Engineering Design and Optimization of Thermofluid Systems

David S. K. Ting

• Publisher: Wiley
• Year: 2021
• ISBN:
  9781119701668
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Mechanical Engineering
• Index: Technology & Engineering

A practical and accessible introductory textbook that enables engineering students to design and optimize typical thermofluid systems

Engineering Design and Optimization of Thermofluid Systems is designed to help students and professionals alike understand the design and optimization techniques used to create complex engineering systems that incorporate heat transfer, thermodynamics, fluid dynamics, and mass transfer. Designed for thermal systems design courses, this comprehensive textbook covers thermofluid theory, practical applications, and established techniques for improved performance, efficiency, and economy of thermofluid systems. Students gain a solid understanding of best practices for the design of pumps, compressors, heat exchangers, HVAC systems, power generation systems, and more.

Covering the material using a pragmatic, student-friendly approach, the text begins by introducing design, optimization, and engineering economics—with emphasis on the importance of engineering optimization in maximizing efficiency and minimizing cost. Subsequent chapters review representative thermofluid systems and devices and discuss basic mathematical models for describing thermofluid systems. Moving on to system simulation, students work with the classical calculus method, the Lagrange multiplier, canonical search methods, and geometric programming. Throughout the text, examples and practice problems integrate emerging industry technologies to show students how key concepts are applied in the real world. This well-balanced textbook:

• Integrates underlying thermofluid principles, the fundamentals of engineering design, and a variety of optimization methods
• Covers optimization techniques alongside thermofluid system theory
• Provides readers best practices to follow on-the-job when designing thermofluid systems Contains numerous tables, figures, examples, and problem sets

Emphasizing optimization techniques more than any other thermofluid system textbook available, Engineering Design and Optimization of Thermofluid Systems is the ideal textbook for upper-level undergraduate and graduate students and instructors in thermal systems design courses, and a valuable reference for professional mechanical engineers and researchers in the field.

1
Introduction

To develop a complete mind: Study the science of art; Study the art of science.

– Leonardo da Vinci

---

Chapter Objectives

• Understand what design and optimization of thermofluid systems mean.
• Differentiate engineering from science.
• Discern development, design, and analysis.
• Become familiar with the design process.
• Be aware of the existing books on thermofluid system design and/or optimization.
• Appreciate the organization and contents of the book.

---

Nomenclature

HVAC	heating, ventilation, and air conditioning
Idir	direct radiation on a horizontal surface
KISS	keep it simple, stupid
LED	light‐emitting diode
PV	photovoltaic
UWCAES	underwater compressed air energy storage
X, x	(design) variables or influencing parameters
Y	a variable, the objective function

1.1 What Are Design and Optimization of Thermofluid Systems?

Design and optimization of thermofluid systems are

the design and, subsequently, optimization of the design of engineering systems involving significant fluid flow, thermodynamics, and/or heat transfer.

To more fully understand Design and Optimization of Thermofluid Systems, we need to clearly comprehend the four main terms:

1. design
2. optimization
3. thermofluid¹
4. systems.²

Within this context,

1. design is the creation of an engineering system which will provide the desired result, and
2. optimization is taking the workable design one step further, attaining not just a better but the best design.

There usually exist a few unavoidable constraints, putting practical limits within which the optimal design is bounded. The optimal car may be the one performing the best in terms of mileage. For a typical middle‐class engineer with four mouths to feed, however, the price of the car may be the deciding factor, limiting the selection to within a low‐budget ceiling.

---

Example 1.1 Design a residential solar thermal energy storage system

Given

An engineering student living in a temperate climate region wishes to store the thermal energy harnessed from the sun when it shines during the day, for residential use during the night.

Find

An appropriate storage system.

Solution

A workable design is running a glycol‐water line from the solar thermal collector into an adequately large insulated water tank. Glycol‐water is appropriately employed to prevent freezing. The temperature of the stored fluid has to be sufficiently high for the intended usage. Reasonable drops in the temperature from the solar collector to the storage tank and to the delivery end use must be accounted for, as some losses are inevitable.

The initial workable design, however, is probably not the best design as it may occupy the entire basement. The use of phase‐change material will probably keep the size in check. Molten salt is also worth exploring, especially when dealing with larger utilization, such as a multiple‐housing residence. Comparing different existing options, such as off‐the‐shelf tank sizes and storage media to achieve the best option is called optimization. Since the budget, as well as the available space for the storage tank, are likely limited, the optimization of the residential solar thermal energy storage system is thus subjected to budget, space, and other constraints.

---

Example 1.1 hints that a workable design does not necessarily need to be the best design. In fact, it typically is not. When the project is adequately large and there are (financial) backings for it, optimization is invoked to deduce the best design. Furthermore, for a company to compete in mass‐selling of such systems, progressively better designs which are cheaper to manufacture are necessary. By and large, there will be budgetary, space, and other constraints. Other constraints for a thermal storage tank can be a maximum workable storage temperature, particular charging and discharging rates, etc. In some sense, moving from a feasible design to an optimum design is like progressing from an “ad hoc art and/or experience” to a “systematic scientific artistic endeavor.”

Figure 1.1 Workable versus optimal design of electricity‐driven household light bulbs. Source: Photos taken by X. Wang and Y. Yang.

A familiar design versus optimization exemplification is the three types of light bulb for everyday usage, see Figure 1.1. The incandescent light bulb is a workable design, and it has been satisfying our need since Thomas Edison invented it in 1879. Much later, the fluorescent light bulb is optimized in terms of energy usage and cost. For this reason, the compact fluorescent light bulb has finally squeez...

Table of contents

• Cover
• Table of Contents
• Title Page
• Copyright
• Dedication
• Preface
• Acknowledgments
• 1 Introduction
• 2 Engineering Economics
• 3 Common Thermofluid Devices
• 4 Heat Exchangers
• 5 Equations
• 6 Thermofluid System Simulation
• 7 Formulating the Problem for Optimization
• 8 Calculus Approach
• 9 Search Methods
• 10 Geometric Programming
• Appendix: Sample Design and Optimization Projects
• Index
• End User License Agreement