Citation
Energy conservation site selection and design

Material Information

Title:
Energy conservation site selection and design case study : planned unit development, Lyons, Colorado
Creator:
MacKinnon, Elsie Booth
Publication Date:
Language:
English
Physical Description:
39 leaves : illustrations, maps, plans ; 22 x 28 cm

Subjects

Subjects / Keywords:
Building sites -- Colorado -- Lyons ( lcsh )
Energy conservation -- Colorado -- Lyons ( lcsh )
Building sites ( fast )
Energy conservation ( fast )
Colorado -- Lyons ( fast )
Genre:
bibliography ( marcgt )
theses ( marcgt )
non-fiction ( marcgt )

Notes

Bibliography:
Includes bibliographical references (pages 37-39).
General Note:
Submitted in partial fulfillment of the requirements for a Master's degree in Landscape Architecture, College of Design and Planning.
Statement of Responsibility:
by Elsie Booth MacKinnon.

Record Information

Source Institution:
University of Colorado Denver
Holding Location:
Auraria Library
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
08970670 ( OCLC )
ocm08970670
Classification:
LD1190.A77 1980 .M315 ( lcc )

Full Text
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ENERGY CONSERVATION site selection and design
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THE UNIVERSITY OF COLORADO AT DENX/ER
ENERGY CONSERVATION SITE SELECTION AND DESIGN
CASE STUDY: PLANNED UNIT DEVELOPMENT, LYONS, COLORADO
A FINAL DESIGN PROJECT SUBMITTED TO THE FACULTY OF THE LANDSCAPE ARCHITECTURE PROGRAM IN CANDIDACY FOR THE DEGREE OF
MASTER OF LANDSCAPE ARCHITECTURE
BY
ELSIE BOOTH MACKINNON DENVER, COLORADO MAY,1980



TABLE OF CONTENTS
Introduction...........................................................1
History and Philosophy.................................................4
Process and Methodology................................................7
Case Study............................................................13
Accept..........................................................14
Analyse.........................................................14
Define..........................................................17
Ideate..........................................................32
Select..........................................................34
Implanent.......................................................34
Evaluate........................................................34
Bibliography..........................................................36



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introduction
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Despite the fact that the world is running out of renewable resources at an alarming rate, many professions continue to operate as if this problem does not exist. Landscape architects, planners and designers in general are no exception. Designs are implemented constantly without regard to the land and its potential for energy conservation. For instance, buildings are oriented so that they receive minimal solar gain in winter; outdoor spaces are often designed to the north of structures rendering them unusable for most of the year; cormunities are planned which use the maximum amount of streets in terms of length and width; and plantings are selected for aesthetic reasons only with little or no regard for functionality.
Ihe purpose of this project is to establish energy conservation criteria for site selection and design and then demonstrate hew these criteria fit into the land planning process. It is basically a landscape architectural approach which can be utilized by planners, architects and developers as well.
It should be considered a first step toward a more complete set of energy efficient criteria. Ideally, energy conservation planning should be developed by an inter-disciplinary team which might be composed of landscape architects, architects, planners, ecologists, climatologists, geologists, soils scientists, transportation specialists and energy related economists.
"In the present century, we have cone to live Increasingly on capital resources o6 oil, coal and other minerals- using up In a (Jew generations what It took tens 0|J millions 0(J years o (J eaAth time to accumulate."
John Simonds
"The energy crisis po&es one o Governor Lamm of Colorado
Energy conservation planning is actually quite basic and yet the fact that it is rarely used in the design process is rationale enough for this project. Ihe effectiveness of using energy conservation techniques is easy to document.
Davis, California established an energy code in 1976 which resulted in the following savings: a southern orientation of a 1,500sf house shewed a 54% energy savings over an exact duplicate oriented to the north; deciduous trees sited on the south-west side of residences reduced wall and roof temperatures by 20-40; vines and evergreens on the north and west reduced
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fuel consumption by 40% by buffering winter winds; and by reducing street widths frcm 40 feet to 24 feet, costs were reduced by 50% and microclimatic temperatures were reduced by 10-15 which in turn reduced air conditioning demands by 15%. Davis has achieved an overall savings of 50% of its energy use through its code and plans to improve on this in the future.
Traditionally the landscape architect's role has been to "Tfi we want everything to 6tag
inventory and analyse the land prior to design in terms of juAt aA it it>, everything haA to
its envirormental, historical and cultural aspects. change
This project is based on the premise that an energy conservation Tancredi
tarplate should be placed on the traditional mode of examining
the land. The identification and application of energy
efficient criteria involves a logical process which will
be demonstrated by this project.
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history & philosophy
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Energy conservation is not a modem concept. Historically, it was an innate component of man's relationship to the earth. All things in the natural world must respond to their environment and its flucuations in order to insure their survival. Adaptive behavoir in plants and animals is "natural". Plants respond in many obvious ways to seasonal changes. Animals migrate, hibernate, change their pigment and, in general, 'knew' how to fulfill their needs. They live in harmony with their particular environmental conditions.
Historically, man, too, shared in a direct symbiotic relationship with the earth. This relationship, termed I-Thou by the philosopher Martin Buber, was based on an innate comprehension of the working order of the earth.
It was passive and almost totally subject to the unpredictableness of nature. Early man stood in awe of his environment and its forces. Although he could not afford to ignore these forces as we have in modem times, he could modify or ameliorate their impact. The need to survive and the desire for comfort led to adaptive designs which we quaintly refer to as indigenous architecture'. These creative problem solving designs supply us with a primary source of information about passive energy conservation techniques. There are examples of adaptive design all over the war Id. The dark fur tents of the nomads of the Sahara, the dry ice igloos of the Eskimos and the pueblos of the American southwest are but a few examples of human ingenuity and adaptation to a given environment. In general, past human habitation was related directly to the local topographical, geographical and microclimatic conditions. The early builders chose suitable sites and built with appropriate materials.
With the Reformation and the Renaissance, man's perception of himself changed radically. Armed with Cartesian logic he felt apart from and superior to nature. Man's relation-
"Over the centuries shelters have been built to aedu.ee -the range o fi local climate, variations; to avoid. some ofi the heat ofi the Sun In a hot climate, to hold more heat In a cold climate, to take advantage ofi winds where the contribute to desired cooling, to defiled or avoid winds, to provide protection firom drenching rains, to permit light to
enter fior the perfiormance ofi work..
All ofi these fiunctions have been combined Into charaderlstlc fiorms that could be built ofi available materials with the degree ofi technical complexity charaderlstlc 0($ the Indigenous culture."
Richard Stein

