scholarly journals Performance Characteristics of Automobile Air Conditioning Using the R134a/R1234yf Mixture

Entropy ◽  
2019 ◽  
Vol 22 (1) ◽  
pp. 4
Author(s):  
Yunchan Shin ◽  
Taejung Kim ◽  
Areum Lee ◽  
Honghyun Cho
Keyword(s):  
Air Temperature ◽  
Cooling Capacity ◽  
Exergy Efficiency ◽  
Coefficient Of Performance ◽  
Exergy Destruction ◽  
Refrigeration System ◽  
Outdoor Air ◽  
Rotating Speed ◽  
Destruction Rate ◽  
Energy And Exergy

In this study, the energy and exergy of an automobile refrigeration system using R134a and R134a/R1234yf were analyzed experimentally with respect to outdoor air temperature and compressor speed. As outdoor air temperature increased from 32.5 °C to 37.5 °C, the coefficient of performance (COP) and total exergy destruction rate of the refrigeration system using Mix30 decreased by 5.19% and 25.8% on average, compared to that of the system using R134a. The exergy efficiency of the Mix30 refrigeration system was on average 21.8% higher than that of the R134a system. As the compressor rotating speed increased from 1000 to 2000 rpm, the cooling capacity of the refrigeration system using R134a and R134a/R1234yf increased, while the COP decreased. The COP and total exergy destruction rate of the refrigeration system using Mix30 decreased by 4.82% and 19.5%, compared to that of the system using R134a. The exergy efficiency of the Mix30 refrigeration system increased on average by 20.7%, compared to that of the R134a system. The total exergy destruction rate of the automobile refrigeration system using R134a/R1234yf decreased with increase in R1234yf, while exergy efficiency increased. In addition, the exergy destruction rate of the automobile refrigeration system decreased as the amount of R1234yf in the R134a/R1234yf automobile refrigeration system increased.

Thermodynamic Analysis of Solar Cooling System for a Residential Buildings Application Capital of Iran

2019 ◽  
Author(s):  
Mohamad Javad Asgari ◽  
Amirhossein Mossafa ◽  
Mohsen Fallah
Keyword(s):  
Industrial Development ◽  
Residential Buildings ◽  
Exergy Efficiency ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Environmental Damage ◽  
Water Tank ◽  
Exergy Destruction ◽  
Refrigeration System ◽  
Economic Implications

The global industrial development, the increasing demand for energy, the limited availability of resources for the future generations of fossil fuels, and the prevention of environmental damage caused by their burning have led to public concern. Increasing energy consumption by buildings has led the wider global attention to its social, environmental, and economic implications. In the present study, in order to reduce the power consumption of the summer, a solar vacuum tube-collecting system, with its high efficiency, with a hot water tank and an absorption refrigeration system in a 5-story residential building in In Tehran Capital of Iran, has been investigated. In addition, the results also indicate that the main source of exergy destruction is solar collectors. In the solar collector, we have 93.22% of the exergy destruction, which accounts for 92.8% of the total exergy cascade. In addition, 18.45% of the exergy destruction occurred in the generator, which was equivalent to 1.598% of the total exergy casualties. Also, the coefficient of performance and exergy efficiency of the whole system were 0.746 and 23.5%, respectively, which showed a significant increase in total exergy efficiency compared to the conventional refrigeration system.

scholarly journals Performance Analysis of Multipurpose Refrigeration System (MRS) on Fishing Vessel

2016 ◽  
Vol 23 (2) ◽  
pp. 48-56 ◽  
Author(s):  
Y. Ust ◽  
A. Sinan Karakurt ◽  
U. Gunes
Keyword(s):  
Performance Analysis ◽  
Loss Rate ◽  
Industrial Applications ◽  
Exergy Efficiency ◽  
Coefficient Of Performance ◽  
Exergy Destruction ◽  
Parallel Operation ◽  
Refrigeration System ◽  
Energy Saving Potential ◽  
Operation Conditions

