Drop-in Replacement For R134a Research Articles

Thermodynamic analysis of a linear compressor vapour compression system

Linear compressors are advantageous in terms of miniaturization, high efficiency, and continuous operation without a crank mechanism. The drop-in replacement for R134a in domestic refrigerators is R1234yf. This study aims to investigate the linear compressor thermodynamic performance in vapour compression system with R1234yf by modelling and measuring key parameters such as pressure-volume (P-V) diagram, refrigerant distribution, mass flow rate, volumetric efficiency, cooling capacity, and coefficient of performance (COP). Results show that at 40 °C condenser temperature and 2 pressure ratio, the linear compressor vapour compression system achieved a maximum 299.1 W cooling capacity, which gives 4.12 COP. The thermodynamic analysis calculations are in good agreement to the results of experimental measurements, verifying the accuracy of the model.

Drop-In Replacement of R134a in a Household Refrigerator with Low-GWP Refrigerants R513A, R516A, and R1234ze(E)

This study proposes the experimental evaluation of alternative refrigerants with low global warming potentials (GWPs) such as R1234ze(E), R513A, and the mixture R516A as a drop-in replacement for R134a in a domestic refrigerator with a volumetric capacity of 513 L. Initially, the optimal charge for each refrigerant was defined based on the minimum energy consumption of the refrigerator, then the thermal and energy performance of the refrigerator was evaluated. Finally, a total equivalent warming impact analysis (TEWI) was performed. The main results indicated that the optimal charge of the alternative refrigerants was below that corresponding to R134a (105 g), of which R516A (86 g) presented the greatest charge reduction. Regarding the average temperature of the refrigerator compartments, very adequate thermal conditions were observed; thus, the alternative refrigerants showed very similar conditions to R134a. For the coefficient of performance (COP) and considering R134a as a reference, it was observed that R513A presented the greatest reduction of around 28%, while R1234ze(E) showed an increase of 13% in relation to R134a. Finally, the TEWI analysis showed R1234ze(E) as the refrigerant with the least impact.

Performance Assessment of Low Global Warming Potential Alternative Refrigerants

Global warming is the general increase in global temperature brought on by higher-than-normal concentrations of greenhouse gases. These gases trap heat waves as they approach the world and allow them to continue entering the atmosphere over time without being able to leave. This study used low global warming potential alternative refrigerants to reduce greenhouse gas emissions, in line with global efforts to phase out chlorinated fluids in order to preserve the ozone layer as a result of the Montreal Protocol. A software program called Cycle-D-Hx, which has a graphical user interface and a thermodynamic model of the refrigeration system, was used to evaluate how well household refrigerators working with various types of refrigerants performed. The model was validated using data from a household refrigerator charged with R134A. The performance of several low global warming potential alternative refrigerants, including R404A, R449A, R513A, and R452A, was then assessed using the model.
 The hydrofluoroolefin based R452A refrigerant is an alternative to R404A and R507 that is non-ozone depleting and has a low global warming potential. An azeotropic blend, R-513A is a drop-in replacement for R-134a in existing systems. Common hydrofluorocarbons and the new hydrofluoro-olefin molecule R1234yf are combined to form R449a, which is made up of R32 (24%), R125 (25%), R134a (26%), and R1234yf (25%). R513A, an aceotropic blend with no temperature glide, is composed of 44% R134a and 56% R1234yf.
 The simulation's findings demonstrate that R452A has a coefficient of performance 1.578, a zero potential for ozone depletion, a 0.5oC temperature glide for the evaporator and condenser and also a low potential for global warming unit count of 2140. Along with these thermodynamic and environmental qualities, R452A blend can take the place of R134A as a refrigerant because it is non-flammable and noncorrosive and will not corrode the metal parts of the compressor and evaporator of the refrigeration system.

