| AEROSPACE AND ENGINEERING MECHANICS |
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Numerical study on influence of supply inlet air parameter distribution on a membrane-type total heat exchanger |
| SHEN Zhijie1, MIN Jingchun1, DUAN Jiangfei2 |
1. School of Aerospace Engineering, Tsinghua University, Beijing 100084, China;
2. China Academy of Aerospace Aerodynamics, Beijing 100074, China |
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Abstract Membrane-type total heat exchangers (THX) are air-to-air heat exchangers with a core made of a water vapor permeable membrane that transfers both heat and moisture. These heat exchangers are often used to reduce building energy consumption and improve indoor air quality. However, non-uniform internal channel structures and external disturbances can lead to maldistributions of the supply inlet air parameters into the heat exchanger. This research numerically examines the effects of various supply inlet air parameter variations on the heat and moisture transfer characteristics, including linear and parabolic distributions of the inlet air temperature, moisture ratio and velocity. The model then simulates the heat and mass transfer in the heat exchanger to predict the temperature, moisture and enthalpy effectiveness distributions as well as the temperature difference and humidity ratio difference contours between the two sides of the membrane for the various inlet conditions. The results show that the linear distribution significantly affects the effectiveness while the parabolic distribution has little effect, with both affecting the temperature difference and humidity ratio difference contours between the two sides of the membrane. The heat transfer and the mass transfer affect each other, with the heat transfer having only a weak effect on the mass transfer. More nonuniform supply inlet air temperature and moisture ratio distributions increase the probability that the heat and mass transfer will be in opposite directions, which reduces both the heat and mass transfer.
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| Keywords
supply inlet air parameter
linear distribution
parabolic distribution
heat and mass transfer
effectiveness
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Issue Date: 31 August 2020
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2020,
Vol. 60
