Cascade Cycles Research Articles

Performance Evaluation of Cryogenic Liquefaction System Precooled by Combined Vapour Compression-Absorption Refrigeration System

Liquefaction is a high-energy-consuming process. One of the most efficient methods of lowering energy consumption use is to run a precooled cycle with a cascade refrigeration system. When compared with the vapour compression system, the merit of adopting a cascade system is that it consumes very less energy. Another advantage is that non-traditional energy sources such as geothermal and solar might be used to power these cycles. This paper examines a precooled Linde Hampson-liquefaction system using a double-stage cascade vapour compression-absorption refrigeration cycle that consists of an absorption system at the high-temperature stage and a compression system at the low-temperature stage to generate cooling at a small temperatures by using various refrigerants in the absorption and compression sections. The system's performance was evaluated by employing various combinations of natural refrigerants in the absorption section. Liquefaction of Nitrogen is carried out using a precooled Linde Hampson system and precooled liquefaction using a cascade refrigeration cycle. Nitrogen was liquefied using two methods in the current study. A thorough examination of the precooled system was conducted, and it was discovered that by employing a cascade refrigeration cycle, the input required per unit mass of gas liquefied is decreased. The performance metrics of the liquefaction system, such as Figure of Merit (FOM) and Liquid Yield, were discovered for both scenarios, and it is concluded that the usage of a cascade refrigeration system has more efficiency and consumes less energy than a system without an absorption chiller. The use of a precooled Linde Hampson system with cascade cycles improved liquefaction characteristics by 5-7%.

Break-even of high-temperature heat pump integration for milk spray drying

Heat pumps are a promising solution for reducing greenhouse gas emissions because they harness environmental or waste heat and can use renewable electricity. Technologically, temperatures up to 160 °C can already be achieved with market-available heat pumps while heat pumps achieving temperatures up to 200 °C are under development. This study focuses on the economic break-even points of market-available, prototypical and simulative heat pump concepts for milk spray drying using the Grand Composite Curve and the Modified Energy Transfer Diagram. Applying a regression-based targeting algorithm, the economic break-even price ratio and technical limit of the corresponding heat pump types are identified and quantified by the Heat Pumping Recovery Rate. The examined heat pump concepts show promising results for future energy price scenarios with the break-even point for full supply of milk spray drying up to 210 °C at electricity-to-reference-fuel price ratios of 1.20 for close-to-market Stirling heat pumps to 1.56 for simulated transcritical cascade cycles. Market-available heat pumps reach drying temperatures of 127.3 °C achieving coverage rates of 60.3% with price ratio requirements of 1.41. The results also emphasise the importance of adapting heat pumps to the process requirements precisely, especially for reaching high sink temperatures. Based on specific process requirements and the presented targeting methods, the selection of refrigerant and the configuration of the heat pump cycles should be done to minimise the Levelised Cost of Heating.

Phase‐Locking of Random Lasers by Cascaded Ultrafast Molecular Excitation Dynamics

AbstractThere are conventionally coherent and incoherent types of random lasers, which are characteristic of broadband and randomly distributed narrow‐band lasing spectrum, respectively. No fixed phase relationship has ever been observed between the lasing modes in such lasers. However, herein a new form of random lasers in patterned organic–inorganic hybrid perovskite MAPbBr3 is discovered, where multiple simultaneously lasing modes are stably locked in phase so that lasing lines are achieved with equal spectral separations. This is the first observation of phase locking between random lasers, which is established by the cascaded molecular absorption‐emission or cascaded excitation‐injection processes between random laser modes. The fixed phase relationship is determined by the ultrafast relaxation of the excited molecules to the lower edge of the excitation band, correlating directly the absorption/excitation and emission/injection processes and producing a fixed phase shift. Thus, the bandwidth and separation of the lasing lines are dependent on the relaxation lifetime of the excited molecules and the number of cascading cycles. Such cascading dynamics has a timescale faster than 300 fs. These characteristics innovate the physics and explore new applications of both the MAPbBr3 material and the random lasers. Such a strong phase‐locking mechanism suggests new mode‐locking schemes for ultrafast lasers.