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ship to the earth shifted from I-Thou to I-It. Nature became depersonalized and semething to subjugate.
Basically, man's role changed frcm passive to active.
The Industrial Revolution was the key to implementing the new philosophy for it produced the tools for the exploitation of nature, the wasting of natural resources, and the building of habitats without regard far the existing environmental conditions. The power to build and destroy coupled with a seemingly inexhaustible supply of energy resources led man to believe he had conquered nature and freed himself from its influence.
This illusion is rapidly fading today as we watch our natural resources dwindle, observe our congested, inefficient cities and note the quality of our air and water.
We must recognize that man and the earth are two complementary components of a system- that our well-being is dependent on natures's well-being. We must develope an enlightened anthropomorphism which embraces a new "land ethic"- an ethic which is firmly rooted in a thorough understanding of ecology. Short term gains must be replaced with long term regeneration. Provincial thinking must give way to regional and global approaches. The adoption of energy conservation techniques in site selection and design is one step toward achieving the new land ethic far it seeks a symbiotic relationship between human needs and environmental conditions.
"Natune is pant ouA humanity, and without some awaneness and expenience o the. divine mysteny, man ceases to be man.
When the Pleiades, and the wind in the gnass one no longen a pant othe human spinit, a pant ofi the veny filesh and bone, man becomes, as it wene, a kind 0|$ cosmic outlaw, having neithen the completeness and integrity o6 the animal non the binthnight ofi a tnue humanity."
Henry Beston
"I am pessimistic about the human nace because it is too eleven fion its own good. OuA appnoach to natune is to beat it into submission. We would stand a betten chance fan sunvival is we accommodated ouselves to this planet and viewed it appneciatively instead o6 skeptically and dictatonially."
E.B. White
1)
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process & methodology
i ________________________._______j


