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Abstract
The structured packing has been widely used in the liquid desiccant systems due to low air pressure drop and large heat and mass transfer area. However, the structured packing is usually expensive and poor in mass transfer against the random packing. In order to provide the cost-effective structured packing with excellent mass transfer performance, Z-type packing made of gauze is proposed and designed in this article. The dehumidification and regeneration performance of the proposed packing are tested experimentally under summer conditions. It is found that the Z-type packing has excellent dehumidification performance with the mass transfer coefficient ranging from 6.5 to 14.2 g/m2s, about 70% higher than the corrugated cellulose packing and the plant fiber packing on average. Although the novel packing is lower in the moisture removal rate and the dehumidification efficiency, it could be made more tightly by shortening the distance between gauze sheets to overcome the shortcoming. The regeneration performance of the Z-type packing is also comparable with the plant fiber packing. The economic analysis is further conducted and it verifies the low cost of the Z-type packing under the same moisture removal/evaporation rate. The proposed packing is expected to be an alternative to the existing packings.
Nomenclature
| A | = | mass transfer area, m2 |
| hd | = | mass transfer coefficient, kg/m2s |
| hc | = | heat transfer coefficient, kW/ m2oC |
| Ma | = | air mass flow rate, kg/s |
| Ms | = | solution mass flow rate, kg/s |
| Md | = | moisture removal rete, kg/s |
| Mr | = | moisture evaporation rate, kg/s |
| p | = | pressure, Pa |
| ta | = | air temperature, oC |
| ts | = | solution temperature, oC |
| va | = | air velocity, m/s |
| wa | = | air humidity ratio, kg/kg |
| we | = | air humidity ratio in equilibrium with solution, kg/kg |
| Xs | = | concentration in salt,% |
Greek letters
| ϵ | = | column efficiency |
Subscripts
| d | = | dehumidification |
| r | = | regeneration |
| i | = | inlet |
| o | = | outlet |
| FDM | = | finite difference model |
| SIC | = | specific initial cost |