Climate Response for the TropicsThree houses as guidelines for contemporary design in San Juan, Puerto Rico

Cristina von Essen

A dissertation submitted in partial fulfillment of the regulations for the Degree of MSc Renewable Energy and Architecture in the University of Nottingham, 2009

September 4, 2009

ii

Thanks to Dr. Mohamed B Gadi for supervising and providing advice on the

development of this dissertation. Special thanks to Arq. Beatriz Del Cueto, FAIA and

Arq. Jorge Rigau, FAIA for providing guidance and historic background information.

The Colegio de Arquitectos y Arquitectos Paisajistas de Puerto Rico and the

Haeussler and Orraca families for providing access to their homes.

Muchas Gracias!

iii

Abstract

! The island of Puerto Rico is located in the Caribbean at 1815"N and 6630"W

within the Tropic of Cancer. It enjoys a stable climate with an average climate of

27C (80F) throughout the year. Although it also benefits of cool breezes from the

Atlantic Ocean, most of the structures are not designed considering the climate. To

better understand the behavior of structures on the Island, three houses from three

architectural periods were selected: Spanish Colonial, Turn-of-the-Century, and

Tropical Modern. The natural lighting conditions, thermal properties and natural

ventilation of these residences were analyzed with the aid of Ecotect and Fluent.

Once the results for each of the structures was analyzed and compared, a set of

design guidelines were produced, based on the individual results, to aid in the design

of climate-conscious structures in San Juan, Puerto Rico.

iv

Table of Contents

Page

AcknowledgementsAcknowledgements iii

AbstractAbstract iv

List of FiguresList of Figures vi

IntroductionIntroduction 1

Part I: Background InformationPart I: Background InformationPart I: Background InformationPart I: Background Information

ChapterChapter

1 Scope and Parameters 5

2 Island Characteristics 7

3 Development of the Island 14

Part II: Experimentation ResultsPart II: Experimentation ResultsPart II: Experimentation ResultsPart II: Experimentation Results

4 Methodology 29

5 Ecotect Results 39

6 CFD Simulation 57

ConclusionConclusion 72

AppendicesAppendices 78

Addendum 1Addendum 1 79

Addendum 2Addendum 2 88

Addendum 3Addendum 3 95

BibliographyBibliography 108

v

List of Figures

Figure Page

Chapter 2 Chapter 2

1Location of Puerto Rico in relation to North, Central and South America

7

2 Wind rose showing direction and magnitude 8

3 Graph showing average monthly temperatures and solar radiation 9

4 Psychrometric Chart for San Juan, Puerto Rico 9

5 Relationship between relative humidity and average temperatures 10

6 Ideal orientation in relation to the sun path 11

7 Sun path diagram for San Juan, PR in plan and side view 12

8* Rendering of the Caribbean Islands and the Puerto Rico Trench 13

Chapter 3 Chapter 3

1** Taino dwellings drawn by Oviedo 15

2Spanish Colonial structures showing the range of adaptations done to the original single-level structures

16

3Architectural details of a typical Spanish Colonial house in San Juan, PR

18

4Details of the Gonzlez-Cuyar Residence, an example of Turn-of-the-Century architecture in San Juan

21

5 Mediopunto in the Gonzlez-Cuyar Residence, San Juan, PR 22

6 Haeussler Residence, 1945 25

Chapter 4 Chapter 4

1 Location of the selected structures in San Juan, Puerto Rico 29

2Aerial picture of Old San Juan indicating the location of San Sebastian #8

30

3Aerial picture indicating the location of the Gonzlez-Cuyar Residence

31

4 Aerial picture indicating the location of the Haeussler Residence 31

5 Table showing the material properties used in Ecotect 33

vi

6 Ecotect model construction 33

7 Sizing of analysis grid 34

8 Creation of mesh in Gambit 35

9 Mesh refinement of zone 1 36

10 Mesh refinement of zone 2 37

11 Example of residuals results after iterations were completed 38

Chapter 5 Chapter 5

1Daylight analysis of the Spanish Colonial structure at 30 and 250 cm

40

2Daylight analysis of the Turn-of-the-Century structure at 30 and 250 cm

41

3Daylight analysis of the Tropical Modern structure at 30 and 250 cm

41

4Thermal comfort analysis of the Spanish Colonial structure at 30 and 250 cm

43

5Thermal comfort analysis of the Turn-of-the-Century structure at 30 and 250 cm

44

6Thermal comfort analysis of the Tropical Modern structure at 30 and 250 cm

44

7 Temperature distribution for the Spanish Colonial structure 46

8 Temperature distribution for the Turn-of-the-Century structure 47

9 Temperature distribution for the Tropical Modern structure 48

10Interior and exterior temperature comparison for the Spanish Colonial structure

49

11Interior and exterior temperature comparison for the Turn-of-the-Century structure

50

12Interior and exterior temperature comparison for the Tropical Modern structure

51

13Outside/Inside temperature difference and comparison for all three structures

52

14Time spent within the comfort zone for the roof, space and floor for the three selected structures

53

15 Yearly gains breakdown for the three selected structures 54

vii

Chapter 6 Chapter 6

1General site plan for San Sebastian #8 indicating wind direction and pressure

58

2Detail site plan for San Sebastian #8 indicating wind direction and pressure

59

3Plan vector plot of San Sebastian #8 indicating wind direction and magnitude

60

4General section of San Sebastian #8 indicating wind direction and pressure

61

5General site plan for Gonzlez-Cuyar Residence indicating wind direction and pressure

62

6Detail site plan for Gonzlez-Cuyar Residence indicating wind direction and pressure

62

7Plan vector plot for the Gonzalez-Cuyar Residence indicating wind direction and magnitude

