Graduation Semester and Year

2021

Language

English

Document Type

Thesis

Degree Name

Master of Science in Mechanical Engineering

Department

Mechanical and Aerospace Engineering

First Advisor

Dereje Agonafer

Second Advisor

Ratan Kumar

Abstract

Evaporative cooling is a smarter way of maintaining optimum operating conditions in data centers. Indirect Evaporative Cooling (IEC) provides the advantage of cooling without changing the humidity of the Data Center (DC) air. We analyze and develop a method of testing to help build IEC modules at larger scales with improved characterization that is intended to help DC engineers achieve stringent Power Utilization Efficiency (PUE) targets by expending minimum power. We study the design parameters pertinent to sizing an IEC module used in DC cooling and develop a test method while technically selecting the components involved. The module is planned with centrifugal plug fans on both primary and secondary sides selected to deliver 8000cfm of air at 2.5 in-wg of static pressure, an air-to-air crossflow heat exchanger, a water distribution system to deliver and distribute water to the wetted channels of the secondary side, a sump for collecting water, and a recirculation piping. The primary side air is set to simulate a typical DC return air. We use 6Sigma software as a tool to size the cabinet, visualize air velocities across different parts such as inlets and outlets, and observe effects for further controlling the outlet air on the secondary side, that is connected to an auxiliary unit designed to supply air at desired temperature and humidity to simulate ambient climatic conditions. The heat exchanger considered in this study is a commercially available plate heat exchanger made of Al 8009 alloy and epoxy coated of size of 48" x 48" x 48". Face velocities up to 600 FPM are considered. Based on the literature surveyed, we recommend two types of spray headers, namely full cone spray nozzle and 360 deg rotating type water sprinkler in arrangements that effectively wet the heat exchanger cross section. Cooling capacity and cooling effectiveness can be documented for several air speeds across the heat exchanger channels. Additionally, evaporation rate, water consumption, and pressure drop for the secondary side can be estimated. Thus, we associate the cooling effectiveness with parameters related to the fan-motor power and water utilization. We build correlations between several distinct parameters for rating the performance of an IEC module. The results from this design and test method will be invaluable in developing phenomenological models of IEC modules which can subsequently be used for developing IEC units at scale to help size and optimize equipment for Data Centers.

Keywords

Indirect evaporative cooling, Data center air cooling, Test method for sizing indirect evaporative air handling unit

Disciplines

Aerospace Engineering | Engineering | Mechanical Engineering

Comments

Degree granted by The University of Texas at Arlington

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