Membrane transport property effects on moisture condensation of a membrane-type total heat exchanger

doi:10.11949/0438-1157.20200679

Abstract

Abstract:

Membrane-type total heat exchanger (THX) is a device that can recover both heat and moisture, it is often used to reduce the building energy consumption and improve the indoor air quality. The effects of membrane transport properties on the moisture condensation of a THX has been numerically studied, the condensation characteristics curves and the critical condensation temperature are obtained to represent the moisture condensation characteristics, and the optimal membrane properties are recommended based on the combined consideration of safety and economy. The results show that the higher the outdoor air temperature and relative humidity, the more likely the moisture condensation takes place. The membrane thermal conductivity has a slight influence on the condensation characteristics and performance of the THX, the increase of the in-membrane moisture diffusivity can significantly improve the anti-condensation characteristics and effectiveness of the THX, with the moisture condensation occurring more easily at the membrane surfaces at the junction of the supply outdoor and exhaust indoor airstreams.

Key words: membrane-type total heat exchanger, membrane transport property, moisture condensation, heat transfer, mass transfer, numerical simulation

摘要：

薄膜式全热交换器是一种可同时回收热量和湿量的装置，通常被用来减少建筑能耗同时改善室内空气品质。数值研究了薄膜输运性质对全热交换器结露特性的影响，得到了结露特性曲线和临界结露温度，用以表征结露特性，并综合考虑安全性和经济性给出了薄膜输运参数的推荐值。研究结果表明：室外空气温度和湿度越高，越容易发生结露，薄膜热导率对全热交换器的结露特性和效能影响很小，而膜内水蒸气扩散系数的增加可以显著提高全热交换器的抗结露特性和效能，且进气侧与排气侧的入口交汇处最容易发生结露。

关键词: 薄膜式全热交换器, 膜输运性质, 结露, 传热, 传质, 数值模拟

CLC Number:

TK 172

Zhijie SHEN, Jingchun MIN. Membrane transport property effects on moisture condensation of a membrane-type total heat exchanger[J]. CIESC Journal, 2020, 71(S2): 32-38.

沈志杰, 闵敬春. 薄膜输运性质对全热交换器结露特性影响[J]. 化工学报, 2020, 71(S2): 32-38.

Figures/Tables 7

Fig.1 Physical model of THX

Table 1 THX core dimensions and membrane parameters

参数	数值
换热芯结构
x_F, y_F/m	0.25
d/mm	2
N	180
δ/mm	0.25
薄膜物性
λ_m/(W/(m·K))	0.1~0.3
D_wm/(kg/(m·s))	1.0×10^-7~5.0×10^-7
C	2.5
w_max/(kg/kg)	0.25

Fig.2 Moisture condensation for different membrane thermal conductivities

Fig.3 Effectiveness of THX for different membrane thermal conductivities

Fig.4 Moisture condensation for different membrane moisture diffusivities

Fig.5 Effectiveness of THX for different membrane moisture diffusivities

Fig.6 Relative humidity contours at membrane surfaces for different membrane materials

