Performance Comparison of a Truck Refrigeration System with R404A, R134a, R1234yf, and R744 Refrigerants under Frosting Conditions

2016 ◽  
Vol 24 (01) ◽  
pp. 1650005 ◽  
Author(s):  
Yunchan Shin ◽  
Honghyun Cho
Keyword(s):  
Analytical Model ◽  
Indoor Air ◽  
System Performance ◽  
Operating Time ◽  
Performance Comparison ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Average Error ◽  
Refrigeration System ◽  
Air Conditioners

A new refrigerant is needed because the GWP of the R404A and R134a that are used in existing refrigerated trucks and automotive air conditioners is so high. This study predicts cooling performance by using an analytical model, for refrigeration systems using R404A and R134a. Furthermore, the performances of those systems were compared with those of alternative refrigeration systems using R1234yf and R744. The performance data of the analytical model had a trend similar to that of the experimental data: the average error between the analytical and experimental results was within 5.4%. The frost thickness of the R404A system for all operating conditions was about 2.4–3.7% larger than that of other systems because the evaporating temperature of the R404A system was lower than that for other refrigerants. For various operating conditions, the coefficient of performance (COP) of the R134a system was higher than that of other systems, while the R744 system showed the lowest performance. However, the COP reduction of the R744 system with operating time was the smallest because the thermodynamic properties of R744 were very superior. In addition, the frost thickness was seriously affected by the variations of indoor air temperature and compressor rotation speeds, and the system performance decreased significantly for severe operating conditions.

An Experimental Investigation on Vapor Compression Refrigeration System Cascaded with Ejector Refrigeration System

2021 ◽  
pp. 2150028
Author(s):  
Vikas Kumar ◽  
Gulshan Sachdeva ◽  
Sandeep Tiwari ◽  
Parinam Anuradha ◽  
Vaibhav Jain
Keyword(s):  
Experimental Investigation ◽  
Thermal Equilibrium ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Compression System ◽  
Vapor Compression System ◽  
Vapor Compression Refrigeration ◽  
Cascaded System

A conventional vapor compression refrigeration system (VCRS) cascaded with a heat-assisted ejector refrigeration system (ERS) has been experimentally analyzed. Cascading allows the VCRS to operate at lower condenser temperatures and thus achieve a higher coefficient of performance. In this cascaded system, the condenser of the vapor compression system does not dissipate its heat directly to the evaporator of the ERS; instead, water circulates between the condenser of VCRS and the evaporator of ERS to exchange the heat. Seven ejectors of different geometries have been used in the ERS; however, all the ejectors could not maintain thermal equilibrium at the desired operating conditions. The compressor of the cascaded VCRS consumed 1.3 times less power than the noncascaded VCRS. Furthermore, the cascaded system provided a maximum 87.74% improvement in COP over the noncascaded system for the same operating conditions. The performance of the system remained constant until the critical condenser pressure of the ERS.

scholarly journals Parametric analysis of a combined ejector-vapor compression refrigeration cycle

2020 ◽  
Vol 15 (3) ◽  
pp. 398-408
Author(s):  
I Ouelhazi ◽  
Y Ezzaalouni ◽  
L Kairouani
Keyword(s):  
Current Model ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Entrainment Ratio ◽  
Constant Area ◽  
Vapor Compression Refrigeration Cycle ◽  
Vapor Compression Refrigeration

Abstract From the last few years, the use of efficient ejector in refrigeration systems has been paid a lot of attention. In this article a description of a refrigeration system that combines a basic vapor compression refrigeration cycle with an ejector cooling cycle is presented. A one-dimensional mathematical model is developed using the flow governing thermodynamic equations based on a constant area ejector flow model. The model includes effects of friction at the constant-area mixing chamber. The current model is based on the NIST-REFPROP database for refrigerant property calculations. The model has basically been used to determine the effect of the ejector geometry and operating conditions on the performance of the whole refrigeration system. The results show that the proposed model predicts ejector performance, entrainment ratio and the coefficient of performance of the system and their sensitivity to evaporating and generating temperature of the cascade refrigeration cycle. The simulated performance has been then compared with the available experimental data from the literature for validation.

