Energy Resources and Conservation Related to Built Environment. Proceedings of the International Conference on Energy Resources and Conservation Related to Built Environment, December 7–12, 1980, Miami Beach, Florida

1281 Pages·1980·52.153 MB·1281\1281

by  Oktay Ural (Eds.)

Pergamon Title of Related Interest
L/ra//HOUSING: Planning, Financing, Construction
Related Journals*
INTERNATIONAL JOURNAL FOR HOUSING SCIENCE AND ITS APPLICATIONS
SPACE SOLAR POWER REVIEW
BUILDING AND ENVIRONMENT
SUNWORLD
*Free specimen copies available upon request.
Sponsors of International Conference
on Energy Resources and Consen^ation
Related to Built Environment
PRESENTED BY:
Florida International University, International Institute for
Housing and Building, Division of Continuing Education,
Department of Conferences
Florida Power and Light Company, Miami, Florida
International Association of Housing Science
CO-SPONSORED BY:
City of Miami Building & Zoning Department, Miami, Florida
College of the Bahamas, Nassau
Florida Investor-Owned Utilities
Florida Solar Energy Center, Cocoa Beach, Florida
Governor's Energy Office, Florida
International Affairs Center, Florida International University
International Association for Hydrogen Energy
Latin Builders Association, Miami, Florida
Mayor's Office, City of Miami, Florida
Mayor's Office, Metropolitan Dade County, Florida
Metropolitan Dade County Building and Zoning Department
South Florida Energy Partnership
Universidad Autσnoma de Guadalajara, Jalisco, Mexico
Universidad Simon Bolνvar, Caracas, Venezuela
University of The Netherlands Antilles, Curacao
University Relations, Development and Alumni Affairs,
Florida International University
ENDORSED BY:
United States Department of Energy
1
PERGAMON
ON INTERNATIONAL
POLICY
DEVELOPMENT
STUDIES
Energy Resources and
Conservation Related
to Built Environment
Volume I
Edited by
Oktay Ural
Professor and Director
International Institute for
Housing and Building,
Florida International University
Proceedings of the
international Conference
on Energy Resources and
Conservation Related to
Built Environment,
December 7-12, 1980,
Miami Beach, Florida
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Copyright © 1980 Pergamon Press Inc.
Library of Congress Cataloging In Publication Data
Main entry under title:
Energy resources and conservation related to built
environment.
(Pergamon policy studies on international
development)
1. Arctiitecture and energy conservation-
Congresses. I. Ural, Oktay. II. Series.
NA2542.3.E53 333.79 80-26309
ISBN 0-08-027170-7
All Rights reserved. No part of this publication may be reproduced,
stored in a retrieval system or transmitted in any form or by any means:
electronic, electrostatic, magnetic tape, mechanical, photocopying,
recording or otherwise, without permission in writing from the
publishers.
Printed in the United States of America
PREFACE
I was born in a small town by the Agean Sea. Our life was full of
enjoyment, but rather simple. We were almost totally self-sufficient,
including the energy we used.
In three decades, the life in the same small town by the Agean Sea has
changed. This change is the result of the construction of many new dwellings
and the excessive use of scarce energy resources. The fishermen replaced
their sail boats by diesel driven ones; the farmers sold their horses; and
are driving their tractors to next towns. The wood and coal stoves are
thrown away; they are replaced by either gas or electric ones. Even the
town barber has an electric clipper. The windmills are not pumping water
anymore to irrigate the gardens. There are more children playing at the
beaches.
As this trend expands in geometric progression, the world energy balance
is disturbed. Several emerging countries are finding themselves in a major
economic crisis. The cost of their imported energy almost equals their
income from their exports. The highly industrialized countries, whose economic
systems are based on high consumption of energy, began to face inflation and
recession. Energy resources, either their excess availability or shortage,
became the major factor in effecting the economic and political trends of
the World. It seems the hope lies on new energy resources and conservation.