Design and optimisation of novel cascade mixed refrigerant cycles for LNG production – Part I: Benchmark cascade cycles

Complex cascade refrigeration cycles are typically used for production of liquefied natural gas (LNG). These include the propane precooled mixed refrigerant (C3MR) cycle, the dual mixed refrigerant (DMR) cycle, and the Phillips Cascade cycle. These are highly energy-intensive processes, resulting in many studies focusing on improving their energy efficiency by reducing their shaft power demand. However, their relative performance remains unclear. Modelling assumptions and natural gas feed differ across the published literature. This work models and evaluates these three commercial cascade cycles on a common basis of modelling assumptions, natural gas feed and process complexity (e.g. number of compression stages). However, the performance of the cycles cannot be compared meaningfully without first optimising the designs. The optimisation strategy proposed combines a genetic algorithm, which includes regeneration of the population to improve diversity, with a nonlinear optimisation. A case study demonstrates the effectiveness of this strategy. This work provides a meaningful comparison of the relative efficiencies of these commercial cascade cycles, to provide a basis for benchmarking novel cascade cycle options in a study to follow.

Optimization and analysis of a hydrogen liquefaction process integrated with the liquefied natural gas gasification and organic Rankine cycle

Combination of the hydrogen pre-cooling and liquefied natural gas gasification processes is forward-looking in the hydrogen liquefaction industry. To enhance the cold energy utilization, a hydrogen liquefaction process integrated in conjunction with a liquefied natural gas gasification process assisted by an organic Rankine cycle is designed. Furthermore, a simplified refrigeration system incorporating a dual-pressure Joule-Brayton cycle is developed to provide efficient cryo-cooling for the hydrogen. A binary mixture consisting of ethylene and propane is preferred as the working fluid for the organic Rankine cycle when liquefied natural gas gasification pressure is 30 bar, which results in 2.2% and 15.5% improvement in the liquefied natural gas cold energy utilization compared to the organic Rankine cycle with the pure refrigeration as the working fluid and the hydrogen pre-cooling process without the organic Rankine cycle, respectively. In the proposed cryo-cooling process using two Joule-Brayton cascade cycles, the utilization rate of the input exergy reaches 48.84%. The exergy loss generated in the compressors and coolers accounts for approximately 66.2% of the total exergy loss. Therefore, they are regarded as the priority targets for improving the hydrogen liquefaction system. After the optimization of the proposed process using the genetic algorithm, optimal results are obtained with a specific energy consumption of 6.59 kWh/kgH2 and an exergy efficiency of 47.0%.

Design and optimisation of novel cascade mixed refrigerant cycles for LNG production – Part II: Novel cascade configurations

Large scale production of liquefied natural gas (LNG) typically employs energy-intensive cascade refrigeration cycles. Three well-established cascade cycles in the LNG industry are the Propane Pre-cooled Mixed Refrigerant (C3MR), Dual Mixed Refrigerant (DMR) and Phillips Cascade cycles. Previous work has focused on improving the energy efficiency of these cascade cycles with various methods (e.g. exergy analysis), as this can bring significant economic benefits. However, potential benefits associated with changes in the configuration of a cascade cycle are usually neglected. This work develops three cascade cycle options, based on structural modifications, to be competitive with the commercial processes. The novel configurations are the CryoMan Cascade cycle, the Bypass Cascade cycle and the Double CryoMan Cascade cycle. The performance of these novel cascade cycles is evaluated with a case study previously used to assess the commercial processes. The optimisation strategy consists of a genetic algorithm with regeneration of the population followed by a nonlinear optimisation. The results obtained demonstrate that the structural changes enable the novel cascade cycles to achieve energy savings of up to 15.6% compared to the C3MR cycle, and up to 5.9% compared to the DMR cycle. Moreover, these energy savings come at the expense of only minor added process complexity, as the number of compression stages and multi-stream heat exchangers are kept the same as in the commercial processes.

Solar-driven dual-mode cascading cycle based on ammonia complexation reaction for flexible seasonal thermal management

Flexible seasonal thermal management, including the summer refrigeration and winter heat pump with seasonal energy storage, is one of the promising routes to achieve the goal of buildings carbon neutrality. However, the previous sensible and latent heat storage technologies were unable to realize seasonal heating supply and refrigeration, and the single-stage sorption cycle was proven inefficient under the severe conditions of high condensation and sorption temperatures. To face the challenge, we propose a solar-driven flexible seasonal thermal management (FSTM) strategy enabled by the MnCl2-CaCl2-NH3 cascading cycle based on ammonia complexation reaction, which can efficiently utilize the solar heat with severe temperature fluctuations to satisfy indoor summer refrigeration and winter heating supply with seasonal energy storage. Subsequently, we design a proof-of-concept FSTM device with two sorption reactors and an ammonia working tank. Experimental results exhibit that when the outdoor ambient temperature is as high as 35°C, the specific cooling capacity and coefficient of performance of FSTM are still up to 157 kJ∙kg−1 and 0.11 respectively in summer, while the thermal energy storage density can exceed 100 kJ∙kg−1 in winter with the highest sorption temperature of 90°C, which illustrates that the cascading cycle is suitable for harsh working conditions to achieve long-term thermal energy storage. Our work provides a promising low-carbon route for seasonal solar energy storage and thermal management of buildings.

