Low Global Warming Potential Refrigerants Research Articles

Low global warming potential (GWP) refrigerant supermarket refrigeration system modeling and its application

• A high fidelity model for a low -GWP refrigerant supermarket refrigeration system was developed. • The model was validated by manufacture and lab testing data with accuracy within ±4%. • A near-optimal high side pressure was obtained through extensive simulation running of the model. • The model was also used to generate battery equivalent model for using in grid interactive controls. As an environmentally friendly low global warming potential (GWP) refrigerant, Carbon dioxide (CO 2 ) has continuously gained popularity and research attention as alternative refrigerant for supermarket refrigeration system. In this paper, to fulfill the increasing need of accurate Low-GWP supermarket refrigeration models for development of supervisory level control and optimization strategies, a high fidelity model is developed for CO 2 transcritical supermarket refrigeration system which includes compressor rack of low temperature (LT) compressors and medium temperature (MT) compressors, air-cooled gas cooler, evaporator, expansion valves and other auxiliary equipment. A resistance-capacity model structure is proposed to simulate the display cases. Semi-thermodynamic models are proposed to estimate reciprocating compressors volumetric efficiency and power consumption. The zone modeling approach is used for evaporator simulation, and air-cooled gas cooler is modeled with distributed modeling method. The expansion valve simulation is based on orifice flow model. To calibrate these models, both manufacture performance data and experimental data are used. The experiments are conducted with a full instrumental CO 2 supermarket refrigeration system installed in Oak Ridge National Lab Flexible Research Platform (FRP). The simulation model can predict the system performance, including power consumption, cooling capacity, mass flow rate, temperature, and pressure, with high accuracy (within ±4%) compared to experimental data. In addition, this developed model has been used to create the system optimum high side pressure for high side expansion valve control, and to generate wide operating range simulation data for developing the batter-equivalent commercial refrigeration system model which can be used in grid interactive control development.

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

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.

Energy and Thermal Conductivity Assessment of Dimethyl-Ether and its Azeotropic Mixtures as Alternative Low Global Warming Potential Refrigerants in a Refrigeration System

Abstract Substituting Hydrofluorocarbons with natural refrigerants in domestic refrigerators will significantly reduce the direct contributions of fluorinated gases to global warming which will be of great environmental benefit. In this study, the performances of dimethyl-ether (RE170) and its azeotropic mixtures (R510A and R511A) in a refrigeration system were assessed theoretically and compare with that of conventional refrigerant. The study revealed that the three investigated alternative refrigerants exhibited significantly good heat transfer characteristics, low pressure ratio, high latent heat in the liquid phase which resulted in their high thermal conductivity and Volumetric Cooling Capacity (VCC). The thermal conductivity of the refrigerants reduces while the evaporating temperature rises and the value obtained for RE170 was the highest among the four refrigerants studied. The Coefficient of Performance (COP) for RE170, R510A and R511A were higher than that of R134a by 6.20, 10.06 and 3.02 % respectively while their power consumptions per ton of refrigeration were lower than that of R134a by 6.99, 11.04 and 1.47 % respectively. In conclusion, dimethyl-ether and its azeotropic mixtures performed better than R134a in that they have higher thermal conductivity, refrigerating effect, VCC, COP, lower power consumption per ton of refrigeration and hence, they can be considered as suitable replacements for R134a in domestic refrigerator.

Performance simulation of HFC-161 as an alternative refrigerant to HCFC-22 for room air conditioner

According to recent Kigali amendment in 2016, ODS (ozone depleting substances) and high GWP (global warming potential) refrigerants must be phased out. There is need to find an alternative refrigerant for air conditioning applications. This article presents the performance comparison for selected low GWP refrigerants commonly used by different air conditioner manufacturers. A baseline test was conducted on a 5.2 kW air conditioner originally designed for HCFC-22 in psychrometric lab as per Indian standard IS 1391 part 1. Simulation tool was tuned and validated against the experimental results within ± 5% accuracy. Parametric analysis was done using IMST-ART tool for the best suitable configuration of compressor capacity, capillary tube, heat exchangers etc. for maximum energy efficiency. Simulation study concluded that the HFC-161 is an energy efficient and climate friendly alternative since it has zero ODP (ozone depletion potential) and ultra-low GWP of 12 except its flammability issue. European standard EN 378, specifies the limit of about 15 g/m3 for charging HFC-161 in the AC system. For HFC-161, the highest cooling capacity of 5.3 kW is achieved in case 4. The HFC-161 gave 27.2% higher EER compared to HCFC-22 system due to 26.47% lowered power consumption. Discharge temperature of HFC-161 is also lowered in the range of 70 °C to 82 °C compared to selected refrigerants. The required charge for HFC-161 was only 55% of HCFC-22.

