Basics Room Conditioning

85 Pages·2017·3.529 MB·German

by  Oliver Klein, Jörg Schlenger

Oliver Klein, Jörg Schlenger
Room
C onditioning

OBelirvte Br iKelleeifne,l dJö -r Sg eSbcahslteinagne Erl Khouli
REnotowmu rfsidee
C onditioning
Birkhäuser
BIRKHÄUSER
Basel
BASEL
Contents
Foreword _7
IntroductIon _8
desIgn prIncIples _10
Comfort requirements _10
Determining the requirements _17
Covering the demands _24
VentIlatIon systems _38
Natural ventilation _39
Mechanical ventilation _45
Deciding on the right system _50
temperIng systems _52
Energy supply _53
Heat and cold storage _63
Heat and cold distribution _63
Heat and cold transfer _65
Choosing the right system _74
combInatIon oF VentIlatIon and temperIng _76
The range of possible solutions _76
Selection criteria _76
In conclusIon _77
appendIx _78
Examples of concepts _78
Standards and Guidelines _84
Literature _84
The authors _85
Foreword
Ensuring people’s protection and wellbeing are important functions
of buildings. They preserve people from fluctuations in the weather and
from its adverse effects. At the same time the interior must be provided
with sufficient fresh air and heat or cold to guarantee comfort. The con-
ditioning of interior space is therefore an important aspect of architec-
ture, which extends far beyond the purely technical implementation of
heating and ventilation systems. Intelligent designs and their realization
link building structure, function and technology holistically, with the aim
of reducing a building’s energy demand or eliminating it entirely.
A wide knowledge of the requirements and possibilities of covering
demand with room conditioning is needed to be able to take this guiding
principle into account from the outset when designing a building. This in-
cludes the technical systems and, above all, an understanding of the in-
teractions and interdependencies. It is important to see drawing up a
room conditioning concept as an integral part of preliminary design.
Room Conditioning elaborates this subject step by step using easi ly
understood introductions and explanations. It is intended for students
and professionals at the start of their careers. First, the book presents
the fundamental comfort requirements and differentiates between them
according to function, use and climatic conditions. The principles used
in determining and covering demand make clear that the direction for the
subsequent technical implementation must be set in the early stages of
project planning, to avoid adverse environmental effects and to keep
energy demand to a minimum.
Further chapters discuss mechanical and natural ventilation con-
cepts, and provide a practical context for system finding. Room temper-
ing is explained systematically, from energy supply and possible storage,
through to its distribution in the building and transfer in the room, and
finally its relationship with ventilation.
The authors provide a sound, broadly based understanding of the
interrelationships and possibilities of room conditioning. The most im-
portant consideration is not the mathematical design of technical sys-
tems, but an intelligent and integrated approach in order to use this
knowledge to achieve an optimum concept for every individual building.
Bert Bielefeld, Editor
7
Introduction
The temperature of While many species are able to adjust their body temperatures to
the human body suit their surroundings, humans require an almost constant body tem-
perature of 37 ± 0.8 °C. As the outside temperature fluctuates depend-
ing on the climate zone, time of the day and season, the human body
attempts to maintain this temperature using an automatic regulation sys-
tem, in which the surface of the skin gives off more or less heat, accord-
ing to the ambient temperature and the level of physical activity. For
example, if the body temperature rises, sweat glands allow moisture to
emerge onto the skin, where it evaporates and gives off heat into the
environment. If the body temperature drops, the skin contracts to reduce
the area giving off heat, and the hairs on the skin stand up (“goose
pimples”). The body also creates additional heat by quivering its muscles
(shivering).
Climatic influences However, this temperature regulation system also has its limits, and
and compensation the human skin can only fulfill this task to a certain extent. Clothing as
additional “thermal insulation,” the “second skin,” and buildings, the
“third skin,” provide the solution.
In human history, the discovery of fire was surely the most impor-
tant step for humankind in achieving independence from climatic condi-
tions and the seasons. It was not only the entry into the fossil fuel age,
i.e. energy conversion dependent on a continuous supply of energy
sources; the “third skin” could then have artificial heat and light – and
thus it was also the original form of room conditioning. Today’s problems
of environmental destruction associated with the use of fossil fuels are