63

8Section a-a of Gonzlez-Cuyar Residence indicating wind direction and pressure

64

9Section b-b of Gonzlez-Cuyar Residence indicating wind direction and pressure

64

10Vector plot for section b-b for the Gonzlez-Cuyar Residence indicating wind direction and magnitude

65

11Section c-c of Gonzlez-Cuyar Residence indicating wind direction and pressure

65

12General site plan for Haeussler Residence (closed) indicating wind direction and pressure

66

13Detail site plan for Haeussler Residence (open) indicating wind direction and pressure

67

14Plan vector plot for the Haeussler Residence (open) indicating wind direction and magnitude

68

15 Vector plot for fixed vent detail 68

16Section a-a of Haeussler Residence indicating wind direction and pressure

69

17Section b-b of Haeussler Residence indicating wind direction and pressure

70

18Section c-c of Haeussler Residence indicating wind direction and pressure

70

viii

ConclusionConclusion

1 Roof exposure 73

2 Roof ventilation 73

3 Elevated slab on ground 74

4 Thermal mass 74

5 Long shading devices 75

6 Louvers 75

7 Openings 75

8 Open structure 76

9 Courtyard as chimney 76

All figures were produced by the author, except those with and asterisk*.* www.usgs.gov** Fernndez de Oviedo, 1851.

ix

Introduction

! Although Puerto Rico"s architecture has been influenced by various cultures

throughout its development, few scientific studies have been conducted on the

structures, technologies, and their efficiency. Most of the research grants and reports

are historic or oriented towards the conservation of the structures. Very few, if any,

scientific investigations have been carried out to study the climatic conditions of the

materials and design solutions of various architectural styles. Most of the

explanations found on books that describe the relation between building materials

and design are based on historic documents and/or formal architectural analysis of

the structures.

! Because of varying reasons, most of the Islands contemporary architecture is

not climatically responsive, causing the users to invest in alternate methods to cool

the structures. This research topic was proposed partially as a response to these

unconsciously designed buildings, and partially because of personal interest. This

research intends to provide a better insight into the historical constructions in Puerto

Rico, and how some of the architectural solutions and materials used at the time of

design could be adapted to contemporary structures to make them more climate

conscious. Ideally, this research will promote interest on the Island to create better

designed structures that deal with the local climate using traditional methods and

construction with a new perspective.

! For this research three single family houses were chosen and analyzed to

better understand their design and construction. The three selected structures

respond to three major changes in the way architecture was carried out in Puerto

Rico. The first occurred when the Island was colonized by the Spaniards. The

second period came as a response to the Spanish-American War, where, as a result,

the Island became a territory of the United States. The third period to be analyzed is

during the Tropical Modernism movement where a wider interest in climate

conscious design in conjunction to new materials and methods resulted in the

creation of structures unlike the previous architectural examples. This research

1

hopes to achieve a better understanding of the construction methods and their

climatic results in order to provide the reader, as well as local architects, with a better

understanding of the historic structures and the possible contemporary design

approaches that could be used.

! Because of Puerto Rico"s location and size, it is necessary to create eco-

conscious designs that have the least amount of impact on the local resources while

still providing the users with all the contemporary commodities. By scientifically

studying the historical buildings, architects and designers can use the results to

achieve certain designs that have spatial and climatic responses. Because these

design guidelines would be based on structures that have endured the test of time,

they would provide a trustworthy benchmark for design. The results and

recommendations, product of this research, could provide guidelines for design for

all future structures on the Island irrespective of their architectural style.

! The main research question to be investigated is How can the traditional

design solutions, including natural ventilation and materials, be adapted for

contemporary use? and Which of the selected houses has the best climatic

performance? The answer to these questions should provide a better understanding

of the design approaches that will be necessary to create climate conscious

buildings in Puerto Rico. Based on on-site experience and observations, it is

expected that the Colonial and the Tropical Modern examples would have the best

results. The Turn-of-the-Century structure would have the least favourable results of

the three.

The research must be completed in a short period of time so two computer

programs will be used to carry out the analysis. Ecotect will provide the results for

the design approach and materials used, while Fluent will analyse the air circulation

patterns of the structures. Line drawings, as well as 3-D models of all the houses

and their context will be constructed for analysis purposes.

As mentioned above, the results obtained from this research have the

possibility to affect the way architecture is perceived in Puerto Rico. The insight

provided could clear speculations on building design efficiency and material

performance. Additionally the results could pose new questions and provide an

impulse into further researches on the Island. On the long run, this research can help

the development of new design approaches to construction in Puerto Rico that use

2

local materials in a manner that can help control the energy demands of the homes.

When the results and guidelines are used by willing architects, the ensuing designs

could even prove to have a lower cost than current housing, making it affordable to a

wider range of families.

For this investigation the implied costs of research could be considered low. A

trip to Puerto Rico would be necessary in order to asses the buildings and record

them with pictures and drawings. Additionally, background research on the

development of the Island as well as the changes in construction would have to be

carried out while in Puerto Rico since there is a broader availability of resources

there. Meetings with local architects that have published works on the houses or

construction periods studied will be conducted to gain a better understanding of the

designs. Apart from the cost of visiting the Island, there is the use of computer

resources in the computer lab of the University for the building analysis.

This research will primarily serve as a base for future works. Because it is the

first time this kind of investigation and comparison is performed on these structures,

it opens the doors for other investigators to study different areas using this research

as a basis. This examination could be expanded into a more detailed report, which

can be done by taking climatic measurements on-site on all the houses as well as

record how the users interact with the structures. This, of course, would need a

much longer period of time to be completed than was available, but could be used in

the future for a PhD or further research.