Viability of Various Sources to Ignite A2L Refrigerants

Environmental considerations are motivating the adoption of low global warming potential refrigerants. Most of these are mildly flammable, i.e., A2L. Their susceptibility to ignition from various ignition sources is poorly understood, particularly for the stoichiometric and quiescent mixtures that are emphasized here. The viability of fifteen residential ignition sources to ignite four A2L refrigerants is considered. Tests are performed in a windowed chamber with a volume of 26 L. The refrigerants are R-32 (difluoromethane); R-452B (67% R-32, 26% R-1234yf, and 7% pentafluoroethane); R-1234yf (2,3,3,3-tetrafluoropropene); and R-1234ze (1,3,3,3-tetrafluoropropene). Two types of ignition sources are confirmed here to be viable: a resistively heated wire at 740 °C and open flames. When the refrigerant concentration was increased slowly, candle flames and butane flames extinguished before initiating any large deflagrations. Eleven other sources were not viable: a smoldering cigarette, a butane lighter, friction sparks, a plug and receptacle, a light switch, a hand mixer, a cordless drill, a bread toaster, a hair dryer, a hot plate, and a space heater. The difficulty to ignite these refrigerants in air is attributed to their long quenching distances (up to 25 mm). Under some conditions the refrigerants were observed to act as flame suppressants.

Advanced high temperature heat pump configurations using low GWP refrigerants for industrial waste heat recovery: A comprehensive study

High temperature heat pumps (HTHPs) have a great potential to improve industrial processes with thermal demand through industrial waste heat recovery and revalorization. Vapor compression HTHPs are very sensitive to the cycle configuration, refrigerant, components, and operating temperatures. This study compares eight advanced cycle configurations and nine low global warming potential (GWP) refrigerants from an energetic, economic, and environmental comprehensive perspective to illustrate an optimum selection for different HTHP applications. Firstly, several single-stage and two-stage compression cycles are proposed adding different components, such as the ejector, economizer, parallel compressor, flash tank, or additional evaporators and condensers. Moreover, an internal heat exchanger (IHX) has been included in all configurations to maximize the energy performance and ensure dry compression. Secondly, HC-601, HC-600, HC-600a, HFO-1336mzz(Z), HFO-1336mzz(E), R-514A, HCFO-1233zd(E), HCFO-1224yd(Z), and HFO-1234ze(Z) are considered as alternative low GWP refrigerants to replace the hydrofluorocarbon HFC-245fa. The results indicate that a two-stage cascade becomes the most appropriate configuration for high temperature lifts (60 K and above). In contrast, single-stage cycles with economizer and parallel compression are suitable for low temperature lifts (50 K and below). HCFO-1233zd(E) and HCFO-1224yd(Z) show a trade-off between coefficient of performance (COP) and volumetric heating capacity (VHC). Advanced HTHPs configurations can save up to 68% of the equivalent CO2 emissions compared to a natural gas boiler.

Comparative analysis of HFO-1234ze(E) and R-515B as low GWP alternatives to HFC-134a in moderately high temperature heat pumps

