Detection of crystallization fouling in a liquid-to-air membrane energy exchanger

Olufade, Adesola Oluwasijibomi; Simonson, Carey J.

doi:10.1016/j.expthermflusci.2017.10.017

Cited by 12 publications

(7 citation statements)

References 44 publications

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“…Schematic of the test facility. 69 Note: The schematic consists of the (a) upstream section, LAMEE, and downstream section of the test facility, (b) side-view cross-section of the LAMEE, and (c) arrangement of perforated holes on the inner pipe of the LAMEE. The diagrams are not drawn to scale.…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, holes are drilled into the inner pipe of the LAMEE to facilitate the exchange of moisture between the air stream and desiccant solution (see Figure 3c). The operational procedure of the test facility and the details of its instrumentation, uncertainty analysis, and mass and energy balances are documented in ref (69).…”

Section: Methodsmentioning

confidence: 99%

“…66−68 However, crystals may precipitate from the desiccant solution and accumulate within the membrane and degrade the performance of the LAMEE. 69…”

Section: Introductionmentioning

confidence: 99%

“…66−68 However, crystals may precipitate from the desiccant solution and accumulate within the membrane and degrade the performance of the LAMEE. 69 In a recent study by the authors, 69 the rate of moisture transfer through the membrane was identified as a key parameter that influences the likelihood of crystallization fouling in LAMEEs. However, the effect of moisture-transfer rate on the evolution of crystallization fouling in membranes was not assessed in the same study.…”

Section: Introductionmentioning

confidence: 99%

“…The membrane exchanger studied in this paper is called a liquid-to-air membrane energy exchanger (LAMEE). Unlike conventional heat exchangers that can only transfer heat between fluid streams, the LAMEE can transfer heat and moisture between air and liquid desiccant streams using a semipermeable membrane. − However, crystals may precipitate from the desiccant solution and accumulate within the membrane and degrade the performance of the LAMEE …”

Section: Introductionmentioning

confidence: 99%

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Characterization of the Evolution of Crystallization Fouling in Membranes

Olufade

Simonson

2018

ACS Omega

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Liquid-to-air membrane energy exchangers (LAMEEs) are promising in heating, ventilating, and air-conditioning applications because they are able to use semipermeable membranes to transfer heat and moisture between air and liquid desiccant streams. However, the development of crystallization fouling in membranes may pose a great risk to the long-term performance of LAMEEs. The main aim of this paper is to characterize the evolution of crystallization fouling in membranes through the use of both noninvasive and invasive methods. Noninvasive methods are used to study the development of fouling in the LAMEE by monitoring the changes in moisture flux through the membrane and overall moisture-transfer resistance of the LAMEE. On the other hand, invasive methods are implemented to characterize fouled membranes by using optical microscopy and scanning electron microscopy (SEM) to depict the morphology of crystal deposits and energy-dispersive X-ray spectroscopy (EDX) to identify the composition of the deposits. Experiments are performed by using air to dehydrate MgCl 2 (aq) at two operating conditions of low and high fouling rates. The results show that the moisture flux decreases and the moisture-transfer resistance increases more considerably during the test at the high fouling rate than in the test at the low fouling rate. SEM micrographs show that cake crystal deposits cover the membrane surface in the test at the high fouling rate, whereas only few crystal particles are observed on the membrane in the test at the low fouling rate. Furthermore, the crystal deposits undergo more structural changes in the tests at the high fouling rate than in the tests at the low fouling rate, possibly because of the higher moisture transfer rate through the membrane in the tests at the high fouling rate. Finally, the SEM–EDX analysis confirms that the crystal deposits primarily consist of Mg, Cl, and O elements.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…66−68 However, crystals may precipitate from the desiccant solution and accumulate within the membrane and degrade the performance of the LAMEE. 69…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%