The World Conference has generated the technical manuscripts which are
included in this Proceedings. The authors have considered many topics
associated with available energy resources, energy conservation schemes,
better design and construction and alternative energy resources. Their
concern and contributions are valid and valuable.
When I revisit the small town by the Agean Sea, usually during Summer
months, I cannot decide if things have changed for the better.
I have to convey my sincere appreciation to all authors who contributed
to this book. Thanks to Earla Karels and Elizabeth Scott for their dedicated
and excellent work in the preparation of the manuscripts.
Oktay Ural
Editor
September 1980
Miami, Florida
xii
AN ENERGY CONSCIOUS DESIGN METHODOLOGY FOR TOWNHOUSES
Robert N, S. Chiang
Professor of Architecture & Environmental Design
Charles William Fotis, Jr.
Graduate Research Assistant
Leland Sangone Chen
Graduate Research Assistant
College of Architecture & Urban Studies
Virginia Polytechnic Institute & State University
Blacksburg, Virginia 24061
ABSTRACT
A typical single family dwelling in the U.S. is designed for a family
of four usually occupies about 2400 square feet floor area. A typical
townhouse for the same family uses only 1600 square feet, and mostly
has only two exposed walls. Therefore, townhouse is most idealistic
for energy conscious housing design. This paper is designed to study
the elements of good townhouse design, and develop criteria and pro­
cess of applying energy efficient techniques of analysis and develop­
ment of townhouse as a viable housing solution. The contents include
the following:
I. INTRODUCTION
II. FUNDAMENTALS OF ENERGY CONSCIOUS TOWNHOUSE DESIGN
1. Site Orientation and Planning
2. Principles of Efficient Townhouse Design
3. Energy Conservation Techniques
4. Passive Solar Techniques
5. Active Solar Potentials
III. TOWNHOUSE DESIGN ANALYSIS
1. Principles of Unit Design
2. Space Use and Layout Analysis
IV. ANALYSIS AND DEVELOPMENT OF TOWNHOUSE DESIGN
V. DESIGN EVALUATION
VI. FINAL NOTES
VII. REFERENCES
I. INTRODUCTION
When beginning to deal with the subject of the energy conscious town-
house and its future p;lace in the housing market, two of the basic
issues that must be addressed are the questions of energy and economics.
A major contention of this paper is that townhouses save energy and are
economical to own. When comparing the Townhouse to the Single Family
House the townhouse saves energy due to a decreased square footage. It
saves energy because it requires less labor and materials to construct
and it saves energy because it has less surface area that is exposed
to climatic impacts. These factors, when combined, make the townhouse
more economical to own and operate.
Until very recently the townhouse was viewed as transition housing for
most Americans; something that they owned and lived in while they waited
to move up to their ideal, the Single Family House. But, with the
astronomical rise of housing prices and mortage rates these potential
buyers are being forced to accept something less than the ideal; owning
their own piece of land with a detached house on it.
Due to these economic factors the townhouse appears to be the most
reasonable alternative to this housing delima; putting ownership of
permanent, affordable housing within the reach of lower and middle
income Americans.
There are numerous passive applications in the single family housing
market not because passive is inappropriate for townhouse design but
due to common preconceptions and government policy. It is possible with
proper orientation and massing of common walls to achieve thermodynamic
results similar to the underground house, but at a lower cost per square
foot; due to the decrease in exposed surface area that does not have to
be buried. Furthermore the potential energy demand of a townhouse
designed for energy conservation can be one half that of a single family
house due to the increase of the net floor area to exposed surface area
ratio.
In developing an Energy Conscious Design Methodology for Townhouses it
is necessary to put the townhouse and the methodology into proper
perscpective. The energy conscious townhouse should not be viewed as a
cure all for housing's energy ills, but must be seen in terms of its
overall impact on the growth, development and use of the environmental
resources. In short this form if housing uses less of everything
(materials, labor, land, energy, etc.). At the same time the methodology
that has been developed has a direct application for all building types;
not only townhouses.
