A dehumidifier for dehumidification system of Thailand climate condition cooperated desiccant coating technical with thermoelectric

Abstract

Bagasse ash is an agricultural waste product of sugar cane and a natural silica source that is highly available, safe to humans, and cost-effective. We choose to use bagasse ash as the primary material in this study. The objectives of this study were to prepare mesoporous silica from bagasse ash (MS-BA). Nitrogen sorption findings revealed that the specific surface area and pore volume of prepared MS-BA increased with increasing NaOH concentration, peaking at 2.0 N and decreasing afterward. The specific surface area, pore volume, and pore size of the MS-BA with 2.0 N NaOH concentration are 525 m2 g-1, 0.61 cm3 g-1, and 15 nm, respectively. The obtained MS-BA particles were spherical-shaped nanoparticles ranging 50 to 100 nm in diameter.

Aqueous salt solutions (LiCl) were impregnated into a porous host matrix to create composite desiccant materials (silica gel). The authors of this paper fabricated and analyzed composite desiccant-coated aluminum sheets (DCAS) with varying LiCl mass concentrations. Nitrogen sorption results revealed that the Brunauer-Emmett-Teller (BET) surface area and pore volume of the composite desiccant-coated aluminum sheets decreased. Furthermore, composite DCAS had lower nitrogen sorption than silica gel-coated aluminum sheets (SGCAS). According to the results, the composite DCAS had the highest thermal conductivity, measuring 6.1 Wm-1 K-1, doubling that of the SGCAS. For evaluating sorption kinetics, the linear driving force model (LDF) was used, and composite DCAS showed greater dynamic sorption quantities and sorption rate coefficients than SGCAS. Furthermore, three different moisture sorption isotherm models were used to fit the experimental results: the Brunauer-Emmett-Teller (BET) model, the Guggenheim-Anderson-Boer (GAB) model, and the double log polynomial (DLP) model. The DLP model was shown to be the best model for predicting the moisture sorption isotherms of DCAS. Additionally, the composite desiccant-coated heat sink (DCHS) of the thermoelectric dehumidifier (TED) was evaluated and compared to silica gel in terms of dehumidification capacity. According to the findings, the outlet air humidity ratio of the composite DCHS reached a minimum of 10.23 g kg-1, and the dehumidification capacity was 0.117 kg h-1 when the input electrical voltage was kept at 9 V.

The purpose of this study was to investigate the application of thermoelectric (TE) technology to a dehumidifying device as a method of decreasing the heat load on conventional vapor-compression refrigeration systems. The experimental prototype of the thermoelectric dehumidifier (TED) was constructed and its working performance was evaluated experimentally with and without a composite coated heat sink. Experiments were conducted to investigate the effects of input electrical voltage on the TE modules and the air flow rate through the heat sink. The cooling capacity increased with the increase in electrical voltage, reaching a maximum of 100.78 W and the corresponding COP is 0.79 at 12 V. On the other hand, the cooling capacity, decreased as the air flow rate increased. At all electrical voltages supplied to the TE modules, the dehumidification capacity of the TED with the composite desiccant was higher than without the composite desiccant (34.44%). As a result, it is anticipated that the suggested TED with the composite desiccant concept will contribute to the reduction in room humidity.

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