Performance Evaluation Of System Research Articles

Carbon and economic prices optimization of a solar-gas coupling energy system with a modified non-dominated sorting genetic algorithm considering operating sequences of water-cooled chillers

To promote the continuous operating of solar energy systems and increase the proportion of renewable energy consumption, solar devices are often integrated with conventional energy systems to reduce greenhouse gas emissions. In this study, a solar-natural gas coupling system is constructed, utilizing solar photovoltaics, thermal collectors, and high-efficiency energy conversion devices. After modelling the energy system, the operating modes are illustrated considering working sequences of water-cooled devices. A modified genetic algorithm, which incorporates reverse learning, controlled elite, and dynamic crowding distance theory, is constructed to optimize the configurations of the proposed energy system, with the aim of minimizing carbon and economic prices of the products. The performance of the energy system is compared with different algorithms and cases, and the results demonstrate that the proposed algorithm addresses the limitations of conventional methods, albeit with increased optimization times. Moreover, the proposed operating mode (Case 1) exhibits a stable performance, leading to a higher environmental and economic performance compared to conventional modes, with carbon and economic prices of 0.242 kg/kWh and 0.067 $/kWh, respectively. This study provides new insights into carbon footprints and economic performance evaluation of high-efficiency energy systems, offering valuable directions for future research in this field.

Performance evaluation and optimization of compact tube-fin latent heat storage system in phase change nanoemulsion discharge mode

The low thermal conductivity of phase change materials (PCMs) and the reduced heat transfer temperature difference along a tube both limit the thermal performance of latent heat thermal energy storage (LHTES). Herein, a compact tube-fin LHTES system based on phase change nanoemulsions was developed and the heat transfer process of nanoemulsion and PCM was numerically investigated. The effects of the heat transfer structure of the heat exchanger and the thermophysical parameters of the heat transfer fluid (HTF) on the cold energy discharge performance of the system were quantified. The optimized model reduced the discharge time by 24.4 % in nanoemulsion mode relative to water. Heat transfer improvement on the PCM side could be achieved by decreasing the fin spacing and tube spacing and by increasing the fin thickness. Such improvement reinforced the heat transfer enhancement of the nanoemulsion. The heat transfer mechanism was explained by the temperature distributions of the HTF and PCM along the tube. The phase-change thermostatic properties of the nanoemulsion and PCM contributed to the formation of dual-phase-change coupled heat transfer (i.e., the heat transfer process when the fluid inside the tube and the PCM filled outside the tube undergo a simultaneous phase change) within the LHTES, increasing the heat transfer temperature difference and the magnitude of the driving force. Increasing the phase change temperature difference accelerated the onset of dual-phase-change heat transfer, while increasing the PCM content prolonged the process. Briefly, this study provided operational and design assistance for LHTES systems in nanoemulsion mode with the intention to accelerate heat transfer rates.

Thermal response and performance evaluation of floor radiant heating system based on fuzzy logic control

The floor radiant heating system is widely used in various buildings due to its advantages such as high efficiency, comfort, and uniform heating. Generally, research on floor radiant heating systems focuses on energy saving, but the issue of slow thermal response during the heating process has not been solved. To solve the problem of slow thermal response and uneven indoor thermal environment in floor radiant heating systems, a fuzzy logic control theory based on optimal fuzzy rules was proposed. The floor radiant heating system based on fuzzy logic control was established by the TRNSYS-MATLAB integrated control platform. The study compared the thermal response and thermal comfort performance of PID control, fuzzy logic control, and optimized fuzzy control methods. The results showed that fuzzy logic control performed better than PID control in controlling the system's thermal performance and indoor thermal environment. Compared to PID control, the optimized fuzzy control reduced the thermal response time by 64.60%, and the total energy consumption of the water pump and heat pump decreased by 222 kWh and 329 kWh, respectively. The proposed fuzzy logic control demonstrates favorable thermal response characteristics and holds substantial potential for energy conservation within the increasingly prevalent floor radiant heating systems.

