Refrigerants R22 Research Articles

The performance analysis of a compressed air energy storage (CAES) for peak moving with cooling, Heating, and power production

This study focuses on modeling and optimizing a multifaceted geothermal-based energy production system within the context of Denmark. The primary objectives revolve around enhancing system efficiency and reducing operational costs. The system under investigation comprises geothermal components, an organic Rankine cycle, a compressed air energy storage facility, and an absorption chiller. The organic Rankine cycle operates using refrigerants R123 and ammonia, effectively converting thermal energy into electricity and thermal energy for various applications. Optimization was carried out employing the Response Surface Method in tandem with Design-Expert software, facilitating the fine-tuning of objective functions. Two key objectives were selected: Exergy Round Trip Efficiency and cost rate, aimed at improving technical performance and curbing economic expenditure. A range of design variables were considered for optimization, including turbine and pump inlet temperatures, geothermal mass flow rate, turbine and pump efficiencies, compressor and gas turbine efficiency, inlet pressure to the compressed air energy storage tank, and evaporator pinch point temperature. The system reached an impressive exergy efficiency peak of 77.98%, accompanied by a modest cost rate of 5.48 $/h. The costliest components in the system were the compressed air energy storage unit, followed closely by organic Rankine cycle 1 and organic Rankine cycle 2. In contemplating the practical implementation of this innovative energy system, ten cities in Denmark underwent rigorous analysis, accounting for technical and economic factors. Subsequent assessments identified Aarhus as the optimal location to initiate the system. The environmental results showed that by producing 13981.9 megawatts of electricity annually in Arhus City, it is possible to help reduce CO2 emissions by 2853.2 tons of CO2/year and avoid environmental costs of 68455.3 $/year. The environmental assessment also highlighted the potential for substantial green space expansion, estimating an additional 13 hectares of green areas in the city of Aarhus, Denmark.

Calculation of exergy losses, exergy efficiency and cooling coefficient of refrigerant R22

This study presents a detailed analysis of the exergy losses, exergy efficiency, and cooling coefficient of performance (COP) for the refrigerant R22 in refrigeration systems. Exergy analysis, which considers both the quantity and quality of energy, is used to identify and quantify the irreversibilities within the system. The objective of this analysis is to provide insights into the areas of inefficiency and potential improvements for enhanced energy performance. Results indicate that the exergy losses in R22 systems are primarily associated with the compressor and expansion valve, highlighting these components as key targets for efficiency improvements. The exergy efficiency was found to vary significantly with operating conditions, suggesting that system performance could be optimized through appropriate design and control strategies. Additionally, the cooling COP of R22 was evaluated, demonstrating its effectiveness in converting input energy into cooling capacity under various conditions. This analysis contributes to the broader understanding of R22's thermodynamic performance and offers a foundation for developing more sustainable and efficient refrigeration technologies.

Design, optimization, and performance analysis of a solar-wind powered compression chiller with built-in energy storage system for sustainable cooling in remote areas

This study aims to develop a sustainable cooling solution for refrigeration in remote areas, utilizing solely wind and solar power. Ensuring that the power generated aligns with consumption throughout the day is a critical challenge. The investigation centers on the integration of an energy storage and a compression cooling cycle to attain the desired objective. This system integrates refrigerant storage on both the evaporator and condenser sides. The storage tanks' volume is variable by time and should be adjusted automatically. The sustainability of the cooling capacity depends on the amount of input power and the type of refrigerant. Moreover, additional heat is extracted to produce hot water. The analysis includes the coefficient of performance, exergy efficiency, cooling capacity, total heating capacity, and environmental impacts for six refrigerants R134a, R22, R717, R125, R500, and R407c. The system is configured to offer a cooling capacity of 15 kW while maintaining a temperature difference of 38K. The best performance is achieved using R717 as the refrigerant with a coefficient of performance of 5.26, an exergy efficiency of 36 %, and a payback period of 2.267 in Sabzevar. Furthermore, R717 does not contribute to ozone depletion or global warming.