This article provides a theoretical energy performance and carbon footprint analysis of the hydrofluoroolefin HFO-1234ze(E) and the mixture R-515B as low global warming potential (GWP) refrigerants to replace the hydrofluorocarbon HFC-134a in different heat pump applications. The reference configuration is a single-stage cycle with an internal heat exchanger (IHX). In this way, the impact of the IHX on medium and moderately high temperature heating applications has been investigated. HFO-1234ze(E) and R-515B result in approx. 25% lower heating capacity than HFC-134a due to a diminution of the latent heat of vaporisation and suction density. The heating capacity difference between HFO-1234ze(E) and R-515B remains below 2%. The heating coefficient of performance (COP) of the alternative low GWP refrigerants is comparable to that of the HFC-134a at the proposed conditions. The environmental analysis illustrates that HFO-1234ze(E) and R-515B can reduce down to 18% and 15%, respectively, the equivalent CO2 emissions compared to HFC-134a in low-temperature space heating applications. In addition, this reduction arrive at 78% when compared to a natural gas boiler, considered as the conventional heating technology in moderately high temperature applications (domestic hot water, industrial processes, and radiators). Although HFO-1234ze(E) and R-515B present comparable energy and environmental performance, the latter refrigerant has an advantage in regard to installation safety requirements as a non-flammable refrigerant (A1).

Experimental assessment of alternative low global warming potential refrigerants for automotive air conditioners application

R134a, one of the most commonly used refrigerants especially for air conditioning (AC) systems, will be banned in automotive air conditioners after 2022 due to a high global warming potential (GWP). R152a and R1234yf are considered as two potential low GWP drop-in alternatives to R134a due to similar thermodynamic properties. In this paper, the performance of R152a, R1234yf, and R134a in an oil-free vapour compression refrigeration (VCR) system is investigated. The absence of oil lubricant enables a wide range of refrigerant selection and highly efficient refrigeration cycle. Experiments for R152a, R1234yf, and R134a were conducted over wide range of operating conditions. The results show that R1234yf is similar to R134a in terms of operating pressure and temperature, but R1234yf has an 11% and 16% deterioration in cooling capacity and coefficient of performance (COP) respectively. The higher volumetric efficiency, adiabatic efficiency and cooling capacity of R152a contributes to a 13% and a 6% higher cooling capacity and COP respectively than that of R134a. At an evaporator temperature of 0 °C, the COP of R152a, R1234yf, and R134a are 2.8, 1.8, and 2.3, respectively. Though flammability restricts the use of R152a in conventional automotive air conditioners, R152a can be considered as a more promising alternative to R134a for oil-free automotive air conditioning than R1234yf due to its high efficiency, low cost, and reasonable safety level benefiting from the absence of oil lubricants.

Flow boiling heat transfer characteristics of low global warming potential refrigerants in a vertical mini-channel

Flow boiling heat transfer characteristics in narrow channels have been investigated extensively by researchers due to its wide range of applications in micro-electromechanical systems, however, being a complex transport process the controlling mechanisms still lack clarity in understanding. Refrigerants related environmental hazards also urged to look for alternative environment friendly refrigerants. It has been noticed that relatively less information is available in the literature specifically for environmentally benign mediums. This study is focused on experimental findings for flow boiling heat transfer performance of low global warming potential refrigerants (R152a, R600a, and R1234yf). The test object was a vertical stainless steel tube (1.60 mm inner diameter and heated surface length 245 mm), experiments were done under upward fluid-flow conditions. The tested conditions were: heat flux 5-245 kW/m2, 50-500 kg/m2s mass velocities while saturation temperatures were 27 ?C and 32 ?C. The effects of operating parameters like heat and mass fluxes, saturation temperature, and vapor quality on heat transfer were analyzed in detail. It was noticed that heat transfer coefficients were significantly influenced by heat flux and operating pressure level whereas the same were not significantly affected by mass flux and vapor quality. The experimental data of heat transfer was compared with the prediction from various macro and micro scale correlations from the literature.

Experimental characterization of an innovative hybrid thermal-electric chiller for industrial cooling and refrigeration application

The energy demand of industries accounts for about 30–35% of world yearly energy consumption, a relevant percentage is due to the need of heating and cooling demand. Solar heating and cooling technologies can be integrated in industrial processes to reduce the fossil fuels consumption as well as the related greenhouse gas emissions. This paper reports the experimental analysis of a novel hybrid sorption-compression chiller for cooling and refrigeration purposes in cascade layout, which uses silica gel/water for the sorption cycle and a low Global Warming Potential (GWP) refrigerant, i.e. propylene for the compression cycle. The experimental results highlighted the flexibility of the system in terms of performances and operating conditions, these were compared to the theoretical performances and it was found out that electricity energy savings from 15% to 25% can be achieved when using the hybrid system over a compression one with the same cooling capacity. The results were converted in performance maps and processed in a statistical model, in order to get a simplified expression for determining the overall performances of the hybrid system through variables that could be measured by a final user, such as the operating temperatures. Optimization strategies were identified for a further enhancement of the performance of the chiller, i.e. the reduction of the electricity consumption, by controlling the intermediate temperature (evaporation temperature of the sorption chiller) through sorption cycle management and the use of variable speed of the pumps in all the circuits to reduce the parasitic consumption especially at low part loads.

