Building Physics : Heat, Air and Moisture - Fundamentals and Engineering Methods with Examples and Exercises

by Hugo S. L. C. Hens (K.U. Leuven, Dept. of Civil Engineering, Building Physics Section)

• ISBN13: 9783433018415
• ISBN10: 3433018413
• Format: Paperback
• Copyright: 2008-04-01
• Publisher: Wiley-VCH

Summary

Bad experiences with construction quality, the energy crises of 1973 and 1979, complaints about 'sick buildings', thermal, acoustical, visual and olfactory discomfort, the move towards more sustainability, have all accelerated the development of a field, which until 35 years ago was hardly more than an academic exercise: building physics. Through the application of existing physical knowledge and the combination with information coming from other disciplines, the field helps to understand the physical performance of building parts, buildings and the built environment, and translates it into correct design and construction. This book is the result of thirty years teaching, research and consultancy activity of the author. The book discusses the theory behind the heat and mass transport in and through building components. Steady and non steady state heat conduction, heat convection and thermal radiation are discussed in depth, followed by typical building-related thermal concepts such as reference temperatures, surface film coefficients, the thermal transmissivity, the solar transmissivity, thermal bridging and the periodic thermal properties. Water vapour and water vapour flow and moisture flow in and through building materials and building components is analyzed in depth, mixed up with several engineering concepts which allow a first order analysis of phenomena such as the vapour balance, the mold, mildew and dust mites risk, surface condensation, sorption, capillary suction, rain absorption and drying. In a last section, heat and mass transfer are combined into one overall model staying closest to the real hygrothermal response of building components, as observed in field experiments. The book combines the theory of heat and mass transfer with typical building engineering applications. The line from theory to application is dressed in a correct and clear way. In the theory, oversimplification is avoided. This book is the result of thirty years teaching, research and consultancy activity of the author.

Author Biography

Hugo S.L.C Hens is professor at the University of Louvain (C.U.Leuven), Belgium. After four year of activity as a structural engineer and site supervisor, he returned to the university to receive a PhD in Building Physics. He taught Building Physics from 1975 to 2003 and Performance Based Building Design from 1970 to 2005 and still teaches building services. Dr. Hens is the author of several text books in Dutch on Building Physics, Performance Based Building Design and Building Services. He has authored and co-authored over 150 articles and conference papers, wrote hundreds of reports on building damage cases and their solution, introduced upgraded, research-based concepts for highly insulated roof and wall construction and directed several programs on building-energy related topics.
For ten years he has been coordinator of the international working group CIB W40 on Heat and Mass Transfer in Buildings. At present he is operating agent of the International Energy Agency's EXCO on Energy Conservation in Buildings and Community Systems, Annex 41 Whole Building Heat, Air and Moisture Response.

Table of Contents

Preface

Introduction

Subject of the Book

Building Physics

Definition

Criteria

Comfort

Health

Architectural and Material Facts

Economy

Environment

Importance of Building Physics

History of Building Physics

References

Units and Symbols

Heat Transfer

Overview

Conduction

Conservation of Energy

Fourier's Laws

First Law

Second Law

Steady State

What Is It?

One Dimension: Flat Walls

Two Dimensions: Cylinder Symmetry

Two and Three Dimensions: Thermal Bridges

Transient Regime

What is Transient?

Flat Walls, Periodic Boundary Conditions

Flat Walls, Transient Boundary Conditions

Two and Three Dimensions

Convection

Overview

Heat Transfer at a Surface

Convection

Convection Typology

Driving Forces

Type of flow

Calculating the Convective Surface Film Coefficient

Analytically

Numerically

Dimensional Analysis

Values for the Convective Surface Film Coefficient

Walls

Cavities

Pipes

Radiation

Overview

Thermal Radiation

Quantities

Reflection, Absorption and Transmission

Radiant Surfaces

Black Bodies

Characteristics

Radiation Exchange Between Two Black Bodies: The Angle Factor

Properties of Angle Factors

Calculating Angle Factors

Grey Bodies

Characteristics

Radiation Exchange Between Grey Bodies

Colored Bodies

Practical Formulae

Applications

Surface Film Coeffi cients and Reference Temperatures

Overview

Inside Environment

Outside Environment

Steady-state, One-dimension: Flat Walls

Thermal Transmittance and Interface Temperatures

Thermal Resistance of a Non-ventilated Infi nite Cavity

Solar Transmittance

Steady State, Cylindrical Coordinates: Pipes

Steady-state, Two and Three Dimensions: Thermal Bridges

Calculation by the Control Volume Method (CVM)

Thermal Bridges in Practice

Transient, Periodic: Flat Walls

Heat Balances

Problems

References

Mass Transfer

In General

Quantities and Definitions

Saturation Degree Scale

Air and Moisture Transfer

Moisture Sources

Air, Moisture and Durability

Linkages between Mass-and Energy Transfer

Air Transfer

In General

Air Pressure Differences

Wind

Stack Effects

Fans

Air Permeances

Air Transfer in Open-porous Materials

Conservation of Mass

Flow Equation

Air Pressures

One Dimension: Flat Walls

Two- and Three-dimensions

Air Flow Through Permeable Layers, Apertures, Joints, Leaks and Cavities

Flow Equations

Conservation of Mass, Equivalent Hydraulic Circuit

Combined Heat- and Air Transfer

Open-porous Materials

Air Permeable Layers, Joints, Leaks and Cavities

Vapour Transfer

Water Vapour in the Air

Ove

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