Molecular simulations of increased thermal energy storage in metal–organic heat carriers with R1234ze(E)/R32 mixtures combined with IRMOF-1

Metal-organic heat carrier (MOHC) nanofluids offer a promising solution to enhance the efficiency of Organic Rankine Cycle systems. In this study, we developed a computational model to assess the thermal energy storage capacity of MOHC nanofluids using a base fluid mixture of R1234ze(E) and R32 refrigerants. Through Grand Canonical Monte Carlo and molecular dynamics simulations, we examined the adsorption characteristics, desorption heat, and thermodynamic properties of MOHCs. Our findings reveal that R32 molecules are preferentially adsorbed in IRMOF-1 compared to R1234ze(E), with adsorption selectivity of R32 over R1234ze(E) increasing under higher adsorption pressures. When the temperature during the endothermic process surpasses the phase transition point of the base fluid, the latent heat of phase transition can be fully exploited to enhance energy storage. Moreover, the inclusion of IRMOF-1 nanoparticles significantly improves the energy storage properties of both R32 and R1234ze(E), as well as their mixtures. The energy storage enhancement provided by IRMOF-1 is particularly pronounced under high working pressures and low temperature differences. These insights offer valuable guidance for selecting appropriate base fluids in MOHC systems, thereby optimizing the utilization of low-grade energy sources.

R744 Refrigeration Solution for Small Supermarkets

Application based technology solution is nowadays preferred to achieve the performance of the cooling system configuration at its best. Therefore, benchmarking is an essential criterion which would add value to the optimum system design for various applications. In this study, a case study is carried out for a Milk Bar (small supermarket) to evaluate the potential of R744 cooling system for the similar cooling demand and tropical conditions. Field data collected during a particular time and temperature zone is further used to develop a yearly round performance of the HFC plug-in cabinets for MT and LT applications. The data is further used to develop a centralized R744 booster system that would meet the similar cooling load and demand of all the cabinets in the shop. Based on the cooling loads for the HFC unit, the yearly performance of the R774 booster system is calculated and compared to the existing plug-in solution. It is observed that the yearly electric energy consumption for the R744 centralized refrigeration system is 3.3 M W·h, 24% lower than with the existing solution based on HFCs. Moreover, the economic prospective of the R744 is further discussed to alternative material for the components and centralized unit structure which could empower the system with more reliability and an effective substitute to the synthetic technology for smaller supermarkets. This article is a translation of the article by Singh S, Pardiñas ÁÁ, Hafner A, Schlemminger C, Banasiak K. R744 Refrigeration Solution for Small Supermarkets. In: Proceedings of the 9th IIR Conference on the Ammonia and CO2 Refrigeration Technologies. Ohrid: IIF/IIR, 2021. DOI: 10.18462/iir.nh3-co2.2021.0030 Published with the permission of the copyright holder.

Computational multiphase mixture simulations of a two-phase R-744 ejector geometry in transcritical R-744 heat pump applications

Purpose Two-phase R-744 ejectors are critical components enabling energy recovery in R-744 heat pump and refrigeration systems, but despite their simple geometry, the flow physics involve complex multiphase mixing phenomena that need to be well-quantified for component and overall system improvement. This study aims to report on multiphase mixture simulations for a specific two-phase R-744 ejector with supercritical inlet conditions at the motive inlet side. Design/methodology/approach Four different operating conditions, which have motive inlet pressure range of 90.1 bar–101.1 bar, are selected from an existing experimental data set. A two-phase thermodynamic equilibrium (TPTE) model is used, where the fluid properties are described by a thermodynamic look-up table. Findings The results show that the TPTE model overpredicts mass flow rates at the motive inlet, resulting in a relative error ranging from 15.6% to 21.7%. For the mass flow rate at the suction inlet, the relative errors are found less than 1.5% for three cases, while the last case has an error of 12.4%. The maximum deviation of the mass entrainment ratio is found to be 8.0% between the TPTE model and the experimental data. Ejector efficiency ranges from 25.4% to 28.0%. A higher pressure difference between the ejector outlet and the diverging nozzle exit provides greater pressure lift. Research limitations/implications Based on the results, near future efforts will be to optimize estimation errors while enabling more detailed field analysis of pressure, density, temperature and enthalpy in the computational domain. Originality/value The authors have two main original contributions: 1) the presented thermodynamic look-up table is unique and provides unique computation for the real-scale ejector domain. It was created by the authors and has not been applied before as far as we know. 2) To the best of the authors’ knowledge, this study is the first study that applies the STAR-CCM+ multiphase mixture model for R-744 mixture phenomena in heat pumps and refrigeration systems.