Comparative energy and exergy analysis of a subcritical cascade refrigeration system using low global warming potential refrigerants

This study examines a variety of evaluation criteria such as various operating and design parameters for thermodynamic performance of a cascade refrigeration system (CRS). R41 is used in low-temperature circuit (LTC), whereas R1243zf, R423A, R601, R601A, R1233zd (E) and RE170 are used for the first time in this study and are adapted for a high-temperature circuit (HTC). This study with four aims are conducted: (1) to analyse refrigerant pairs with low global warming potential (GWP) to further contribute to the literature; (2) to investigate the impact of various operating parameters on system performance; (3) to suggest potential alternative refrigerant to R423A; (4) to also compare the performance of the refrigerant pairs used in this study with those analysed by researchers in the literature. The results demonstrate that condenser and evaporator temperature ranges have a significant effect on the performance parameters studied in the system designed for six refrigerant pairs. The greatest reduction in COP occurs in R41-R423A with about 43.85% in a change of 10°C in the condenser temperature. A change of 10°C in the evaporator temperature causes the COP of the CRS to rise by approximately 19% for all refrigerant pairs. For applications that desire low temperatures, R41-R423A exhibits the lowest COP and exergy efficiency with 1.105 and 33.93%, respectively, whereas R41-RE170 presents the highest COP and exergy efficiency with 1.210 and 37.18%, respectively. Furthermore, exergy destruction in HTC compressor is made up almost to one-third of total exergy destruction. RE170 is proposed as an alternative refrigerant for R423A by the reason of its low environmental detriment and superior performance. Furthermore, there is a maximum COP improvement of 13.05% compared to studies in the literature.

Energy and Exergy Analysis of Low-Global Warming Potential Refrigerants as Replacement for R410A in Two-Speed Heat Pumps for Cold Climates

Heat pumps (HPs) are being developed with a new emphasis on cold climates. To lower the environmental impact of greenhouse gas (GHG) emissions, alternate low global warming potential (GWP) refrigerants must also replace the exclusive use of the refrigerant R410A, preferably without re-engineering the mechanical hardware. In this paper, we analyze the performance of four low-GWP alternative refrigerants (R32, R452B, R454B, and R466A) relative to the conventional R410A and draw conclusions on the relative performances for providing heating in cold climates based on the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) 210/240 standard for two-speed heat pumps. The simulations are carried using the Department of Energy, Oak Ridge National Laboratory (DOE/ORNL) Heat Pump Design Model (HPDM), a well-known heating, ventilation, and air conditioning (HVAC) modeling and design tool in the public domain and the HVAC research and development community. The results of the simulation are further scrutinized using exergy analysis to identify sources of systemic inefficiency, the root cause of lost work. This rigorous approach provides an exhaustive analysis of alternate low-GWP refrigerants to replace R410A using available compressors and system components, without compromising performance.

Techno-economic analysis of high-temperature heat pumps with low-global warming potential refrigerants for upgrading waste heat up to 150 °C

This work investigates the techno-economic aspects of high-temperature heat pumps used for waste heat recovery. The heat pump produces heat at a temperature up to 150 °C from heat of below 100 °C based on both single- and two-stage cycles, with the aim of identifying the most cost-effective among various heat sink and heat source temperatures. Refrigerants with low-global warming potential are considered and a validated heat pump model is used to calculate the cycle performance. Then, the equipment cost of the different configurations is calculated as a function of the component parameters and system scale. This approach provides a trade-off between high efficiency versus high cost, in order to identify the most cost-effective configuration at each temperature level. The results show that the specific equipment cost of the heat pump is usually in the range of 150 to 300 EUR/kW, mostly depending on the cycle design and temperature. Moreover, the discounted payback period of industrial installations shows a large scatter, and can even be as short as 3 to 4 years. The overall outcome is that the single-stage cycle with an internal heat exchanger is favoured in terms of economic performance, except with large temperature lifts of over 50 K, in which a two-stage cycle shows superior cost-effectiveness.