Thermodynamic analysis for novel vapor compression/absorption cascade refrigeration system for LNG liquefaction processes in Egypt

This research demonstrates a novel vapour compression/absorption cascade refrigeration system for LNG liquefaction process to replace the air-cooled condenser equipped in Propane precooling refrigeration circuit, via either seawater or cooling towers to remove the heat rejected from precooling cycle of propane. The current investigation focuses on the novel configuration consists of ConocoPhillips optimised cascade cycle using three vapour compression refrigeration circuits which are Propane, Ethylene and Methane, besides one vapour absorption refrigeration cycle. The first aim of this paper is to perform thermodynamic analysis of LNG plant produces 50 kg/s of LNG. The second aim is to present a comparative parametric study for different number of stages which are 6, 7, 8 and 9 stages to evaluate and enhance the coefficients of performance of these design configurations. The results of design configurations for LNG plant conclude that number of stages has significant effects on both Coefficients of performance and the liquefaction efficiency. The Coefficients of performance is strengthened by using the design configurations consist of nine and eight compression stages. The coefficient of performance for vapour compression/absorption cascade for LNG plant can be slightly reduced rather than tradition vapour compression cascade cycles in LNG production from 0.741 to 0.704 for nine stages and from 0.838 to 0.709 for eight stages. The specific power consumptions in (kWhr/kgLNG) can be optimized and adopted from 0.1875 to 0.225 kWhr/kgLNG, for the highly recommended design configurations consist of nine and eight stages. The novelty of this study introduces economical and energy-analysis comparative studies to assess and optimize the performance of several design configurations for LNG plant regarding both economics and thermal performance. The conclusions can support the practical application.

A cascade energy cycle based on solid oxide fuel cell with electric energy storage option

ABSTRACT Recently, solid oxide fuel cells (SOFCs) have been known as a popular technology due to their versatility in fuel intake, carbon-free process, and scalability in various applications. Besides that, the utilization of their exhaust heat in cascade cycles improves the process behavior by increasing the energy production rate. From the literature, gas turbines (GTs) are typically utilized as the downstream cycle of SOFCs. However, thermionic generators (TIGs) can be integrated with SOFCs in order to utilization the released heat to produce more electric power. TIGs can be more reliable and stable compared to GTs. Moreover, TIG’s environmental pollution is significantly lower than GTs. On the other hand, thermoelectric generators (TEGs) are devices that require lower grade heat compared to TIGs. In this study, a conceptual-evaluation study of a SOFC-based cascade cycle integrated with TIG and TEG is presented and discussed under the effective parameters. The introduced cascade system is able to produce electric power to meet consumer demand. In this regard, by using SOFC, the chemical energy of hydrogen is converted into electric power and excess heat under electrochemical reactions. By directing waste heat first to TIG and then to TEG, more electric power is yielded during two processes. Further, when the consumer does not need electricity, electric energy is stored by the hybrid pumped hydro and compressed air system (PHCAS) for later utilization. Therefore, the energy structure introduced in the current article suggests a new arrangement and configuration for electrical energy generation and storage. The outcomes of simulation revealed that the considered structure can produce nearly 3.9 kWh of electric energy per day. The energy efficiency of the system in such a context is almost 69.6%. Moreover, 16.12 moles of hydrogen gas (as fuel of SOFC) are required per hour. Additionally, PHCAS with a volume of nearly 2.98 m3 is required to store electrical energy. Also, improving the storage performance depends on the use of efficient storage equipment and setting the initial pressure in values close to the peak point.