3

Part One: Background information

4

Chapter 1

Scope and parameters

! Before the subject of architecture in Puerto Rico can be approached, there

are certain terms and parameters that must be clarified. Due to the short duration of

this research, a basic study of the impact of natural ventilation on the architecture of

the Island is to be conducted. Computer analysis using CFD and Ecotect, instead of

actual measurements, will be used to analyze the selected structures. This also

poses restrictions as the data collected from these computer simulations will be

based on average meteorological data and ideal conditions that would be difficult to

obtain in real-life scenarios. In order to complete the analysis in the alloted time, only

three structures, one for each study period, were selected. This leaves, however, the

possibility for this research to be carried out further and in more detail in the future.

! Since this research is based on the architecture of Puerto Rico, it is necessary

to note that geographical determinism played a mayor role in the development of the

designs. As will be explained in Chapter 2, the island of Puerto Rico boasts an

expansive array of micro climates and geological features that favored some

solutions and discarded others. Geographical determinism, as a theory that

maintains that the culture and habits of a society are based on the direct interaction

with their environment, has provided the Island"s inhabitants with a broad spectrum

of conditions to which to adapt. From coast lines to mountain ranges; from

mangroves to rivers; from rain forests to dry forests, Puerto Rico offered variations

and the residents reacted, in the majority of cases, accordingly. The response from

the inhabitants and the assimilation of alien architectural styles make the distinction

between traditional and vernacular architecture necessary.

! To define vernacular architecture, the Plan Carimos provides a good

definition, it states that, It is the product of the tropics that does not require master

5

builders, but rather, unschooled architects formed in the school of tradition.1 It also

states that it is a resultant of the habitat and is defined by the climatic conditions.2 It

is the architecture that is shaped and improved upon by the users throughout

generations, based on the geographical determinism. In contrast, traditional

architecture is that which is planned and emulated through a period of time. It

contains elements that are part of an aesthetic-oriented interpretation rather than a

functional one. It is an accepted vocabulary that is repeated as part of a cultural

tradition. Vernacular architecture can be transformed into traditional once the

designs are interpreted through an aesthetic lens. On the other hand, it is difficult for

established traditional architecture to become vernacular.

! For this study, three periods representing mainly traditional examples were

selected. These are the Spanish Colonial (from the end of the sixteenth century to

the end of the nineteenth), Turn-of-the-Century (from the end of the nineteenth

century to the 1930s), and the Tropical Modernism (from the 1940s to the 1970s).

These periods were selected as they marked a clear break from the architecture

styles of previous years and introduced new vocabularies. These will be discussed in

more detail in Chapter 3. In order to focus the research, representative single family

residencies were selected. One house from each period was chosen within the

metropolitan area of Puerto Rico. Additionally, due to the construction materials

used, the structures have a level of permanence that have allowed them to remain

relevant in contemporary society.

6

1 Carimos, 2000, p.21.

2 Idem.

Chapter 2

Island Characteristics

! The island of Puerto Rico is located on the northeastern corner of the Antilles

archipelago surrounded by the Atlantic Ocean to the north and the Caribbean Sea to

the south [Fig. 1]. Off the west coast there is the Mona Channel, considered a

treacherous passage where the Atlantic Ocean and the Caribbean Sea meet

creating dangerous currents. It is considered the smallest of the Greater Antilles and

the biggest of the Lesser Antilles. This strategic location was of most importance as

a port of entry to the Americas and as a control point during the colonization, hence

providing the Island with the nickname of The Key to the Indies.

! Puerto Rico"s location also provides the island with trade winds all year-round

that primarily sweep in from the northeast and supply the Island with cool air. The

aliz winds generally blow during the winter months, providing Puerto Rico with a

steady supply of cool air from Europe and the North Atlantic. The trade winds also

steer rain systems towards the island, and during the summer months, they are

partially responsible for the Hurricanes that hit land. Because of the direction of

Fig. 1 Location of Puerto Rico in relation to North, Central and South America.

7

these winds and the Central Mountain Range, the north coast receives most of the

precipitation, making it very green and lush, while the south remains dry.

! As can be seen in the wind rose [Fig. 2] the principal wind direction during the

year are the aliz winds from an east northeast direction, between 60 and 95 from

North. The chart also indicates that the principal speed is between 20 km/hr (12

mph) and 30 km/hr (18 mph). The wind direction and speed are very important for

the natural ventilated design process in the Island since the designed structures

should take advantage of the available wind for cooling. Although at a much lower

speed and occurrence, there is an occasional breeze from the southeast that should

be taken into consideration during the design process. Usually this wind originates in

the Caribbean Sea and is heated as it enters the south of the Island. Therefore, it is

warm air, that, if it is to be used, should be conditioned and cooled.

! With a latitude of 1815"N and a longitude of 6630"W, Puerto Rico is located

between the Equator and the Tropic of Cancer and has a tropical climate. Because

Fig. 2 Wind rose showing direction and magnitude

8

of its small size and ideal location, most of Puerto Rico has favorable temperatures

throughout the year. The average yearly temperature is 27C (80F), with the

average maximum being 31C (87.8F) and the lowest average being 22C (71.6F)

with an average humidity of 65% [Fig. 3]. The ideal location for comfortable

temperatures is along the coastline and in the mountains where, the temperature can

be up to five degrees lower than in the coastal plains.

Fig. 3 Graph showing average monthly temperatures and solar radiation

Fig. 4 Psychrometric Chart for San Juan, Puerto Rico

9

! Despite the fact that the actual temperatures of Puerto Rico are within the

comfort zone, the high humidity percentage makes the climate seem hotter than it

actually is. This is the main reason why the psychrometric chart shows most of the

temperatures outside comfort throughout the year [Fig. 4]. The relationship between

temperature and humidity can be seen in Fig. 5. It is noticeable that, on average, the

lowest humidity occurs when the temperatures are at their highest, between noon

and four in the afternoon. This graphs also indicates that the most humid moments

during the day are in the early morning and night times. This should be taken into

consideration when designing structure that depend on natural ventilation, since

additional devices might be needed for the control of the humidity levels.