Evaluation of Turkey’s Healthcare System Performance in COVID-19 Pandemic Period

The main objective of this study is to evaluate the performance of Turkey’s Health System during the COVID-19 pandemic. A cross-sectional study was conducted in Turkey among 656 people using a questionnaire. STATA 14.0 statistical software package was used for analysing the data. Frequency, percentage, mean, standard deviation, t-test and one-way analysis of variance test were used. The participants’ Healthcare System Performance Evaluation Scale total score mean [Formula: see text] = 3.60 ± 0.6 in the sub-dimension of ‘Safe and Security’ [Formula: see text] = 3.63 ± 0.8, in the sub-dimension of ‘Transparency’ [Formula: see text] = 3.15 ± 1.1, in the sub-dimension ‘Accessibility’ [Formula: see text] = 3.79 ± 0.9, in the sub-dimension ‘Affordability’ [Formula: see text] = 3.83 ± 0.8 was determined. The Healthcare System Performance Evaluation Scale and a sub-dimension of this scale, accessibility, scores of them are high and differed statistically by age. The affordability sub-scale score was statistically different from income groups ( F = 6.47; p < .05). Although the performance of the general healthcare system is high, it was seen that the scores regarding the transparency of the information shared during COVID-19 were partially lower than other dimensions.

Text Classification on Customer Feedback: A Systematic Literatures Review

User feedback in text classification serves multiple purposes, including refining models, enhancing datasets, adapting to user preferences, identifying emerging topics, and evaluating system performance, all of which contribute to the creation of more effective and user-centric classification systems. Many text classification techniques, including data mining, machine learning, and deep learning approaches, have been employed in previous literature, each making significant contributions to the field. This paper aims to contribute by guiding researchers seeking commonly used classification techniques and evaluation metrics in text processing. Additionally, it identifies the classification technique that generates higher accuracy and works as a basis for researchers to synthesize studies within their respective fields. PRISMA methodology is adapted to systematically review 28 current literatures on text classification on user feedback. The results obtained are guided by four research questions; paper distribution year, dataset source and size; evaluation metric and model accuracy. The review has shown that support vector machines (SVM) are frequently employed and consistently achieve high levels of accuracy as high as 97.17% with various datasets used. The future direction of this work could explore models that integrate sentiment analysis and natural language understanding to more accurately capture nuanced user opinions and preferences.

A novel sensor with excellent high-temperature performance for in-situ temperature measurement

Real-time access to critical information about system temperature variations is essential for evaluating system performance in some of the high-temperature and harsh environments. Given the technical difficulty of accurately obtaining the temperature of a high-temperature and harsh environment, a new sensor package structure is proposed. Combining ceramic sintering and isostatic pressure molding methods, the thermal junction is fixed in the temperature measurement end face of the alumina ceramic substrate, while the shell design threads play a role in fixing the sensor and preventing loosening. This paper conducted repeatability, upper-temperature limit, and high-temperature serviceability assessment tests on the sensor. The results show that the sensor maximum repeatability error is 2.4%. The sensor can continue to operate at 1200°C for more than 6 hours with no signal interruption and the upper limit of temperature measurement is 1307°C. The results demonstrate the feasibility and practicality of temperature measurement by this sensor in high-temperature and harsh environments.

Contributions of Initial Conditions and Meteorological Forecast to Subseasonal-to-Seasonal Hydrological Forecast Skill in Western Tropical South America.

Hydrological predictions at subseasonal-to-seasonal (S2S) time scales can support improved decision-making in climate-dependent sectors like agriculture and hydropower. Here, we present an S2S hydrological forecasting system (S2S-HFS) for western tropical South America (WTSA). The system uses the global NASA Goddard Earth Observing System S2S meteorological forecast system (GEOS-S2S) in combination with the generalized analog regression downscaling algorithm and the NASA Land Information System (LIS). In this implementation study, we evaluate system performance for 3-month hydrological forecasts for the austral autumn season (March-May) using ensemble hindcasts for 2002-17. Results indicate that the S2S-HFS generally offers skill in predictions of monthly precipitation up to 1-month lead, evapotranspiration up to 2 months lead, and soil moisture content up to 3 months lead. Ecoregions with better hindcast performance are located either in the coastal lowlands or in the Amazon lowland forest. We perform dedicated analysis to understand how two important teleconnections affecting the region are represented in the S2S-HFS: El Niño-Southern Oscillation (ENSO) and the Antarctic Oscillation (AAO). We find that forecast skill for all variables at 1-month lead is enhanced during the positive phase of ENSO and the negative phase of AAO. Overall, this study indicates that there is meaningful skill in the S2S-HFS for many ecoregions in WTSA, particularly for long memory variables such as soil moisture. The skill of the precipitation forecast, however, decays rapidly after forecast initialization, a phenomenon that is consistent with S2S meteorological forecasts over much of the world.