Modelling the barriers to low global warming potential refrigerants adoption in developing countries: A case of Indian refrigeration industry

Conventional synthetic refrigerants are responsible for ozone depletion and have high global warming potential (GWP). Thus, countries across the globe are progressively phasing out such refrigerants by 2050 under the Kigali amendment. While the developed countries in Europe are the pioneers in promoting the use of low GWP refrigerants, the developing countries are still lagging. This is happening despite these countries being a signatory to the Kigali amendment. However, it is contextual to mention here that the refrigeration industry in developing countries, such as India, faces several barriers to the adoption of low GWP refrigerants. The phasing out of high GWP refrigerants will be considerably delayed if these issues remain unresolved, and there is inadequate research on such barriers to the adoption. With an aim to investigate the precincts of limited adoption, this study identifies 18 barriers through an extensive literature survey. It also contributes to the literature by proposing two more factors responsible for the limited adoption of low GWP refrigerants in the Indian context. Interpretive structural modelling (ISM) methodology is used to elucidate the hierarchical relationship among these barriers. Lack of government incentives emerges as the most compelling factor limiting the adoption of low GWP refrigerants. The research also suggests a four-pronged strategy to promote the adoption of low GWP refrigerants in India.

Seasonal energy performance characteristics of novel ejector-expansion air conditioners with low-GWP refrigerants

The objective of this study is to investigate the seasonal performance characteristics of novel ejector-expansion air conditioners (EEACs) with low global warming potential refrigerants. A simplified simulation model for EEACs is developed and validated using measured data. Using a simulation model, the coefficient of performance, cooling seasonal performance factor, and life cycle climate performance of the EEACs employing low global warming potential refrigerants are analyzed at various operating conditions and modes. In addition, the climatic effects on the cooling seasonal performance factors and life cycle climate performances of the EEACs are evaluated at four different weather conditions. The EEAC with R290 exhibits the cooling seasonal performance factor and total CO2 emissions that are 22% higher and 23.3% lower, respectively, than those of the baseline air conditioner with R410A. In general, R290 is the best working fluid for EEACs in terms of the seasonal performance and lifetime environmental factor.

On simple method for predicting burning velocities for lower flammability refrigerants using quenching distance measurement

Abstract For extensive use of low global warming potential refrigerants with low flammability, there is a need to develop a simple method to distinguish the lower flammability refrigerants from the higher flammability ones. The purpose of this paper is to investigate the applicability of the test method for flat-plate quenching distance (dq) for predicting the maximum burning velocity (Su0, max) of near 10 cm s−1. The dq measurement was carried out by the ASTM E582–07 method and the modified method for six binary blends that all have Su0, max of approximately 10 cm s−1. It was found that the standard 25-mm diameter glass plates placed in the vertical position give at most 11% smaller dq values than 50-mm diameter plates placed in the horizontal position, which was due to the upward motion by the buoyancy. Based on the thermal loss theory, a simple equation using the experimental dq was obtained to predict the Su0, max of the lower flammability blends.

Performance assessment of optimized heat pump water heaters using low-GWP refrigerants for high- and low-temperature applications

In this study, performance improvements of optimized heat pump water heaters (HPWHs) employing low global warming potential refrigerants are numerically evaluated against the performance of the conventional R-410A HPWH. A simulation model for HPWHs is developed and validated based on experimental results obtained in the R-410A and R-32 HPWHs. The performances of the HPWHs employing R-32, R-446A, and L-41b are simulated considering for high-temperature applications (HTAs) and low-temperature applications (LTAs) based on EN 14511. The heat exchanger design parameters of the HPWHs are optimized for achieving the maximum coefficient of performance (COP) for each alternative refrigerant. The optimized L-41b HPWH exhibits the highest COP, and the COP improvements thereof are 6.3% and 4.6% in the HTA and LTA conditions, respectively, compared with those of the R-410A HPWH. Moreover, the total equivalent warming impacts of the optimized HPWHs employing the alternative refrigerants are 5.9–9.9% lower than those of the R-410A HPWH.