Experimental Analysis on Vapour Compression Refrigeration System Using Nanolubricant with HFC-134a Refrigerant

Nano Hybrids ◽  
2015 ◽  
Vol 9 ◽  
pp. 33-43 ◽  
Author(s):  
A. Manoj Babu ◽  
S. Nallusamy ◽  
K. Rajan
Keyword(s):  
Energy Consumption ◽  
System Performance ◽  
Mineral Oil ◽  
Coefficient Of Performance ◽  
Refrigeration System ◽  
Hfc 134A ◽  
Reduce Energy Consumption ◽  
And Performance ◽  
Vapour Compression ◽  
Better Than

This paper investigates the reliability and performance of a refrigeration system using nanolubricant with 1, 1, 1, 2-Tetrafluoroethane (HFC-134a) refrigerant. Mineral Oil (MO) is mixed with nanoparticles such as Titanium Dioxide (TiO2) and Aluminium Oxide (Al2O3). These mixtures were used as the lubricant instead of Polyolester (POE) oil in the HFC-134a refrigeration system as HFC-134a does not compatible with raw mineral oil. An investigation was done on compatibility of mineral oil and nanoparticles mixture at 0.1 and 0.2 grams / litre with HFC-134a refrigerant. To carry out this investigation, an experimental setup was designed and fabricated in the lab. The refrigeration system performance with the nanolubricant was investigated by using energy consumption test. The results indicate that HFC-134a and mineral oil with above mentioned nanoparticles works normally and safely in the refrigeration system. The refrigeration system performance was better than the HFC-134a and POE oil system. Thus nanolubricant (Mixture of Mineral Oil (MO) and nanoParticles) can be used in refrigeration system to considerably reduce energy consumption and better Coefficient of Performance (COP).

Performance Investigation of Single Adsorption Refrigeration System Driven by Solar Heat Storage

2018 ◽  
Vol 26 (03) ◽  
pp. 1850025
Author(s):  
Hicham Boushaba ◽  
Abdelaziz Mimet
Keyword(s):  
System Performance ◽  
Heat Storage ◽  
Cooling Capacity ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Solar Irradiation ◽  
Cooling Power ◽  
Condensation Temperature ◽  
Adsorption Refrigeration ◽  
Solar Heat

The aim of this paper is to provide a global study of an adsorption refrigeration machine driven by solar heat storage and collected by parabolic trough collector. The system operates with ammonia (as refrigerant) and activated carbon (as adsorbent). A mathematical model interpreting the progression of the heat and the mass transfer at each element of the prototype has been developed. The solar irradiation and the real ambient temperature variations corresponding to a usual summer day in Tetouan (Morocco) are considered. The system performance is evaluated trough specific cooling power (SCP) as well as solar coefficient of performance (SCOP), which was estimated by a dynamic simulation cycle. The pressure, temperature and adsorbed mass profiles in the Adsorber have been calculated. The effects of significant design and operating parameters on the system performance have been investigated. The results show the capability of our system to realize an encouraging performance and to overcome the intermittence of the adsorption refrigeration machines. For a daily solar irradiation of 18[Formula: see text]MJ[Formula: see text]m[Formula: see text] and operating conditions of evaporation temperature [Formula: see text]C, condensation temperature [Formula: see text]C and generation temperature [Formula: see text]C, the results show that the process could achieve an SCP of 115[Formula: see text]W[Formula: see text]kg[Formula: see text] and it could produce a daily specific cooling capacity of 3310[Formula: see text]kJ[Formula: see text]kg[Formula: see text], whereas its SCOP could attain 0.141.