Evaluating R450A as a drop-in replacement for R134a in household heat pump tumble dryers

This paper presents the results of an experimental study evaluating R450A as a possible drop-in replacement for R134a in household heat pump tumble dryers. A heat pump installed in a tumble dryer was equipped with pressure and temperature sensors, and electrical power meters. First, the energy consumption according to the IEC 61121 standard was evaluated using R134a. Then the refrigerant was replaced with R450A and a new optimal charge was determined. The tumble dryer performance was then evaluated again and compared with the previous results. It was found that R450A is a suitable drop-in replacement for R134a in heat pump tumble dryers. The total energy consumption of the tumble dryer decreased by 3.7% and several other benefits such as a better utilized evaporator, and a lower refrigerant temperature at the compressor outlet were observed. Additionally, the refrigerant charge CO2 equivalent was reduced by more than 50%. However, the duration of the drying cycle increased by 4.2%, due to a slightly lower condensing temperature in the heat pump.

Energy efficiency evaluation of the use of R513A as a drop-in replacement for R134a in a water chiller with a minichannel condenser for air-conditioning applications

This work presents an experimental assessment on the use of R513A refrigerant as a drop-in replacement for R134a in a water chiller for air-conditioning applications. The study discusses from an energy efficiency point of view this replacement option for warm countries. A vapor-compression refrigeration system (VCRS) working with a minichannel air heat exchanger as a condenser and driven by a 0.92 kW piston-type compressor was used to compare the performance of both refrigerants. A fixed water inlet temperature of 12 °C and a fixed outlet temperature of 7 °C were set for all the experiments whereas different air temperatures (between 20 and 35 °C) and velocities were tested at the condenser side. In all the cases studied, R513A showed an energy efficiency ratio (EER) worse than R134a for cooling capacities between 1.8 and 2.5 kW. On average, EER of R513A was 24% worse than that of R134a. The higher vapor density of R513A at the suction side of the compressor resulted in a higher mass flow rate and a lower isentropic and mechanical efficiency when compared to those of R134a. In the present application, the efficiency of the reciprocating compressor was found to be sensitive to the refrigerant mass flow rate. When R513A was used as a drop-in, the mass flow rate increased ~15% what resulted in a significant increase of the pressure drop in some lines, an increase of the compressor compression ratio and a reduction of ~8% in both the isentropic and mechanical efficiencies of the reciprocating compressor.

Energy performance evaluation of R600a/MWCNT-nanolubricant as a drop-in replacement for R134a in household refrigerator system

Vapour compression refrigerator systems working with R134a are associated with high energy demand and environmental problems and refrigerator consumers’ prioritise energy consumption in choosing their choice of refrigerator systems. Therefore, this research work investigated R600a in MWCNT-nanolubricant (0.4 g/L and 0.6 g/L) as a drop in replacement for R134a refrigerant in a household refrigerator system with varied mass charge of R600a (50, 60 and 70 g). The refrigerator was instrumented at the inlet and outlet of the refrigerator compressor, condenser, expansion valve and evaporator. Two bourdon type pressure gauges were connected to the compressor inlet and outlet of the system. The results were taken and evaluated and compared with the result obtained through R134a refrigerant in the system. The result showed that R600a perform better in terms of COP, power consumption and cooling capacity compared to R134a in the system with lower evaporator temperature of −11°C and power consumption of 0.0639 kW and highest COP in the system. Therefore, R6000a/MWCNT- nanolubricant can serve as a drop in replacement for R134a in the household refrigerator.

Energy and exergy analyses of R513a as a R134a drop-in replacement in a vapor compression refrigeration system

R513a (XP10), a mixer of 56% R1234yf (C3H2F4) and 44% R134a (CH2FCF3), has similar thermophysical characteristics to R134a but only half of its global warming potential (GWP). This paper uses an economized-cycle vaper compression refrigeration system as an example to investigate the energy and exergy performance of R513a used as a drop-in replacement for R134a. Differing from previous research, this study examines the entire system operating zone to identify the performance differences in terms of capacity, COP, exergy destruction rate, and exergy efficiency between R513a and R134a systems. The analysis found that a system with drop-in R513a demonstrates reduced capacity by up to 12% and efficiency (up to 9% with COP and 14% with exergy efficiency) under a majority of operating conditions, while exhibiting less irreversibility (5% to 13%) under high-ambient, high-space temperature conditions and better exergy efficiency of 3% in low-ambient conditions. In addition, the contribution of each individual component to the exergy destruction rate at various operating conditions is identified. To improve the energy and exergy efficiency of a R513a system, the analysis results indicate that the compressor is the first component that should be redesigned or reselected, followed by the economizer, valves, and evaporator. The condenser influence is negligible.

