Equilibrium Vapor Pressure Research Articles

A New Approach to Characterizing the Partitioning of Volatile Organic Compounds to Cotton Fabric.

Chemical partitioning to surfaces can influence human exposure by various pathways, resulting in adverse health consequences. Clothing can act as a source, a barrier, or a transient reservoir for chemicals that can affect dermal and inhalation exposure rates. A few clothing-mediated exposure studies have characterized the accumulation of a select number of semi-volatile organic compounds (SVOCs), but systematic studies on the partitioning behavior for classes of volatile organic compounds (VOCs) and SVOCs are lacking. Here, the cloth-air equilibrium partition ratios (KCA) for carbonyl, carboxylic acid, and aromatic VOC homologous series were characterized for cellulose-based cotton fabric, using timed exposures in a real indoor setting followed by online thermal desorption and nontargeted mass spectrometric analysis. The analyzed VOCs exhibit rapid equilibration within a day. Homologous series generally show linear correlations of the logarithm of KCA with carbon number and the logarithms of the VOC vapor pressure and octanol-air equilibrium partition ratio (KOA). When expressed as a volume-normalized partition ratio, log KCA_V values are in a range of 5-8, similar to the values for previously measured SVOCs which have lower volatility. When expressed as surface area-normalized adsorption constants, KCA_S values suggest that equilibration corresponds to a saturated surface coverage of adsorbed species. Aqueous solvation may occur for the most water-soluble species such as formic and acetic acids. Overall, this new experimental approach facilitates VOC partitioning studies relevant to environmental exposure.

Vapor pressure and vapor-liquid equilibrium data for eugenol/caryophyllene binary system at low pressures by experimental and predictive methods

The main objective of this study was to determine the vapor-liquid equilibrium of the binary mixture eugenol/caryophyllene at reduced pressures and to obtain pure compounds vapor pressure data in the same low-pressure condition. Isobaric vapor–liquid equilibrium (VLE) data have been measured in a Fischer ebulliometer at 5.0, 10.0, and 20.0 kPa. The vapor pressure of the pure compounds was determined by direct measurement of the equilibrium temperature at different pressures. The extended Antoine equation and the Clarke and Glew equation were fitted to the experimental data and compared with a predictive method. The thermodynamic consistency of the VLE experimental data was checked using the Redlich-Kister area test and the Van Ness point test. The binary interaction parameters of NRTL, Wilson, and UNIQUAC activity coefficient models were fitted from regression of experimental data. The average absolute deviation of the temperature (AAD(T)) and vapor-phase molar fraction (AAD(y)) are less than 0.22 K and 0.0119, respectively, proving a good adherence of the models for the calculation of the VLE system. The COSMO-SAC model was used to predict activity coefficients, compared with classic thermodynamic models, and was able to represent the azeotrope presented by the mixture.

Simulation research on absorption refrigeration system based on NH3-H2O-LiBr vapor-liquid equilibrium calculation model

In order to investigate the NH3+H2O+LiBr (lithium bromide) absorption refrigeration cycle process and to simulate it accurately, a vapor-liquid equilibrium calculation model was proposed to obtain thermodynamic characteristic data of the ternary mixtures. The calculation of parameters of liquid phase is based on Wilson?s equation and non-random two liquid equation. The vapor phase, assumed to consist of NH3 and H2O only, is described by The Redlich-Kwong Equation of State. The data of the equilibrium vapor pressure and the NH3 concentration in liquid phase calculated by this model was compared with the experimental data, the difference is between 0.5% to 9.6% within the temperature range from 303 K to 425 K. The COP obtained by the simulation matches with that obtained by experiment and the absolute deviation is less than 0.02. Therefore, this calculation model can be used for simulation to extend the temperature range and pressure range of the system, so as to determine the design parameters of the absorption refrigeration system. The simulation results indicates that under different working conditions, the optimal generator temperature and concentration of adding LiBr can be selected, to which the theoretical explanations were given in this paper.