Fig. 5 Relationship between relative humidity and average temperatures

10

! When analyzed the ideal orientation for a structure in San Juan is facing north

[Fig. 6]. Because the Island is located near the Equator, the most intense direct

sunlight and solar radiation comes from the South [Fig. 7]. It is therefore necessary

to take the needed precautions when designing structures so that by means of

shading devices the spaces are shielded from the sun. Additionally, because the

climate of Puerto Rico is constant throughout the year, the shading devices used

should protect the structure at all times. The east and west surfaces also receive

direct sunlight, but as Figure 6 indicates, the area of these should be kept at a

minimum. By studying the sun path and the ideal orientation for a building, design

decisions can be made that favor the interior spaces in terms of natural lighting while

admitting the least possible radiation from the sun. Since the light that comes from

the North is not direct, it provides ideal lighting conditions without the added heat

gains to the spaces.

Fig. 6 Ideal orientation in relation to the sun path

11

! Although Puerto Rico is small in size, 180 km (112 miles) east-west by 64 km

(40 miles) north-south, it has three distinct geographical zones; coastal plains,

mountain region and the karst. The center is composed of the Central Mountain

Range with the highest peak reaching an altitude of 1,338 m (4,390 feet) above sea

level. The mountains slope gradually to the north until they reach the Northern

Coastal Plains. Towards the south, the drop in altitude is abrupt providing the area

with short fast-moving rivers while the north has long strong-flow rivers. Although

there are coastal plains on the north and south strips of the island, two-thirds of the

land is mountainous. Towards the northwest the landscape is overpowered by the

Karst, a combination of haystacks and sinkholes made of limestone.1

! The position of Puerto Rico also exposes it to unfavorable natural events. To

the north of the Island, about 121 km (75 miles) offshore, is located the deepest part

of the Atlantic Ocean, the Puerto Rico Trench [Fig. 8]. This is where the Caribbean

and Atlantic tectonic plates meet. It has a maximum depth of 8,380 m (27,493 feet)

and spans an area of 1,750 km (1,087 miles) east-west and 97 km (60 miles) north-

south. Due to the adjacency, Puerto Rico has experienced strong earthquakes in the

past, the latest one being in 1918 with a magnitude of 7.5 in the Richter Scale. As a

result of this event, a Tsunami wave was created that hit land and caused extensive

Fig. 7 Sun path diagram for San Juan, PR in plan and side view

12

1 Jimenez De Wagenheim, 1997.

damage. Although the Island has not had a major earthquake in 91 years, it

experiences occasional tremors.

! Another weather threat is the Hurricane season where the main trajectory for

the systems brings them close or over the Island. The last major Hurricane to hit

Puerto Rico was Georges in 1998, with sustained winds of 175 km/hr (109 miles/hr).

Since there is a threat from tropical storm systems hitting the Island every year, most

of the construction is reinforced concrete and/or steel that can withstand the heavy

beating of the wind and rain. Just as the trade winds bring cool air, they help steer

tropical systems towards Puerto Rico as well as carry dust from the Sahara that is

deposited on the island and drastically reduces the air quality.

! The combination of all these conditions heavily influenced the way Puerto

Rico was developed and settled. It was necessary for the early settlers to strike a

balance between all the conditions and find the most favorable location, orientation,

and materials to establish a village. This process of selection and organization will be

discussed in the next chapter.

Fig. 8 Rendering of the Caribbean Islands and the Puerto Rico Trench

13

Chapter 3

Development of the Island

! The island of Puerto Rico had been inhabited by several peoples which have

influenced the culture, traditions and, consequently, the architecture. Since its

discovery during Christopher Columbus" second journey in 1498, it has been widely

impacted by all the civilizations that settled on the Island. The traditional methods

that all these culture introduced were then interpreted and absorbed into what then

became the vernacular architecture of Puerto Rico. As Carol Jopling explains:

Puerto Rican society evolved from the merging of different peoples, three of

whom were of greatest importance: the Taino indians who populated the

island at the time of the first European contact, the Spaniards who conquered

the island early in the sixteenth century, and the black Africans who were

brought as slaves from the sixteenth to the middle of the nineteenth

century. ... Since 1898, the major and pervasive influence has come from the

United States. The architectural styles of all these peoples are still identifiable

even though they were always modified and adapted so as to become

distinctly Puerto Rican.1

The Island has been able to develop an individual style compared to other Caribbean

Islands. To this day, examples of the influence from these other societies are visible

throughout Puerto Rico in buildings ranging from the Colonial period to contemporary

structures. To better understand the evolution of vernacular architecture, it is

necessary to first understand how the Taino lived and organized their villages and

how that slowly was integrated into town layouts during the Colonial period.

! The local indians built their communities around a central plaza called the

batey. The chief, or cacique, lived in elliptical or polygonal hut or bohio located in the

batey with the rest of the village living in round bohios, between 10 to 12 meters in

14

1 Jopling, 1992, p. 5.

diameter, shared among multiple families [Fig. 1]. Shortly after the arrival of the

Spaniards, the local Taino adapted their structures to rectangular shapes with a roof

of two slopes.2 Other tribes in the neighboring islands maintained their structures

unmodified as recorded by Fernndez de Oviedo. This adaptation marks the start of

the assimilation between the vernacular architecture of Puerto Rico and the

traditional methods of the immigrants. Steadily, the Spaniards adapted the bohio to

the building techniques from their homeland and created structures so that any lord

could lodge in one of them3. These bohio type buildings continued to be used by the

Spanish conquistadors until 1590 when the houses in the islet of San Juan were

destroyed by a hurricane and were thus replaced by more permanent structures

made of stone or adobe4 and wood.5

! These more permanent structures were similar to the ones constructed in

Spain in Estremadura and Andaluca, where most of the first colonists originated

Fig. 1 Taino dwellings drawn by Oviedo.