well known to us and omnipresent.
Energy-optimized The term “room conditioning” is understood as the creation of an
room conditioning indoor climate for people to enjoy a feeling of wellbeing, which is above
all unaffected by any outside influences by tempering (heating or cool-
ing), lighting and the introduction of sufficient fresh air (ventilation); with
suitable technology, this can lead to an ultimately uniform architecture
that is unrelated to its location. In extreme cases, these buildings are her-
metically sealed with glass facades, fully air-conditioned by the extensive
use of high technology, and can be found built to practically the same
design in all climatic regions of the world. In addition to disturbing user
sensitiv ities, another disadvantage is the very high energy requirement
for heating, cooling and lighting. The fact that 50% of the total energy
consumed worldwide is used in buildings shows that other ways must be
devised to provide energy-optimized room conditioning.
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A building should always be designed to provide comfort using only
a small amount of additional energy. First, all available constructional
(passive) measures for room conditioning should be exploited, taking into
account local conditions, before turning to technical (active) measures.
> Chapter Design principles
The effective combination of passive and active measures in which
all the technical components are mutually compatible is always crucial
to obtaining an energy-optimized overall concept for room conditioning.
The following chapters explain the basic principles and their various inter-
actions, and are intended to enable an individual and balanced room con-
ditioning system to be developed for every building project.
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Design principles
comFort requIrements
Thermal comfort
The term “comfort” describes a feeling of wellbeing, which is influ-
enced by a number of factors. In the field of building services systems, it
generally refers to thermal comfort, describing a state in which the body’s
thermal balance is in equilibrium with the climatic conditions of the sur-
roundings. The user perceives the climatic conditions of the surround-
ings as neither too hot nor too cold.
Importance Thermal comfort is not a luxury; it is an important criterion for being
of comfort able to use a building fully for its intended purpose. The quality of the
space in a building has many different effects on the ability of its occu-
pants to concentrate and work effectively, as well as their state of health
(e.g. in offices). If comfort is inadequate in production areas, this may
give rise to premature fatigue with the corresponding consequences for
safety at work. The reliable provision of an indoor climate appropriate to
use is therefore an important quality characteristic of a successful build-
ing concept.
Influence factors
Our perception of comfort depends on a number of influence factors,
which are shown in Figure 1.
The designers of a building are normally only able to influence physi-
cal conditions, some of which are described in detail in the following
chapters. However, the clothing and activity of the user clearly affect his
or her perception of comfort. Along with the user’s ability to adapt and
acclimatize, both belong to a group of “intermediate” factors and are
influenced by both physical and physiological conditions.
In some cases, other factors may also play an important role in the
preliminary building design, the knowledge of which and the conscious
creation of a building concept specifically for a defined user group are
often indispensable for the design process. For example, older people
often find higher temperatures comfortable, which must be taken into
account by providing appropriately higher room air temperatures when
designing a nursing home for the elderly.
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Physical conditions Physiological conditions
Air movement Age
Air temperature Constitution
Relative humidity Body size
Surrounding surfaces temperature Cultural influences
Food intake
Composition of the air Gender
Acoustic influences
Optical influences
Atmospheric electricity
Barometric pressure
Thermal comfort
Clothing
Activity level
Psychosomatic factors
Room occupancy
Primary,
Time of day, season dominating factors
Adaption and
acclimatisation Secondary and
assumed factors
Additional factors
Intermediate conditions
Fig. 1: Factors influencing thermal comfort
Physical conditions
After air temperature, the most important physical factor is the av- Air and radiation
erage temperature of the surrounding surfaces. Like any other body, the temperature
human body is also continuously exchanging heat with surrounding sur-
faces by means of radiation. Depending on the distance and the
temperature difference between two bodies, more or less heat will be
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