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Energy conservation site selection and design involves working with instead of against the forces of nature.
It is necessary not only to have a thorough understanding of these forces, but also to knew methods for modifying than in terms of .creating human confort zones. In addition, a design process must be adapted with an accompanying methodology in order to successfully develop and implanent an optimum site specific design.
The systematic process which is suggested for this project invlolves the following seven stages or phases:
PROCESS
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The seven stages of process:
I.
accept
situation
problem solving.
Ccmit to identifying intentions and establishing a general process for
II. Gather facts and opinions, discover
analyse interrelationships, establish
familiarity with the problem to be solved, relate to similiar cases, seek advise.
III.
define
Make a bridge between analysis and synthesis, clarify directions for action, transform facts into criteria, establish conceptual guidelines.
IV.
ideate
Generate a list of options or alternatives, discover various strategies for reaching
established objectives.
V.
select
Decide which choice best balances the potentials and constraints of the problem, determine the 'best' solutions in terms of the needs of the program.
VI.
implement
Put the selected idea to a test, translate the selected solution into reality.
VII.
evaluate
be objective.
Criticise process with hindsight, assign valiie or worth to achievement, appraise,
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If process is the direction of action, then methodology is the type of action- that is, the particularness of action appropriate to each phase of the process. Methodology is the techniques and tools which a problem solver uses to reach a specific goal. The following methodology for establishing and applying site selection and design criteria far energy conservation is one approach to the problem.
"1(5 pnocaA-4 i.6 whana you ana going than mathodology iA hou) you gat thana."
H. Duane Blossom
First, a program must be established which clearly states the requirements and constraints of the project, client or site.
In this project there are two clients. Hie first is general in nature. It is those designers, planners and developers who are concerned with a method for approaching energy conscious design. The goal of this first portion of the program, then, is the establishment of an objective, rational and clear methodology for site selection and design for energy conservation. The second client is a developer with a specific site in Lyons, Colorado. Hie requirements for this site are to design an energy efficient planned unit development on 31.6 acres for 101 units. Hie goal of the second portico of the program is the development of an optimum energy efficient site specific design which utilizes the methodology established for the first client.
I.
accept
situation
This stage involves basic research into the field of energy conservation which might invlolve seme or all of the following:
II.
analyse
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regional and local climatic data, a literature search a comparison of comparable projects and studies and the relevant energy conservation legislation and incentives.
III. define At this stage it is necessary to
develop and define criteria for energy conservation. After this criteria has been established, it must be placed in a hierarchical order. Then, the site can be explored in terms of its topography, slope, climate, geology, soils, vegetation, hydrology, and man made elements. These components of the site can then be interpreted through the grid of the established energy conservation criteria. Although the elements of a site are always investigated prior to design, this project is proposing to explore them with respect to their relevance to energy conservation. For example, slopes are traditionally investigated in terms of degrees and aspect. An energy efficient design should reflect these parameters but also should take into account the implications for solar access and map this criteria as potentials or constraints. Soils are usually classified in terms of their capacity for sustaining buildings and other inpacts but they should also be examined for their capabilities for sustaining the vegetation proposed for conserving energy. The existing vegetation should be mapped and designated, if appropriate, as potentials or constraints in terms of its functionality. For example, an existing clump of trees may serve as an excellent wind barrier or it may inhibit solar access. Climatic factors such as winter wind direction, surtmer breezes and the solar path should be identified and addressed in the design. The synthesis of both the traditional and energy conservation data will result in a suitability map of the site which will demonstrate protected areas, exposed