Annual performance analysis of an air source heat pump water heater using a new eco-friendly refrigerant mixture as an alternative to R134a

The air source heat pump water heater (ASHPWH) is an efficient and environmentally friendly system that is widely used in China. In this study, a refrigerant mixture R290/R600a/R13I1 with low global warming potential (GWP) and no ozone depletion potential (ODP) is proposed as drop-in replacement for R134a in ASHPWH. A theoretical model for an ASHPWH is developed based on MABLAB linking with REFPROP. The cycle performances of the proposed mixture, a contrast mixture, and R134a are analyzed under different working conditions, to investigate the feasibility of substitution. The annual performances of the ASHPWH that uses different refrigerants are also studied for comparison. The results show that compared with R134a, the proposed mixture has better performance with lower condensing pressure and compression ratio, and higher specific heating capacity and coefficient of performance (COP). The discharge temperature is also reasonable. Therefore, it is feasible to replace R134a with the proposed mixture. The ASHPWH using the proposed mixture has obvious advantages when the ambient temperature is very low. The annual average COP with the proposed mixture is 4.65, which is about 6.2% higher than with R134a, and the total equivalent warming impact (TEWI) can be reduced by 18.99%.

Experimental study of R1234yf as a drop-in replacement for R134a in an oil-free refrigeration system

R1234yf is a synthetic refrigerant with global warming potential (GWP) of 4 and similar thermodynamic properties to R134a. This paper experimentally compares the performance of R1234yf with R134a in an oil-free vapour compression refrigeration (VCR) system. The oil-free VCR system consisting of oil-free linear compressors, an off-the-shelf condenser and an evaporator with an electric heater avoids the impact of oil lubricant on the heat transfer so that the two refrigerants can be appropriately compared with each other. Experiments for two refrigerants were carried out for compressor strokes of 9–13 mm, operating frequency of 32–38 Hz, pressure ratios of 2–4, and condenser temperatures of 40–50 °C with refrigerant charge of 250 g. The experimental results show that the coefficient of performance (CoP) of R1234yf is 20% lower than R134a with condenser temperature of 40 °C and evaporator temperature of 0 °C. The volumetric efficiency of R1234yf is 5% lower than R134a with condenser temperature of 40 °C and evaporator temperature of −1.5 °C. Results of evaporator pressure drop, superheat, power input, and cooling capacity are also reported.

Exergoeconomic performance comparison of R1234yf as a drop-in replacement for R134a in a domestic refrigerator

The replacement of refrigerants in domestic refrigerators is nowadays one of the approaches used to enhance the performance and environmental impact of these systems. Theoretical and experimental research, mainly focused on energy or exergy analysis, is currently found in the literature, but only a few studies are focused on exergoeconomic approaches. Therefore, in order to include the overall costs of a domestic refrigerator, an exergoeconomic cost analysis is applied to an experimental installation. Exergoeconomic parameters such as the unit exergy cost (cp) and the exergoeconomic factor (f) are used as a comparative indicator of performance. Based on the unit exergy cost, the results show that R134a performs better than R1234yf at different operating conditions. The exergoeconomic factor presents higher values for R134a than for R1234yf, which implies less exergy destruction in the system. The optimization allows reducing the cost of the produced cold by 9.8% when using R134a and by 6.5% when using R1234yf.