Abstract The use of efficient refrigerator/freezers helps considerably to reduce the amount of the emitted greenhouse gas. A two-circuit refrigerator-freezer cycle (RF) reveals a higher energy saving potential than a conventional cycle with a single loop of serial evaporators, owing to pressure drop in each evaporator during refrigeration operation and low compression ratio. Therefore, several industrial applications and fish storage systems have been utilized by using multipurpose refrigeration cycle. That is why a theoretical performance analysis based on the exergetic performance coefficient, coefficient of performance (COP), exergy efficiency and exergy destruction ratio criteria, has been carried out for a multipurpose refrigeration system by using different refrigerants in serial and parallel operation conditions. The exergetic performance coefficient criterion is defined as the ratio of exergy output to the total exergy destruction rate (or loss rate of availability). According to the results of the study, the refrigerant R32 shows the best performance in terms of exergetic performance coefficient, COP, exergy efficiency, and exergy destruction ratio from among the other refrigerants (R1234yf, R1234ze, R404A, R407C, R410A, R143A and R502). The effects of the condenser, freezer-evaporator and refrigerator-evaporator temperatures on the exergetic performance coefficient, COP, exergy efficiency and exergy destruction ratios have been fully analyzed for the refrigerant R32.

scholarly journals Thermodynamic Analysis of Split Air Conditioner Using Energy and Exergy Viewpoint with Low GWP Refrigerants Alternative to R410A

2021 ◽  
Vol 309 ◽  
pp. 01141
Author(s):  
Punit Mishra ◽  
Shubham Soni ◽  
Govind Maheshwari
Keyword(s):  
Global Warming ◽  
Thermodynamic Analysis ◽  
Exergy Efficiency ◽  
Performance Criteria ◽  
Coefficient Of Performance ◽  
Air Conditioner ◽  
Exergy Destruction ◽  
Energy And Exergy ◽  
Air Conditioning Systems ◽  
Low Global Warming Potential

In this paper, a comparative thermodynamic analysis on energy and exergy viewpoint is done on different low global warming potential (GWP) refrigerants to find the possible alternative of high GWP refrigerant R410A. R410A is used nowadays in air conditioning systems due to its ozone-friendly characteristic as zero ozone depletion potential (ODP=0) but it has high GWP (GWP=1924) that leads to global warming. Now a day’s global warming is considered to be one of the critical aspects when environmental protection is taken into consideration and researchers from every corner of the globe are working to find refrigerants that not only have zero ODP but it has low GWP too. In this analysis, four prospect refrigerants namely R32, R447A, R447B, and R452B have been studied to find their suitability to replace R410A on different performance criteria as the coefficient of performance (COP), power consumption, exergy efficiency, and exergy destruction. Thermodynamic properties of the studied refrigerants have been taken from the Genetron Properties 1.4 software. The result indicates that all the studied refrigerants have better performance characteristics compared to R410A but R447A has maximum COP and exergy efficiency along with the least total exergy destruction that makes it a possible alternate of R410A.

scholarly journals Thermal Performance Analysis of Low-GWP Refrigerants in Automotive Air-Conditioning System

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Yousuf Alhendal ◽  
Abdalla Gomaa ◽  
Gamal Bedair ◽  
Abdulrahim Kalendar
Keyword(s):  
Air Conditioning ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Exergy Destruction ◽  
Air Conditioning System ◽  
Capacity Coefficient ◽  
Automotive Air Conditioning ◽  
Automotive Air Conditioning System ◽  
Compressor Power ◽  
Low Global Warming Potential

The energy and exergy of low-global warming potential (GWP) refrigerants were investigated experimentally and theoretically. Refrigerants with a modest GWP100 of  ≤ 150 can be sufficient for bringing down emissions which were concerned for the automotive air-conditioning system. Three types of low-GWP refrigerants, R152a, R1234yf, and R1234ze(E), were examined with particular reference to the current high-GWP of R134a. The effect of different evaporating and condensing temperatures in addition to compressor speed was considered. The purpose was to bring a clear view of the performance characteristics of possible environment friendly alternatives of R134a. The analysis was carried out with compressor power, cooling capacity, coefficient of performance, exergy destruction, and exergy efficiency. It was noted that the total exergy destruction of R1234yf was reduced by 15% compared to that of R134a. The refrigerant R1234ze(E) has the highest energetic and exergetic performance compared with the other investigated refrigerants.

