EVAPORATIVE COOLING SYSTEM

Evaporative Cooling System in General Building

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Table of Contents

Chapter 1: Overview3

Introduction3

Working Principle of Evaporative Cooling System3

Evaporative Cooling and Heat Stress4

Chapter 2: Cooling Technology For Evaporative Systems6

Selection of Cooling Technology6

Additional Requirements and Considerations6

Attributes of System Data Centres7

Power Usage Effectiveness: Metric for Energy Efficiency8

Performance Comparison8

References10

Chapter 1: Overview

Introduction

An evaporative cooling system is a system that cools the air by evaporation of water. The evaporative cooling system is different from air conditioning typical refrigeration cycles using vapour compression or absorption (Heidarinejad et al. 2009). The operating principle of evaporative cooling is based on using the large enthalpy of vaporization of water. The temperature of the dry air can be significantly reduced by the phase transition of liquid water to water vapour, which requires much lower power consumption than the power consumption of the drives that work by cooling (Vahid et al. 2011).

Some evaporative coolers may also be used as humidifiers in the heating season. Besides its use in dry climates areas in sites with moderate levels of moisture there are many uses advantageous from an economic standpoint for evaporative cooling (Walker, 1981). For example, in industrial plants, commercial kitchens, laundries, and laundries with dry cleaning, greenhouses, site-specific cooling and areas of agricultural practices indoors (breeding poultry, pigs and dairy cows) are often used in systems based evaporative cooling (Heidarinejad et al. 2009). Finally, in climates with high humidity, it has very limited use for the benefits of cooling by evaporation.

Working Principle of Evaporative Cooling System

A good heat conducting metal such as copper is replaced by a large number of parallel, vertical holes into which the bottom of a cooling liquid, usually water, is pumped. This evaporates on the hot surface and it needs a lot of heat energy which is called the latent heat. This heat in turn provides very effective cooling of the metal (Chen et al. 2011). The steam is drawn off and elsewhere by an air condenser passed, whereby the vapour condenses, and releasing heat again. Bores have opposite flat surfaces and provides the advantage that the rising vapour bubbles cause stronger turbulent flow and thus produce the film boiling with insufficient heat transfer from the metal to prevent liquid.

The great advantage of evaporative cooling over other cooling method is the very high power density, and the protection against overheating, while coolant is pumped in. It can be combined with water to achieve heat flux densities of up to 300 kW/, without damaging the heat transfer surfaces. One kilogram of water at 100 °C and 1013 mbar is to evaporate and the heat of vaporization = 2257 kJ/kg. The specific heat capacity of liquid water stands at only 4.187 kJ/ (kg • K). In order to achieve with conventional water cooling with identical coolant circulation same heat dissipation, thus the water would be heated to 813 °C. The result of this step is the flow of water vapour (Heidarinejad et al. 2009).

Evaporative Cooling and Heat Stress

Heat stress is perceived by people, animals as well as mechanical and electronic ...