Molecular dynamic simulation and SAFT modeling of the viscosity and self-diffusion coefficient of low global warming potential refrigerants

Hydrofluoroolefins (HFOs) are among the recommended options to replace the currently used high global warming potential (GWP) hydrofluorocarbon (HFC) based refrigerants. The viscosity of both refrigerant classes was extensively measured in the literature. However, little to no information is available on the microscopic mobility of these molecules. In this work, the liquid densities (ρ), viscosities (η) and self-diffusion coefficients (D) of R-32, R-152a, R134a, R-1234yf, R-1234ze(E), R-1233zd(E), R-1224yd(Z) and R-1336mzz(Z) were predicted near saturation using molecular dynamic (MD) simulation. Data are reported across a wide range of conditions from 243 to 403 K. Results suggest a Stokes-Einstein type behavior that was exhibited by all refrigerants. Simulations also show that the DR-1234yf ≈ DR-152a, DR-1234ze(E) ≈ DR-134a and DR-1233zd(E) ≈ DR-1224yd(Z). The dynamic behavior of refrigerants is explained in relation to their molecular size, structure and interactions. Rosenfeld's entropy scaling was applied to correlate the viscosities and self-diffusion coefficients. Residual entropies were computed using the polar and perturbed chain form of the statistical associating fluid theory (Polar PC-SAFT).

Chinese policy leadership would cool global air conditioning impacts: Looking East

The International Energy Agency expects the global stock of room air conditioners (RACs) to triple between today and 2050, with critical implications for energy use and greenhouse gas emissions. Because China produces approximately 70% of the world's RACs, it is in a unique position to lead a global transition to higher-efficiency RACs with substantially lower environmental impact. To date, however, Chinese policies have targeted relatively modest RAC efficiency increases. We recommend that China target production of RACs that use low global warming potential (GWP) refrigerants and are at least as efficient as the most efficient RACs produced today in China or on the global market. Specifically, we recommend that China set minimum energy performance standards for RACs at China annual performance factor (APF) 5.4 in 2025 and China APF 6.9 in 2030. This leadership would provide a longer-term policy signal to RAC manufacturers in China, enabling them to meet the efficiency targets cost-effectively by providing adequate time for investment planning. We project that full implementation of our recommended policy could result in global electricity consumption savings of 74 petawatt-hours, CO2 reductions of 49 billion metric tons, and bill savings of 6 trillion U.S. dollars (cumulative benefits 2020–2050). The policy is viable in China because of its provision of long-term certainty for manufacturers and their demonstrated ability to produce low-GWP RACs with the required efficiencies. Exploiting the parallel transition away from high-GWP refrigerants under the Kigali Amendment to the Montreal Protocol would provide manufacturing efficiencies and substantial savings opportunities.

Correlations for liquid thermal conductivity of low GWP refrigerants in the reduced temperature range 0.4 to 0.9 from saturation line to 70 MPa

Abstract This paper presents a literature survey of the experimental thermal conductivity data for environmentally friendly refrigerants, namely HydroFluoroOlefins (HFOs) and HydroChloroFluoroOlefins (HCFOs), in the liquid phase. A total of 2073 experimental data for six alternative refrigerants, i.e. R1233zd(E), R1234yf, R1234ze(E), R1234ze(Z), R1224yd(Z), and R1336mzz(Z), was collected in the temperature range from 203.18 K to 434.99 K and in the pressure range from 0.10 MPa to 66.62 MPa. Literature correlations not considering the pressure dependence were compared for reduced pressures lower than 1. Di Nicola et al. (2014a) correlation was re-fitted and new coefficients expressly dedicated to low global warming potential refrigerants were given. The proposed equation gives an overall deviation of 1.78% for the data measured at reduced pressure up to 1. The liquid thermal conductivity dependence on pressure was also considered adding new terms on Di Nicola et al. (2014a) correlation and on Latini and Sotte (2012) correlation. The proposed equations give overall deviation of 1.45% and 1.99%, respectively, for the complete dataset.