15

2 Jopling, 1992, p. 7.

3 Ibid, p. 9.

4 It is a common mistake to confuse adobe wall construction to tapia wall construction. See note 6 for

tapia for definition and clarification of the terms.

5 Jopling, 1992, p. 15.

form. These buildings would integrate local materials into the construction such as

stones, tapia6, clay tiles, ausubo7, and mampostera8. Carol Jopling explains:

The style of the early Spanish Colonial house consisted of a simple, austere

one-story structure built of mampostera at curb height, enhanced only by

such restrained details as repeating straight lines of shallow relief, dentils

bellow the soffit of the cornice and horizontal moulding. The style is

characterized by a feeling of solidity and weight, conveyed by the materials,

the thickness of the walls, and the horizontal lines.9

At first, these structures changed very little, but as the time passed they were

progressively adapted to the climatic conditions of the Island, thus creating the

Spanish Colonial Architecture style [Fig. 2].

Fig. 2 Spanish Colonial structures showing the range of adaptations done to the original single-level buildings.

16

6 Tapia- massive wall of mud or clayish soil, straw and lime mixture, and plastered inside and out with

a thick lime plaster coat. [Del Cueto, 1997] This should not be confused with adobe construction,

since it is based on the sun-drying of mud bricks that are then used for construction while the tapia is

built up from the ground by layers. Del Cueto states that to this day there has been no recorded

adobe construction on the island.

7 Ausubo- Manilkara bidentata, commonly known as bulled-wood. Slow growing mastic tree found in

the West Indies; a hardwood; most roof beams and purlins in Puerto Rico Colonial buildings were

made from this wood due to its durability. [Del Cueto, 1997]

8 Mampostera- any rubble-form of masonry (clay, lime, river stones, pieces of brick held together with

mortar and covered by lime plaster and then lime-washed). [Del Cueto, 1997]

9 Jopling, 1992, p.15.

! In his book Puerto Rico 1900: Turn-of-the-Century Architecture in the Hispanic

Caribbean, Jorge Rigau mentions, The Colonial period produced an architecture of

great cultural significance, pregnant with meaning, but- value judgements aside- in

many ways removed from contemporary building concerns. In the best examples,

thick walls, tall spaces, and large openings constitute direct climatic solutions which

seem of limited importance today.10 As the time passed, the spanish colonizers

continued to establish a clear difference between them and the Taino and the African

slaves that were introduced early in the sixteenth century. The Spaniards considered

themselves gente de razn (people of reason) and insisted in maintaining close ties

with Spain which was reflected in their architecture. The construction of these

houses was a clear sing of social standing and descent. By the end of the eighteenth

century, the Spanish Colonial houses revealed a Puerto Rican identity, and a

broader sense of security and wealth.11

! The construction materials for these buildings was readily available in Puerto

Rico and therefore less costly than the use of brick which was imported. Stone

masonry was not common on the Island since stone masons were not readily

available for construction works. These conditions led to the subsistence of the tapia

construction method for buildings. Apart from using locally ready materials, these

walls would sustain hurricanes and earthquakes while aiding in the climatic control of

the interior spaces. Beatriz del Cueto explains:

The strength and permanence of this building system, in spite of earthquakes

and hurricanes, together with the availability of primary construction materials

and the relative simplicity of its assemblage proved to be the most efficient

solution for local construction in general from the sixteenth to the nineteenth

century, and was specifically favored by the Spanish government for its Public

Works projects.... Another quality that contributed to the extensive use of the

rubble-masonry was that it maintained a considerably cooler temperature in

the interior spaces due to wall thickness, natural transpiration of the materials,

and the achievement of overall high ceilings made possible through the wall"s

massiveness. Many examples of this type of construction still remain

17

10 Rigau, 1992, p.14.

11 Jopling, 1992, p.26.

throughout Puerto Rico. These walls, when repaired in a proper manner (with

mixtures compatible to those used originally), remain functional indefinitely.12

These walls have an average thickness around half a meter and have an average

hight from 3.5 to 5 meters. The roof of the structures was integrated into the wall

construction since the ausubo beams were placed during the construction of the

parapet. These were mainly flat and consisted of ausubo beams, crossed by fine

wood slats and two to three alternate layers of thin flat roofing brick13. This

technique allowed for an aesthetic finish in the inside and a strong exterior surface

that could withstand the onslaught of the local climate. To aid with the air circulation

in the spaces, the openings were fitted with movable louvers that also provided a

certain level of privacy. [Fig. 3]

Fig. 3 Architectural details of a typical Spanish Colonial house in San Juan, Puerto Rico: a. Wall thickness and spatial relationship, b. main faade, c. doors with movable louvers, d. ceiling detail.