Advanced two-stage cascade configurations for energy-efficient –80 °C refrigeration

In response to the COVID-19 pandemic, some vaccines have been developed requiring ultralow-temperature refrigeration, and the number of these freezers has been increased worldwide. Ultralow-temperature refrigeration operates with a significant temperature lift and, hence, a massive decrease in energy performance. Therefore, cascade cycles based on two vapor compression single-stage cycles are traditionally used for these temperatures. This paper proposes the combination of six different cycles (single-stage with and without internal heat exchanger, vapor injection, liquid injection, and parallel compression with and without economizer) in two-stage cascades to analyze the operational and energy performance in ultralow-temperature freezers. All this leads to 42 different configurations in which the intermediate cascade temperature is optimized to maximize the coefficient of performance. Ultra-low global warming potential natural refrigerants such as R-290 (propane) and R-170 (ethane) for the cascade high- and low-temperature stage have been considered. From the thermodynamic analysis, it can be concluded that liquid and vapor injection cascade configurations are the most energy-efficient. More specifically, those containing a vapor injection in the low-temperature stage (0.89 coefficient of performance, 40 % higher than traditional configurations). Then, using an internal heat exchanger for such low temperatures is unnecessary in terms of energy performance. The optimum intermediate cascade temperature varies significantly among cycles, from −37 °C to 2 °C, substantially impacting energy performance. Parallel compression configuration improves energy performance over single-stage cycles, but not as much as multi-stage (between 20 % and 30 % lower coefficient of performance). For most of low-temperature cycles, the high-temperature stage can be based on a single-stage cycle while keeping the maximum coefficient of performance.

Target-triggered tertiary amplifications for sensitive and label-free protein detection based on lighting-up RNA aptamer transcriptions

Proteins play vital roles in regulating a series of living activities and can be potentially considered to be useful indicators for diagnosing various diseases. Here, a target-triggered transcription cascade amplification strategy with the use of the fluorescence switch-on RNA aptamer is constructed for label-free and sensitive platelet-derived growth factor-BB (PDGF-BB) protein biomarker detection. The target molecule of PDGF-BB binds a rationally designed multifunctional hairpin probe to switch its structure and to expose a primer binding region. The primer sequence further binds such a region to initiate the target recycling and lighting-up RNA aptamer transcription cascade cycles to yield tremendous RNA aptamers. And, the fluorescence of the organic dye is substantially enhanced upon binding to these RNA aptamers for realizing highly sensitive and label-free PDGF-BB detection with the detection limit being lowered to 0.8 pM. Moreover, the developed strategy has superior selectivity and exhibits a promising potential to detect PDGF-BB spiked into serums with buffer dilution, which makes this method an attractive sensing system for detecting other biomarkers at trace levels.

Comparison of C3MR and Arctic Cascade Cycles for Operation in Arctic Conditions Using Entropy-Statistical Analysis Method

Comparison of C3MR and Arctic Cascade Cycles for Operation in Arctic Conditions Using Entropy-Statistical Analysis Method

A comparison of using organic Rankine and Kalina cycles as bottom cycles in a solar‐powered steam Rankine cycle

AbstractThis study has attempted to compare two thermodynamic cascade cycles, which in this paper are presented as Systems A and B. System A was consisted of a steam Rankine cycle (SRC) as a top cycle and an organic Rankine cycle (ORC) as a bottom cycle. System B was consisted of the same SRC as the top cycle and a Kalina cycle as the bottom cycle. The comparison of both systems has been made by changing a number of parameters. The chosen parameters for this comparison were bottom cycle mass flow rate, aperture area of the collector, top cycle condensing pressure, and bottom cycle turbine inlet and outlet pressures. Also, a short economic evaluation has been made between two proposed cascade cycles (Systems A and B). The result indicated that the Kalina cycle shows superiority over the ORC as the bottom cycle in a solar‐driven SRC. Furthermore, it was determined that the most effective parameters on the overall efficiency of the systems are the condensing pressure of the top cycle and the outlet pressure of the bottom cycle turbine. Also, among the chosen parameters, the outlet pressure of the bottom cycle turbine had the highest effect on the efficiency of the bottom cycles. Considering the economic aspect, the results showed that the levelized costs of energy for both systems are quite equal at 0.011 ($/kWh).

