate. The measurement results for the system with and without activating ejectors were compared. It was observed that the system with a multi-ejector operation had considerable performance superiority. The ejectors improved the cooling capacity of the medium temperature stage of the system by 17.4%. The system with active ejectors had 7.5% less total power consumption compared to the ejector off mode of the same system

Performance of integrated R744-packs part 1: compressor mass flow estimation based on data-driven models using analytical methods and actual field measurements

Rising concerns for climate change impacts along with the new legislation aimed at lowering emissions indicates the inevitable transition in the cooling/heating industry towards a more energy-efficient solution with minimal environmental impact. Integrated refrigeration, air condition and heat recovery solutions by CO2 (R744) packs are efficient solutions to high energy demanding building (supermarkets and hotels). Proven performance enhancement of Multi Ejector SolutionTM makes the R744 systems more energy efficient, especially in warm climates, compared to the most conventional synthetic refrigerant systems in food retail applications. Pilot installation in the frame of MultiPACK, an EU funded project (Horizon 2020), provided a wide range of data, offering the possibility of evaluating the real performance of each ejector group: high pressure (HP), low pressure (LP) and liquid ejector (LE), by running the system in different operating modes. Analysis of the data indicated performance improvement of a system with ejector, on average a 35% lower energy consumption compared to baseline parallel compression R744 system without ejectors. Availability of mass flow measurement, 5 Coriolis mass flow meters on this pilot, enabled the possibility of comparison of mass flow rate estimation based on data acquisition from compressors with actual measurement. Methods utilized include: Energy balance, volumetric displacement, manufacturer polynomials, and data-driven method. The comparison reveals the importance of compressor suction and discharge parameters for obtaining reliable results based on energy balance, volumetric displacement, manufacturer polynomials methods. The current study shows data-driven method performs well after enough training time with error bounded to 3% and 10 % on low and medium temperature level compressors, respectively