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• The VLE data for R32/R1216 were measured at four temperatures range from 285 to 315 K. • The experimental results were correlated with PR-HV-NRTL model. • The performance of the azeotrope R32/R1216 (0.9/0.1) is between pure R32 and R410A. • Azeotrope R32/R1216 (0.9/0.1) can serve as a drop-in replacement of R32 and R410A in RAC systems. In order to accurately evaluate the performance of R32 and unsaturated fluorinated olefins (HFOs) binary mixtures in residential air condition (RAC) system, the vapor-liquid phase equilibrium (VLE) data of R32 and R1216 binary mixture has been measured with a liquid phase circulation system in the temperature range from 285 to 315 K. The experimental data were correlated by Peng-Robinson (PR) equation of state with Huron-Vidal (HV) mixing rule and non-random two-liquid (NRTL) activity coefficient model. Maximum deviation of the pressure and the mole fraction was 1.38% and 0.013, respectively. The azeotropic behavior was observed for the R32 and R1216 binary mixture when the mole fraction of R32 was around 0.9. The RAC system with standard refrigeration, heating and variable evaporation temperature operating condition was simulated. The cycle performance of binary mixtures of R32 + R1216, R1234yf and R1234ze(E) at different concentrations was compared. The azeotrope R32/R1216 (molar ratio 0.9/0.1) has an extremely low GWP, the COP, refrigeration/heating capacity per unit volume and condensation pressure close to pure R32, and lower discharge temperature. At the same time, it also has well variable operating conditions performance and can be considered as a drop-in replacement for R32 and R410A in RAC systems. [ABSTRACT FROM AUTHOR]

Worldwide epidemiological studies indicate that the adverse health effects associated with ozone exposure might be modified by ambient temperature. In China, the health risks associated with ozone exposure are poorly understood due to the lack of data. In addition, it is insufficient how temperature modifies the ozone exposure-cardiovascular mortality association. In this study, we adopted two advanced time-series Poisson generalized additive models (GAMs) including a nonparametric bivariate response surface model and a stratification parametric model to investigate the modification effect of temperature on ozone-related cardiovascular mortality in 13 cities in China from 2014 to 2016. We categorized temperature into three levels (low, moderate, and high) considering four temperature percentiles, including the 25th and 75th, 15th and 85th, 10th and 90th, and 5th and 95th temperature percentiles. Subsequently, under different temperature stratifications, we evaluated acute cardiovascular mortality risks associated with the maximum 8-h average ozone concentration (O 3-8hmax) in each city and assessed these O 3-8hmax -cardiovascular mortality associations by meta-analysis in all cities together. The results confirmed that high temperature strongly increased the O 3-8hmax cardiovascular mortality association; in particular, the O 3-8hmax mortality risk was highest when the 95th temperature percentile cut-off was applied. On days with daily mean temperatures exceeding the city-specific 75th, 85th, 90th, and 95th percentiles, a 10-μg/m3 increase in the O 3-8hmax during the current and previous day (lag01) increased the cardiovascular mortality risk by 0.74%, 0.76%, 0.80%, and 1.11%, respectively. However, the O 3-8hmax mortality risk did not change appreciably under moderate or cold temperature conditions defined by different temperature cut-offs. Our findings validate the theory that high temperature increases health risks associated with the O 3-8hmax ; thus, mitigating ozone exposure will be of utmost importance, especially under the context of a changing climate. • High temperatures aggravated the harmful effects of O 3 exposure on cardiovascular mortality. • The modification effects of temperature on O 3 -mortality relationships varied across geographic regions. • Both temperature and geography factors should be considered in the assessment of O 3 health risks. [ABSTRACT FROM AUTHOR]

In the present paper, the refrigerant mixture R32/R290 (68%/32% by weight) is investigated as the drop-in replacement for R410A in household air conditioners. The GWP of it is only 22% of that of R410A. Theoretical and experimental investigations are conducted on the performance of the air conditioners working with both R32/R290 and R410A. Experimental results show that the refrigerant charge amount of R32/R290 is reduced by 30.0%–35.0%; the cooling and heating capacities are increased by 14.0%–23.7%. For further reducing charge amount and flammability, the micro-channel heat exchanger (condenser) is employed to replace the finned tube one. Compared with the R32/R290 system using finned tube heat exchanger, the R32/R290 charge amount and the power consumption are reduced by 34.1% and 0.4%, respectively; the cooling capacity and the COP are increased by 6.4% and 6.8%, respectively. [ABSTRACT FROM AUTHOR]