Research on Performance Evaluation of Full Process Cost Management in Expressway Projects

The research purpose of this article is to optimize the performance evaluation of cost management throughout the entire process of highway projects. Currently, China's highway construction is booming, but cost management is complex and requires the construction of a scientific performance evaluation system to comprehensively supervise and evaluate engineering costs. This article used literature induction method for literature review, followed by expert scoring method to assign scores to indicators, and finally used Analytic Hierarchy Process to determine indicator weights. From the results, this study identified key factors that affect the overall cost management performance of highway projects, and constructed relevant evaluation models and weight hierarchy tables. Therefore, the results of this article are helpful in accurately controlling project costs, evaluating benefits, and optimizing fund management, which is of great significance for improving the level of highway project management and investment return rate.

Performance evaluation and comparative research of underwater wireless optical communication system by using different structured beams

Structured beams have attracted increasing interest in free-space and fiber-based optical communications. Underwater wireless optical communication (UWOC) is becoming a prospective technique in marine exploration. We investigated UWOC performance using different representative structured beams. The transmission performances of the Gaussian, Bessel–Gaussian (BG), Ince–Gaussian (IG), and radially polarized Gaussian (RPG) beams were experimentally demonstrated and evaluated in underwater channels subjected to thermal gradient. The experimental results show that the BG, IG, and RPG perform better against the thermal gradient. Compared with the Gaussian beams, the beam wanders of BG, IG, and RPG beams under the thermal gradient have been reduced by 56.9%, 8.2%, and 59%, the scintillation indices have been decreased by 12.8%, 17.3%, and 28.9%, and the BER performance of the BG, IG, and RPG beams have been improved by ∼5.5, ∼3.7, and ∼5.2dB at the forward error correction threshold (FEC threshold). Based on the above results, the RPG beam is a more promising light source for UWOC. The experimental results provide a promising beam choice for UWOC.

유아교사의 유아교육기관 ESG 인식 및 중요도에 따른 교육 요구도 분석

Objectives The purpose of this study is to explore the educational needs of early childhood educators based on the analysis of their current awareness levels and perceived importance of ESG, utilizing the Borich needs assessment and The Locus for Focus model. Methods For this purpose, a study was conducted with 202 kindergarten teachers in the metropolitan area(Seoul, Gyeonggi Province, Incheon) using SPSS 23.0 and Excel programs. Through IPA analysis, we identified areasin need ofimprovement and areasofexcess. We conducted a t-test to examine the difference between the current level and importance of ESG. Additionally, we determined the top priority for educational support by comparing the Borich needs assessment and The Locus for Focus Model. Results The main results are as follows, First, within the IPA framework, HH was categorized into four areas, all of which fall under the “S” domain. HL comprised a total of three areas, with two falling under the “E” domain and one falling under the “G” domain. LL also had a total of three areas, with one falling under each of the “E”, “S”, and “G” domains. LH consisted of four areas, with two categorized under the “E” and “G” domains. Second, The analysis of the difference between the current perception levels and importance of ESG items revealed statistically significant differences in the “E” domain. Specifically, there were significant differences inthe items related to ‘waste recycling in early childhood education institutions,’ ‘implementation of environmental management policies in early childhood education institutions,’ and ‘establishment of environmental performance evaluation systems in early childhood education institutions.’ In the “S” domain, there were statistically significant differences observed for the items related to the establishmentand implementation of policies for employee stability within early childhood education institutions, as well as the establishmentand implementation of fair trade, anti-corruption, and ethical management policies for cooperation with suppliers within early childhood education institutions. Similarly, in the “G” domain, statistically significant differences were found for the items related to ‘public disclosure of management activities’ onthe website of early childhood education institutions and ‘prevention of inappropriate succession methods in early childhood education institutions.’ These differencesindicatethat these items are perceived as more important than the current level of awareness. According to the Borich Needs Assessment, the priority areas were ranked as follows:‘wasterecycling in early childhood education institutions,’ ‘prevention of inappropriate succession methods in early childhood education institutions,’ ‘implementation of environmental management policies in early childhood education institutions,’ ‘public disclosure of the management activities on the early childhood education institution’ swebsite, ‘and’ establishmentand implementation of fair trade, anti-corruption, and ethical management policies for cooperation with suppliers within early childhood education institutions.' Third, According to the analysis of The Locus for Focus model, the HH domain consists of 5 items, including ‘waste recycling in early childhood education institutions,’ ‘implementation of environmental management policies in early childhood education institutions,’ ‘establishment and implementation of policies for employee stability within early childhood education institutions,’ and ‘establishment and implementation of fair trade, anti-corruption, and ethical management policies for cooperation with suppliers within early childhood education institutions,’ as well as ‘prevention of inappropriate succession methods in early childhood education institutions.’ Fourth, The results indicate a common priority for the followingitems

How metric-based performance evaluation systems fuel the growth of questionable publications?