Experimental comparison of an air-to-water refrigeration system working with R134a and R1234yf

In this work, the use of R1234yf as a drop-in replacement for R134a in an air to water refrigeration system used to produce cool water at 7 °C is studied. This equipment was constructed in our laboratory with a minichannel heat exchanger working as condenser and a plate heat exchanger working as evaporator resulting in a 2.5 kW water chiller, which initially was working with R134a as refrigerant. A brief description of the refrigeration system and the installation used to test its behaviour as well as the uncertainty analysis is presented.Then, the test matrix defined in order to evaluate the effect of the different variables of interest on the performance of the refrigeration cycle is also presented. Air inlet temperature in the condenser was varied in order to analyse the influence of a variation in the ambient temperature. Other variables were varied in order to analyse the influence of different operating conditions as a variation in the compressor frequency or in the condenser fan velocity (by varying air inlet velocity). Finally, the subcooling degree was varied in order to compare a system with refrigerant receiver (no subcooling) and a system without refrigerant receiver and different refrigerant charge (different subcooling).According to the results obtained, R1234yf performs worse than R134a, presenting lower cooling capacity and higher compressor consumption in all tests, with a global efficiency around 25% lower. This can be explained by its lower isentropic and volumetric efficiency, which could be related to the type of lubricant used.

Experimental analysis of R1234yf as a drop-in replacement for R134a in a small power refrigerating system

This paper presents an experimental study of the R1234yf drop-in performance in an R134a small power vapor-compression refrigeration system. Experiments were performed for two compressor supply frequency values of 40 and 60 Hz, evaporation temperatures from −5 to +5 °C and condensation temperatures of 45, 50 and 55 °C. From the experimental measurements, parameters such as the cooling power, compressor electric power or the energy efficiency ratio (EER) of the system are obtained and compared between the two refrigerants. Results show that R1234yf may be an adequate drop-in refrigerant for R134a as it closely matches its cooling capacity at the expense of lower EER values.

Comparison of transient response of an evaporator model for water refrigeration system working with R1234yf as a drop-in replacement for R134a

This study is developed to evaluate the possibility of R1234yf to be a drop-in replacement for a pre-designed system with R134a, including the characterization of control system in a vapor compression system. The control algorithms are required for regulating the refrigerant flow rate into the evaporator and their control parameters depend intrinsically on refrigerant fluid. This paper presents a comparison of the effects of R134a and R1234yf refrigerants on the transient response of an evaporator operating with water as secondary fluid (counter-flow). The dynamic heat exchanger distributed model combines principles of thermodynamics, heat and mass transfer with empirical correlations, which are proposed in the literature, in order to compute the void fraction, pressure drop and heat transfer in two-phase flow. Experimental tests are carried out on a fixed refrigeration system for cooling capacity less than 3 kW, with constant condensation conditions, variable evaporating temperature and compressor speed to validate the model. The results demonstrated that a good agreement between simulation results and experimental data was achieved. The evaporation temperature data were within ± 1 °C error band. Furthermore, comparative simulations between the refrigerants R-134a and R-1234yf exhibited a similar dynamic behavior during a step at the inlet mass flow rate, and the gain and time constant for superheat control were not considerably modified. Therefore, the refrigerant changing does not demand many changes in the expansion device control strategy.

Thermodynamic modeling of VLE and VLLE for the ternary system of 2,3,3,3-tetrafluoroprop-1-ene(R1234yf) + propane (R290) + 1,1,1,2-tetrafluoroethane(R134a) at 253.15 K-313.15 K

The excess Gibbs free energy-equation of state (GEEoS) models is presented based on the Peng-Robinson (PR) EoS combined with the Wong-Sandler (WS) mixing rule and the modified UNIFAC group contribution method (PR-WS-MUNIFAC). The average absolute deviation (AAD) of vapor phase mass fraction and the absolute average relative deviation (AARD) of pressure are 0.0047 and 0.53%, respectively, for R152a + R1234yf; 0.0064、0.0050 and 1.59%, respectively, for R32 + R125 + R134a. The VLE properties of the ternary mixture R1234yf + R290 + R134a as a drop-in replacement for R134a were predicted over the temperature range of (253.15–313.15 K) at 10 K intervals. The vapor–liquid-liquid equilibrium (VLLE) was qualitatively analyzed in theory, and the relevant phase equilibrium diagrams were constructed. The R290 + R134a system has clear characteristics of VLLE near the azeotropic point; the pressure of the upper critical end point (UCEP) is approximately 1.627 MPa. Liquid phase separation also exists in the ternary system of R1234yf + R290 + R134a.

