Low Global Warming Potential Refrigerants Research Articles

Thermodynamic and technoeconomic limitations of Brayton refrigeration for air conditioning{fr}Limites thermodynamiques et technoéconomiques de la réfrigération Brayton pour la climatisation

With global cooling demand increasing, there is a need for refrigeration cycles that use low global warming potential (GWP) refrigerants. Researchers have flirted with the idea of using the Brayton cycle for refrigeration over the years, but it has yet to prove competitive in performance or cost when compared to the widely used vapor compression cycle. The recent development of an electrochemical Brayton refrigeration cycle has renewed interest in the thermodynamics of Brayton refrigeration. This work provides a parametric study of the COP of a Brayton cycle air conditioner (either mechanical or electrochemical in nature) as a function of the characteristics of the cycle components (thermal conductances and isentropic efficiencies). When the isentropic efficiencies of the adiabatic components (i.e., the compressor and turbine in the mechanical Brayton cycle) are 90%, the cycle COP is limited to a value of ∼1. Furthermore, a thermodynamic comparison to the vapor compression cycle reveals that the Brayton refrigeration cycle generates ∼8 × more entropy, and that the thermodynamic favorability of the vapor compression cycle is due to the presence of phase change.

Thermodynamic performance and compression characteristics analysis of low GWP refrigerant in compressors: Experimental investigation and 0-D/3-D simulation

The utilization of low global warming potential (GWP) refrigerants is crucial for reducing greenhouse gas emissions. Among these alternatives for hydrofluorocarbons (HFCs), R290 stands out as a natural refrigerant with a low GWP value of 3. Therefore, it is beneficial to promote its widespread adoption and enhance the efficiency of compressors and their systems that utilize R290 to mitigate the greenhouse effect. The present study investigates and compares the thermodynamic performance and compression characteristics of a high-speed compressor employing R290 as a refrigerant with those of an R32 compressor. In contrast to previous studies, this paper presents a novel approach by developing validated the zero-dimensional (0-D) and three-dimensional (3-D) simulation model, along with experiments, to investigate the distribution of performance loss and suction-compression characteristics in high-speed R290 compressors. The results demonstrate that the R290 compressor exhibits superior volumetric efficiency, while excessive compression at high speeds leads to a noticeable reduction in indicated power. The combination of increased over-compression loss and motor loss at high speeds resulted in a 11.7% rise in input power, leading to an 8.4% decline in thermodynamic performance for the R290 compressor under standard heating compared to the R32 compressor.

Evaluation and development of flow condensation correlations using the data from low GWP refrigerants in an axial micro-fin aluminum tube

To mitigate global warming, the world is transitioning to refrigerants with low global warming potential (GWP). Supporting this shift requires a model that can accurately predict the heat transfer and pressure drop of new refrigerants, crucial for designing efficient heat exchangers. Existing models, however, are largely based on currently deployed refrigerants and primarily developed for unexpanded micro-fin tubes with spiral angles of 6° to 30°. Their applicability to new refrigerants, especially in expanded micro-fin tubes, is uncertain. This study assesses the performance of four well-known condensation models for six emerging refrigerants—R-32, R-454B, R-454C, R-455A, R-1234yf, and R-1234ze(E)—against experimental data. Initially, the Han and Lee (2005) model shows the best prediction accuracy with a mean absolute deviation (MAD) of 22.1 %. To enhance the accuracy of heat transfer models for new refrigerants and geometries with large temperature glides, two approaches are proposed. The first approach applies a simple correction factor, reducing the MAD of the Cavallini et al. (2009) model from 68.2 % to 15.4 %. The second approach uses the variable metric method for minimization, fitting new constants to the data. This optimization results in the Kedzierski and Goncalves (1997) model achieving the highest accuracy, with a MAD of 13.1 %. For pressure drop models, the Cavallini et al. (1997) model is the most accurate with a MAD of 6.4 %, followed by the Haraguchi et al. (1993) model with a MAD of 9.4 %. Due to its simplicity, the Haraguchi et al. (1993) model is a practical option for predicting frictional pressure drop.

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.