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areas, patterns of solar radiation,shadow patterns, wind patterns, precipitation and tanperature patterns and water or drainage patterns. This stage of the process, then, dictates "kncwing" the land and its environment.
IV. ideate At this stage the designer is ready
- to generate conceptual designs based
on the knowledge of the program requirements, the criteria for climate modification and the trade offs involved in using the criteria. Although these trade offs will be ennumerated in the site specific case study, an example would be choosing to build on the south facing slope and gaining additional solar radiation fully realizing construction expenses would be higher than building on the flats where solar gain is less. A variety of conceptual designs which lie within the established guidelines should be generated to enhance the quality and validity of the final design.
A choice is made based on all the preceeding stages which best reflects a balance of the program in terms of an optimum design for human habitation.
select
VI. implement This stage involves the rendering of
J a final site design package which may include the design, sections, working drawings, specifications, bid documents and observation; of construction.
100% evaluation could occur only after years of record keeping but oarparisons with other projects and studies would be valid criteria.
VII.
evaluate
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case study
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CASE STUDY: PLANNED UNIT DEVELOPMENT, LYONS,-COLORADO
I.
accept
The program for the site in Lyons is as follows: integrate energy conservation criteria with the analysis of the natural determinants of the land and design a planned unit development for 101 dwelling units with a recreation center on 31.5 acres.
II.
analyse
Any site which is designed for energy efficiency must first be examined in its regional context in terms of altitude and climatic designation. The latitude in which the study occurs will determine general climatic parameters for the designer.
Because this project lies at 40 latitude, the sun's path and angle can be known for any time of the year. The sun's position is defined by two angles- the altitude and the azimuth. Altitude is the height of the sun abctve the horizon and azimuth is the east-west position of the sun based on a true south reference point. The altitude of the sun changes during the day due to the earth's rotation around its axis. Seasonal tilts of the earth's axis result in higher or ldwer altitudes as well. For instance, in sunnier, because the tilt is greater,the altitude of the sun is greater, the days are longer and the earth receives more solar radiation than in winter. On June 21st or summer solstice, the sun reaches its maximum altitude. Azimuth changes seasonally as well. At 40 latitude, on June 21st, the azimuth is 121 and on December 21, it is 59. The latitude of the site in conjuction with the topography also reveals radiation tables and shadew lengths which in turn, determine the amount and ease of solar access on a given site.
To protect for solar access for the whole year, it is necessary to design for december 21st when the sun's altitude is minimum and shadows cast are maximum.
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For instance, at 40 latitude on december 21st:
SLOPE NORTH FACING SOUTH FACING EAST FACING WEST FACING
Horizontal
radiation 675 BTU 675 BTU 675 BTU 675 BTU
shadow length* 20 ft. 20 ft 20ft 20 ft
10% Slope
radiation 445 BTU 897 BTU 666 BTU 666 BTU
shadow length 30.9 ft 14.8 ft 20 ft 20 ft
20% Slope
radiation 224 BTU 1101 BTU 637 BTU 637 BTU
shadow length 73.7 ft 11.6 ft 20 ft 20 ft
* shadow length is calculated for a 10 foot pole, multiply by 2 for a two story building.
The United States is divided into four major climatic zones each of which suggests an optimum orientation for heating from the sun and cooling tram the prevailing breezes.
Colorado is located in the temperate zone which means very generally, that buildings should be oriented 17.5 south to south-east, active living spaces to the south for winter warmth, deciduous trees should be planted to the south for summer shade and the south roofs should have overhangs to provide summer shade but allow access for winter sun.
Although these criteria are very general, the regional context of a site is an appropriate beginning for data collection.
Despite the fact that Colorado shares the temperate regional zone with such diverse areas as Kansas and Ohio, it is a unique area in terms of topography, geology and climate.
__________________15J




In addition, the areas near the mountains experience a great number of natural hazards such as wildfire, flash floods, avalanches, rockslides, severe erosion, seismicity, swelling soils and highly destructive winds.