Highlights: [•] A method for determining the critical velocity for safety is proposed. [•] Effects of main factors on transportation safety of ice slurry are investigated. [•] IPF is suggested to be 20–25% to improve both transport safety and capacity. [•] Reducing ice particle size to 100μm can greatly improve transportation safety. [•] Reducing pipe size is beneficial to transportation safety in ice cooling systems. [ABSTRACT FROM AUTHOR]

Some experimental data have been published on the basic thermophysical properties of R290, R1216, R1234ze(E) and their mixtures, but the EoV (enthalpy of vaporization) are mostly indirectly calculated by saturated vapor pressure data and Clausius-Clapeyron equation, with limited accuracy, especially for mixtures. Therefore, this paper developed a method to directly measure the EoV of refrigerants and their mixtures based on a microcalorimeter and its supporting equipment. In this work, the enthalpy of vaporization of refrigerants and mixtures has been investigated experimentally and theoretically, and an accurate and simple method for directly measuring EoV has been developed. The EoV of R290, R1216, R1234ze(E) and their mixtures were measured at temperatures from 260 to 290 K using a modified high-pressure differential scanning calorimeter combined with a pressure balance unit and a sample injection system. Compared the experimental results with commonly used estimation methods, such as Clausius-Clapeyron equation and Helmholtz-energy equation of state. The experimental results were in good agreement with Helmholtz equation, with the maximum deviation within 1.89%. The empirical formula was used to fit the experimental results [Display omitted] • A novel method for directly measuring the enthalpy of vaporization of refrigerants and mixture by DSC was proposed. • The enthalpies of vaporization of R290/R1216 and R290/R1234ze(E) at different components were measured. • A novel equation for correlating the enthalpy of vaporization of refrigerants and binary mixtures was proposed. In this work, the enthalpy of vaporization (Δ vap H) of refrigerants and mixtures has been investigated experimentally and theoretically, and an accurate and simple method for directly measuring Δ vap H has been developed. First of all, the Δ vap H of R290, R1216, R1234ze(E) and their mixtures were measured at temperatures from 260 to 290 K using a modified high-pressure differential scanning calorimeter combined with a pressure balance unit and a sample injection system. Seven temperature points were measured for each component. After that, compared the experimental results with commonly used estimation methods, such as Clausius-Clapeyron equation and Helmholtz-energy equation of state. The experimental results were in good agreement with Helmholtz equation, with the maximum deviation within 1.89%. In the end, the empirical formula was used to fit the experimental results. The average absolute deviations between the experimental values and the fitting values were between 0.07% and 0.40%, and the maximum absolute deviations were between 0.11% and 1.05%. [ABSTRACT FROM AUTHOR]

• The VLE data for R1234ze(E) + R1216 binary mixtures were measured at five temperatures range from 275 to 315 K. • The experimental results were correlated with PR-HV-NRTL model. In this work, the vapor–liquid phase equilibrium (VLE) data of R1234ze(E) and R1216 binary mixtures has been investigated experimentally and theoretically. The VLE data for the binary system of R1234ze(E) + R1216 were measured with a recirculation system at five temperatures range from 275 to 315 K. The experimental results were correlated by Peng-Robinson equation of state combined with Huron-Vidal mixing rule or Wong-Sandler mixing rule and non-random two-liquid activity coefficient model, and van der Waals mixing rule. The calculated values were in well agreement with the experimental results, with the maximum deviations of the pressure and the mole fraction of the vapor phase within 0.87% and 0.016, respectively. The average absolute deviations of the pressure and the mole fraction of the vapor phase between the experimental values and calculated values were 0.35% and 0.005, respectively. [ABSTRACT FROM AUTHOR]