1. Definitions
In general a townhouse is defined as and limited to a living unit
that provides approximately 1200 to 1600 square feet and contains
2-3 floors as part of series of units as little as 3 and as large as
12 in a group.
Rowhouse
This housing form, while containing the above space and floor
criteria, has front and rear wall exposure with shared side walls,
and three exposed walls on end unit.
Cluster House
This living unit also has the same space and floor criteria as well
as roof exposure but differs from the townhouse in that the front
and sidewalls are exposed, usually two jointed walls are shared.
2. Background Analysis
Even before one can begin to consider the questions, ramifications
and problems associated with the energy conscious townhouse it is
necessary to examine this multi-family form of housing in its
historical context.
The two most commonly known energy conscious and passive solar
applications in housing are the Igloos of the Alaskan Eskimos and
the adobe dwellings of the Pueblo Indians of the Southwest.
The primary design strategy of the Igloo is the conservation of
heat. This is accomplished with a spherical shape that deflects wind
and offers a minimum amount of exposed surface area. Insulation is
provided by the surrounding snow and an ice seal on the interior face
of the igloo combats air infiltration. A tunnel entrance is oriented
away from the prevailing winds to prevent the escape of warmed air.
In the hot arid region of the American Southwest the design strategy
of the Pueblo's was to reduce the excessive impact of the summer
sun and to provide winter heat gains. This was accomplished by
providing summer shading and designing these communal structures for
the mutual protection of heat. The massive adobe roofs and walls
possesed good insulative values and had the capacity to delay heat
impacts until night (time lag principals) when they were needed. By
packing the buildings together total exposed surface area was
reduced, which combated excessive summer heat gains. Winter heat
gains were maximized by using a rectangular shape, long side
oriented due south and solar impacts were reduced with the narrow
sides of the rectangle oriented along the east and west axis,
reducing morning and afternoon heat impacts.
3. Scope
This paper is limited to the analysis and proposal of An Energy
Conscious Design Methodology for Townhouses. The Townhouse is
limited to two basic types: Rowhouse and Cluster House. The
information provided relates specifically to this type of design.
II. FUNDAMENTALS, ENERGY CONSCIOUS TOWNHOUSE DESIGN
1. Site Orientation and Planning
It is essential, the elements of Energy Conscious Site Planning are
identified and analyzed not only in terms of energy, but in creating
and im.proving the environment that the townhouse and the user will
be to exist in. The task of the Architect is to understand and weld
the functional and energy requirements or quantitative aspects of the
site design, that of making a better place to live in.
A. Building Orientation
(1) Solar Exposure
This is the most important element that must be considered
when orienting the townhouse(s) because the sun affects all
facets of the design; including the building's siting,
orientation, envelope design, glazing requirements, HVAC,
lighting, operating and maintenance policies.
The control of on site solar radiation patterns is of criti­
cal importance in the design of the south, east and west
facades; in order to maximize winter heat gains and prevent
summer overheating. The precise effects will vary according
to the season, time of year and day. Failure to address
this problem will result in the creation of a structure
that perpetuates the faults of the old.
In general it can be said that the townhouse(s) should be
oriented due south; a variation of approximately 15 degrees
will not significantly affect system performance. The
intensity direction, duration of sunlight and effects of
direct solar penetration into the building is the first
consideration. The second consideration is whether and
how the sunlight is to be controlled or collected. Sun
must be shaded in summer to prevent solar heat gains, but
shaded in winter only when there is overheating problems.
(2) Wind Exposure
The velocity and prevailing wind direction on any given
site will affect the shape, orientation and components of
the envelope design. The wind also increase infiltration
(air leakage) and thermal conductance (heat transmission)
over the townhouse's entire skin and especially the glazed
areas. This is because the wind decreases the exterior
film of still air, increasing thermal vulnerability of the
roof and walls; and in turn increasing the building heating
and cooling loads.
In general, windward side walls should be designed with
minimum of openings for winter to reduce air infiltration;
but designed with proper openings for summer to increase
ventilation control.