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.

scholarly journals COP enhancement of vapour compression refrigeration system using dedicated mechanical subcooling cycle

2020 ◽  
Vol 39 (3) ◽  
pp. 776-784
Author(s):  
T.S. Mogaji ◽  
A. Awolala ◽  
O.Z. Ayodeji ◽  
P.B. Mogaji ◽  
D.E. Philip
Keyword(s):  
System Performance ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Condensation Temperature ◽  
Refrigeration System ◽  
Wide Range ◽  
Cascade Refrigeration System ◽  
Cascade Refrigeration ◽  
Vapour Compression ◽  
Better Than

This study focused on development of an improved vapour compression refrigeration system (IVCR system). Dedicated mechanical subcooling cycle is employed in attaining the developed IVCR system. The system is composed of two cycles cascade refrigeration system working with R134a. It consists of a rectangular shape with total storage space of 0.582 m3, made of galvanized mild steel and internally insulated with 0.05 m polystyrene foam. Tests under a wide range operating temperature conditions were carried out on the developed IVCR system. Performance evaluation of the system was characterized in terms of cooling capacity and coefficient of performance (COP). Experimental results showed that the COP of the subcooled system improved better than that of the main system from 18.0% to about 33.5% over an evaporating temperature range of -10 to 30oC. It can be concluded that the use of dedicated sub cooling cycle in VCR system is more efficient and suitable for the betterment of thermal system performance. Keywords: Vapour compression Refrigeration system, Coefficient of performance, dedicated subcooled system, Condensation temperature, Evaporation temperature.

Effect of Hydrofluorocarbons and Hydrofluoroolefins in a Household Refrigerator as a Substitute for R134a

2019 ◽  
Vol 969 ◽  
pp. 199-204
Author(s):  
Shaik Mohammad Hasheer ◽  
Kolla Srinivas
Keyword(s):  
Cooling Capacity ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Condensation Temperature ◽  
Outlet Temperature ◽  
Refrigeration System ◽  
Volumetric Cooling ◽  
Work Done ◽  
Theoretical Results ◽  
Hfc 152A

Now a days R134a can be used in domestic refrigerators and in air conditioning of automobiles. As per Kyoto protocol the usage of R134a is restricted due to their higher GWP value. The GWP value of this refrigerant is around 1430. So in this article, thermodynamic analysis of HFC-152a, HFO refrigerants-1234ze(E) and 1234yf was done in a household refrigeration system as direct substitute to HFC-134a.The performance of the household refrigerator was compared in terms of outlet temperature of the compressor, volumetric cooling capacity (VCC), refrigeration effect, work done by the compressor and coefficient of performance (COP). The entire analysis is carried out at various operating conditions of condenser and evaporator temperatures i.e. condensation temperature of 25°C,35°C & 45°C and evaporating temperatures ranging between −20°C to 10°C.From the theoretical results, it can be concluded that R1234yf can be used as a direct substitute to R134a.

scholarly journals Exergetic performance analysis of low GWP alternative refrigerants for R404A in a refrigeration system

2021 ◽  
Author(s):  
Mehmet Altinkaynak
Keyword(s):  
Cooling System ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration System ◽  
Alternative Refrigerants ◽  
Condenser Temperature ◽  
Parametric Analyses ◽  
Low Global Warming Potential ◽  
Very High

Abstract According to the regulation of European Union laws in 2014, it was inevitable to switch to low global warming potential (GWP) fluids in the refrigeration systems where the R404A working fluid is currently used. The GWP of R404A is very high, and the potential for ozone depletion is zero. In this study, energetic and exergetic performance assessment of a theoretical refrigeration system was carried out for R404 refrigerant and its alternatives, comparatively. The analyses were made for R448A, R449A, R452A and R404A. The results of the analysis were presented separately in the tables and graphs. According to the results, the cooling system working with R448A exhibited the best performance with a coefficient of performance (COP) value of 2.467 within the alternatives of R404A followed by R449A and R452A, where the COP values were calculated as 2.419 and 2.313, respectively. In addition, the exergy efficiencies of the system were calculated as 20.62%, 20.22% and 19.33% for R448A, R449A and R452A, respectively. For the base calculations made for R404A, the COP of the system was estimated as 2.477, where the exergy efficiency was 20.71%. Under the same operating conditions, the total exergy destruction rates for R404A, R448A, R449A and R452A working fluids were found to be 3.201 kW, 3.217 kW, 3.298 kW and 3.488 kW, respectively. Furthermore, parametric analyses were carried out in order to investigate the effects of different system parameters such as evaporator and condenser temperature.