18

12 Del Cueto, 1997, page 9.

13 Ibid, page 10.

! Most of the structures that were built during the early Colonial period were

adapted or, in some cases, expanded to accommodate more affluent living and to

the display the wealth of the families. As the relationship with Spain began to

become strained in the nineteenth century, influence on the Island started to arrive

from other countries and introduced new materials for construction. Jopling writes:

During the period after 1850, Puerto Rican houses lost much of their

provincialism and narrow affinity with Spain and became more closely allied

with the architecture of Europe, other areas of the Caribbean, and the United

States. Though specifically recognizable styles were adopted by Puerto

Ricans, in the houses based on these, materials often drifted from those of

the originals, and designs were farther adapted to the tropical climate and

different social milieu.14

The advancements of technology and the growing population in San Juan made it

necessary for certain design guidelines to be followed in order to maintain healthy

living conditions. In his book Puerto Rico 1900: Turn-of-the-Century Architecture in

the Hispanic Caribbean 1890-1930, Rigau explains: By 1889 residences in San

Juan were required to have a convenient distribution of light and air, access to the

sun"s rays, and vents or shafts which would allow communication with outside

air.15 The structures that were being built, as well as the existing, continued to

apply these concepts to the Colonial style homes of the period.

! It was not until the Spanish-American War in 1898 that a change became

evident in Puerto Rico. As part of the Treaty of Paris, Puerto Rico was to become a

territory of the United States. All direct ties with Spain were ended and a new culture

was to be assimilated into the Island. The residents of Puerto Rico were forced to

adopt English as an official language, the social classes were shaken as the

economy of Puerto Rico became part of the North American process of production

and consumption.16 Del Cueto explains that:

The drastic socio-cultural and economic modifications that resulted as a

consequence of the Spanish-American War, and the accelerated changes

that were produced at the turn of the 19th century created considerable

19

14 Jopling, 1992, p.40.

15 Rigau, 1992, p.37.

16 Jopling, 1992, p.41.

changes to local architecture island-wide. The 20th century brought with it the

influence and traditions of continental North America as Puerto Rico became

a territory of the United States. Nonetheless, attachment to European

traditions and Ibero-American concepts were initially maintained.17

Apart from a change in sovereignty, Puerto Rico also felt the changes that where

happening worldwide. The Industrial Revolution, with its capacity for mass

production, the specification of reinforced concrete18 and the introduction of the

balloon-frame19 construction presented the first major change in the way architecture

in the island was approached since the arrival of the Spaniards20.

! With all these new technologies a new type of residential architecture was

being produced. As a response, new construction guidelines were established to

assure the maximum safety and wellness. Rigau states that among these

recommendations for healthy living were:

Structures had to be raised from the ground by a minimum of about sixty

centimeters, either on stilts or over a perforated masonry wall to allow for the

free flow of air. Rooms were deliberately tall and the roof and ceiling could not

share the same surface, for the space sandwiched between them protected

the dwelling from high temperatures. In many cases, walls were required to

be of wood sheathing on both sides with an insulation pocket between the

inside and outside surfaces. Over each door and window a transom for

permanent ventilation had to be provided. Although their shapes could vary

form rectangular to semicircular, transoms were sized in terms of a specific

percentage of the total opening below, and detailed to allow air to pass

through them.21

20

17 Del Cueto, 1997, page 12.

18 Reinforced concrete was introduced in England in the mid-nineteenth century with the production of

Portland Cement in the 1824. This technology was introduced in Puerto Rico around the same time

as the United States ca. 1860. It became popular for construction in the island in the early nineteenth

century, and continues to be in the present.

19 Construction system introduced in the U.S. ca. 1833 that allowed for easy construction and setup. It

consisted of the use of mass-produced cuts of wood held together by nails creating a light frame

structure that could be lifted into place quickly and easily.

20 Jopling, 1992, p.41.

21 Rigau, 1992, p.37.

Although these guidelines where in tune with the period!s obsession with salubrity

and hygiene22 they were based on the local climate and therefore allowed the

houses to ventilate and maintain comfortable temperatures.

"

" Nevertheless, these were guidelines for design and in some cases residences

were being built with concrete blocks with ornamental surfaces instead of wood. Del

Cueto states that during the twentieth century some architects on the Island were

specifying the use of ornamental concrete blocks for the construction of the exterior

walls. It is not certain wether the blocks were produced in the west coast of Puerto

Rico, or if they were brought from the U.S., but it is clear that they were preferred

over brick and quarry stone since they were mass produced. This meant that there

was a broader availability of factory-produced components that gave an ornate

Fig. 4 Details of the Gonzlez-Cuyar residence, an example of Turn-of-the-Century architecture in San Juan: a. main faade, b. wood and zinc roof detail, c. louvered doors, d. back faade.

21

22 Rigau, 1992, p.37.

appearance to the surface.23 It should be noted that, although the walls were built

with concrete, these structures continued to have a wooden trussed roof with an

exterior corrugated zinc roof and a separate ceiling surface. [Fig. 4]

! In addition to the strategies mentioned before, the turn of the century

structures introduced the mediopunto24 [Fig. 5]. Rigau describes this as not only

underlying transitions in an interior sequence, but also helping to articulate, yet

never completely separate, adjoining spaces. He continues to explain that the

mediopunto was also used in architecture in North America and in the other hispanic

Caribbean Islands, but that those examples very rarely have the same spatial

meaning as their Puerto Rican counterparts. In Puerto Rico the mediopunto was part

of a spatial sequence from the front entrance, through the house, and to the back

patio or garden. Rigau states about the mediopunto that; This pursuit of

ambivalence as a desired spatial effect- an intellectual concern not manifest before

on the island- is one of the most persuasive design conceptions of Turn-of-the-

Century architecture in Puerto Rico.25

Fig. 5 Mediopunto in the Gonzlez-Cuyar residence, San Juan, PR.

22

23 Del Cueto, 1997, page 14.

24 Mediopunto- ornamental wooden screen utilized in Victorian architecture to articulate interior

spaces. [Del Cueto, 1997.]