In general, the Rocky Mountains serve as a major climatic determinant. Prevailing moisture laden winds from the Pacific hit the west side of the mountains and drop most of their precipitation resulting in semi-arid conditions on the eastern slope. The Rockies also serve as a conductor for both northerly artic winds and southerly Gulf stream winds which produce, respectively, very lew temperature in winter and heavy smews in spring.
front range air flow pattern
The predominant land forms- mountains, canyons, valleys and ridges produce a wide variety of micro-climates.
Sunny south facing slopes contrast with adjacent cool canyons. Weather is extremely variable and often changes dramatically over short distances. Dcwnslope breezes during the night and ups lopes during the day are caused by fairly great temperature differences frcm night to day. It is very important when designing near or in the Reeky Mountains to identify the microclimatic conditions of a given site. By "reading" the land, the microclimate can be known and those elements which contribute to energy efficiency can be taken advantage of and the inefficient elements can be modified.
Bounded on the east by the Great Plains and on the west by the mountain ranges, the Front Range rises from 5,600 ft to 13,000 ft in two giant steps culminating in the upper most ridges which form the Continental Divide. The Paleozoic and Mesozoic sediments have long ago been eroded frcm the high portions of the range leaving uplifted gneiss, granite and schist. The lower edge of the Front Range was formed by a different process. Sand deposited as beaches or sand bars along the edge of a sea which lay at the base of the Front Range in Permian times was deeply
arctic
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embedded, compacted, and then sharply uplifted. Ccrtmonly known as Lyons sandstone, these formations are very prevalent along the foothills.
From east to west the Front Range is divided by elevation, land form and climate into the following five ecosystems: The Plains, Foothills, Montane, Subalpine and Tundra. Although the climate of the Front Range can only be characterized as highly variable, certain generalizations can be made. An increase in altitude will resdlt in a decrease in temperature with an accompanying increase in relative humidity and a rise in precipitation. This means that the ecosystems became colder and wetter as altitude increases. Each condition produces a characteristic pallette of vegetation as well. Microclimates and their vegetative and erosive implications can be anticipated for east-west valleys along the Front Range. North facing slopes are wetter then east facing slopes and consequently have denser vegetation, more developed soils and greater resistance to erosion. Because of these conditons, north facing slopes have relatively steep gradients. South facing slopes, on the other hand, experience higher insolation and subsequent evapotranspiration. They characteristically have less dense vegetation, higher run off and lesser gradients than north facing slopes.
III.
define
ENERGY CONSERVATION CRITERIA
Traditionally in tnis country, communities have been planned on a grid system with single family dwellings on single lots. In terms of energy conservation, this type of design is inefficient and extremely rigid. Planned unit developments or cluster housing offers a unique opportunity for acheiving most if not all energy conservation criteria. By reducing lot size and density
FRONT RANGE ECOSYSTEMS
typical north and south facing slopes
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regulations, more efficient use of the land can be achieved. For instance, mixed use buildings can be clustered, existing vegetation can be utilized for shading and ventilation and roads and utilities can be reduced t>y 50%. PUD's are excellent vehichles for establishing trade offs. For example, higher densities can be exchanged for trails or pedestrian networks which link the ccmnunity to transit stations or other ccmnunity nodes thereby reducing automobile traffic and saving energy.
When compared to the one house-one lot suburban sprawl which exists today, planned unit developments represent an enlightened approach to land planning- an approach which soon will become the norm.
"d~| a
a a j a
a a a
Q o a 1 a
aaaaa u ?
[a |oB
traditional layout
pud layout
Optimum street layout in the temperate zone is on an east-west axis to avoid being a wind channel for winter winds and to provide easy access for summer breezes. If east-west lay out is not possible, climate modification such as wind breaks will have to be designed. Streets should be shaded and narrow to reduce heat accunulation. On a 90 day asphalt reaches a temperature of 140. Narrow streets also reduce construction and maintenance costs, lower the amount of run-off and reduce automoblile speed within the development.
V.


