Thermal and Fluids

in Architectural Engineering

1. Introduction

Jun-Seok Park, Dr. Eng., Prof.

Dept. of Architectural Engineering

Hanyang Univ.

Where do we learn in this chaper

1. Introduction

2.The first law

3.Thermal resistances

4. Fundamentals of fluid mechanics

5. Thermodynamics

6. Application

7.Second law

8. Refrigeration,

heat pump, and

power cycle

9. Internal flow

10. External flow

11. Conduction

12. Convection

14. Radiation

13. Heat Exchangers15. Ideal Gas Mixtures

and Combustion

1.1 Overview

1.2 Thermal and fluids systems Analysis

1.3 Thermodynamics

1.4 Heat transfer

1.5 Fluid mechanics

Contents

1.1 Overview

□ The focus of Thermal-Fluid system is on Energy

1) Energy Use

2) Transformation (One form to another)

For examples,

- Heating and Air conditioning in buildings

- Building Integrated Photo-volatic System (BIPV)

- Wind Power Generation

1.1 Overview

□ The word, “Thermal” is from Greek word,

“theme”, meaning “heat”

Thermal ↔ Heat ↔ Energy

□ Thermal-fluid Engineering has to use

the basic principles of below disciplines

- Thermodynamics

- Heat transfer

- Fluid mechanics

1.1 Overview

□ Scope and focus of the principles

- The principles of (Thermodynamics /

Heat transfer / Fluid Mechanics) are applied in

some components of building systems

For examples

-Engine Block

-Building

-double skin of envelop

□ The previous examples show that

- How thermodynamics, heat transfer and fluid

mechanics are all needed in building design or

engineering design

□ System analysis process includes,

(1) Translate a system (reality) into physical model

(2) Create mathematical model using the physical laws

(3) Solving and looping (experiments/Simulation)

1.2 Thermal-fluids systems Analysis and Engineering

□ System analysis process

1.2 Thermal-fluids systems Analysis and Engineering

Physical System

(reality)

Physical Model

(simplified)

Mathematical

Model

(Simulation/Cal)

Assumption

Experience

Judgment

Thermal laws

Physical laws

(Thermodynamics,

heat transfer,

and fluid dynamics)

□ Thermodynamics is a unifying idea for the solution

of thermal-fluid system problems

□ The main laws are

- Conservation of mass

- Conservation of Energy (First law of thermodynamics )

- Energy flow direction (Second law of thermodynamics )

1.3 Thermodynamics

□ System, boundary, and surroundings

- System > the object we analyze

- Control volume > the region in the space that

contains system

- Boundary (control surface) > the line between

control volume and surroundings

1.3 Thermodynamics

□ Three types of systems

- Closed system : No mass flow

- Open system : Mass and energy flow

- Isolated system : No mass and energy flow

□ Type of process

- Steady process (state) : No changes with time

- Unsteady process (state): Changes with time

1.3 Thermodynamics

□ Energy flow or transformation Process

- “ A process occurs whenever some property of a

system changes, and if there is an energy or

mass flow across boundary

□ Schematic Analysis

- The simplest way of energy and mass flow analysis

For examples

- Drawings in the class / black box

1.3 Thermodynamics

□ heat is transferred at

- There is a temperature difference between

two substances (solid, liquid, gas, plasma )

through three types

(Conduction / Convection / Radiation)

For examples- Heat gain from sun

- Heat transfer through envelops of buildings

1.4 Heat transfer

□ Fluid mechanics includes

- fluids at rest (hydrostatics)

- fluid flows between a fluid and a solid

(fluid dynamics)

For examples- Pump and Toile / he or she can alive in toilet

- Cold draft in winter

1.5 Fluid mechanics