The Joint Use of a Phase Heat Accumulator and a Compressor Heat Pump

This article presents an example of the joint use of a compressor heat pump that uses propane as a natural, ecological thermodynamic medium and a phase heat accumulator that uses paraffin as a medium. Special attention has been paid to the solidification process of the phase change material, and a simple theoretical model of the solidification of this material has been proposed. Thermodynamic balance calculations were carried out for the compressor heat pump and the phase heat accumulator. This paper presents a theoretical analysis of two examples of heating using a compressor heat pump, implementing the Linde cycle for the refrigerant R290 (propane): high-temperature heating at a temperature of 80 °C and low-temperature (surface) heating at a temperature of 60 °C, with the same unit heat output of 0.376 kW taken from the lower-temperature heat source of each evaporator. This heat is generated by the solidification of the PCM. The compressor power is 77 W in the first case and 40 W in the second. The energy efficiency coefficients of the compressor heat pump for the proposed combination of a phase heat accumulator and compressor heat pump are 5.98 and 10.40. The joint use of a heat accumulator and a heat pump presented in this paper can be used in applications for the heating of domestic water or water for space heating.

Innovative simplified approach and numerical investigation for flow and heat transfer in internally threaded tubes

Internally threaded tubes exhibit exceptional heat transfer capabilities, holding paramount significance in enhancing energy efficiency, reducing energy consumption, and tackling thermal challenges across aerospace, automotive, and environmental domains. Nonetheless, their intricate structural features, software modelling intricacies, extensive grid requirements, and challenges in maintaining grid quality render numerical simulation investigations a demanding endeavor. This study elucidates the influence mechanisms of thread spacing on the distribution of single-phase and two-phase flows. It delves into the condensation heat transfer of the R32 refrigerant and the single-phase heat transfer of water within internally threaded tubes. At the same Reynolds number, the heat transfer rate can be improved by approximately 19.61% with the optimized internally threaded parameters. When the Reynolds number varies from 18,626 to 51,222, the heat transfer rate per unit length for Tube-5 remains around 2,478.9 W/m, with a variation of less than 5.19%. Furthermore, it presents a simplified numerical simulation approach tailored for internally threaded pipes. This method manipulates wall roughness and regulates wall rotation speed to mimic fluid dynamics phenomena akin to conventional numerical simulation techniques. The findings reveal that the proposed simplified numerical simulation approach yields heat transfer and pressure drop predictions with less than 3% discrepancies compared to traditional numerical simulation predictions. Simultaneously, compared to directly simulating threaded pipes through conventional means, this approach significantly mitigates grid generation complexities, slashing computational time costs by at least 85% and facilitating efficient thermal design and structural optimization processes.

Experimental and Numerical Study on Scroll Compressor under Different Profile Correction and Discharge Ports Shapes

The scroll compressor is an essential component in air conditioning and heat pump systems. This study examined an electric scroll compressor using R22 refrigerant, focusing on how modifications in the scroll head profile and discharge structure affect its performance. Initially, a semi-empirical model based on mathematical formulas was developed to predict the performance improvements of the updated scroll compressor. Three-dimensional simulation software was then used to illustrate changes in the internal flow dynamics before and after enhancements. The predictions were validated through experimental testing. Both the semi-empirical model and the three-dimensional unsteady numerical calculation model analyzed the effects of modifications to the tooth head profile and discharge port shape on compressor performance. The adoption of a PMP profile correction delayed the compressor discharge process, shifting the starting discharge angle from 315°to 344°, thereby reducing under-compression occurrences during operation and increasing volumetric efficiency by 1.31%. Additionally, mathematical formulas correlating temperature with compressor performance were developed from fitting data, predicting compressor behavior under various conditions. Moreover, replacing a circular discharge port with a waist-shaped port reduced power consumption by 0.59 kW, resulting in a more uniform temperature distribution and enhanced mass flow rate during compressor operation.