The proliferation of questionable publishing practices has raised serious concerns in academia, prompting numerous discussions and investigations into the motivations behind researchers’ preference for such journals. In this study, we aimed to explore the impact of current academic performance evaluation systems on scholars’ questionable journal preferences in Turkey. Utilizing data from the comprehensive study conducted by Kulczycki et al. (2021) on questionable journals, we analyzed the academic careers of 398 researchers who authored 417 articles in this context. Our findings reveal a clear association between current research evaluation systems and journal selection, particularly during the process of applying for associate professorship. Notably, 96% of the articles published in questionable journals were listed in scholars’ academic profiles, indicating their use in academic promotion or incentive portfolios. While this study contributes valuable insights into the relationship between academic performance evaluation systems and questionable journal preferences, additional research is required to comprehensively understand the motivations behind scholars’ publishing choices and to devise effective strategies to combat questionable publishing practices in academia.

Selection of optimal intensity measures for seismic performance evaluation of underground utility tunnel and internal pipeline system

Seismic intensity measures (IMs), which are closely related to both earthquake hazards and structural responses, play a critical role in the performance-based earthquake engineering (PBEE) framework. This paper aims to investigate and define the most representative IMs for probabilistic seismic demand model (PSDM) for the longitudinal utility tunnel and internal pipeline system. Similar to the requirements by the Chinese Code for seismic design of urban rail transit structures, the utility tunnel in this study is assumed being buried in four typical engineering site classes for the analyses. Soil-tunnel-pipeline interactions are simulated using a double-beam system resting on a nonlinear foundation. Soil-tunnel interaction, tunnel-pipeline interaction and joint connections are modeled as nonlinear springs with different mechanical properties. A series of 17 pairs of outcrop ground-motion records and 27 commonly used IMs are selected in the analyses. Engineering demand parameter (EDP) is defined based on the maximum joint opening and the maximum strain of the utility tunnel and internal pipeline, respectively. The selected IMs for predicting the seismic responses of tunnel-pipeline systems are tested using different criteria, i.e., correction, efficiency, practicality, and proficiency. The final decision-making procedure employs a fuzzy multi-criteria decision method. The numerical results indicate that: (1) The velocity-related IMs are the most representative IMs based on the four criteria for structures buried in four sites of different conditions; (2) The optimal seismic IMs vary with different criteria, site classes and structure types. According to the fuzzy multi-criteria decision approach, optimal IMs for the tunnel-pipeline system are PGV, PGV, EPV and HI for site classes I – IV, respectively. The proposed optimal IMs can be utilized to construct seismic fragility curves of utility tunnel, internal pipeline and tunnel-pipeline systems in four different site classes.

Long term performance evaluation of a commercial vanadium flow battery system

This paper describes the results of a performance review of a 10 kW/100 kWh commercial VFB system that has been commissioned and in operation for more than a decade. The evaluation focused on the system efficiencies, useable capacity, electrolyte stability and stack degradation. The analysis shows that the system has stable performance and very little capacity loss for over a decade since commissioning. Only very recently, a slight decrease in system discharge capacity (approximately 5 %) was observed and indicated by changes in the electrolyte valence state. The capacity was restored to the original level after conducting a rebalancing procedure. This demonstrates the advantage that the flow batteries employing vanadium chemistry have a very long cycle life. Furthermore, electrochemical impedance spectroscopy analysis was conducted on two of the battery stacks. Some degradation was observed in one of the stacks reflected by the increased charge transfer resistance. To further investigate the ageing of the stacks, reverse polarity tests were carried out. It is found that reversing the polarity both hydraulically and electrically can restore the stack performance. The study shows that the VFB is a reliable technology for large-scale energy storage applications.