B. Massing
Basic research has established optimums for the overall size of
a townhouse project. The trend at this point is towards a
smaller complex having a size of approximately 125 units. The
reason for this number is that the larger projects have a higher
level of user dis-satisfaction, are more inefficient to plan.
design, operate and manage. Also there is a higher risk factor
with the fluctuating economy.
(1) Macro Climate Modifications
The climate of the Townhouse Macro Environment can be
controlled and modified by creating protected open space.
This protected open space serves two functions, that of a
sun space moderating the exterior winter environment
through its heat gains, and if the area is properly
oriented to take advantage of summer wind patterns and
shaded against summer sun penetration, a cool outdoor area
can be created; further moderating the external seasonal
environment.
Landscapping can be used to combat and/or enhance the impact
of natural factors on the site. It can be used for winter
wind protection, to maximize summer shading/cooling and
enhance the warming effects of the sun in winter.
The climate can be further moderated and controlled by the
placement of the individual as well as groupings of
townhousesi η order to block and channel on site wind
patterns as well as create an open and protected sun space.
(2) Shape and Volume
Depending upon the intent of the overall design strategy
there are two ways of looking at the question of exposed
surface area. If the overall design strategy is one of
energy conservation then the cubic shape is the optimum
townhouse form because it has the least amount of exposed
surface area. If the strategy is one of providing
maximum heat gain then a rectangular shape with its long
side oriented to the south is the optimum strategy.
The most efficient shape of a building is a cube with as
many floors as possible and the most efficient use of
resources for a building is one with the smallest enclosure
to floor area ratio. This is because the real useful
space of a building is the net floor area. Any offsets,
recesses or cavities will increase the exposed enclosure
and more floors will increase floor area.
(a) Townhouse
When examining the question of how much exposed
surface area to provide in the design of a townhouse
it is necessary to examine the spatial characteristics
of the individual units. Basically, most townhouses
have more depth than width and shared side walls with
a minimum amount of southern exposure. This shape is
not condusive to the basic principals of maximizing
heat gain; providing the greatest amount of exposed
surface area oriented to the south.
The problem of minimized surface exposure due to depth
can be overcome by grouping the units in a row and
orienting them due south. Individually the units have
a less than optimum shape for maximizing heat gain but
collectively they are able to achieve the prefered
rectangular shape. The rectangular shape also has the
additional benefit of providing a decreased amount of
exposed surface area on the west facade minimizing the
thermal impacts of the hot afternoon sun.
(b) Cluster House
In the grouping of the individual Cluster Houses it is
necessary to take advantage of and utilize the
rectangular shape (as in the townhouse) in order to
maximize southern heat gains and minimize them on the
west facade.
(3) Environmental Quality
There is a direct relationship between density and user
satisfaction. In general it can be said that the higher the
density the lower the level of satisfaction and that the
lower the density higher the level of satisfaction. But
what is critical is the density of the immediate
environment.
In the previous section, open space landscapping and
placement of the individual townhouse units were used to
illustrate methods of Macro-Climate control. These
elements can be used not only to moderate the immediate
outside environment but to enhance the overall quality of
life in that environment.
Because the potential user is being asked to live with
higher on site densities that are usually associated with
townhouse living, it is necessary to create open space to
combat the closed in feeling; landscapping can be used to
increase privacy and views, particularly from hillside
townhouses, which can be used to make a site seem less
crowded.
Another way the overall site can be made to feel more
spacious is the manner in which the units themselves are
positioned and grouped on the site. Short rows of 4-6 units
and small clusters are more desireable than long rows of
uniform housing. People identify with a smaller area. For
that reason, it is more desireable to create small neighbor­
hoods using not only the grouping of individual units but
grade changes, plantings and open space to divide the site
and create these areas.
C. Landscaping
The purpose of landscaping in townhouse design is two fold, that
of controling and modifying seasonal climatic changes and
improving the immediate outside environment. This is done