Waste heat utilization: Energy and economic benefits from multi-ejector chiller sub-cooling R744 supermarket refrigeration systems

This study investigated the energy and economic benefits of a novel sub-cooling technique using a heat-driven multi-ejector chiller (HDEC) in R744 supermarket refrigeration systems. Two configurations were evaluated: a conventional booster system with HDEC (CBEC) and a parallel compression system with HDEC (PCEC). Among various natural refrigerants, R717 was identified as most suitable for the HDEC. Various multi-ejector combinations were examined to assess the potential for waste heat utilization and energy savings in the R744 refrigeration system. The CBEC system provided effective operation only at ambient temperatures above 31 °C, whereas the PCEC system was effective above 24 °C. Performance of the proposed configurations were compared with a conventional R744 booster system (CB) and a parallel compression system (PC) both devoid of HDEC. The PCEC system showed improvements in the coefficient-of-performance ranging from 4.2 % to 23.9 % at ambient temperatures between 28 °C and 40 °C compared to the baselines. In various warm-climatic zones, including India, the Middle East, Thailand, and the USA, energy savings of approximately 2.1 %–9.5 % were observed compared to the PC system. Economic analysis indicated a reasonable payback period of 2.1–2.7 years for the additional investment required for deploying the PCEC system in Phoenix.

Performance assessment on a modified precision refrigeration cycle using low GWP mixtures

Recently, with the increasing worldwide demand for low-temperature freezers, applying natural working medium hydro-carbon refrigerants for them has been widely concerned. Auto-cascade refrigeration cycle (ARC), as an efficient refrigeration technology, has been widely applications. However, the low separation efficiency of the refrigerant mixtures of the conventional ARC leads to its poor performance. Therefore, this paper presents a modified auto-cascade refrigeration cycle (MARC) using low GWP hydro-carbon refrigerants R170 and R290 for low-temperature freezer applications. In MARC, the two auxiliary separators are applied to make more low-boiling working fluid into evaporator to improve the volumetric cooling capacity (qev) and COP. The characteristics of conventional ARC and MARC are evaluated with theoretical method. The important parameters such as evaporating temperature and intermediate temperature for MARC are also detailed discussed. The theoretical research results suggest the MARC is more energy-saving and feasible. The improved cycle offers significant improvements in qev, COP and exergy efficiency. In detail, for MARC, the qev can be lifted by 40.3–91.3 % and the COP can be improved by 30.6–70.4 % compared with the ARC system. Therefore, the modified MARC shows its potential advantages for low-temperature freezer applications.

Simulation of diffusion of combustible refrigerants R1234yf and R290 leakage in automotive air conditioning

Electric vehicles that utilize a heat pump system have a refrigerant charge increase of at least 400 g compared to traditional fuel vehicle air conditioning systems. If combustible refrigerants are used, the risk of combustion increases when the refrigerant leaks and spreads to the passenger compartment. This paper dynamically monitored the volume concentrations of combustible refrigerants R1234yf and R290 as they leaked and entered the passenger compartment accompanied by air supply by numerical simulation. The results indicated that refrigerants are more prone to accumulate in the rear row than in the front. After a leak, the average volume concentration of R1234yf at the four air outlets was 1.58 %, and 3.36 % for R290. at the breathing points of four passengers, the average volume concentration was 0.99 % for R1234yf and 2.39 % for R290. Near the feet of the passengers, the average volume concentration was 0.95 % for R1234yf and 2.27 % for R290. The highest volume concentration of R1234yf in the passenger compartment was below its LFL, whereas all monitoring points for R290 exceeded its LFL. Compared to experimental data, the difference in maximum refrigerant volume concentration was approximately 1.2 %.

Benefits and challenges in deployment of low global warming potential R290 refrigerant for room air conditioning equipment in California

High global warming potential gases (“high GWP”) are the fastest growing sector of greenhouse gas emissions in the world and in California and are primarily used as refrigerant gases in refrigeration and cooling equipment. Hydrofluorocarbons (HFCs) refrigerants are the dominant type of high GWP gases with GWP values thousands of times larger than CO2 on a 100-year timescale. Refrigerant-grade propane (“R290”) has a very low GWP (GWP = 3.3) with good thermodynamic properties and good cooling equipment performance but the flammability of any leaked refrigerant makes equipment design, handling, and maintenance critical factors to manage. This paper focuses on the potential climate benefits and costs of transitioning to R290 refrigerant in small room air conditioning (AC) units, specifically window AC, packaged terminal AC/heat pumps (PTAC/PTHP), and mini-split heat pumps. Overall climate impact for a transition to all three types of air conditioning units in the 2022–2051 timeframe is found to be from 15 to 64 million metric tons of greenhouse gas (GHG) savings in California with a cost of saved CO2eq that ranges from $14.50 per ton of CO2eq saved to −$50.30 per ton of CO2eq saved (net savings) depending on whether the baseline refrigerant is R32 or R410A and depending on the relative energy efficiency for R290 units compared to baseline units.

