scholarly journals Dehumidification performance investigation of run-around membrane energy exchanger system

2016 ◽  
Vol 20 (6) ◽  
pp. 1927-1938 ◽  
Author(s):  
Miklos Kassai ◽  
Gaoming Ge ◽  
Carey Simonson
Keyword(s):  
Salt Solution ◽  
Moisture Transfer ◽  
Heat And Moisture Transfer ◽  
Solution Flow ◽  
Permeable Membrane ◽  
Air Temperatures ◽  
Air Stream ◽  
Membrane Energy ◽  
Air Conditioning Systems ◽  
Heat And Moisture

Liquid-to-air membrane energy exchanger is a novel membrane base energy exchanger, which allows both heat and moisture transfer between air and a salt solution. It uses semi-permeable membrane to eliminate entrainment of liquid desiccant as aerosols in air stream and allow simultaneous heat and moisture transfer between salt solution flow and airflow. The heat and mass transfer performance of a single liquid-to-air membrane energy exchanger is significantly dependent on two dimensionless parameters. They are the number of heat transfer units (NTU) and the ratio of heat capacity rates between solution flow and air flow (Cr*). The liquid-to-air membrane energy exchangers can also be applied in a run-around membrane energy exchanger system, which is mainly comprised of two liquid-to-air membrane energy exchangers and a closed loop of aqueous desiccant solution and used as a passive energy recovery system to recover the energy (both heat and moisture) from the exhaust air to precondition the supply air in air conditioning systems. In this study the dehumidification capacity of a run-around membrane energy exchanger is investigated numerically at different exhaust air temperatures and Cr* values. Increasing the exhaust air temperature or the Cr* would enhance the dehumidification capacity of the a run-around membrane energy exchanger system under Cr*?1, but the improvement is limited. The dehumidification capacity at low Cr* is much lower than that under the optimal Cr* value (Cr*=3.2) where the maximum latent effectiveness is obtained.

Steady-State Performance of a Prototype (200 cfm) Liquid-to-Air Membrane Energy Exchanger (LAMEE) Under Summer and Winter Test Conditions

2013 ◽  
Author(s):  
Davood Ghadiri Moghaddam ◽  
Gazi Mahmood ◽  
Gaoming Ge ◽  
John Bolster ◽  
Robert W. Besant ◽  
...  
Keyword(s):  
Steady State ◽  
Salt Solution ◽  
Air Conditioning ◽  
Winter Conditions ◽  
Test Conditions ◽  
Membrane Energy ◽  
Air Conditioning Systems ◽  
New Generation ◽  
Heat And Moisture ◽  
Steady State Performance

Liquid-to-air membrane energy exchangers (LAMEEs) are a new generation of energy exchangers in air-conditioning systems to transfer both heat and moisture. In this paper, the performance of a 200 cfm LAMEE is numerically and experimentally investigated under summer and winter test conditions when Lithium Chloride (LiCl) is used as a salt solution in the exchanger. The results show that the LAMEE has almost the same total effectiveness at summer and winter conditions, but the latent effectiveness of the LAMEE is higher at the summer conditions. Also, the agreement between the experimental and numerical results is acceptable for all the tests, and they are within their uncertainty ranges except for the latent effectiveness of the LAMEE tested under winter test conditions.

scholarly journals Application Method of a Simplified Heat and Moisture Transfer Model of Building Construction in Residential Buildings

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4180
Author(s):  
Joowook Kim ◽  
Michael Brandemuehl
Keyword(s):  
Latent Heat ◽  
Moisture Transfer ◽  
Residential Buildings ◽  
Building Energy ◽  
The United States ◽  
Building Envelope ◽  
Outdoor Environment ◽  
Transfer Model ◽  
Heat And Moisture Transfer ◽  
Heat And Moisture

Several building energy simulation programs have been developed to evaluate the indoor conditions and energy performance of buildings. As a fundamental component of heating, ventilating, and air conditioning loads, each building energy modeling tool calculates the heat and moisture exchange among the outdoor environment, building envelope, and indoor environments. This paper presents a simplified heat and moisture transfer model of the building envelope, and case studies for building performance obtained by different heat and moisture transfer models are conducted to investigate the contribution of the proposed steady-state moisture flux (SSMF) method. For the analysis, three representative humid locations in the United States are considered: Miami, Atlanta, and Chicago. The results show that the SSMF model effectively complements the latent heat transfer calculation in conduction transfer function (CTF) and effective moisture penetration depth (EMPD) models during the cooling season. In addition, it is found that the ceiling part of a building largely constitutes the latent heat generated by the SSMF model.

Simultaneous determination of thickness, thermal conductivity and porosity in textile material design

2016 ◽  
Vol 24 (1) ◽  
Author(s):  
Dinghua Xu ◽  
Peng Cui
Keyword(s):  
Thermal Conductivity ◽  
Human Body ◽  
Moisture Transfer ◽  
Least Squares Method ◽  
Weighted Least Squares ◽  
Optimal Solution ◽  
Comfort Level ◽  
Textile Material ◽  
Heat And Moisture Transfer ◽  
Heat And Moisture

AbstractThe thickness, thermal conductivity and porosity of textile material are three key factors which determine the heat-moisture comfort level of the human body to a large extent based on the heat and moisture transfer process in the human body-clothing-environment system. This paper puts forward an Inverse Problem of Textile Thickness-Heat conductivity-Porosity Determination (IPT(THP)D) based on the steady-state model of heat and moisture transfer and the heat-moisture comfort indexes. Adopting the idea of the weighted least-squares method, we formulate IPT(THP)D into a function minimization problem. We employ the Particle Swarm Optimization (PSO) method to stochastically search the optimal solution of the objective function. We put the optimal solution into the corresponding direct problem to verify the effectiveness of the proposed numerical algorithms and the validity of the IPT(THP)D.

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