Synthetic oils based on pentaerythritol esters. Vapor pressure and enthalpy of vaporization

Pentaerythritol esters (2,2-bis(hydroxymethyl)propane-1,3-diol) esters and other esters are widely used as components of machine oils, motor oils, hydraulic fluids and plasticizers. The advantages of such esters are high thermal oxidative and hydrolytic stability, and good tribological properties. In this work, the equilibrium vapor pressures and enthalpies of vaporization (298.15 K) of nine esters of pentaerythritol combined with C2–C7 acids of various structures were determined by the vapor transpiration method in the temperature range of 358–433 K. The vaporization enthalpies of the pentaerythritol esters with homologous acids are found to correlate with their retention indicies and the number of carbon atoms in the linear acid residue. Enthalpies of vaporization of the compounds studied have also been calculated by the QSPR-method. These results have been verified by experimental values.

Freezing of Dilute Aqueous-Alcohol Nanodroplets: The Effect of Molecular Structure.

We investigate vapor-liquid nucleation and subsequent freezing of aqueous-alcohol nanodroplets containing 1-pentanol, 1-hexanol, and their 3-isomers. The aerosols are produced in a supersonic nozzle, where condensation and freezing are characterized by static pressure and Fourier transform Infrared (FTIR) spectroscopy measurements. At fixed water concentrations, the presence of alcohol enables particle formation at higher temperatures since both the equilibrium vapor pressure above the critical clusters and the cluster interfacial free energy are decreased relative to the pure water case. The disappearance of a small free OH peak, observed for pure water droplets, when alcohols are added and shifts in the CH peaks as a function of alcohol chain length reveal varying surface partitioning preferences of the alcohols. Changes in the FTIR spectra during freezing, as well as changes in the ice component derived from self-modeling curve resolution analysis, show that 1-hexanol and 1-pentanol perturb freezing less than their branched isomers do. This behavior may reflect the molecular footprints of the alcohols, the available surface area of the droplets, and not only alcohol solubility. The presence of alcohols also lowers the freezing temperature relative to that of pure water, but when there is clear evidence for the formation of ice, the ice nucleation rates change by less than a factor of ∼2-3 for all cases studied.

Vaporization behavior of Ir4(CO)12 and Re2(CO)10 measured by torsion effusion gravimetric method

Metal carbonyls are of great importance in chemical vapor deposition (CVD), composite materials fabrication, and other near-net shape technologies. Carbonyl CVD is used for deposition of high-purity metallic and alloy coatings for which vapor pressure data is essential. In this study, we report vapor pressures of solid Ir4(CO)12 and Re2(CO)10 carbonyls measured by using the Knudsen Cell methodology using a torsion effusion thermogravimetric system. The vapor pressure of the Ir4(CO)12 exhibited incongruent vaporization, as the molecular weight (MW) of the effusing species was determined as 128 g/mol as compared to the theoretical MW of 1105 g/mol. It is proposed that the Ir4(CO)12 (s) partially decomposed (∼66%) to Ir4(CO)12(g), Ir(s), and CO(g). The Re2(CO)10 on the other hand, showed congruent behavior with Re2(CO)10(s) vaporizing to Re2(CO)10(g) in the measured temperature range. The raw data for vapor pressures was measured using two sets of Knudsen cells with different orifice sizes, and the equilibrium vapor pressures were calculated using Whitman-Motzfeldt methodology. The equilibrium vapor pressures of these carbonyls, partial pressures of gaseous species in case of decomposition, average molecular weights of the effusing gasses were determined. The vapor pressures and Gibbs energies of vaporization reactions of the two above mentioned carbonyls, as well as comparison of vaporization thermodynamics these two carbonyls with other carbonyls from Group VIB to VIIIB are presented in this paper.

New association schemes for tri-ethylene glycol: Cubic-Plus-Association parameterization and uncertainty analysis