Performance assessment and comparison of a catalytic steam reforming enhanced closed-brayton-cycle power generation system for hypersonic vehicles

Hypersonic vehicles as next-generation aircraft have broad applications, but existing technologies of onboard power generation are hardly applicable due to the change of engines. In this research, a catalytic steam reforming enhanced closed-Brayton-cycle power generation system based on is developed. This system combines the closed Brayton cycle (CBC) and catalytic steam reformed fuel vapor turbine (CSRFVT) to supply electric power. The zero-dimensional models of CBC and the CSRFVT are established to evaluate system performance. Results indicate the products with a water content of 30% have the strongest working ability, which can reach 330 kJ/kg. Moreover, the thermal efficiency and electric power of the parallel arrangement are higher than that of the series arrangement. Besides, the lower pressure of water is beneficial to the electric power. However, the difference in electric power between various pressures is less than 1 kW. In addition, under the same heat absorption, the total electric power of the system based on fuel and water is higher, and the former's outlet temperature of cooling channels is lower. The maximum total electric power of the novel system is about 120 kW. This research provides an innovative technical solution for the power generation of hypersonic vehicles.

Pilot and data power optimization problems in multiple Aerial Relay Stations cell‐free communication systems

SummaryA cell‐free (CF) technology and unmanned aerial vehicles (UAVs) acting as aerial relay stations (ARSs) are gradually viewed as viable technologies for usage in sixth‐generation (6G) wireless networks owing to their outstanding advantages, such as large coverage, uniform service quality, huge connections, flexible deployment in all geographical areas, and high line‐of‐sight (LoS) probability. As a result, the combination of the CF model and UAVs is suitable for densely populated urban areas, shopping malls, festivals, and locations with complex geography. Furthermore, the integration of the CF model and UAV communication can improve system quality and is considered an entirely new research direction as there is no comprehensive investigation of this combined model. In this study, we investigate the quality of the multi‐ARS CF communication system, where ARSs are equipped with multiple antennas and stochastic distribution within a specific region to simultaneously serve numerous ground users. We establish a closed‐form formulation for the uplink and downlink throughput of individual users by using the matched filtering method and conjugate beamforming technology, respectively. Moreover, we propose a novel method to optimize the pilot and data transmission power coefficients for improving channel estimation and increasing throughput per user, thereby ensuring a high quality of service. The power optimization method is executed via the successive convex approximation (SCA) method, second‐order cone program (SOCP), and linear program. We evaluate system performance according to the cumulative distribution function (CDF) of user throughput based on various parameters, such as the number of users, the number of ARSs, and the length of pilot sequences. The analytical findings also reveal that the system with the proposed power optimization method is always superior to the system without the proposed method in both uplink and downlink.

Systematic Review of the Circular Economy Performance Assessment System Under International Management Paradigms

Objective: To present a Systematic Literature Review (SLR) on Performance Evaluation in the Circular Economy (PECE), addressing its temporal evolution and critically analyzing the metrics found in empirical studies. Theoretical Framework: The research starts from theoretical contributions on the characteristics of a metric and the levels of performance assessment systems, compared with the evolution of performance assessment in the management of natural resources until we reach the circular economy. Method: Utilization of Systematic Literature Review following the Knowledge Development Process-Constructivist approach (ProKnow-C), assessing secondary data from articles comprising the Research Portfolio (RP). Results and Discussion: The literature presents a variety of circularity metrics at different scales, yet there is a predominance of individual metrics and a lack of comprehensive focus on Performance Evaluation Systems (PES). Research Implications: Identifies the need for more comprehensive and integrative metrics aligned with CE principles and capable of encompassing multiple levels of action. Future research has the potential to significantly enrich society by exploring the development of more comprehensive metrics, considering the interaction between levels of circularity and environmental performance. Originality/Value: Highlights the growing concern with metrics in the Circular Economy (CE), identifies gaps in understanding the full impacts of each approach in the supply chain, and underscores the need for more robust and integrative metrics aligned with CE principles.