25 Rigau, 1992, p.166.

! Another item characteristic of the times were the doors. These doors allowed

the user to adapt and control the privacy, light, security, and air in the space. The

doors consisted of a revolving transom, double doors, double shutters, clear and

colored glass, louvers, and a protection bar.26 These doors successfully dealt with

all the problems that modern counterparts face. The ability to allow the user to

transform the door depending on the climate and the different uses during the day

makes this design a staple for the Turn-of-the-Century houses. Apart from the

ventilation provided by the doors, wrought-iron or wood grilles were often integrated

into different parts of the house to help with the air circulation. These provided the

ventilation that the houses needed to maintain comfortable temperatures while

serving as a decorative and often sophisticated detail.

! This type of architecture style was maintained, mostly unchallenged, until the

arrival of Modernism to Puerto Rico. Meanwhile, in the 1930"s, a period economic

depression struck the Island and poverty became widespread. Enrique Vivoni writes:

In more than one sense the advances that had been achieved, for example,

in the years just prior to the change of sovereignty were turned back or

cancelled, so that modernization as a coordinated and operational system

had to wait a convergence of radical modifications. And as we might say of

the entire first half of the twentieth century, the moment of change would be

marked by emergency-the Great Depression and the advent, twenty years

after the first, of a second great world war.27

Is was not until after the effects of the wars and the depression started to lift that

Puerto Rico started to see changes. The appointment of Rexford Tugwell28 as

governor of Puerto Rico in 1941 brought a sense of change and progress, the basis

for the modernist movement in the Island.

23

26 Rigau, 1992, p.162.

27 Vivoni, 2006, p. 275.

28 Rexford Tugwell, born in New York, was the last appointed American governor of Puerto Rico. He

served in office from 1941 to 1946. He was key in the appointment of the first Puerto Rican governor,

Jesus T. Piero, who served from 1946 to 1949. Piero was then succeeded by the first

democratically selected governor, Puerto Rican, Luis Muoz Marn, who served from 1949 to 1965.

! During this time of transition into Modernism, the population in San Juan grew

exponentially in the 1930s as the rural workers moved into the city in search of jobs

and a better life for their families.29 Vivoni explains this transition period:

Puerto Rican history tells us that in 1941 Puerto Rico experienced a

peaceful revolution. The revolution occurred within the establishment, and it

used models of administration different from before, but was unable to alter,

fundamentally, the true problems inherent to the relationship between the

United States and Puerto Rico. In 1941, after centuries of colonialism, the

Puerto Rican situation was desperate.... The effect of the peaceful revolution

was felt in several aspects of Puerto Rican life. Puerto Rico engaged in a

process of homogenization in which cultural, economic, and social differences

were leveled out by industrialization and internationalism. The practice of

architecture in Puerto Rico also reflected the search for an image of

international equality. Through the Committee on Design of Public Works, the

government set out to modernize architecture in Puerto Rico.30

During this time many foreign architects arrived in Puerto Rico to work in

modernizing the Island. Among these architects was Henry Klumb, a German who,

after being an apprentice to Frank Lloyd Wright, went on to become one of the best

known architects in the mid twentieth century in Puerto Rico.

! The modernist movement on the Island was belated, unequal, and out-of-

synch and was therefore received with disillusionment and criticism.31 Following

the definition offered by Bruno Latour, The adjective "modern# designates a new

regime, an acceleration, a rupture, revolution in time. When the word "modern#,

"modernization#, or "modernity# appears, we are defining, by contrast, an archaic and

stable past.32; Klumb is the perfect example of the "modern# architect in the island.

He stated that the Spanish Revival, which was the official architectural vocabulary

chosen by the government, was the most wretched [architecture] imaginable.33 He

then proposed an architecture that was his own interpretation of the Prairie Style,

24

29 Jopling, 1992, p.57.

30 Vivoni, 2006, p.20.

31 Ibid, p. 256.

32 Latour, 1993, p.10.

33 Bameneche, 2003, p.17.

developed by Wright, that would take into consideration the climatic conditions of the

Island. Additionally, Klumb found himself in constant struggle against the new

technologies, such as the air conditioner, that, for him, were unsustainable in the

economy of the time.34

!

! In 1945 Klumb designed one of his first particular dwelling, the Haeussler

Residence [Fig. 6], on the Island after forming his private practice, The Office of

Henry Klumb. As with his other designs, the house integrates the local climate and

surrounding green spaces to form part of the dwelling. The roofs are high with a

single slope, and on the east side the break between the two surfaces is used as

ventilation for the interior spaces. The house, built of reinforced concrete, is divided

into two main areas, one public, open to the surroundings, and one private, where

the living quarters are located. As part of his integration to nature, Klumb performed

Fig. 6 Haeussler Residence, 1945: a. main faade, b. perspective of main faade and entrance, c. perspective of the west faade, d. living room detail.

25

34 Vivoni, 2006, p.39.

an analysis of the prevailing breeze in order to provide the house with an ideal

orientation for natural ventilation. As with most of his residential designs, he was so

successful in creating comfortable living conditions that the houses have remained,

in their majority, as designed, or with small adjustments done under the consent of

the architect.35

! This kind of approach separated Klumb, and other architects with similar

strategies, from the houses that were being built as part of the modernization of

Puerto Rico. George Holliday states that, The new houses have been completed

with no consideration whatsoever to the fact that this is a tropical country.36 Most of

these structures where built as part of a plan to provide decent housing to the lower

classes. Carol Jopling explains:

Because of their economic accessibility, practicality, and durability,

Urbanizacin37 style houses have received wide acceptance. Moreover,

standardization of structure has challenged rather than stultified individual

expressiveness.... Yet, in contrast to the expression of community loyalty

through conformity to particular styles that obtained among Criollo houses,

these dwellings are intended as individual personal statements of

ownership and status. Upper-class houses are designed by architects as

personal statements of architect and owner; at middle and lower social

levels, homeowners personalize their developer-built houses with

ornament and paint.38

The model for these other houses has continued to be relevant in the minds of many

Puerto Ricans until the present day. These urbanizaciones have been developed for

all social levels in order to give the inhabitants a place to escape the violence and

problems contained in the city. As a result of this exodus most of the historical city

centers are empty and in disrepair.