Experimental Study With Analytical Validation of Energy Parameters in Parabolic Trough Collector With Twisted Tape Insert

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
U. C. Arunachala
Keyword(s):  
Experimental Study ◽  
Performance Evaluation ◽  
Analytical Model ◽  
System Performance ◽  
Operating Conditions ◽  
Twisted Tape ◽  
Hydraulic Efficiency ◽  
Parabolic Trough ◽  
Parabolic Trough Collector ◽  
Maximum Percentage

Abstract Thermo-hydraulic performance evaluation of parabolic trough collector is important while introducing heat transfer augmentation techniques to it. In the present outdoor experimental study, the role of twisted tape is justified in laminar flow-based parabolic trough collector. For the Re range of 544–1742 and solar beam radiation of 400–750 W/m2, the use of twisted tape (twist ratios: 5.2, 4.1, and 2.7) resulted in maximum instantaneous efficiency of 22.3%, 29.5%, and 40%, respectively, against 19.1% with plain receiver. The effect of pressure drop rise on system performance due to twisted tape is found to be insignificant as effective thermo-hydraulic efficiency recorded are 21.8%, 29.3%, and 39.7%, respectively, with maximum uncertainty involved of 1.01%. In view of the importance of system performance evaluation over a wide range of operating parameters and limitation of outdoor experiments, an analytical model has been developed which followed the similar trend. The model takes into account various operating conditions, viz. laminar, twisted tape-based laminar and turbulent flow condition as well as air-in-annulus and evacuated receiver cases. Using the model (laminar region) in both plain and twisted tape cases, the maximum percentage deviation in the prediction of exit fluid temperature (in °C) and effective thermo-hydraulic efficiency are 1.6 and 13.3, respectively. Further, for a turbulent case, the maximum percentage deviation in exit temperature (in °C) noticed is 2.9. Hence, the developed analytical model is having a good agreement with the experimental outcomes.

Performance investigation of organic Rankine-vapor compression refrigeration integrated system activated by renewable energy

2019 ◽  
Vol 20 (2) ◽  
pp. 206 ◽  
Author(s):  
B. Saleh ◽  
Ayman A. Aly ◽  
Ageel F. Alogla ◽  
Awad M. Aljuaid ◽  
Mosleh M. Alharthi ◽  
...  
Keyword(s):  
Renewable Energy ◽  
System Performance ◽  
Organic Rankine Cycle ◽  
Integrated System ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Vapor Compression ◽  
Working Fluids ◽  
Vapor Compression Refrigeration

In this article, the performance and working fluid selection for an organic Rankine cycle-vapor compression refrigeration (ORC–VCR) integrated system activated by renewable energy is investigated. The performance of the system is described by the system coefficient of performance (COPS), and the refrigerant mass flow rate per kilowatt refrigeration capacity (m˙total). Twenty-three pure substances are proposed as working fluids for the integrated system. The basic integrated system performance is assessed and compared using the proposed working fluids. The basic VCR cycle works between 35 and 0 °C, while the basic ORC works between 35 and 100 °C. The impacts of different operating parameters such as the evaporator, the boiler, and the condenser temperatures on the ORC–VCR system performance are also examined. The results show that the cyclopentane accomplished the highest system performance under all investigated operating conditions. Accordingly, among the examined 23 working fluids, cyclopentane is the most appropriate working fluid for the integrated system from the viewpoints of environmental concerns and system performance. Nevertheless, due to its high flammability, further restrictions should be taken. The basic integrated system COPS, refrigeration effect, and the corresponding m˙total utilizing cyclopentane are 0.654, 361.3 kW, and 0.596 × 10−2 kg/(s kW), respectively.

Sign in / Sign up

Export Citation Format

Share Document