Thermal and experimental analysis of cross-flow closed cooling tower

Abstract

Background: Cross-flow closed cooling towers (CCCT) are an indirect-contact evaporative cooler in which ambient air, spray water, and process fluid work together. The thermal performance of this cooling tower has significant impact on the thermal performance of the system in which it is implemented. CCCT introduces considerable difficulty in its thermal analysis particularly because it has two-dimensional analysis in its heat characteristics. Methods: In this work, a novel correlation between the tower effectiveness (ε) and its number of transfer units (NTU) was developed to simulate analytically the thermal performance/design of CCCT. This relationship is featured by its simplicity in use and has non-iterative procedure to be employed as the traditional one in the literature. Results: The new relationship was verified through comparison with experimental work. The simulated results from the new model show a satisfactory agreement with those obtained from the our experimental work of less than ±5%, less than ±2% difference from experimental work done by Jiang et al. [8], and with deviation of −3.89% from those obtained by Krӧger [9]. On the other hand, there is a good agreement between the present model and those obtained from the traditional ԑ-NTU method with maximum deviation of −4.56%. Conclusions: These new correlations are handy to be used by the process engineer or CCCT designer and they are featured by direct input parameters and no need for iterative process.

Keywords

• Cross-flow closed cooling tower
• Experimental analysis
• Effectiveness
• Number of transfer units (NTU)
• Enthalpy potential