The cardioprotective actions of statins in targeting mitochondrial dysfunction associated with myocardial ischaemia-reperfusion injury

During cardiac reperfusion after myocardial infarction, the heart is subjected to cascading cycles of ischaemia reperfusion injury (IRI). Patients presenting with this injury succumb to myocardial dysfunction resulting in myocardial cell death, which contributes to morbidity and mortality. New targeted therapies are required if the myocardium is to be protected from this injury and improve patient outcomes. Extensive research into the role of mitochondria during ischaemia and reperfusion has unveiled one of the most important sites contributing towards this injury; specifically, the opening of the mitochondrial permeability transition pore. The opening of this pore occurs during reperfusion and results in mitochondria swelling and dysfunction, promoting apoptotic cell death. Activation of mitochondrial ATP-sensitive potassium channels (mitoKATP) channels, uncoupling proteins, and inhibition of glycogen synthase kinase-3β (GSK3β) phosphorylation have been identified to delay mitochondrial permeability transition pore opening and reduce reactive oxygen species formation, thereby decreasing infarct size. Statins have recently been identified to provide a direct cardioprotective effect on these specific mitochondrial components, all of which reduce the severity of myocardial IRI, promoting the ability of statins to be a considerate preconditioning agent. This review will outline what has currently been shown in regard to statins cardioprotective effects on mitochondria during myocardial IRI.

Comparative investigations of sorption/resorption/cascading cycles for long-term thermal energy storage

Long-term thermal energy storage is one of the potential and critical solutions to solve the mismatching between thermal energy supply and demand. Even though single-stage sorption cycle, resorption cycle and multi-stage cascading cycle have been proposed for long-term thermal energy storage, the results are difficult to be utilized for selecting optimal cycles because most of them are investigated under different conditions and their performances are not compared under the same criterion experimentally. Herein, the experimental comparative study of different energy storage cycles is implemented for a wide range of heat source temperature and output temperature. For cycles with CaCl2/expanded nature graphite treated by the sulphuric acid (ENG-TSA) sorption bed as the output side, CaCl2/NH4Cl-NH3 cascading cycle has distinct advantage on effective discharging time. Under the general working conditions with relatively high heat source temperature and low output temperature, CaCl2-NH3 sorption cycle is the optimal choice. For cycles with MnCl2/ENG-TSA sorption bed as the output side, MnCl2-NH3 sorption cycle has the maximum thermal energy storage density, thermal energy storage efficiency and temperature lift of 420 kJ·kg−1, 0.51 and 15.0 °C, respectively, at high heat source temperature of 175 °C. Under the critical conditions such as the heat source temperature lower than 155 °C, MnCl2/CaCl2-NH3 cascading cycle is more suitable and shows optimum adaptability to unsteady heat source. The experimental results exhibit the suitable working range of heat source temperature and output temperature for different cycles, and the guidance is revealed for selecting optimal cycles for different types of low-grade thermal energy.

Thermodynamic and economic evaluation of biomethane and carbon dioxide liquefaction process in a hybridized system of biogas upgrading process and mixed fluid cascade liquefaction cycle

In recent years, the use of liquefied biogas in the power plant for peak shaving and transportation industries from an environmental and economic perspective has been considered. Simultaneous design of biogas purification and liquefaction processes reduces the number of equipment required and energy consumption. In this paper, a novel purification and liquefaction integrated structure includes a biogas upgrading process by cryogenic separation and amine scrubbing methods and a biomethane liquefaction cycle based on the mixed fluid cascade. In this integrated structure, 2.393 kg/s biogas and 2730 kW power are consumed and 0.5387 kg/s bioLNG, 0.1280 kg/s bioCH4, and 0.2102 kg/s liquid bioCO2 are produced along with 1.625 kg/s hot water. The required cooling of cryogenic biogas upgrading and required heat for the biogas upgrading by amine scrubbing method are provided through mixed refrigerant cascade cycles and waste heat in the integrated structure, respectively. The total thermal energy and exergy efficiencies are 73.11 % and 72.58 %, respectively. The specific power consumption and coefficient of performance of the mixed fluid cascade cycle are calculated to be 0.4761 kW h/kg bioLNG and 3.675, respectively. The economic analysis illustrates that the prime cost of product and return period are 0.2399 US$/kg LNG and 2.122 years, respectively.