Surface tension measurement and molecular simulation for new low global warming potential refrigerants R1132(E) and R1132a

This study performed surface tension measurements assisted by molecular simulations for new candidate refrigerants R1132(E) and its isomer R1132a, which exhibit extremely low global warming potentials. Because the measured saturation density required for the surface tension measurement by the differential capillary rise method is insufficient at low temperatures, the density data was extrapolated by molecular simulations. In the process, quantum chemical and molecular dynamics simulations were performed to reproduce the vapor–liquid equilibrium state, and the accuracy of the obtained molecular force fields was verified by comparing them with the measured data. Based on the obtained surface tension data, validated temperature correlation equations were proposed for R1132(E) and R1132a, respectively, validated in the temperature range from 209 K to 225 K. Furthermore, their parachors, which relate surface tension to saturation density, were determined from the above data as 116.1 and 116.7 for R1132(E) and R1132a, respectively.

Mitigation of safety and environmental challenges posed by refrigerants

The abatement of safety and environmental burden associated with low and ultra-low Global Warming Potential (GWP) refrigerants is a critical undertaking. As the industry shifts towards more environmentally friendly alternatives, mitigating the potential risks and ensuring safety standards becomes paramount. The adoption of mildly and highly flammable refrigerants contributes significantly to minimizing the greenhouse gas impact on the environment, aligning with global climate and sustainability goals. However, it is essential to address safety concerns and potential environmental implications associated with the end use of these refrigerants.A method to mitigate the safety risk in a flammable refrigerant based heating, ventilation, air-conditioning, and refrigeration (HVACR) system is the primary focus of this paper. Advent of A2L and A3 refrigerants as replacements to high GWP refrigerants requires careful handling of leak episodes to lower or eliminate the risk associated with creating flammable mixtures capable of fire/explosion hazard. Solid materials tailored to target the molecule of interest (i.e., refrigerant.) by engineering the microporous structure as well as chemically functionalizing the surface to attract and hold on to the chemical compound being removed from the gas stream was realized. Quantitative analysis reveals the adsorbent's effectiveness in reducing leak potential in the range of 40 %–100 % for various refrigerants. Strategic placement and active leak management with negative pressure offer promising avenues for capturing leaked refrigerants, enhancing overall safety.

District heating utilizing waste heat of a data center: High-temperature heat pumps

Data centers are energy-intensive facilities with substantial low-grade waste heat. High-temperature heat pumps can be critical in boosting the data center’s waste heat for district heating, improving the system-level energy efficiency of data centers, and reducing CO2 emissions in district heating. This study built thermodynamic models to assess high-temperature heat pumps with six configurations using low global warming potential refrigerants to supply heat up to 120 °C. The heat pump configurations include single-stage or two-stage cycles with advanced components, such as internal heat exchanger, economizer, flash tank, or parallel compressor. The refrigerants include R1234ze(Z), R1233ed(E), R1224yd(Z), R600, and R600a, and R245fa is used as a reference. A case study was carried out to recover the waste heat from the Frontier high-performance computing data center and provide hot water for district heating at the US Department of Energy’s Oak Ridge National Laboratory campus. The optimized performance of high-temperature heat pumps is characterized with various effectiveness of internal heat exchangers, and the operating parameters of economizer or flash tank, as well as their combination. The results show that the configurations of two-stage cycles with internal heat exchanger + flash tank and internal heat exchanger + economizer/parallel-compressor provide the highest coefficient of performance under scenarios of the maximum allowable value and a fixed value (0.3) of the internal heat exchangers’ effectiveness, respectively. R1234ze(Z) and R600a are the most promising refrigerants, considering trade-offs between the coefficient of performance and the volumetric heating capacity. The single-stage cycle with internal heat exchanger + economizer/parallel-compressor using R1234ze(Z) is recommended for utilizing Fronter’s waste heat in district heating. A one mega-watt high-temperature heat pump will reduce 33,100–33,200 metric tons of CO2 emission annually, corresponding to 85.4 %–85.6 % of equivalent CO2 emissions from natural gas boilers. This study provides good guidelines for designing and deploying high-temperature heat pumps to support sustainable data centers and decarbonize district heating in the US.