Site selection is optimum in terms of conserving energy on the middle or upper portions of the south to south eastern facing slopes. Maximum solar gain is found on these slopes in winter. West facing slopes should be avoided if possible, because of the heat accunmultion in sunmer. North facing slopes which are coolest in winter should be utilized for lew density develcpent and only if necessary. Good siting will avoid winter wind paths and valley bottoms which are frost pockets.
Because no site will offer optimum siting capacity, sane modification either for shade, wind or reflectivity will be necessary.
The best lot layout for energy conservation is north-south if single lot design is used. Appropriate building siting for this area is south to south east and 17.5 east of south for maximum winter solar gain. Shadow patterns must be studied when siting all units in order to maintain maximum solar access. Shadow patterns are determined by the height of the unit and the path and angle of the sun. (see chart on page 15 ) Tallest buildings,which cast the largest shadows, should be sited to the north of shorter buildings.
optimum siting: southfacing slope
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Location and type of vegetation is extremely important. For example, deciduous trees with fine branching patterns are appropriate on the south and southwest to provide relief frcm solar gain in sunrmer. In addition, high canopy trees are preferrable because they encourage sumner breezes.
Evergreen trees are appropriate on the north and northwest to screen winter winds. The shelter belt created by these plantings will be 10 times the height of the trees. Wind velocity can be reduced by 50% in the sheltered area resulting in a considerable reduction in heating requirements. For instance, to maintain interior comfort zones in a lOmph wind 80.6 are required whereas in a 1/10 mph wind, 62 are necessary.
In the Foothills ecosystem evergrees grow very slowly consequently design must reflect a reasonable average height of 10 to 12 feet and place them accordingly.
Man made wind screens may have to be designed for semi-arid environments to complement natural plantings. Needless to say, all plantings should be drought tolerant or indigenous in order to reduce water consumption and insure survival.
Earth berms are effective climate modifiers though are usually expensive. Special attention must be paid to the soil type and the possibility of creating drainage problems elsewhere on the site.
high canopy trees encourage
summer breezes
shelter belt* 10 times tree height
berms as wind breaks
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The first criteria for integration of architecture and site is that there should be minimal disturbance to the land. Topography and vegetation should be impacted as little as possible. To preserve site character, architectural forms and materials must be appropriate to the specific site. At this stage, architectural consulting and functional design planning is necessary. Conceptually,, architecture can interface with the natural surface of the land, rise above it or be recessed into it or a ccmbinaticn of the three. Building materials should be appropriate to the area as well as contribute to energy efficiency.
For winter solar gain, meduim coloured hard surfaces should be placed on south facing terraces and patios. Ground covers and grasses should be planted around the residence to reduce albedo and modify day time temperatures.
Energy conservation criteria obviously cannot all be met on every site but a knowledge of their relative importance is helpful in understanding the trade offs in discarding sane of them. The criteria have been placed in hierarchical order and related to one another in the form of the matrix on the following page.
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Hie site design options for the Front Range have been placed in a hierarchical order and then rated according to their potential for energy and cost efficiency. Because PUD or cluster development offers the greatest flexibility in terms of solar access, solar gain and wind reduction, it is considered an optimum ccrrrnunity design. Also in terms of cost efficiency, it is one half the upfrcnt construction cost of a traditional single family/ single lot layout.
Aspect or the direction a slope is facing is considered the next crucial criteria. If development is sited on a north facing slope, minimal BTU's will be received which will result in the least efficient solar gain and access whereas the oost of oonstuction will not vary from any other aspect given equivalent slopes.
Laying out streets on an east-west axis allows far maximum solar gain, solar access and potential for wind reduction, whereas with north-south orientation, energy efficiency is minimal. If north-south streets are necessary due to topography, adequate wind breaks must be provided and buildings must be sited awkwardly in relation to the street. Narrow streets allow for less heat gain and lower construction oost. If wide streets are necessary, adequate shade trees must be provided to offset the heat gain.
north south
east west
Optimum building sites on a lot, if individual lots are used, are on an east-west axis to provide maximum solar gain in winter and minimum solar gain in summer. A north-south orientation would result in just the reverse.
Taller buildings must be sited to the north of shorter ones to insure solar access. If they are not sited to the north, even active solar systems would be useless in the mid winter months.
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Evergreen trees are extranely efficient in terms of wind reduction when planted to the north ard northwest of a structure but seriously impede solar access when planted to the south. Deciduous trees are useless in terms of functionality when sited to the north and extremely efficient for shading the sunmer sun when planted on the south and southwest. Existing vegetation must be thoroughly analyzed for its energy efficiency potentials. It is possible that seme vegetation will have to be removed entirely or transplanted if conditions allow.
By determining a hierarchy of energy conservation criteria it is possible to grasp the trade offs involved in planning an efficient community.
SITE SPECIFIC DATA
The case study for this project lies in the foothills ecological zone which is located between the high plains and the montane ecosystems. It is characterized by rough mountains with deep, narrow valleys, many small intermittent streams, broad topped windy ridges and steep to gentle slopes. Soils are best and deepest where the small tributaries enter the larger valleys. Climatically, the zone is relatively dry and warm. Falls are dry and winters are cool. Snow pack remains on north facing slopes through most of the winter though rarely on south facing slopes. Westerly winds prevail all year although the coldest winds ccme fran the north.
The vegetation in this zone has been heavily impacted by man by means of fire, mining, logging, grazing and cultivation. Dominant species are pcnderosa pine, douglas fir, shrubs and grasses.
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Stone canyon is located just east and north of Lyons,
Colorado which is nestled against the Front Range at the confluence of the North and South St. Vrain Rivers. The Lyons area is relatively protected form devastating winds due to its proximity to the mountains. Mean temperatures range from 27 in winter to 70 in sumner and annual precipitation is 15.5". Mean cloudy days are only 16% making Lyons an excellent place for passive solar energy design. Stone canyon rises fran its confluence with the St. Vrain River seven miles due north. A typical colluviun valley situated between sandstone ridges, its vegetation is predominately grasses, yucca, shrubs and cactus.
The site itself is 31 acres divided by an intermittent stream and swale. A county road cuts through the property servicing the existing rock quarries at the top of the canyon. Surrounding land use is predominately undeveloped with the exception of seme older residences to the southwest. Winter winds flow down the canyon from north to south generally following the path of the swale. Summer breezes flew upward from the south east. For the most part, the soils are colluvium which is tolerant for building although a soils engineer may recccrrmend basanent-less buildings. The wertem most ridges are considered moderately tolerant in terms of soils. The eastern ridges are considered to be very inadequate for building due to their high degree of bedrock. 100 feet to either side of the intermittent stream is considered to be a severe constraint for building as well. Views from the site are spectacular panoramas of mountains and valleys and should be utilized in design and preserved if possible.
The constraints are mapped on the following page which reflect vegetation to be saved, slopes too steep to build on without incurring great costs and impact and the area of the flood plain.
Following the constraints is the Solar Access map which Solar Access
designates good, moderate and poor slopes for passive design.
27
Site Analysis
Constraints