Copper nanoparticles loaded polymer vesicles as environmentally amicable nanoreactors: A sustainable approach for cascading synthesis of benzimidazole

This paper reports the synthesis and characterization of Cu nanoparticle loaded, surfactant free metallovesicles (CuNPs@vesicles) as nanoreactors to produce benzimidazoles via cascade reaction. The vesicles exhibited uniform size distribution, spherical morphology, excellent stability and efficient Cu loading. This strategy is unique for the fact that, environmental contaminants like nitroaniline have been utilized as precursor and converted into fine chemicals of commercial significance via non-toxic intermediates. CuNPs@vesicles reduces 2-nitroaniline to o-phenylenediamine which further acts as precursor for benzimidazole synthesis. Thus the reaction occurs via two step cascade pathway comprising reduction and CN cross coupling reactions in water. The preliminary studies suggest encouraging results for performing dehydrogenative coupling under relatively mild conditions using CuNPs@vesicles as a catalyst. All the products are obtained in good to excellent yield with facile catalyst regeneration and recyclability upto 5 cascading cycles.

Hydrogenation of CO2 to methanol catalyzed by a manganese pincer complex: insights into the mechanism and solvent effect.

Herein, density functional theory (DFT) calculations were employed to explore the reaction mechanism of three cascade cycles for the hydrogenation of carbon dioxide to methanol (CO2 + 3H2 → CH3OH + H2O) catalyzed by a manganese pincer complex [Mn(Ph2PCH2SiMe2)2N(CO)2]. The three cascade cycles involve: the hydrogenation of CO2 to formic acid, the hydrogenation of formic acid to methanediol and the decomposition of methanediol to formaldehyde and water, and the hydrogenation of formaldehyde to methanol. The calculated results demonstrate that hydrogen activation is the rate-determining step of each catalytic cycle under solvent-free conditions, and the energy span of the whole reaction is 27.1 kcal mol-1. Furthermore, the solvent was found to be of importance in this reaction. In three different solvents, the rate-determining steps of this reaction are all the hydrogen transfer step of the formic acid hydrogenation stage, and the corresponding energy spans in water, toluene and THF solvents are 21.3, 20.8 and 20.4 kcal mol-1, respectively. Such a low energy span implies that this manganese complex could be a promising catalyst for the efficient conversion of CO2 and H2 to methanol at temperatures below 100-150 °C.

Comparative study on the series, parallel and cascade cycles of a multi-mode room temperature magnetic refrigeration system

Abstract Magnetic refrigeration has been investigated as an appropriate alternative for vapor-compression refrigeration to reduce the greenhouse effect. However, the commercialization process of MR is obstructed by the inadequate cooling condition. In this paper, a multi-mode MR system with series, parallel and cascade cycle modes is constructed. The optimal utilization factors, internal cycle mechanisms and refrigeration characteristics of three modes are compared. The magnetocaloric material used is 277.4 g of gadolinium, and two NbFeB permanent magnets are assembled to provide a maximum magnetic field intensity of 1.5 T. The results show that different modes affect the MR system performance. The series mode increases the temperature span by increasing the length of the regeneration zone. The parallel mode improves the cooling power owing to the simultaneous output of double regenerators. The novel cascade cycle constructs the higher- and lower- temperature regeneration stages, which are effectively utilized to provide a large temperature span and suitable cooling power. The obtained no-load temperature spans are 5.66 K, 4.16 K and 7.35 K in the series, parallel and cascade cycles, respectively, and the corresponding maximum specific cooling powers are 29.02, 39.47 and 34.79 W/kg. Compared with the parallel mode, the cycle characteristics of the series and cascade modes receive a greater degree of investigation. The series mode shows a larger potential for large-temperature-span output system, and the cascade cycle is most likely to meet both the temperature span and cooling power output requirements simultaneously. The results provide some guidelines for the design of magnetic refrigeration prototypes.

Climate Change and Refrigerants: Thermodynamic Properties of Low-GWP Fluids for Domestic Applications and Binary Systems for Low-Temperature Options

The most commonly used refrigerants are potent greenhouse gasses that can contribute to climate change. Hydro-Fluoro-Olefins are low Global Warming Potential fluids. A summary of our experimental research activity on the thermodynamic properties of two environmentally friendly Hydro-Fluoro-Olefins, namely R1234yf and R1234ze(E), is reported. In particular, the measurements were performed with an isochoric apparatus and the apparatus specifically built to reach temperatures down to about 100 K. The data elaboration confirms the validity of the choice and that R1234yf and R1234ze(E) can be adopted in many domestic applications. Moreover, considering the reduction of the flammability issues of R1234yf and R1234ze(E), the properties of binary systems containing these fluids and carbon dioxide were analyzed. The presented mixtures could be very interesting for low-temperature applications such as cascade cycles.