References 30

1	辛焰. 浅谈室内环境污染及对健康危害[J]. 环境技术, 2003, (3): 11-13, 10.
	Xin Y. Study of harm of indoor air pollution on human health [J]. Environment Technology, 2003, (3): 11-13, 10.
2	朱蓓丽, 程秀莲, 黄修长. 环境工程概论[M]. 4版. 北京: 科学出版社, 2016: 112-116.
	Zhu B L, Cheng X L, Huang X C. Introduction to Environmental Engineering [M]. 4th ed. Beijing: Science Press, 2016: 112-116.
3	张宁, 张立志. 膜式热湿调控原理与技术进展[J]. 科学通报, 2015, 60(18): 1678-1689.
	Zhang N, Zhang L Z. Membrane-based heat and moisture control: progress on theory and technology [J]. Chinese Science Bulletin, 2015, 60(18): 1678-1689.
4	Zhang L Z, Niu J L. Effectiveness correlations for heat and moisture transfer processes in an enthalpy exchanger with membrane cores [J]. Journal of Heat Transfer-Transactions of the ASME, 2002, 124(5): 922-929.
5	Kassai M, Ge G M, Simonson C J. Dehumidification performance investigation of run-around membrane energy exchanger system [J]. Thermal Science, 2016, 20(6): 1927-1938.
6	苏铭. 膜吸附传递理论及薄膜式全热换热器性能分析[D].北京: 清华大学, 2006.
	Su M. Membrane adsorption theory and analysis of performance of membrane-type total heat exchanger [D]. Beijing: Tsinghua University, 2006.
7	Min J C, Duan J F. Comparison of various methods for evaluating the membrane-type total heat exchanger performance [J]. International Journal of Heat and Mass Transfer, 2016, 100: 758-766.
8	Min J C, Duan J F. Membrane-type total heat exchanger performance with heat and moisture transferring in different directions across membranes [J]. Applied Thermal Engineering, 2015, 91: 1040-1047.
9	Al-Waked R, Nasif M S, Mostafa D B. Enhancing the performance of energy recovery ventilators [J]. Energy Conversion and Management, 2018, 171: 196-210.
10	Li Z X, Zhong T S, Niu J L, et al. Conjugate heat and mass transfer in a total heat exchanger with cross-corrugated triangular ducts and one-step made asymmetric membranes [J]. International Journal of Heat and Mass Transfer, 2015, 84: 390-400.
11	Sharqawy M H, Zubair S M. Efficiency and optimization of straight fins with combined heat and mass transfer — an analytical solution [J]. Applied Thermal Engineering, 2008, 28(17): 2279-2288.
12	Turkyilmazoglu M. Efficiency of heat and mass transfer in fully wet porous fins: exponential fins versus straight fins [J]. International Journal of Refrigeration, 2014, 46: 158-164.
13	Zhang L Z, Niu J L. Energy requirements for conditioning fresh air and the long-term savings with a membrane-based energy recovery ventilator in Hong Kong [J]. Energy, 2001, 26(2): 119-135.
14	Nasif M S, Al-Waked R, Behnia M, et al. Air to air fixed plate enthalpy heat exchanger, performance variation and energy analysis [J]. Journal of Mechanical Science and Technology, 2013, 27(11): 3541-3551.
15	Liu P, Alonso M J, Mathisen H M, et al. Energy transfer and energy saving potentials of air-to-air membrane energy exchanger for ventilation in cold climates [J]. Energy and Buildings, 2017, 135: 95-108.
16	Guo Z Y, Zhou S Q, Li Z X, et al. Theoretical analysis and experimental confirmation of the uniformity principle of temperature difference field in heat exchanger [J]. International Journal of Heat and Mass Transfer, 2002, 45(10): 2119-2127.
17	Guo J F, Huai X L, Cheng K Y, et al. The effects of nonuniform inlet fluid conditions on crossflow heat exchanger [J]. International Journal of Heat and Mass Transfer, 2018, 120: 807-817.
18	Koester S, Falkenberg M, Logemann M, et al. Modeling heat and mass transfer in cross-counterflow enthalpy exchangers [J]. Journal of Membrane Science, 2017, 525: 68-76.
19	Dugaria S, Moro L, Del Col D. Modelling heat and mass transfer in a membrane-based air-to-air enthalpy exchanger [C]// 33rd Uit (Italian Union of Thermo-Fluid Dynamics) Heat Transfer Conference. 2015, 655: 012035.
20	Vali A, Simonson C J, Besant R W, et al. Numerical model and effectiveness correlations for a run-around heat recovery system with combined counter and cross flow exchangers [J]. International Journal of Heat and Mass Transfer, 2009, 52(25/26): 5827-5840.
21	Lee E J, Lee J P, Sim H M, et al. Modeling and verification of heat and moisture transfer in an enthalpy exchanger made of paper membrane [J]. International Journal of Air-Conditioning and Refrigeration, 2012, 20(3): 1250015.
22	Lee E J, Lee J P, Kim N H. Moisture transfer characteristics of a LiCl-impregnated paper membrane used for an enthalpy exchanger [J]. Journal of Mechanical Science and Technology, 2013, 27(5): 1527-1537.
23	Duan J F, Min J C. Membrane-type total heat exchanger performance simulation with consideration of thermal entrance effect [J]. Journal of Physics: Conference Series, 2017, 891: 012126.
24	Zheng W, Worek W M. Numerical-simulation of combined heat and mass-transfer processes in a rotary dehumidifier [J]. Numerical Heat Transfer Part A - Applications, 1993, 23(2): 211-232.
25	Wang L N, Min J C. Thermodynamic analysis of adsorption process at a non-equilibrium steady state [J]. Chinese Science Bulletin, 2010, 55(31): 3619-3625.
26	Incropera F P. Fundamentals of Heat and Mass Transfer [M]. New York: Wiley, 1981: 139-162.
27	Shah R K, London A L, White F M. Laminar flow forced convection in ducts [J]. Journal of Fluids Engineering, 1980, 102(2): 431-455.
28	Kuehn T H, Ramsey J W, Threkeld J L. Themal Environmental Engineering [M]. NJ: Prentice Hall, 1998: 246.
29	Simonson C J, Besant R W. Energy wheel effectiveness (I): Development of dimensionless groups [J]. International Journal of Heat Mass Transfer, 1999, 42(12): 2161-2170.
30	Struchtrup H. Thermodynamics and Energy Conversion [M]. Heidelberg, Berlin: Springer, 2014: 433-453.