Experimental investigation of the supercritical heat transfer of the low GWP refrigerant R1234ze(E): calibration and validation of test rig

Heat transfer of supercritical refrigerants is applied in practical systems such as the transcritical organic Rankine cycle or supercritical heat pump. The concept of supercritical heat transfer is not new and has already been studied and applied for decades in several applications. However, results on one fluid cannot be directly translated to another one. This is because the thermohydraulic behavior of fluids is heavily influenced in the near-supercritical region due to sudden variations in the thermophysical properties when the fluid is heated or cooled close to its critical point. For refrigerants under horizontal flow, the research is limited. Most studies in literature are on small diameter tubes and on R134a, which has a high global warming potential. Therefore, an experimental test rig has been built to measure the supercritical heat transfer of low global warming potential refrigerants over a large temperature and pressure range in the supercritical region. In this work, the calibration and validation of this test rig is presented using the refrigerant R1234ze(E). The test section consists of a 4 m long horizontal tube with an inner diameter of 22.9 mm, equipped with thermocouples at both the tube wall and in the bulk of the flow, and is heated by resistance wires wrapped around the tube. For the calibration, the temperature profiles under both non-heating and heating conditions are evaluated. For the validation, the average Nusselt numbers obtained through experiments under subcritical conditions are compared to the average Nusselt numbers calculated based on the Dittus-Boelter and Gnielinski correlation.

Energy, environmental and economic analysis of low GWP refrigerant heat pumps for simultaneous heating and cooling applications

Industries such as hotels, pharmaceuticals, dairy and food and beverage units require heating and cooling for their functional requirements. These industries mostly use fossil fuel-fired boilers for heating (hot water at 60 to 90 °C) and vapor compression refrigeration systems for cooling (−30 to 5 °C), which results in higher primary energy consumption and CO2 emissions. Heat pumps (HPs) are a sustainable option for meeting the simultaneous heating and cooling demands. However, HPs use synthetic refrigerants with high global warming potential (GWP). Therefore, this research aims to evaluate the potential of low and medium-temperature HPs using low GWP refrigerants such as R744, R290, R600a, R161, R1234yf, R1234ze(E) and R1233zd(E). The best refrigerant for the HPs is proposed based on energy efficiency, environmental impact and economic feasibility as critical factors, compared with the conventional high GWP refrigerant (R134a). The occurrence of pinch points across the gas cooler/condenser is evaluated in the analysis. Life cycle climate performance (LCCP) is assessed to study the environmental impact. Also, the operating costs of these HPs are estimated and compared with the conventional systems used in the industry. Results show that R744 HP is an energy-efficient and clean solution for simultaneous heating and cooling applications, primarily at higher temperature lift (lower Tw,i and higher Tw,o) conditions.

Transitioning to low GWP refrigerants in automobiles: A numerical simulation study on R1234yf/R152a’s heat transfer characteristics in porous microchannels

Automobile air conditioning systems significantly contribute to vehicle energy consumption. The transition to new, environmentally sustainable refrigerants in place of traditional ones is a critical trend shaping the future of this industry. The prevalent refrigerant R134a, used in automotive air conditioning, is environmentally detrimental, necessitating the development of low Global Warming Potential refrigerants as viable long-term alternatives. This study examines the flow heat transfer characteristics of the proposed refrigerant blend R1234yf/R152a in porous microchannel tubes via numerical simulation. It assesses the impact of heat flux, mass flow rate, saturation temperature, and wall superheat on the Jakob number, vaporization core density, and boiling heat transfer coefficient. Furthermore, it compares these parameters with those of R134a and R1234yf to evaluate the potential of R1234yf/R152a as a substitute. The findings indicate that the Jakob number differences among the three refrigerants are negligible. Notably, R1234yf/R152a consistently exhibits higher vaporization core density and the highest boiling heat transfer coefficient, coupled with the lowest pressure drop, thereby affirming its suitability as a heat transfer-efficient alternative. These insights could inform the enhancement and gradual transition from R134a in automotive air conditioning systems.