Transportation of natural gas extracted from subterranean reservoirs is subject to several risks introduced by the presence of water. These risks can be mitigated through subsea dehydration, the design of which requires an accurate understanding of the thermodynamics of these systems. Having previously investigated the use of mono-ethylene glycol as a dehydration agent, this research focusses on the industry workhorse: tri-ethylene glycol (TEG). The Cubic-Plus-Association (CPA) equation of state has previously provided a good description for systems of equal complexity and in this work the literature 4C and 6D association schemes, as well as four newly proposed association schemes (4F, 5F, 6F and 5C) are evaluated for the description of TEG. These association schemes, which are explained in the manuscript, represent different ways of self-association for TEG.Pure component parameters are estimated by fitting to vapor pressure, liquid density, and liquid-liquid equilibrium data, with statistical uncertainty analysis implemented to determine the confidence intervals of the parameters. Binary interaction parameters are similarly fitted to binary vapor-liquid equilibrium (VLE) data. Optimized parameters are evaluated by testing their performance in predicting binary and ternary VLE systems.Due to the strong influence of certain experimental data sets, the literature 6D parameters are shown to be unsuitable for the applications in this work. The need for consistent experimental data quantifying both vapor and liquid phases, specifically for TEG – CH4 has been highlighted. The best overall performance was obtained using the newly proposed 4F association scheme. Along with improved overall description of various VLE and LLE systems, with average absolute relative deviations generally between 2-20%, single parameter sensitivity analysis shows improved optimality for several systems also not included in the parameterization. This is indicative of a better fundamental characterization of the TEG molecule. The value of the uncertainty analysis is shown for the binary interaction parameters, where for TEG – CH4 VLE a temperature-dependent correlation is shown to be unnecessary using the optimum association schemes.

Molecular dynamics simulation and thermodynamic model of vapor–solid coexistence of the Lennard–Jones fluid in cylindrical nanopores

Molecular dynamics (MD) simulations were used to study the coexistence of solids and vapors of Lennard–Jones methane condensed within cylindrical carbon nanopores. The simulated unit cell includes both the inside and outside of the pores. This allowed us to observe the solid-vapor coexistence within the pores while simulating the pressure depression of the bulk vapor outside the pores. The condensates in the pores were cooled in stages, and the equilibrium vapor pressures were determined at each temperature. The obtained vapor–solid coexistence curves showed significantly lower shifts in pressure than those in the bulk phase. The results of the MD simulations were compared with the Clausius–Clapeyron equation starting from the triple point in the nanopores. The thermodynamic model successfully predicted the simulation results without introducing tunable parameters, demonstrating this concept’s validity. Thus, a whole Lennard-Jones phase diagram in cylindrical nanopores can now be predicted.

Numerical study of bubble behaviors and heat transfer in pool boiling of water/NaCl solutions using the lattice Boltzmann method

Through modification of the equation of state applicable to the non-volatile salt solution and characterization of the effect of solute concentration on the physical properties of the solution, a lattice Boltzmann pseudopotential model was developed and used to study the pool boiling processes of pure water and NaCl solutions. The model quantitatively verified the equilibrium vapor pressure reduction and boiling point rise of the NaCl solution with solute concentration. The complete pool boiling curves of pure water and the NaCl solution were simulated, and the differences in bubble behaviors and heat flux evolutions in pure water and the NaCl solution at different superheats were analyzed. The results revealed that the difference of heat flux between water and NaCl solution in the nucleate boiling regime is dominated by the nucleation site density and bubble departure frequency at lower superheats, while dominated by the bubble interactions at larger superheats. As a result, the NaCl solution presents a lower nucleate boiling heat flux than that of water when the imposed superheat is smaller than a critical superheat, while it exhibits a larger heat flux even a higher critical heat flux than water when the superheat is higher than the critical superheat. Furthermore, the lower bubble departure frequency in NaCl solution film boiling was captured by simulation. The simulated film boiling heat flux of the NaCl solution was smaller than that of water, and both the simulated results fitted the Berenson correlation well.

Investigating the Condensation of Benzene (C6H6) in Titan’s South Polar Cloud System with a Combination of Laboratory, Observational, and Modeling Tools

Abstract We have combined laboratory, modeling, and observational efforts to investigate the chemical and microphysical processes leading to the formation of the cloud system that formed at an unusually high altitude (>250 km) over Titan’s south pole after the northern spring equinox. We present here a study focused on the formation of C6H6 ice clouds at 87°S. As the first step of our synergistic approach, we have measured, for the first time, the equilibrium vapor pressure of pure crystalline C6H6 at low temperatures (134–158 K) representative of Titan’s atmosphere. Our laboratory data indicate that the experimental vapor pressure values are larger than those predicted by extrapolations found in the literature calculated from higher-temperature laboratory measurements. We have used our experimental results along with temperature profiles and C6H6 mixing ratios derived from observational data acquired by the Cassini Composite Infrared Spectrometer (CIRS) as input parameters in the coupled microphysics radiative transfer Community Aerosol and Radiation Model for Atmospheres (CARMA). CARMA simulations constrained by these input parameters were conducted to derive C6H6 ice particle size distribution, gas volume mixing ratios, gas relative humidity, and cloud altitudes. The impact of the vapor pressure on the CIRS data analysis and in the CARMA simulations was investigated and resulted in both cases in benzene condensation occurring at lower altitude in the stratosphere than previously thought. In addition, the stratospheric C6H6 gas abundances predicted with the new saturation relationship are ∼1000× higher than previous calculations between 150–200 km, which results in larger particle sizes.