STONE CANYON SOLAR ACCESS > elsie booth mackinnon
planned unit development landscape architecture
lyons, boulder co, Colorado ucd may, 1980 29,


The Suitability map is then generated by overlaying the Suitability
Site Analysis, Constraints and Solar Access maps. By
using the overlay method, it is easy to rate areas in
terms of suitability for energy conservation site
selection. The most suitable areas on this site are the
gently rising south and south-east facing slopes which
have tolerant soils and no flood plain or vegetative
constraints. Moderately suitable areas are those with
similiar conditions to the most suitable areas but are
located on south-west facing slopes and consequently,
receive only moderate solar access. Areas considered
least suitable are those which have steep slopes, flood
plain, highly erodible soils or bedrock and poor solar
access. The suitability map enables the designer to
make intelligent choices for site selection and easily
determine the trade offs inherent in those choices.
Once site selection has occurred, design begins.
31




IV. I ideate I At this stage conceptual design
' * options are generated and evaluated
in terms of the program requirements, the established energy conservation criteria and the trade offs involved in using the criteria.
Alternative A: This option, uses north-south streets with feeder cul-de-sacs consequently a wind channel is created for winter winds and the units are not sited optimally far solar access. In addition, it utilizes slopes over 18% adding to construction costs but increasing the number of BTUs recieved.
Alternative B: This option creates maxiiwn open space by stacking the units into high rises. Although optimum siting for solar access is attained, shadow patterns inhibit anything but active solar systems for the units furthest north. Also the soils cannot sustain high rises without considerable expense. It is questionable whether high rises are appropriate for this area as well.
This option does have minimal street lengths and consequently minimum heat build up.
Alternative C: Streets in this option are laid out along the contours in roughly an east-west direction although they are almost twice the length as those in option B. Buildings on the west are oriented for optimum solar access while those on the east are moderate in terms of solar access but are sited there to reduce the congested, almost urban atmosphere of Alternative A.
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V. select Although all three alternatives
utlilize cluster development, the selected plan, at left, is the most responsive to the program in that there is less crawling of units and appropriate heights ( a maximum of three stories and a mean of two.) The streets are laid out along the contours for minimal site disturbance and they are oriented on as much of an east-west axis as possible. Buildings are sited to the south-east for maxinun solar gain, deciduous trees are placed on the south to south west for summer shade and evergreens block the winter winds an the north and north west. Most units are two story and are sited appropriately for insuring solar access. None of them are closer than 29.6 feet which is their maximum shadow pattern cast on December 21st. Pedestrian trails are provided throughout the site linking the units and the community center.
VI.
implement
This stage would involve the final drawings, specifications, bid documents,
and observation of actual construction which is beyond the scope of this project.
VII.
evaluate
Definitive evaluation in terms of energy conservation could, of course, only occur after the project was built and in the ground for a few years but a comparison can be made between the proposed site plan for this project and the proposed more traditional plan for the same site. A grid system was proposed with single family-single lots. Street widths and lengths are double that of the cluster development. Most streets are oriented north-south. 75% of the lots are oriented for minimal solar gain. Lots are proposed not only on the steep bedrock slopes but also in the flood plain and open space is at an absolute minimum. The costs of constructing the energy conservation plan would be less than the traditional plan beacuse the streets and consequently the utlities are half
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the cost, by building with instead of against the contours, considerable costs are saved in site preparation and earth moving, and building construction costs are lower using attached units as opposed toseparate units.
In conclusion, this project has demonstrated one method for applying energy conservation criteria to the site selection and design process. The tanplate of energy conservation fits well into the established design process and can be energy as well as cost effective. Neither complicated nor profound in itself, the application of energy conservation techniques has profound implications far the future in terms of the quality of both human life and the environment.