First and second thermodynamic law analyses applied to a solar dish collector

2014 ◽  
Vol 39 (4) ◽  
Author(s):  
Vahid Madadi ◽  
Touraj Tavakoli ◽  
Amir Rahimi
Keyword(s):  
Heat Transfer ◽  
Solar Radiation ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Exergy Efficiency ◽  
Exergy Destruction ◽  
Flow Rates ◽  
Energy And Exergy ◽  
Mass Flow Rates

AbstractThe energy and exergy performance of a parabolic dish collector is investigated experimentally and theoretically. The effect of receiver type, inlet temperature and mass flow rate of heat transfer fluid (HTF), receiver temperature, receiver aspect ratio and solar radiation are investigated. To evaluate the effect of the receiver aperture area on the system performance, three aperture diameters are considered. It is deduced that the fully opened receivers have the greatest exergy and thermal efficiency. The cylindrical receiver has greater energy and exergy efficiency than the conical one due to less exergy destruction. It is found that the highest exergy destruction is due to heat transfer between the sun and the receivers and counts for 35 % to 60 % of the total wasted exergy. For three selected receiver aperture diameters, the exergy efficiency is minimum for a specified HTF mass flow rate. High solar radiation allows the system to work at higher HTF inlet temperatures. To use this system in applications that need high temperatures, in cylindrical and conical receivers, the HTF mass flow rates lower than 0.05 and 0.09 kg/s are suggested, respectively. For applications that need higher amounts of energy content, higher HTF mass flow rates than the above mentioned values are recommended.

THERMODYNAMIC ANALYSIS AND PERFORMANCE ASSESSMENT OF A CASCADE ACTIVE MAGNETIC REGENERATIVE REFRIGERATION SYSTEM

2013 ◽  
Vol 21 (03) ◽  
pp. 1350016 ◽  
Author(s):  
HADI GANJEHSARABI ◽  
IBRAHIM DINCER ◽  
ALI GUNGOR
Keyword(s):  
Exergy Efficiency ◽  
Heat Transfer Fluid ◽  
Total Power ◽  
Design Parameters ◽  
Refrigeration System ◽  
Total Power Consumption ◽  
Energy And Exergy ◽  
And Performance ◽  
Cascade Refrigeration ◽  
Important Design

In the present study, a thermodynamic model is proposed to analyze and assess the performance, through energy and exergy, of a cascade active magnetic regenerative (AMR) refrigerator operation a regenerative Brayton cycle. This cascade refrigeration system works with Gd x Tb 1–x alloys as magnetic materials where the composition of the alloy varies for different stages. In this model, the heat transfer fluid considered is a water– glycol mixture (50% by weight). The refrigeration capacity, total power consumption, coefficients of performance (COP), exergy efficiency and exergy destruction rate of a cascade AMR refrigeration (AMRR) system are determined. To understand the system performance more comprehensively, a parametric study is performed to investigate the effects of several important design parameters on COP and exergy efficiency of the system.

scholarly journals Effect of Titanium Oxide Nano Lubricants Applied to R134a Refrigeration System

2020 ◽  
Vol 8 (5) ◽  
pp. 5557-5559
Keyword(s):  
Steady State ◽  
Tio2 Nanoparticles ◽  
Titanium Oxide ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Refrigeration System ◽  
Compressor Work

In this work experiment is performed by using titanium oxide (Tio2) nanoparticles at three different nanoaparticles containing lubricants 0.2g/l,0.4g/l as well as 0.6g/l . An experiment was performed by dispersing titanium oxide (Tio2) nanoparticles and the variables such as compressor work, Coefficient of performance (C.O.P) and refrigeration has been analysed.The experiment was conducted with R134a refrigerant under steady state conditions.Inclusion of Tio2 nanoparticles improved the coefficient as well as cooling capacity of presentation and the compressor work is get reduced.

scholarly journals Performance of Air Conditioning Unit under Constant Outdoor Wet-Bulb Temperature and Varied Dry-Bulb Temperature

