Experimental study and correlations for heat and mass transfer coefficients in the dehumidifier of a frost-free heat pump system

Su, Wei; Li, Weihao; Sun, Bo; Zhang, Xiaosong

doi:10.1016/j.ijheatmasstransfer.2018.11.078

Cited by 25 publications

(8 citation statements)

References 36 publications

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“…The correlations of Liu et al [61] and Langoudi et al [64] for LiBr solutions had comparable Sh numbers and were higher than the other three correlations for LiCl solutions. Similarly, the other three correlations of Zhang et al [63], Su et al [65] and Varela et al [66] for LiCl solutions also shared similar Sh numbers under the same conditions.…”

Section: Adiabatic Typesupporting

confidence: 59%

“…(9) Su et al correlation [65] Su et al [65] recently developed an empirical correlation for a cross-flow dehumidifier with structured packing in a frost-free heat pump system under cold winter operating conditions.…”

Section: Adiabatic Typementioning

confidence: 99%

“…Langoudi et al [64], Zhang et al [63], Su et al [65] and Varela et al [66] were compared because their form of mass transfer coefficient was easy to determine in practical application. The other correlations presented in the manuscripts, such as those of Onda et al [51] and Chuang et al [56],…”

Section: Adiabatic Typementioning

confidence: 99%

See 2 more Smart Citations

A review of correlations and enhancement approaches for heat and mass transfer in liquid desiccant dehumidification system

Wen

2019

Applied Energy

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Section: Adiabatic Typesupporting

confidence: 59%

Section: Adiabatic Typementioning

confidence: 99%

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A review of correlations and enhancement approaches for heat and mass transfer in liquid desiccant dehumidification system

Wen

2019

Applied Energy

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“…The sample was placed into the sample injector (5), and then, the equilibrium cell (7-e) was evacuated to a certain vacuum level. The three-way ball valve (6) was adjusted to connect the vacuum pump (3) with the sample injector (5), allowing the sample to be drawn into the equilibrium cell (7-e). After that, the three-way ball valve (6) was quickly closed, resulting in the disconnection of all three parts.…”

Section: Methodsmentioning

confidence: 99%

Vapor Pressure of Aqueous Solutions of Ethylene Glycol, Glycerol, and Triethylene Glycol as Working Fluids of Frost-Free Air-Source Heat Pumps at 253 to 323 K

Huang

Wang

et al. 2023

J. Chem. Eng. Data

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Organic solutions are commonly used in frost-free air-source heat pumps (FFASHPs) due to their lower corrosiveness and cost-effectiveness. However, there is a shortage of vapor pressure data for organic solutions, which is crucial for their application in FFASHPs, particularly at subzero temperatures. This paper developed an apparatus with low leakage and good insulation for measuring vapor pressure using the static method and proposed experimental procedures that included zero setting, cleaning, drying, leak hunting, rinsing, multiple degassing, recording, and remeasuring of discharged solutions. The reliability and accuracy of the apparatus and procedures were verified by comparing experimental data with standard data of distilled water from 278 to 323 K and pure n-heptane from 253 to 303 K. The equilibrium vapor pressures of three organic solutions, namely, aqueous solutions of ethylene glycol, glycerol, and triethylene glycol, commonly utilized in FFASHPs, were measured in a temperature range of 253 to 323 K and a concentration range of 0 to 54.5 wt %. A total of 199 data points were obtained, ranging from 0.0858 to 12.3990 kPa, and fitted using modified Antoine equations, with temperature and concentration serving as independent factors. The mean absolute relative deviations between the experimental and calculated data were determined to be 1.48, 2.35, and 2.13% for aqueous solutions of ethylene glycol, glycerol, and triethylene glycol, respectively. The study’s findings provide crucial data and equations for the three organic solutions employed in FFASHPs.

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“…Passive measures include mechanical modifications of heat exchang-ers, the coating of surfaces with additional materials that reduce the risk of freezing and frost formation [9]. Active measures include auxiliary heaters [4], desiccant dehumidifiers [10], melting ice using a reversible gas cycle or hot gas bypass [11], as well as high and low-frequency vibrations and high voltage electromagnetic fields, etc. In addition, ASHPs come with solar thermal, photovoltaic and hybrid thermal systems integrated [12].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Frost Formation Influence on an Air Source Heat Pump Evaporator

2021

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The application of heat pumps in the heating systems of buildings in the cold or transitional season is becoming an increasingly common practice not only in Lithuania but in other countries as well. Due to the growing popularity of air-to-air or air-to-water heat pumps in the building sector, the problem of the evaporator heat exchanger freezing is also becoming more and more relevant. As the outdoor temperature drops, so does the heat pump’s coefficient of performance (COP) for heating. The freezing of the evaporator surface increases the energy consumption of the system, has a negative effect on heat exchange, distorts the normal operating cycle of the heat pump and the energy is wasted for defrosting processes. This article describes the experimental investigation of an air-to-water heat pump, presents the results obtained during the experiments and their interfaces. The experiments were carried out during the transitional/cold season. It was found that frost formation on the evaporator started when the outdoor temperature was <3.5 °C and the relative humidity reached 88%. The defrosting cycle took an average of 5 min. The impact of the evaporator freezing on the operation and COP of the heat pump was assessed.

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Experimental study and correlations for heat and mass transfer coefficients in the dehumidifier of a frost-free heat pump system

Cited by 25 publications

References 36 publications

A review of correlations and enhancement approaches for heat and mass transfer in liquid desiccant dehumidification system

A review of correlations and enhancement approaches for heat and mass transfer in liquid desiccant dehumidification system

Vapor Pressure of Aqueous Solutions of Ethylene Glycol, Glycerol, and Triethylene Glycol as Working Fluids of Frost-Free Air-Source Heat Pumps at 253 to 323 K

Experimental Investigation of Frost Formation Influence on an Air Source Heat Pump Evaporator

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