V.
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GENERAL BACKGROUND
Lynch, Kevin, Site Planning, MIT Press, Cambridge, 1975.
Marsh, William M., Environmental Analysis, McGraw Hill, New York, 1978.
Pasko, Carolyn, Ed., Solar Directory, Ann Arbor Science, 1975.
Simonds, John 0., Earthscape, McGraw Hill, 1978.
Spam, Stephen, Integrated Life Support Systems, Joint Venture, Boulder, 1975. Wines, James, Ed., On Site/ On Energy, Charles Scribner, New York, 1974.
Progressive Architecture, Special issue: "Energy Conscious DesignApril 1979. ------------- Special issue: "Energy Conscious Design',' April 1980.
HISTORY AND PHILOSOPHY
Boughey, Arthur, Man and the Environment, Macmillon & Co, New York, 1971.
Brown, Lester, The Twenty Ninth Day, Norton & Co., 1978.
----------World Without Borders, Vintage Books, 1973.
Dubos, Rene, A God Within, Charles Scribner, New York, 1972.
Ewald, William, jr., Ed., Environment and Policy, Indiana University Press, 1967. Goldman, Marshall, Ecology and Economy, Prentice Hall, New Jersey, 1967.
McHarg, Ian, Design With Nature, Doubleday, New York, 1971.
Rudofsky, Bernard, Architecture Without Architects, Doubleday, 1964.
Schumacher, E. F., Small is Beautiful, Harper & Bcm, 1973.
Steadman, Philip, Energy, Environment and Building, Cambridge University Press, 1971. Whyte, William, H., The Last landscape, Double day, 1968.
PROCESS AND METHODOLOGY
Halprin, Lawrence, Creative Processes in the Human Environment, George Braziller, Inc. N.Y.,1976. Kbberg, Don and Jim Bagnall, The Universal Traveler, William Kuafman, Inc., Los Altos, 1976.
FRONT RANGE CLIMATE
Anderson, Bette, Weather in the West, American Publishing Co., Palo Alto, 1976. Barry and Chorley, Atmosphere, Weather and Climate, Methuen and Co. 1978
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Berry, Roger G., Climatic Environmnet of the East Slope of Hie Colorado Front Range, INSTAAR, 1972.
Brooks, F.A., An Introduction to Physical Microclimatology, University of California, Davis, 1960.
Ford, Kritina, Ed., Remote Sensing for Planners, State University of New Jersey, 1979.
Foss, Philip, O., Ed., Environment and Colorado, CSU, Ft. Collins
Hansen, Chronic and Matelock, Climatology of the Front Range Urban Corridor and Vicinity,Colorado,
US Government Printing, 1979.
Lockwood, John G., Causes of Climate, John Wiley & Sons, New York, 1979.
Madole, Richard, F. "Environment Inventory and Land Use Recocrnendations for Boulder County Co'.' INSTAAR, 197! Marr, John W. Ecosystems of the East Slope of the Front Range in Colorado, INSTAAR, 1967.
Cke, T.R., Boundary Layer Climates, Wiley & Sona, 1978.
Olgyay, Victor, Design With Climate, Princeton University Press, 1973.
Siemer, Eugene, Colorado Climate, Colorado Experiment Station, 1977.
Yoshino, Masatoshi, Climate in a Small Area, University of Tokyo Press, 1975.
GEOLOGY
Chronic, John and Halka, Prairie, Peak and Plateau, Colorado Geologicn Survey Bulletin # 32, 1972. Ambleton, Clifford & Thanas, Process in Gecmorphology, John Wiley & Sons, New York, 1979.
Robinson, G.D. and Spieker, A., Ed.,"Nature to be Carmanded',' Geologic Survey Proffessional Paper 950, US Goverrment Printing, 1978.
Shelton, David and Prolty, Dick,"Nature's Building Codes',' Colrado Department of Natural Resources, Special Publication # 12, 1979.
Way, Douglas, Terrain Analysis, McGraw Hill, 1978.
PASSIVE SOLAR
Crowther, R., Sun Earth, Charles Scribner, 1977.
Eccli, Eugene, Lew Cost Energy Shelter,Rodale Press, 1976.
Joint venture, Here Canes the Sun, Joint Venture, Boulder, 1975.
Mazria, Passive Solar Energy Book, Rodale Press, 1979.
Wright, David, Natural Solar Architecture, A Passive Primer, Van Nostrand, New York, 1978. Progressive Architecture, Watson, "Insolations", November, 1979.
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ARCHITECTURE & ENERGY
Burberry, Peter, Building for Energy Conservation, Halsted Press, John Wiley & Sons, New YOrk, 1978. Villecoo, Marguerite,"Architecture as Energy',' Design Quarterly 103, Walker Art Center, 1977.
Stein, Richard, Architecture and Energy,Doubleday, New York, 1977.
Untermann and Small, Site Planning for Cluster Development, Ven Nostrand, 1977.
Underground Space Center, Earth Sheltered Housing Design, VanNostrand, 1979.
DESIGN
Bainbridge ard Hammond,"Planning for Energy Conservation',' Davis, California, 1976.
Carpenter, Walker, Lanphear, Plants in the Landscape, Freenan & Co., 1975.
US Department of Connerce, Options for Passive Energy Conservation in Site Design, Center for Landscape, 1978.
Ntoore, Fuller, "Alleys of Richmond',' Richmond City Energy Program.
Ridge way, James, Energy- Efficient Caimunity Planning, JG Press, Inc., 1979.
Robinette, Ed., Landscape Planning for Energy Conservation, Environmental Press, 1977. ---------Plants, People and Environmental Quality, Department of the Interior, 1973.
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