Identifying effective parameters on capillary tube performance with HCFCs, HFCs blends, and hydrocarbon refrigerants: Numerical assessment

This work offers a comprehensive numerical evaluation of the performance of capillary tube utilizing different refrigerants, including HCFCs, HFCs blends (Zeotropic, Azeotropic), and hydrocarbon, such as such as R22, R404A, R407C, R410A, R507A, and R290 refrigerants to predict the critical length of the adiabatic capillary tube. Utilizing a comprehensive thermodynamic model is applied to simulate the behavior of different refrigerants. Moreover, the effective design parameters based on the internal diameter for the adiabatic capillary tube (ACT), inside surface tube roughness, degree of subcooled, metastable region, condenser diameter, design of evaporator pressure (at critical length), condenser operating pressure, and refrigeration capacity are considered. The numerical model is developed based on the governing equations for mass, momentum, and energy, while a specified empirical equations are employed to represent each of the friction factor for single-and-two phase flow and metastable region. The results showed that the longest length of the ACT of 10.5 m revealed with R410A at mass flow rate of 8 g/s compared with 0.25 m at mass flow rate of 16 g/s for R290. Also, the results showed that the minimum value of friction factor of 0.0189 for R410A compared with maximum value of 0.0208 for R407C. The developed model is validated with available experimental results and models under different operation conditions and is found expectable with a good agreement. Where the standard error for different refrigerant with range value between (2.774% to 3.677%). However, the model represents accurate prediction the flow behavior and the thermal performance of the ACT.

Nucleate pool boiling bubble dynamics for R32 and R1234yf on machined micro-structured surfaces

Efficient electronics cooling has always been a perpetual challenge, with the limits of single-phase cooling almost being reached. Two-phase cooling in the form of pool boiling is an attractive next step, with much research being devoted to it. While refrigerants operating at lower saturation temperatures are key to achieving effective cooling, surface modifications have been shown to also affect bubble dynamics and enhance nucleate pool boiling heat transfer. A simple, easy to implement fabrication method was sought, with the goal of expanding the knowledge of bubble dynamics. To this end, single bubble growth on structured surfaces that are achievable on a lathe, with an average roughness of 75 μm and differing indentation angles between 90° and 46°, was studied numerically using an OpenFOAM multiphase library. Conjugate heat transfer was applied, with heat fluxes ranging between 7.6 and 28 kW/m2 for pure refrigerants R32 and R1234yf. By comparing the bubble equivalent diameter with that of a smooth surface at a fixed heat flux, it was found that the bubble growth rates of structured surfaces were largely independent of indentation angles less than 90°, but lower than for smooth surfaces. For structured surfaces, a critical indentation angle of approximately 60° was identified which affected the bubble dynamics. For angles greater than the critical angle the bubble growth time was up to 150 % longer, which also resulted in larger departure diameters. However, the opposite trend was observed as the indentation angle was decreased below the critical angle. From a force analysis, it was found that the physical limitation imposed on the bubble growth was responsible for the critical indentation angle behaviour, with the most acute angle of 46° showing the shortest departure time. Furthermore, the bubble growth from a single cavity corresponded better with the trends of a smooth surface than a structured surface with comparable indentation angles. On a structured surface, once the bubble reached the edge of the cavity, its base diameter was limited by the physical characteristics of the surface. For the single cavity surface, however, bubble growth was uninhibited beyond the cavity, mimicking a completely smooth surface. The marked difference between results of a fully structured surface and the single cavity implies that future research will have to take the structural limitations on bubble growth imposed by a roughened surface into account.

Recent advancements in solar collector-evaporator for direct expansion solar heat pump

The direct expansion solar heat pump (DX-SHP) is a competent and sustainable option for domestic heating and drying applications. The solar collector-evaporator is a vital component of DX-SHP, which operates on solar energy and low-temperature ambient energy. The heat collection capacity, coefficient of performance, and evaporation temperature are used to quantify its performance. In this context, a systematic literature review on recent advancements in the collector-evaporator of DX-SHP is presented. This paper highlights and discusses the various configurations of solar collector-evaporators, theoretical and experimental investigations, and the selection method of eco-friendly refrigerants. The impact of different performance factors, such as ambient conditions, structural parameters, and types of refrigerants, on solar collector-evaporators is also reviewed. The optimal range for solar radiation, wind speed, and temperature is found to be 350 W/m2-700 W/m2, 0.5 m/s -2.5m/s, and 5°C to 35°C. The DX-SHP system produces hot water from 15°C to 60°C, with an average COP of 1.5 to 4.5. The finned solar collector-evaporator with R290 refrigerant performs optimally in various climatic conditions. Integrating solar collector-evaporators with innovative technologies such as microchannel, heat pipe, thermoelectric generators, photovoltaic thermal collectors with compound parabolic and Fresnel lenses can improve the system's performance. In this review, researchers can find scope for performance enhancement of the collector-evaporator used in DX-SHP.