Pool boiling heat transfer characteristics of low-GWP refrigerants in a horizontal tube bundle configuration

Heat transfer enhancement techniques have been adapted on the shell side to improve the overall performance of the flooded evaporators, such as finned tubes. In recent years, it has been demonstrated that the metal foam structure can offer enhanced heat transfer performance under pool boiling conditions. However, there are not much research in the open literature that examine the feasibility of metal foam embedded tubes in horizontal tube bundle configurations. Therefore, this paper proposed a novel metal foam embedded tube (i.e., foam embedded outside the tube) to improve the heat transfer behavior of flooded evaporators. The experiments were performed on a horizontal tube bundle with a staggered arrangement. Moreover, the performance of low global warming potential (GWP) refrigerants (R-1234yf and R-1234ze(E)) is compared against R-134a for both plain tubes and metal foam tubes with porosities of 81%, 75%, and 62%. The results showed that a metal foam tube with a porosity of 62% showed a maximum heat transfer coefficient (HTC) enhancement of 291% compared to the plain tube. As compared with R-134a, the HTCs of R-1234yf and R-1234ze(E) are nearly 10% higher and 5% lower, respectively.

Flow boiling heat transfer of R454B in a 24-port microchannel tube

R454B is a relatively low Global Warming Potential refrigerant, and it has emerged as a promising substitute for traditional refrigerants. Understanding the heat transfer and fluid dynamics characteristics of R454B becomes important for applying it. An experimental setup was built for measuring heat transfer coefficient (HTC) and pressure gradient (dP/dz) in a 24-port microchannel tube. The test condition covers mass fluxes of 100–250 kg-m-2s−1, heat fluxes of 2–8 kW-m−2, and saturation temperatures of 10–30 °C. The mass flux had a significant impact on the HTC, particularly at higher vapor quality. Additionally, the heat flux also played a crucial role in determining the HTC, with a stronger influence observed at lower vapor quality. The saturation condition had a relatively minor effect on HTC, showing a positive impact at low vapor quality but a negative impact at moderate and high vapor quality. The dP/dz tended to increase with vapor quality. Both the mass flux and saturation condition exhibited strong effects on dP/dz. However, the heat flux had a negligible impact on the dP/dz. The study also compared the performance of R454B with R32, R1234yf, and three R32/R1234yf mixtures (85/15, 50/50, and 15/85 by mass). The results showed that R454B had a HTC close to R1234yf and the 85/15 mixture. However, it had the lowest dP/dz compared among the compared fluids. The results were compared to existing correlations and those with less error were recommended. This study pioneered the examination of R454B flow boiling in microchannel tubes, and employed Pearson correlation coefficient analysis which presents a first-of-its-kind quantitative analysis of the impact of operational conditions on HTC and dP/dz, marking a significant advancement in thermal systems optimization.

Flow boiling heat transfer of R1234ze(E) in a horizontal mini-channel at medium and high saturation temperatures

This study reports experimental results of flow boiling heat transfer characteristics of R1234ze(E) (a low global warming potential refrigerant) at moderate and high saturation temperatures. The study was performed in a single horizontal circular smooth tube of 2.07 mm internal diameter. Heat transfer characteristics and flow pattern visualization through high-speed camera were investigated for saturation temperatures ranging from 60 to 95 °C, corresponding to reduced pressures from 0.35 to 0.75, mass velocities from 300 to 500 kg/m2s, heat fluxes from 30 to 50 kW/m2 and vapor qualities from 0 to 1. The pre-dryout data (214 data points) measured were compared against different prediction methods from the literature developed under different theories. The study revealed that the saturation temperature has a significant effect on heat transfer coefficient whereas the mass velocity presented a less pronounced or negligible effect. Furthermore, the heat transfer coefficient was observed to decrease slightly to a minimum in the low vapor quality region and then levels off or increases slightly with increasing vapor quality until dryout occurs. As a result, nucleate boiling was observed to be the dominant mechanism controlling the heat transfer. It was observed that the higher the saturation temperature, the earlier the vapor quality at which dryout incipience occurs. Considering the 214 pre-dryout data points analyzed, the methods proposed by Kew and Cornwell (1997), Lazarek and Black (1982) and Choi et al. (2007) were the most accurate, predicting the entire pre-dryout database with mean absolute errors (MAEs) of 13.7%, 13.9 % and 14.4 %, respectively.

