Performance analysis of a two-stage evaporative cooler

Mohammad Jaafarian,Mohammad Ehsan Kazemian

doi:10.1051/meca/2017013

Mohammad Jaafarian, Mohammad Ehsan Kazemian

Open Access

https://doi.org/10.1051/meca/2017013

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Journal: Mechanics & Industry	Publication Date: Jan 1, 2017
Citations: 2	License type: cc-by

Affiliation: Bam University of Medical Sciences

Abstract

In the present study, a mathematical model of a two-stage evaporative cooling (TSEC) system is presented, which consisted of two direct evaporative coolers and a heat exchanger. In this system, the temperature of the inlet air into evaporative pads decreases through indirect heat exchange with the outlet air stream from the conditioned space, using an unmixed heat exchanger. The outlet air from the conditioned space is also cooled down, prior to cooling the inlet air, through a second evaporation process. The governing equations of the energy and mass are presented and solved simultaneously. The numerical results are then compared with the experimental data reported in the literature to establish confidence in the model. The sensitivity of the performance of the system to the temperature and humidity of the ambient air, efficiency of the direct evaporative pads and overall heat transfer coefficient of the heat exchanger were calculated. The results are discussed to find the parameters with more significant effects on the performance of the system. The sensitivity analysis reveals that further improvements to the performance of the system is possible through increasing of the overall heat transfer within the indirect heat exchanger and increasing of the direct evaporative cooling efficiency.

Highlights

Mechanical vapor compression (MVC) and evaporative cooling systems are used in dwelling applications
Most of the working fluids used in MVC systems are harmful for environment, while evaporative cooling systems use water, which is environmentally benign
An evaporative cooling system works based on the difference between the wet and dry bulb temperatures of the ambient air

Summary

Introduction

Mechanical vapor compression (MVC) and evaporative cooling systems are used in dwelling applications. An evaporative cooling system works based on the difference between the wet and dry bulb temperatures of the ambient air. The efficiency of these systems in cooling of the air decreases in humid climate, where the difference between the wet and dry bulb temperatures decreases. This has motivated the researchers to look for new options to increase the efficiency of the evaporative cooling systems in various ambient conditions such as humid and hot climates. Sheng and Agwu Nnanna [2] studied the direct evaporative coolers experimentally.

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