Possible contribution of the Gibbs−Thomson effect to filling nanopipes in GaN homoepitaxial layers

Reported suppression of the transformation of screw dislocations into nanopipes in GaN homoepitaxial layers by increasing total pressure (P total) during metalorganic vapor-phase epitaxy was assumed to be a phenomenon of nanopipe formation followed by its refill. We thermodynamically calculated equilibrium vapor pressure of Ga (P Ga) by considering the Gibbs−Thomson effect. Even with an assumption of a small surface free energy of 1.4 J m−2, the difference between the calculated P Ga’s in the vicinity of a wafer surface and in a nanopipe rapidly increased at P total > 750 hPa, explaining the increased vapor-phase diffusing flux of Ga into a nanopipe.

Synthetic naphtha recovery from water streams: Vapour‐liquid–liquid equilibrium (VLLE) studies in a dynamic VL‐cell unit with high intensity mixing

AbstractThis work describes vapour pressure measurements of a water/synthetic naphtha mixture using a dynamic CREC‐VL‐Cell, designed to obtain reliable vapour measurements (). The CREC‐VL‐Cell is used to measure vapour pressures for immiscible or partially miscible liquids, given its high multiphase mixing capability. Runs in the CREC‐VL‐Cell involve a dynamic method, operating with a set heating ramp, with continuous tracking of both saturation vapour pressure and temperature within the cell. This system allows for the establishment equilibrium vapour pressures, in a recommended 50–120°C range, emulating the conditions of the naphtha recovery in oil sand processes. Results obtained in the CREC‐VL‐Cell at 1080 rpm are validated using data from Aspen‐Hysys with a Peng‐Robinson fluid package for pure octane and water. On the other hand, using a 2.5 wt.% and 4 wt.% synthetic naphtha in 97.5 wt.% water blend, experimental data shows partial agreement with the Aspen‐Hysys Peng‐Robinson fluid package predictions, demonstrating the value of the experimental vapour‐liquid–liquid (VLL) data obtained in the CREC‐VL‐Cell.

Investigation of the relationship between skin-emitted volatile fatty acids and skin surface acidity in healthy participants—a pilot study

Volatile organic compounds (VOCs) emitted from human skin are of great interest in general in research fields including disease diagnostics and comprise various compound classes including acids, alcohols, ketones and aldehydes. The objective of this research is to investigate the volatile fatty acid (VFA) emission as recovered from healthy participant skin VOC samples and to characterise its association with skin surface acidity. VOC sampling was performed via headspace-solid phase microextraction with analysis via gas chromatography-mass spectrometry. Several VFAs were recovered from participants, grouped based on gender and site (female forehead, female forearm, male forearm). Saturated VFAs (C9, C12, C14, C15, C16) and the unsaturated VFA C16:1 (recovered only from the female forehead) were considered for this study. VFA compositions and abundances are discussed in the context of body site and corresponding gland type and distribution, and their quantitative association with skin acidity investigated. Normalised chromatographic peak areas of the recovered VFAs were found to linearly correlate with hydrogen ion concentration measured at each of the different sites considered and is the first report to our knowledge to demonstrate such an association. Our observations are explained in terms of the free fatty acid content at the skin surface which is well-established as being a major contributor to skin surface acidity. Furthermore, it is interesting to consider that these VFA emissions from skin, governed by equilibrium vapour pressures exhibited at the skin surface, will be dependent on skin pH. It is proposed that these pH-modulated equilibrium vapour pressures of the acids could be resulting in an enhanced VFA emission sensitivity with respect to skin surface pH. To translate our observations made here for future wearable biodiagnostic applications, the measurement of skin surface pH based on the volatile emission was demonstrated using a pH indicator dye in the form of a planar colorimetric sensor, which was incorporated into a wearable platform and worn above the palm surface. As acidic skin surface pH is required for optimal skin barrier function and cutaneous antimicrobial defence, it is envisaged that these colorimetric volatile acid sensors could be deployed in robust wearable formats for monitoring health and disease applications in the future.

