Theoretical analysis on heat and mass transfer in a direct evaporative cooler

Wu, Jiangbo; Huang, Xiang; Zhang, H.

doi:10.1016/j.applthermaleng.2008.05.016

Cited by 173 publications

(63 citation statements)

References 9 publications

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“…Under the constant inlet air condition, the evaporative cooler outlet air temperature increases from 19.4°C to 23.8°C and the evaporative effectiveness decreases from 0.72 to 0.37 as the cold water temperature rises from 10.0°C to 20.0°C. In this system, the cold water supplied at a lower temperature not only evidently leads to the better evaporative cooling performance [23] but also contributes to an improvement in the dehumidification performance as discussed in Section 4.1.3. …”

Section: Evaporative Cooling Performancementioning

confidence: 99%

“…The effectiveness of the direct evaporative cooling system is in the range of 70% to 90%, while the effectiveness ranges only from 40% to 60% for the indirect system. The direct evaporative cooling system adds moisture to the cooled supply air, whereas the indirect evaporative cooling system provides only sensible cooling to the supply air without any moisture being added, which is more preferred in the humid climate [23].…”

Section: Introductionmentioning

confidence: 99%

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Performance assessment of a membrane liquid desiccant dehumidification cooling system based on experimental investigations

Chen

Zhu

Bai

2017

Energy and Buildings

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A membrane-based liquid desiccant dehumidification cooling system is studied in this paper for energy efficient air conditioning with independent temperature and humidity controls. The system mainly consists of a dehumidifier, a regenerator, an evaporative cooler and an air-to-air heat exchanger. Its feasibility in the hot and humid region is assessed with calcium chloride solution, and the influences of operating variables on the dehumidifier, regenerator, evaporative cooler and overall system performances are investigated through experimental work. The experimental results indicate that the inlet air condition greatly affects the dehumidification and regeneration performances. The system regeneration temperature should be controlled appropriately for a high energy efficiency based on the operative solution concentration ratio. It is worth noting that the solution concentration ratio plays a considerable role in the system performance. The higher the solution concentration ratio, the better the dehumidification performance. However simultaneously more thermal input power is required for the solution regeneration, and a crystallization risk in the normal operating temperature range should be noted as well. The system mass balance between the dehumidifier and regenerator is crucial for the system steady operation. Under the investigated steady operating condition, the supply air temperature of 20.4°C and system COP of 0.70 are achieved at a solution concentration ratio of 36%.

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Section: Evaporative Cooling Performancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Performance assessment of a membrane liquid desiccant dehumidification cooling system based on experimental investigations

Chen

Zhu

Bai

2017

Energy and Buildings

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“…The process is 100% effective when the air is cooled to the wet-bulb temperature. The effectiveness of direct evaporative cooling systems, in terms of temperature reduction, is approximately 70-95% [10,11]. The cooling effect is as high as the moisture content of the external air is low, therefore the evaporative cooling system is very suitable for hot and temperate climates, where the humidity is usually low also in the hot season [12,13].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Evaporative Cooling Systems in Industrial Buildings

Angelis¹,

Medici²,

Saro³

et al. 2015

IJHT

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“…Due to increase in the awareness of environmental problems resulting from greenhouse emissions, various applications of evaporative cooling have been extensively studied and used for industrial and residential sectors, such as, humidifier, cooling tower and evaporative cooler [1][2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Performance of Direct Evaporative Cooling System under Egyptian Conditions

Khater¹

2014

J Climatol Weather Forecasting

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The main objective of this research is to optimize the parameters affecting the performance of the direct evaporative cooling system, to achieve that, a mathematical model of heat and mass balance of the evaporative cooling pads was developed to predict most important factors affecting the performance of the system. The model was able to predict the temperature, humidity ratio, wet bulb effectiveness, dew point effectiveness and temperaturehumidity index of outlet air at different ambient air temperatures (25, 30, 35 and 40°C), different inlet air velocities (1.5, 3, 4.5 and 6 m s -1 ), ambient air humidities (0.01, 0.02, 0.03 and 0.04 kg kg -1 ) and different lengths of pad (0.5, 1.0, 1.5 and 2.0 m). The results showed that the outlet temperature increases with increasing ambient temperature, inlet air velocity, ambient air humidities and lengths of pad. The results also showed that the wet bulb effectiveness ranged from 0.927 to 1.086. The dew point effectiveness ranged from 0.561 to 0.747. The humidity ratio ranged from 0.027 to 0.035 kg kg -1 . The temperature-humidity index ranged from 21.15 to 33.56°C on study treatments. The predicted outlet temperatures were in a reasonable agreement with those measured, where, it ranged 17.027 to 29.978°C theoretically while it was from 19.605 to 30.748°C experimentally. The prediction of temperature determines the optimum condition of plant growth in greenhouse, so that the model helps this optimization.

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Theoretical analysis on heat and mass transfer in a direct evaporative cooler

Cited by 173 publications

References 9 publications

Performance assessment of a membrane liquid desiccant dehumidification cooling system based on experimental investigations

Performance assessment of a membrane liquid desiccant dehumidification cooling system based on experimental investigations

Evaluation of Evaporative Cooling Systems in Industrial Buildings

Performance of Direct Evaporative Cooling System under Egyptian Conditions

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