Equilibrium vapor pressure of aqueous sodium acetate and potassium acetate solutions used as working fluids in frost-free air–source heat pumps at 263–328 K

IF 2.8 3区工程技术 Q3 CHEMISTRY, PHYSICAL

Fluid Phase Equilibria Pub Date : 2024-07-28 DOI:10.1016/j.fluid.2024.114183

Hongshuo Qu , Libo Wang , Xiao Zhang , Chunwen Che , Xiaosong Zhang , Shifang Huang

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引用次数: 0

Abstract

Aqueous solutions of sodium acetate (CH₃COONa) and potassium acetate (CH₃COOK) are considered effective alternative heat exchange media for frost-free air–source heat pumps (FFASHPs) owing to the low corrosiveness, low viscosity, and low cost. Equilibrium vapor pressure is the most crucial property that characterizes freezing point and latent heat transfer. However, studies on this property, especially in subzero temperature ranges are scarce. This study was conducted to experimentally investigate the equilibrium vapor pressure of CH₃COONa and CH₃COOK solutions. The developed apparatus and procedures were based on the static method, and validated by evaluating the vapor pressure of distilled water, n-heptane, and calcium chloride (CaCl₂) aqueous solution. Their average absolute deviations were within 1.94%. As the temperature increased from 263 to 328 K and solute concentration increased from 9.27 to 33.81 wt%, 124 data points of the vapor pressure of the CH₃COONa and CH₃COOK solutions were obtained, ranging from 0.2759 to 13.2608 kPa. Modified Antoine equation and ion interaction (Pitzer) model were established for correlation of the experimental data. The average absolute deviations of the CH₃COONa and CH₃COOK solutions produced by Antoine equation were 2.08 and 2.48%, respectively. Those produced by Pitzer model further decreased to 1.36 and 1.45% due to the import of osmotic coefficient and the accuracy improvement. Furthermore, according to the experimental and calculation results, the vapor pressure of the CH₃COONa solution was lower than that of the CH₃COOK solution. Therefore, under the same antifreezing conditions, the CH₃COONa solution facilitates latent heat absorption from ambient air, while the CH₃COOK solution is conducive to achieve regeneration. The results of this study provide foundational data for the vapor pressure of the two solutions and can promote their application in FFASHPs.

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263-328 K 下用作无霜空气源热泵工作流体的醋酸钠和醋酸钾水溶液的平衡蒸气压

醋酸钠（CH3COONa）和醋酸钾（CH3COOK）水溶液由于腐蚀性低、粘度低和成本低，被认为是无霜空气源热泵（FFASHPs）的有效替代热交换介质。平衡蒸汽压是表征冰点和潜热传递的最关键特性。然而，有关这一特性的研究很少，尤其是在零下温度范围内。本研究对 CH3COONa 和 CH3COOK 溶液的平衡蒸汽压进行了实验研究。所开发的仪器和程序基于静态法，并通过评估蒸馏水、正庚烷和氯化钙 (CaCl2) 水溶液的蒸气压进行了验证。它们的平均绝对偏差在 1.94% 以内。随着温度从 263 K 升高到 328 K，溶质浓度从 9.27 wt% 升高到 33.81 wt%，CH3COONa 和 CH3COOK 溶液的蒸气压得到了 124 个数据点，范围从 0.2759 到 13.2608 kPa。建立了修正的安托万方程和离子相互作用（Pitzer）模型，用于实验数据的相关性分析。安托万方程得出的 CH3COONa 和 CH3COOK 溶液的平均绝对偏差分别为 2.08% 和 2.48%。由于渗透系数的引入和精度的提高，Pitzer 模型得出的平均绝对偏差进一步降至 1.36% 和 1.45%。此外，根据实验和计算结果，CH3COONa 溶液的蒸汽压低于 CH3COOK 溶液。因此，在相同的防冻条件下，CH3COONa 溶液有利于从环境空气中吸收潜热，而 CH3COOK 溶液则有利于实现再生。本研究结果为这两种溶液的蒸汽压提供了基础数据，可促进它们在全氟汽车空调水泵中的应用。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Fluid Phase Equilibria 工程技术-工程：化工

CiteScore

5.30

自引率

15.40%

发文量

223

审稿时长

53 days

期刊介绍： Fluid Phase Equilibria publishes high-quality papers dealing with experimental, theoretical, and applied research related to equilibrium and transport properties of fluids, solids, and interfaces. Subjects of interest include physical/phase and chemical equilibria; equilibrium and nonequilibrium thermophysical properties; fundamental thermodynamic relations; and stability. The systems central to the journal include pure substances and mixtures of organic and inorganic materials, including polymers, biochemicals, and surfactants with sufficient characterization of composition and purity for the results to be reproduced. Alloys are of interest only when thermodynamic studies are included, purely material studies will not be considered. In all cases, authors are expected to provide physical or chemical interpretations of the results. Experimental research can include measurements under all conditions of temperature, pressure, and composition, including critical and supercritical. Measurements are to be associated with systems and conditions of fundamental or applied interest, and may not be only a collection of routine data, such as physical property or solubility measurements at limited pressures and temperatures close to ambient, or surfactant studies focussed strictly on micellisation or micelle structure. Papers reporting common data must be accompanied by new physical insights and/or contemporary or new theory or techniques.