Comparative Study of Cold Sintering Process and Autoclave Thermo-Vapor Treatment on a ZnO Sample

Analysis of scanning electron microscopy images was used to study the changes in the crystal size distribution of ZnO, which occurred during its processing in an aqueous medium at 220–255 °C and an equilibrium vapor pressure in an autoclave. The results were compared with those of ZnO placed in a die for treatment under similar conditions supplemented with mechanical pressure application in the cold sintering process. In both cases, ZnO was treated in the presence of an activating additive: either zinc acetate or ammonium chloride. During autoclaving, a powder consisting of fine ZnO monocrystals was obtained, while the cold sintering process led to ceramics formation. Under vapor pressure and mechanical pressure, the aqueous medium affected ZnO transformation by the same mechanism of solid-phase mobility activation due to the additives’ influence. The higher the content of additives in the medium, and the higher the mechanical pressure, the more pronounced activating effect was observed. Mass transfer during the cold sintering process occurred mainly by the coalescence of crystals, while without mechanical pressure, the predominance of surface spreading was revealed. In the initial ZnO powder, the average crystal size was 0.193 μm. It grew up to 0.316–0.386 μm in a fine-crystalline powder formed in the autoclave and to an average grain size of 0.244–0.799 μm in the ceramics, which relative density reached 0.82–0.96. A scheme explaining the influence of an aqueous medium on the solid-phase mobility of ZnO structure was proposed. It was found that the addition of 7.6 mol% ammonium chloride to the reaction medium causes the processes of compaction and grain growth similar to those observed in ZnO Cold Sintering Process with the addition of 0.925 mol% zinc acetate.

Equilibrium vapor pressure properties for absorbent and adsorbent materials

• Vapor pressure correlations compiled for 38 refrigerants and 262 working pairs. • Refrigerants include water, ammonia, CO 2 , alcohols, HFCs, HFOs, and hydrocarbons. • Generalized vapor pressure functional forms enable cross comparisons. • Correlation valid ranges are provided where available. • An enabling dataset for thermodynamic simulations of sorption systems. Sorption devices are important tools for the efficient utilization of fuels and waste heat. Amid a tremendous diversity of cycles and applications, all sorption systems have an equilibrium vapor pressure that depends on the sorbent temperature and composition. The vapor pressure properties of working fluids are reported in the literature in a variety of ways, which impedes wide-ranging cross comparisons or screening studies for novel applications. This work compiles equilibrium vapor pressure properties for 123 liquid absorbents with 31 absorbates and 139 solid adsorbents with 16 adsorbates. The adsorption pairs are represented with six functional forms. Most of the absorption pairs are represented with 10 functional forms, plus several that are represented with custom empirical equations. Because the functional forms used in the literature vary widely, in this work each functional form was generalized. This paper is designed to facilitate comparisons of working fluid properties for screening studies, provide a quick reference to existing research, and present a framework for standardizing the reportage of vapor pressure equilibrium data for existing and future working pairs.

Thermodynamic optimization of the As–S system

Literature review, critical assessment and thermodynamic modeling of the liquid and solid phases in the As–S system are presented. A set of optimized model parameters was obtained to reproduce previously published experimental data. The literature data included enthalpies of formation, heat capacity, vapor pressure and phase equilibrium data. A significant discrepancy among different sets of literature data was revealed. The model for the liquid phase was developed within the framework of the Modified Quasichemical Model (MQM) in pair approximation. The resulting set of model parameters was merged and tested within a larger multicomponent thermodynamic database for pyrometallurgical copper, lead and recycling industrial operations.

Discussion on Water Condensation in Membrane Pores during CO2 Absorption at High Temperature.