[1]	Jiahao SONG, Wen WANG. Study on coupling operation characteristics of Stirling engine and high temperature heat pipe [J]. CIESC Journal, 2023, 74(S1): 287-294.
[2]	Siyu ZHANG, Yonggao YIN, Pengqi JIA, Wei YE. Study on seasonal thermal energy storage characteristics of double U-shaped buried pipe group [J]. CIESC Journal, 2023, 74(S1): 295-301.
[3]	Jingwei CHAO, Jiaxing XU, Tingxian LI. Investigation on the heating performance of the tube-free-evaporation based sorption thermal battery [J]. CIESC Journal, 2023, 74(S1): 302-310.
[4]	Cheng CHENG, Zhongdi DUAN, Haoran SUN, Haitao HU, Hongxiang XUE. Lattice Boltzmann simulation of surface microstructure effect on crystallization fouling [J]. CIESC Journal, 2023, 74(S1): 74-86.
[5]	Zhanyu YE, He SHAN, Zhenyuan XU. Performance simulation of paper folding-like evaporator for solar evaporation systems [J]. CIESC Journal, 2023, 74(S1): 132-140.
[6]	Shuangxing ZHANG, Fangchen LIU, Yifei ZHANG, Wenjing DU. Experimental study on phase change heat storage and release performance of R-134a pulsating heat pipe [J]. CIESC Journal, 2023, 74(S1): 165-171.
[7]	Yifei ZHANG, Fangchen LIU, Shuangxing ZHANG, Wenjing DU. Performance analysis of printed circuit heat exchanger for supercritical carbon dioxide [J]. CIESC Journal, 2023, 74(S1): 183-190.
[8]	Aiqiang CHEN, Yanqi DAI, Yue LIU, Bin LIU, Hanming WU. Influence of substrate temperature on HFE7100 droplet evaporation process [J]. CIESC Journal, 2023, 74(S1): 191-197.
[9]	Mingxi LIU, Yanpeng WU. Simulation analysis of effect of diameter and length of light pipes on heat transfer [J]. CIESC Journal, 2023, 74(S1): 206-212.
[10]	Zhiguo WANG, Meng XUE, Yushuang DONG, Tianzhen ZHANG, Xiaokai QIN, Qiang HAN. Numerical simulation and analysis of geothermal rock mass heat flow coupling based on fracture roughness characterization method [J]. CIESC Journal, 2023, 74(S1): 223-234.
[11]	Yitong LI, Hang GUO, Hao CHEN, Fang YE. Study on operating conditions of proton exchange membrane fuel cells with non-uniform catalyst distributions [J]. CIESC Journal, 2023, 74(9): 3831-3840.
[12]	Yubing WANG, Jie LI, Hongbo ZHAN, Guangya ZHU, Dalin ZHANG. Experimental study on flow boiling heat transfer of R134a in mini channel with diamond pin fin array [J]. CIESC Journal, 2023, 74(9): 3797-3806.
[13]	Cong QI, Zi DING, Jie YU, Maoqing TANG, Lin LIANG. Study on solar thermoelectric power generation characteristics based on selective absorption nanofilm [J]. CIESC Journal, 2023, 74(9): 3921-3930.
[14]	Ke LI, Jian WEN, Biping XIN. Study on influence mechanism of vacuum multi-layer insulation coupled with vapor-cooled shield on self-pressurization process of liquid hydrogen storage tank [J]. CIESC Journal, 2023, 74(9): 3786-3796.
[15]	Song HE, Qiaomai LIU, Guangshuo XIE, Simin WANG, Juan XIAO. Two-phase flow simulation and surrogate-assisted optimization of gas film drag reduction in high-concentration coal-water slurry pipeline [J]. CIESC Journal, 2023, 74(9): 3766-3774.