The Performance Evaluation of a Hybrid System Combining an Alkaline Fuel Cell with an Inhomogeneous Thermoelectric Generator

To harness the full potential of the exhaust heat produced by an alkaline fuel cell (AFC), a novel coupling system that combines an AFC with an inhomogeneous thermoelectric generator (ITEG) is proposed. Detailed models of both the AFC and ITEG are developed, accounting for various irreversible losses. Following model validations, mathematical expressions for the power output density (POD) and energy efficiency (EE) of the hybrid system are derived. Though performance comparisons, the hybrid system’s effectiveness and competitiveness are demonstrated. Our calculation results reveal that the hybrid system achieves a 31.19% increase in its maximum POD and 54.61% improvement in its corresponding EE compared to that of the standalone AFC. Furthermore, numerous parametric studies are conducted. Some findings indicate that the POD of the hybrid system can be improved by elevating the operating temperature of the AFC and the environmental temperature, and that it can be optimized using the geometric characteristics of an ITEG. However, the EE of the hybrid system gains improvement via increasing the operating temperature of the AFC or decreasing both the environmental temperature and geometric characteristics of the ITEG. Additionally, the coefficient of the spatial inhomogeneity of the ITEG determines the optimal operating current density of the AFC. These insights offer valuable guidance for the integration and operation of practical hybrid systems.

Research on Performance Evaluation of Sponge City PPP Projects in the Yangtze River Delta Region

In order to alleviate urban water ecological problems and promote sustainable urban development, many cities in my country are building sponge cities. At present, the country is vigorously promoting the application of the PPP model for project construction. The national government departments are actively preparing for the construction of sponge cities, promoting the construction of sponge cities in 30 pilot cities across the country, and encouraging sponge city construction projects using the PPP model, attracting a large amount of social capital to participate, and promoting The PPP model has been widely used in sponge city construction projects. This article takes the sponge city PPP project as the research object. In order to scientifically and rationally evaluate the construction performance of the sponge city PPP project, and on the basis of studying and summarizing the characteristics of the sponge city PPP project model and the development status of the performance evaluation system in my country, we conduct an analysis of the content of the performance evaluation. and research; establish and select a performance evaluation index system; conduct a comparative analysis of this model with other commonly used models, and build a PSIR-based PPP project performance evaluation model based on the design flaws of the existing performance evaluation system; and analyze and summarize the data. , clarifying its specific application and impact in practice; finally, a summary and outlook of the entire research are given.

Increasing the Utilization of Solar Energy through the Performance Evaluation of Air-Based Photovoltaic Thermal Systems

Photovoltaic thermal (PVT) systems are attracting a significant amount of attention in research because they can generate electricity outside of daytime hours, unlike photovoltaic (PV) systems, and can increase efficiency and collect additional energy by reducing the temperature of PVT panels. However, a somewhat lower amount of collected energy is used in the summer than in the winter, and research on this issue is lacking. In this study, first, we experimentally evaluated the performance of PV and PVT systems by season and verified the improvement in the performance of the PVT system. Second, experiments were conducted to verify the enthalpy reduction via mist cooling and dehumidification, and the temperature and humidity control effect via mist cooling and dehumidification was verified. Based on our research findings, we propose a model that can be integrated with indoor ventilation systems to increase the solar energy utilization of PVT systems. Using the PVT system, we improved the panel power generation efficiency by up to 5.89% and generated up to a 38.0% higher collection efficiency than that of the PV system. The air that passed through the PVT system was then subjected to mist cooling and dehumidification to reduce its temperature and increase its humidity, resulting in a 23.2% reduction in enthalpy.

Performance evaluation of VCR system with pure and various blends of R134a, R1234yf, and R1234ze (E) refrigerants

AbstractThe current small passenger car vapor compression refrigeration systems use high global warming potential (GWP) refrigerants causing the greenhouse gas effect. In the present work, the low GWP of two pure refrigerants, R1234yf and R1234ze (E), and 16 blends of R134a, R1234yf, and R1234ze (E) are analyzed numerically. The experiments were conducted with R134a refrigerant to validate the numerical results. The experiments were conducted at the compressor speed of 600–1500 rpm and the condensing air at 30–40°C, relative humidity of 85%, and velocity of 1–3 m/s. The simulation and experimental results for R134a are deviated by a minimum of 10% and a maximum of 15%. It is found that the latent heat of vaporization of the two refrigerant mixtures with 80% R134a–20% R1234yf and the three refrigerant blends of 50% R134a–10% R1234yf–40% R1234ze (E) are the highest among 16 combinations. The other blends show a moderate difference of latent heat with R134a, but for maximum cooling capacity, the blends with 80% R134a–20% R1234yf and 50% R134a–10% R1234yf–40% R1234ze (E) are found to be more suitable for practical applications.