2021 ◽  
Vol 39 (5) ◽  
pp. 1483-1490
Author(s):  
Andriyanto Setyawan ◽  
Susilawati Susilawati ◽  
Tandi Sutandi ◽  
Hafid Najmudin
Keyword(s):  
Energy Efficiency ◽  
Air Temperature ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Air Conditioner ◽  
Outdoor Air ◽  
Efficiency Ratio ◽  
Liquid Line ◽  
Discharge Temperature ◽  
Line Temperature

An experiment has been carried out for examining the performance of an air conditioning unit under constant outdoor wet-bulb temperature and varied dry-bulb temperature. During the experiment, the wet-bulb temperature of the compartment for outdoor unit was maintained at 22℃ and the dry-bulb temperature was varied from 24℃ to 36℃. The increase of outdoor air temperature results in the increase of supply air temperature, discharge temperature, suction temperature, and liquid line temperature. These cause the degradation of the air conditioner performance. An increase of power consumption by 1.4% and decrease of cooling capacity by 0.8% were observed for each 1℃ increase of outdoor air temperature. As a result, the energy efficiency ratio drops by 2% for each 1℃ increase of outdoor air temperature.

scholarly journals Evaporator Frosting in Refrigerating Appliances: Fundamentals and Applications

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5991
Author(s):  
Christian J. L. Hermes ◽  
Joel Boeng ◽  
Diogo L. da Silva ◽  
Fernando T. Knabben ◽  
Andrew D. Sommers
Keyword(s):  
First Principles ◽  
Simulation Models ◽  
Cooling Capacity ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Trial And Error ◽  
Refrigeration System ◽  
Duty Cycles ◽  
Transfer Principles ◽  
Frost Layer

Modern refrigerators are equipped with fan-supplied evaporators often tailor-made to mitigate the impacts of frost accretion, not only in terms of frost blocking, which depletes the cooling capacity and therefore the refrigerator coefficient of performance (COP), but also to allow optimal defrosting, thereby avoiding the undesired consequences of condensate retention and additional thermal loads. Evaporator design for frosting conditions can be done either empirically through trial-and-error approaches or using simulation models suitable to predict the distribution of the frost mass along the finned coil. Albeit the former is mandatory for robustness verification prior to product approval, it has been advocated that the latter speeds up the design process and reduces the costs of the engineering undertaking. Therefore, this article is aimed at summarizing the required foundations for the design of efficient evaporators and defrosting systems with minimized performance impacts due to frosting. The thermodynamics, and the heat and mass transfer principles involved in the frost nucleation, growth, and densification phenomena are presented. The thermophysical properties of frost, such as density and thermal conductivity, are discussed, and their relationship with refrigeration operating conditions are established. A first-principles model is presented to predict the growth of the frost layer on the evaporator surface as a function of geometric and operating conditions. The relation between the microscopic properties of frost and their macroscopic effects on the evaporator thermo-hydraulic performance is established and confirmed with experimental evidence. Furthermore, different defrost strategies are compared, and the concept of optimal defrost is formulated. Finally, the results are used to analyze the efficiency of the defrost operation based on the net cooling capacity of the refrigeration system for different duty cycles and evaporator geometries.

Performance Evaluation of the Thermophotovoltaic-Driven Thermoionic Refrigerator

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Emin Açıkkalp ◽  
Süheyla Yerel Kandemir ◽  
Mohammad H. Ahmadi
Keyword(s):  
Energy Source ◽  
Performance Evaluation ◽  
Solar Energy ◽  
Cooling Rate ◽  
Power Output ◽  
Exergy Efficiency ◽  
Exergy Destruction ◽  
Destruction Rate ◽  
Operation Conditions

Abstract In this study, the thermophotovoltaic (TPV)-driven thermionic refrigerator (TIR) is presented as an alternative refrigerator operated by the solar energy. Solar energy is the main energy source and its performance is analyzed. Power output density of the TPV, cooling rate density, COP, exergy destruction rate densities, and exergy efficiencies are the considered parameters. Calculations are performed numerically; results are presented and discussed. The most suitable operation conditions are defined. According to the results, the cooling rate density is 648 W/m2, power output densities are 1189.86 W/m2 and 667.234 W/m2 for the eg = 0.3 eV and eg = 0.4 eV, and the exergy efficiency of the system is about 0.071.

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