Water condensation is a possible cause of membrane wetting in the operation of membrane contactors, especially under high-temperature conditions. In this study, water condensation in pores of polytetrafluoroethylene (PTFE) hollow fiber membranes was investigated during high-pressure CO2 absorption around 70 °C. It was found that the liquid accumulation rate in the treated gas knock-out drum was constant during continuous operation for 24 h when all experimental conditions were fixed, indicating a stable degree of membrane wetting. However, as the operating parameters were changed, the equilibrium vapor pressure of water within membrane pores could change, which may result in a condensation-conducive environment. Water condensation in membrane pores was detected and proven indirectly through the increase in liquid accumulation rate in the treated gas knock-out drum. The Hagen–Poiseuille equation was used to correlate the liquid accumulation rate with the degree of membrane wetting. The degree of membrane wetting increased significantly from 1.8 × 10−15 m3 to 3.9 × 10−15 m3 when the feed gas flow rate was reduced from 1.45 kg/h to 0.40 kg/h in this study due to water condensation in membrane pores. The results of this study provide insights into potential operational limitations of membrane contactor for CO2 absorption under high-temperature conditions.

Survey of Cryogenic Nitrogen Thermomechanical Property Data Relevant to Outer Solar System Bodies

AbstractThe outer Solar System has many bodies of interest that have continued to captivate the planetary science community, recently Triton, a captured Kuiper belt object (KBO) of Neptune, and Pluto. Limited fly‐by observational data shows evidence that nitrogen is the dominant constituent on these two bodies, potentially also existing on other KBOs as well. Current simulations related to answering fundamental science questions and also to develop future mission science packages and vehicles require accurate, reliable thermodynamic, and mechanical property data of solid and gaseous nitrogen at relevant surface and atmospheric conditions. This paper thus presents an exhaustive review of all available experimental N2 property data dating back to 1887. Each historical study is systematically analyzed and summarized and then the consolidated database is assembled. Comments are made on the validity of data sets, with an emphasis on specific heat capacity at constant pressure and constant volume (CP, Cv), thermal conductivity (κ), volume thermal expansion (αV), density (ρ), equilibrium vapor pressure (Pvap), heat of sublimation (ΔHS), heat of transition (ΔHT), Gruneisen parameter (γG), adiabatic and isothermal compressibility (xS, xT) and moduli of elasticity (C11, C12, C13, C33, C44). Results here can be used directly and immediately to perform new simulations on N2‐based bodies as well as to determine gaps in the consolidated database for future experiments.

Effect of deep eutectic solvents based on choline chloride on the thermodynamic and transport properties of D-fructose in aqueous solution

In this work, the effect of some deep eutectic solvents (DESs) based on choline chloride on the thermodynamic and transport properties of D-fructose in aqueous solutions was investigated. Using the vapor-liquid equilibrium (VLE) data, water activity (aw), osmotic coefficient and vapor pressure data were obtained. The performance of different local composition models such as Wilson, e-NRTL, and UNIQUAC for correlating of these data have been examined. The calculated negative values of Gibbs free energies of transfer (ΔGtri) indicate favorable interaction of DESs with D-fructose. Further, the standard partial molar volumes Vφ0, partial molar isentropic compressibility Kφ0, viscosity B-coefficient and molar refractions RD for the solutions have been calculated from the measured density and speed of sound, viscosity and refractive index data at T = (288.15 to 318.15) K. Interaction volume Vint and cavity volume Vcav have been computed from scaled particle theory (SPT) to probe solute-solvent interactions. The viscosity B-coefficients was used to discuss structure-making tendency of the solutions studied.

A Novel Framework to Study Trace Gas Transport in Deep Convective Clouds

AbstractDeep convective clouds reach the upper troposphere (8–15 km height). In addition to moisture and aerosol particles, they can bring aerosol precursor gases and other reactive trace gases from the planetary boundary layer to the cloud top. In this paper, we present a method to estimate trace gas transport based on the analysis of individual air parcel trajectories. Large eddy simulation of an idealized deep convective cloud was used to provide realistic environmental input to a parcel model. For a buoyant parcel, we found that the trace gas transport approximately follows one out of three scenarios, determined by a combination of the equilibrium vapor pressure (containing information about water‐solubility and pure component saturation vapor pressure) and the enthalpy of vaporization. In one extreme, the trace gas will eventually be completely removed by precipitation. In the other extreme, there is almost no vapor condensation on hydrometeors and most of the gas is transported to the top of the cloud. The scenario in between these two extremes is also characterized by strong gas condensation, but a small fraction of the trace gas may still be transported aloft. This approach confirms previously suggested patterns of inert trace gas behavior in deep convective clouds, agrees with observational data, and allows estimating transport in analytically simple and computationally efficient way compared to explicit cloud‐resolving model calculations.