Going below the wet-bulb temperature by indirect evaporative cooling: Analysis using a modified ε-NTU method

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Abstract

The objective of this paper is to study a method to achieve sub-wet bulb temperature by indirect evaporative cooling of air (without using a vapor compression machine). For this purpose, an analytical model is developed based on the effectiveness-NTU method (ε-NTU). The main idea for achieving a sub-wet bulb temperature by indirect evaporative cooling of air is by indirectly pre-cooling the working air before it enters the wet passage. It is shown that a modified analytical model for indirect evaporative coolers could be based on the ε-NTU method for sensible heat exchangers when proper adjustments are made by redefining the potential gradients, transfer coefficient, heat capacity rate parameters and assuming a linear saturation temperature-enthalpy relation of air. This modified model is used to find the performance of a regenerative indirect evaporative cooler. The model results show very good agreement with results from experimental measurements and a numerical model.

Original languageEnglish
Pages (from-to)237-245
Number of pages9
JournalApplied Energy
Volume89
Issue number1
DOIs
Publication statusPublished - Jan 2012
MoE publication typeA1 Journal article-refereed

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Cooling
cooling
air
Air
Analytical models
temperature
Temperature
heat capacity
enthalpy
Specific heat
Heat exchangers
Numerical models
Enthalpy
Compaction
Vapors
compression
saturation
analysis
method
rate

Keywords

  • Effectiveness-NTU method
  • Indirect evaporative cooling
  • Sub-wet bulb temperature

Cite this

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abstract = "The objective of this paper is to study a method to achieve sub-wet bulb temperature by indirect evaporative cooling of air (without using a vapor compression machine). For this purpose, an analytical model is developed based on the effectiveness-NTU method (ε-NTU). The main idea for achieving a sub-wet bulb temperature by indirect evaporative cooling of air is by indirectly pre-cooling the working air before it enters the wet passage. It is shown that a modified analytical model for indirect evaporative coolers could be based on the ε-NTU method for sensible heat exchangers when proper adjustments are made by redefining the potential gradients, transfer coefficient, heat capacity rate parameters and assuming a linear saturation temperature-enthalpy relation of air. This modified model is used to find the performance of a regenerative indirect evaporative cooler. The model results show very good agreement with results from experimental measurements and a numerical model.",
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Going below the wet-bulb temperature by indirect evaporative cooling : Analysis using a modified ε-NTU method. / Hasan, Ala.

In: Applied Energy, Vol. 89, No. 1, 01.2012, p. 237-245.

Research output: Contribution to journalArticleScientificpeer-review

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