This paper thermodynamically analyzes an air-cooled type double effect absorption refrigeration system using ammonia/lithium nitrate and ammonia/sodium thiocyanate solutions as working pairs and driven by high temperature heat source such as waste heat energy, innovatively, an air-cooled type non-adiabatic absorber is implemented in the system to improve the cycle performance. Comparing to the single effect absorption refrigeration system, the double effect system is designed not only to directly and efficiently utilize high temperature waste heat energy for cycle performance improvement, but also to greatly extend the application occasion to high ambient temperature condition. Parametric analysis of the present system show that COP of the double effect system is 30–60% higher than the single effect system under air cooling working condition and the high pressure generating temperature of the double effect system can be extended to as high as 220 °C. Influences of high pressure generator temperature, low pressure generator temperature, absorber outlet solution temperature as well as other system working parameters on cycle performance are numerically simulated and parametric optimization is provided in the present model. Cycle performance comparison of NH 3 /LiNO 3 system with NH 3 /NaSCN system has been carried out. According to the simulation results, COP of NH 3 /NaSCN system is found to be 10–15% higher than that of NH 3 /LiNO 3 system in evaporating temperature range of - 10 ° C < T e < 5 ° C . However in low evaporating temperature conditions, T e ⩽ - 10 ° C , NH 3 /LiNO 3 systems are found to be more competitive than that of NH 3 /NaSCN system. The main concern of the present study is that implementation of non-adiabatic absorbers in air-cooled type double effect ammonia/salt absorption refrigeration systems is essential, and only under non-adiabatic absorption conditions can the double effect ammonia/salt system realize miniaturization. [ABSTRACT FROM AUTHOR]

This paper presents a methodology of exergy analysis for ammonia-lithium nitrate and ammonia-sodium thiocyanate absorption refrigeration cycle which applies a novel air-cooled type non-adiabatic absorber to improve both the coefficient of performance and exegetic efficiency of the system under air cooling condition. A modified entropy calculation method for NH 3 /NaSCN and NH 3 /LiNO 3 solutions is presented in this literature and different results are obtained comparing to previous research. In addition to the variation of solution temperature and pressure from specific working state to the reference state, the variation of solution concentration, which was always neglected by previous researchers in ammonia/salt solution exergy calculation, has been taken into account while analyzing the least potential of ammonia/salt solution for doing useful work, and a corresponding approach for specific exergy calculation is presented. The effects of generator temperature, absorber outlet temperature, absorber efficiency and other system parameters on system exergetic efficiency have been discussed in this study. Analysis results indicate that relatively high system performance can be obtained by air-cooled type ammonia/salt absorption refrigeration cycles when non-adiabatic absorbers are applied in these systems. [ABSTRACT FROM AUTHOR]

Abstract: Supercooled water is used as a superior method to generate ice slurry for its high efficiency and energy conservation. However, the ice blocking occurred in the supercooling heat exchanger is a prominent problem that reduces the efficiency of the ice generation system. In this study, in order to avoid or retard ice blocking, a fluorocarbon coating with super-hydrophobicity was applied onto the surface of the supercooling heat exchanger to continuously make ice slurry without any additives. As experimental parameters include supercooled degree, ice production, start time of ice blocking and flow rate etc. The experimental data were obtained by using a data acquisition system, and then were analyzed and discussed. It was concluded that the supercooling heat exchanger with the fluorocarbon coating could be fully applied to improve the efficiency of ice production due to the properties of the coated surface. [Copyright &y& Elsevier]

Abstract: Icing is a common phenomenon in many fields, from aeronautics to power lines. Recently, researchers have paid much attention on the superhydrophobic surface as one of the favorable anti-icing techniques. In the present study, we investigated the performance of water icing on a superhydrophobic surface with a nano-fluorocarbon film in the average thickness around 10nm. The surface topographies and wettabilities were characterized by a scanning electron microscopy system and a video-based contact angle measurement system respectively. To investigate the effects of this nano-fluorocarbon coating on water icing, the water droplet shape, the starting icing time and the whole icing process were observed on both the coated and uncoated surface. It was found that the coated surface has a good ability to retard the starting time of icing while the whole icing time on the coated surface was longer compared the uncoated one under the experimental conditions. The test results showed that the nano-fluorocarbon coating expresses a good anti-icing performance and can be used as a coating material to avoid ice-blocking in the dynamic ice-making system. [Copyright &y& Elsevier]

This paper presents a comparative analysis on leakage losses of a rolling piston type rotary compressor with refrigerants of R290, R22 and R410a. In particular, the difference of leakage losses characteristics between R290 compressor and that of other refrigerant compressors has been studied. Leakage losses through radial clearance, clearances between rolling piston faces and the cylinder head walls, clearances between the sliding vane faces and the cylinder head walls, as well as the clearances between the sides of the sliding vane and the side walls of the chutes inside the cylinder have been studied in the present methodology. Radial leakage caused by the wall velocity has been taken into account in the present study. Simulation results indicate that smaller radial clearance is required for R290 compressor to obtain relatively high efficiency comparing to that of R22 and R410a compressors under the same condition. [ABSTRACT FROM AUTHOR]