Seasonal performance assessment and experimental investigation of R32 drop-in and BPHX size in an R410A chiller when using two compressor modulation strategies

The decrease in fossil fuel reserves and high energy consumption by HVAC&R equipment require the use of compressors with better efficiencies and capacity modulation strategies. Usually, seasonal performance studies focus on compressor capacity modulation methods, however the current study explores the idea of improving the seasonal performance of two compressor modulation techniques: a two-stage and a variable speed compressor with different capacity modulation ranges by using larger condensers in an R410A water ethylene glycol chiller system. The analysis shows that oversizing the heat exchangers has larger benefits with the compressor modulation strategy with lower range. Additionally, the seasonal performance estimated according to AHRI 551/591 (2020) of a two-stage compressor with oversized condenser is higher than a basic single speed compressor with a better motor indicating that oversizing brazed plate heat exchanger (BPHX) might yield higher performance than improving the compressor motor efficiency. Due to the high global warming potential (GWP) of R410A, there is a focus on replacing it with low GWP refrigerants such as R32 to reduce CO2 emissions. This study would also compare the performance when using R32 as a drop-in refrigerant in the two different R410A compressor capacity modulation strategies with comparable cooling capacity. When the refrigerant was changed from R410A to R32, the integrated part load value (IPLV.SI), an efficiency metric for variable speed compressor remains relatively constant at 5.5 while it increases from 3.9 to 4.4 for the two-stage compressor. It is hypothesized that low refrigerant mass flow rate (m˙ref) provided by the variable speed compressor when matching the load at the lower part load conditions leads to refrigerant maldistribution in BPHX and reduced IPLV.SI.

A novel approach for designing efficient and sustainable cooling cycles with low global warming potential refrigerants

With the current legislation on the phase-out of 3rd generation refrigerants, new cooling cycles are expected to operate with 4th generation refrigerants, hence, the need for optimal system performance with these new working fluids. In this study, an innovative optimization approach was applied for the design of cooling cycles with 4th generation refrigerants based on integrating statistical analysis design of experiments (DoE) with molecular modeling using the polar soft-SAFT model. First, a detailed multi-criteria assessment was applied for the selection of 4th generation refrigerants in medium–low temperature applications. Results demonstrated the potentiality of trans-1,3,3,3-tetrafluoroprop-1-ene (R1234ze(E)) or cis-1,2,3,3,3-pentafluoroprop-1-ene (R1225ye(Z)) in terms of environmental, safety, and technical criteria in basic cooling cycles under specific operating conditions. Multi-objective optimization guided using statistical analysis tools were implemented to study potential enhancement in cooling cycle performance using these promising refrigerants in terms of energy and exergy efficiency. This included evaporator and condenser temperature, fluid choice, compression yield, superheating/subcooling degrees, and cycle type. The evaporation and condenser temperature, and the compressor efficiency are shown to monopolize more than three-quarters of the cumulative contribution on system efficiency for those operated with R1234ze(E) in advanced liquid-to-suction line heat exchangers (LL/SL-IHX). Further optimization through examining the effect of heat transfer phenomena assisted in determining optimal operating conditions for new systems operating with low GWP refrigerants, instilling annual cost savings of $1.59 K and reduction in CO2 emissions by 1.02 tCO2-eq compared to the baseline system.