Energy and exergy analysis of R1234yf as drop-in replacement for R134a in a domestic refrigeration system

This paper presents an energy and exergy analysis of a domestic refrigeration system using R1234yf as a drop-in replacement for R134a. We base our analysis on a series of independent tests using two refrigerants, namely R1234yf and R134a. The test equipment consists of a fully instrumented domestic refrigeration system. A computational model is developed to work out the thermodynamic parameters such as coefficient of performance, exergy destruction ratio, exergy-based rational efficiency, component efficiency defect as well as the dimensionless exergy balance for both refrigerants. The parameters varied in the analysis were the evaporator and condenser temperatures as well as the amount of refrigerant used in the system. The results indicate that irreversibilities are mainly concentrated in the compressor, this is the case both for R1234yf and R134a. This exergy analysis proposed for evaluation of refrigerants in domestic refrigerators permitted to determine that R1234yf may not be a likely alternative to R134a.

Experimental study of R1234yf as a drop-in replacement for R134a in a domestic refrigerator

This paper presents an experimental study for three identical domestic refrigerators using R1234yf as a drop-in replacement for R134a. An alternative methodology was proposed to estimate the optimal mass charge for R1234yf; with the use of such methodology, new evidences were sought on the thermal behavior of the refrigerator compartments as well as at the heat exchangers. Additionally, energy performance for both refrigerants was measured, and, finally, a TEWI analysis was conducted. For the type of refrigerator evaluated, results showed that R1234yf presented an average (for the 3 refrigerators) of 0.4 °C for the fresh food compartment, and 1.2 °C for the freezer, among different charges with respect to R134a. The optimal charge for R1234yf was 92.2 g, which is about 7.8% lower than the one for R134a, which represents a small increase of 4% in energy consumption in comparison to R134a. Finally, the TEWI analysis for the R1234yf was 1.07% higher than the R134a.

HFO1234ze as Drop-in Replacement for R134a in Domestic Refrigerators: An Environmental Impact Analysis

Abstract In this paper are reported the results of an experimental comparative analysis between R134a and HFO1234ze, when they are employed as refrigerants in a domestic refrigerator. Under sub-tropical conditions, it have been measured the energy consumptions in accordance with the UNI-EN-ISO15502. For each experiment it have been estimated both the TEWI and the Life Cycle Climate Performance indexes to assess the environmental impact due to HFO1234ze when used in place of R134a.

HFO1234yf as a Drop-in Replacement for R134a in Domestic Refrigerators: A Life Cycle Climate Performance Analysis

HFO1234yf as a Drop-in Replacement for R134a in Domestic Refrigerators: A Life Cycle Climate Performance Analysis

HFO1234yf as a drop-in replacement for R134a in domestic refrigerators: a life cycle climate performance analysis

HFO1234yf as a drop-in replacement for R134a in domestic refrigerators: a life cycle climate performance analysis

Energy evaluation of R152a as drop in replacement for R134a in cascade refrigeration plants

An experimental comparison has been performed of a cascade refrigeration facility working with the refrigerant pairs R134a/R744 and R152a/R744. This kind of facility is suitable for industrial and commercial refrigeration applications. The high GWP refrigerant R134a has been substituted with the low GWP refrigerant R152a, in accordance with the new environmental regulations aimed at mitigating the Greenhouse effect. As both refrigerants belong to the family of HFC fluids, the replacement has been carried out as a drop-in. Apart from safety considerations, as R152a is included in the A2 group, the results of the wide range of tests conducted show that no special energy improvement or worsening is achieved, and that the replacement of R134a with R152a is technically and energetically feasible.