Performance profile of Cold Storage Using R32 as Refrigerant for Traditional Fishing Boat with Photovoltaic as Energi Source

This paper discusses the performance of cold storage using R32 refrigerant. R32 is one of the recommended refrigerant with the main advantage low ODP and GWP (Global Warming Potential) value of around 0 and 675. However, because of this refrigerant classified as a new refrigerant, the implementation is limited to air conditioning and heat pump. In this paper, R32 will be tested for cold storage applications. The cold storage performance will be studied about the achieved temperature, power consumption, cooling capacity and Coefficient of Performance without load. The testing was carried out in 2 ways, cold storage testing on a lab scale and direct testing on a 5 GT fishing boat. The performance results show that both tests on a lab scale and tests directly on a fishing boat without a load can reach a cold storage room temperature of -18oC. Meanwhile, the compressor power consumption supplied by photovoltaic is 0.653-0.776 kW. Based on the test results, shows that R32 has a positive possibility of being applied to cold storage.

Numerical Study with CFD of the Refrigeration in a Vehicle Cabin with two Refrigerants R32 and R600a

Numerical Study with CFD of the Refrigeration in a Vehicle Cabin with two Refrigerants R32 and R600a

Performance Enhancement of Heat Pump Dryer using Heat Recovery

The purpose of this research was to study on performance of a heat pump dryer using R32 refrigerant by recovering waste heat from an external condenser. Drying was carried out with drying temperatures of 45, 50 and 55 °C and water flow rates in the heat exchanger of 2, 3 and 4 L/min. Criteria for evaluating performance of heat pump dryer include: drying rate (DR), specific moisture extraction rate, specific energy consumption (SEC) and coefficient of performance of heat pump (COPh). The result shown that the performance of a heat pump dryer with heat recovery is higher than that of a traditional heat pump dryer. It was also found that increasing in drying temperature and water flow rate in heat exchanger resulted in an increase in the drying rate, power of the heat pump dryer and the specific moisture extraction rate. Whereas the specific energy consumption had decreased.

Comparison of the impact of R449-A and R290 on refrigerated display cabinets using life-cycle climate performance method

Due to the high energy consumption of refrigerated display cabinets used in supermarkets, a life cycle cooling performance analysis to increase energy efficiency and reduce environmental impacts is the main subject of this study. It also emphasizes the need for cabinets that consume less energy and provide environmentally friendly working conditions. The Life Cycle Climate Performance (LCCP) of the two refrigerants R290 and R449-A was evaluated using measured data to compare the environmental impact of the refrigerants over the entire fluid and equipment life cycle, including energy consumption. Both vapor-compressed cooling cycles were thermodynamically modeled with the parameters taken from the experiments and the efficiency of system was calculated by using the EES software. The results show that the cabinet using R290 has lower compressor power utilization. The COP of the R290 system increased by 13% compared to the R449A system. The total daily energy consumption was also significantly lower for the R290 system. The energy efficiency index provides a standardized metric that can be used to compare the performance of different cooling systems. In this study, the energy efficiency index value was 17.3 points lower for the R290 system, indicating higher energy efficiency. The energy classes are “E” for the R449-A system and “C” for the R290 system, with the R290 system two classes higher in terms of energy class labeling. The EEI value of the system with R290 refrigerant has been reduced by 33% in comparison with the system with R449A refrigerant. The system using R290 refrigerant achieved a 33% reduction in energy consumption compared to the system using R449A refrigerant. The study also assessed the life cycle climate performance of the two systems. It was found that the R449-A system emits 19032.45 kg CO2e more over its lifetime compared to the R290 system. This was attributed to the relatively high global warming potential and energy consumption of R449-A refrigerant. However, when considering safety (flammability), it was concluded that R-449A has a lower environmental impact than R-290.