In tube condensation of low global warming potential refrigerants in an axial micro-fin aluminum tube

Environmental regulations have driven the development of refrigerants with low global warming potential (GWP). To design heat exchangers using these new refrigerants, data are needed concerning the heat transfer coefficient and pressure drop in two-phase flow. Another change is the increasing use of aluminum tubes rather than copper tubes to reduce heat exchanger cost. Hence, this study presents an experimental investigation of flow condensation using an expanded axial micro-fin aluminum tube with a fin-tip diameter of 5.96 mm. The experiments included single compounds R-32, R-1234yf, and R-1234ze(E), zeotropic mixtures with low glide (R-454B), and zeotropic mixtures with high-glide (R-454C and R-455A). Experiments were conducted at condensation temperatures ranging from 40 °C to 50 °C, reduced pressures ranging from 0.21 to 0.55, and mass fluxes ranging from 150 to 350 kg/(m2 s). Data obtained for these refrigerants constitute one of the first reports for high-glide refrigerants using axial micro-fin aluminum tubes. An evaluation of heat transfer degradation of zeotropic mixtures due to mass transfer resistance at the liquid/vapor interface is presented. This information can be used to design heat exchangers for next generation air conditioning and refrigeration systems.

Assessment of Low Global Warming Potential Refrigerants for Waste Heat Recovery in Data Center with On-Chip Two-Phase Cooling Loop

Assessment of Low Global Warming Potential Refrigerants for Waste Heat Recovery in Data Center with On-Chip Two-Phase Cooling Loop

Optimizing adsorption refrigeration with MOF-propane integration: a sustainable approach

Optimizing adsorption refrigeration by integrating MOFs with a low-global warming potential refrigerant, propane.

Performance analysis of automotive air conditioning systems with electric compressors using R1234yf refrigerant: Insights into power consumption, cooling capacity, and energy efficiency

R1234yf, a low global warming potential (GWP) refrigerant, offers a promising alternative to traditional refrigerants like R134a. This study analyzes automotive air conditioning systems (AAC) equipped with electric compressors and utilizing R1234yf refrigerant. The interrelationships between refrigerant charge, compressor speed, power consumption, cooling capacity, and energy efficiency are examined. The results show that increasing refrigerant charge and compressor speed leads to higher power consumption due to increased compressor work. However, higher refrigerant charges and compressor speeds improve cooling capacity in line with heat transfer principles. As refrigerant charge and compressor speed increase, the energy efficiency, measured by the Coefficient of Performance (COP), tends to decrease, indicating a trade-off between cooling capacity and energy efficiency. Optimizing refrigerant charge and compressor speed is crucial to strike a balance between cooling performance and energy efficiency. R134a outperforms R1234yf, with an average percent difference in COP approximately 25% higher at all compressor speeds. This study contributes to the understanding of AAC system performance and guides the development of energy-efficient automotive air conditioning. Future research can further explore system components and conditions to enhance energy efficiency and advance air conditioning technology.

Study of vapor compression refrigeration system with suspended nanoparticles in the low GWP refrigerant.

The rising global temperatures, attributed to the high global warming potential (GWP) of conventional refrigerants, necessitate the adoption of low-GWP alternatives in HVAC systems. However, these low-GWP refrigerants often exhibit high toxicity and flammability, limiting their usage. To address these challenges, compact heat exchangers incorporating blended refrigerants have been introduced to enhance HVAC system performance. Researchers have also made significant strides in improving HVAC system efficiency by introducing the concept of suspending nanolubricants and nanorefrigerants within the system. This review paper seeks to comprehensively assess the potential of alternative refrigerants containing suspended nanoparticles, commonly referred to as nanorefrigerants. The paper reviews various mechanisms and potential combinations of different nanorefrigerants employed to enhance refrigeration system effectiveness and efficiency. A detailed examination of key heat transfer parameters and the performance predictions of low-GWP refrigerants, including those from the hydrofluoroolefin (HFO) and hydrocarbon (HC) classes, is conducted through energy and exergy analyses. Commercial refrigerants like R-134a, R-290, R-600, R-600a, R-123, R-125, R-22, R-141b, R-152, R-11, R-113, R-404a, R-407c, R-502, R-600a, R-507a, R-1234yf, R-1234ze, 1336mzz(Z), and R-410a are evaluated in conjunction with suspended nanoparticles, considering their specific properties. The findings indicate that the utilization of nanorefrigerants leads to notable improvements in overall system performance, characterized by reduced compressor workloads and increased heat transfer rates. Consequently, the integration of blended nanoparticles into refrigerants holds significant promise for advancing the HVAC field.