! As a response to this type of construction, Beng Tan Hock explains, Many of

the architects working in the [tropical] region today appear to have forgotten how to

26

35 Vivoni, 2006, p.41.

36 Holliday, 1938, p.18.

37 Urbanizacin is the term used to describe suburban residential developments where all the houses

were the same and contained the basic spaces for living.

38 Jopling, 1992, p.59.

design bearing in mind the climate and landscape. They are now caught in the

homogenizing forces of the mass media and are repeating the built mediocrities of

international fashion.39 He continues to explain that there are some architects that

reject these fashions and are still in-tune with the local climates and argues that they

have an awareness of working in a specific spatial and temporal environment [that

is] strong and confident. They are producing and architectural ensemble that is

environmentally tuned, with a sensual refinement and sure sense of place.40 This

also holds true for certain Puerto Rican architects that have had the subtleness to

produce successful climate conscious designs amongst a wave of poorly designed

and executed concrete boxes.

27

39 Tan Hock, 1994, p.15.

40 Ibid.

Part 2:

Experimentation results

28

Chapter 4

Methodology

! For the analysis, three houses were selected, one from each one of the

periods described in chapter 3. The examples are single-family residences, of one

level, located in an urban context and in San Juan, PR [Fig. 1].1 These houses have

remained in use since the moment they were built, therefore they are in a good

structural condition. Additionally the structures were easily accessible for the on site

assessment and photographic documentation that was carried out. [Supplementary

images and drawings of the residences can be found in Addendum 1]

A. House selection

! The house selected as an example of the Spanish Colonial architecture

on the Island is located in San Sebastian Street #8 [Fig. 2]. It can be argued

Fig. 1 Location of the selected structures in San Juan, Puerto Rico.

29

1 Although the Haeussler Residence is officially in the Municipality of Guaynabo, it is located on the

municipal boundaries. Because it continues the urban layout of San Juan, and its location, it was

considered as one of the houses to examine.

that the houses in this area could have been among the first to be developed

because of their proximity to the San Jose Church and the Casa Blanca2.

Additionally, because of its proximity to the Casa Blanca, the back of the

chosen house opens to a courtyard within the block, which helps ventilate the

space. The original single-level structure has a north orientation and shares a

party-wall to the east and west. As explained in Chapter 3, the walls were built

with mampostera and have a thickness of half a meter. The ceilings are high

(between 3 to 3.5 meters (10 to 11.5 feet)) and the window and door openings

have an average hight of 2.5 meters (8 feet).

!

! The Turn-of-the-Century house that was selected for this study was

built in 1910 in Del Parque Street [Fig. 3]. This street was the main tramway

connection between the district of Condado and Santurce, hence it was widely

developed. The selected structure is one of the few examples that can be

found in this area that remain as close to their original state as possible. The

Gonzlez-Cuyar Residence was restored in 1992 and used as the

headquarters for the Colegio de Arquitectos de Puerto Rico. The single story

house has a northwest orientation and is built out of concrete blocks that give

Fig. 2 Aerial picture of Old San Juan indicating the location of San Sebastian #8

30

2 The San Jos Church is considered one of the first churches built by the Spanish in the New World.

The Casa Blanca, built in 1521, was the house for the Island"s first governor Juan Ponce de Len. It is

one of the oldest structures in Old San Juan.

the appearance of stone. The ceilings have a hight of 4.3 meters (14 feet)

while the doors and windows have an average hight of 3.0 meters (10 feet).

! The Heussler Residence was built in 1945 and it is the selected

example for Tropical Modern construction [Fig. 4]. This house is one of the

Fig. 3 Aerial picture indicating the location of the Gonzlez-Cuyar Residence

Fig. 4 Aerial picture indicating the location of the Haeussler Residence

31

few that have remained unaltered since construction, making it a very

valuable resource for analysis. The residence was designed by architect

Henry Klumb and was primarily focused on the proper house orientation in

order to take advantage of the breeze for natural ventilation. The structure has

an east-northeast orientation and is constructed of reinforced concrete. The

ceilings are an average height of 3.4 meters (11 feet) with the doors and

windows having a hight of 2 meters (6.5 feet) and 2.5 meters (8 feet),

respectively.

! In order to complete the experimentation aspect of the research within the

time restrictions, computers were used to simulate the air flow and environmental

conditions in the selected houses. The programs analyzed the use of materials and

the layout and orientation of the structure, the results where then assessed

individually and in compared, to establish the conclusion on the performance of the

houses. The two computer programs selected for the simulations were Ecotect and

Fluent. Each one of these programs provide different analysis perspectives that,

when compared and studied, provide an overall condition survey. The setup and

analysis process for each of the programs is described below.

B. Ecotect

! This program was selected for the material and interior conditions

analysis for the individual structures. Ecotect allows the user to load the

weather data for the selected site and conducts the analysis based on the

local conditions. This provides an excellent alternative for on-site

measurements under the time constraints of the research. In order for the

analysis to be as realistic as possible, the material library was adapted to

comply with the technologies that were used when the structures were built.

! It is necessary to specify the appropriate materials in Ecotect since the

thermal behavior of the structure greatly depends on their reactions. Because

some of the materials used in the construction of the houses that were

selected are not common, new materials were created from the material

library available in the program. Their thermal characteristics were

recalculated, and some of the properties are listed in Fig. 5. For even more

accurate results, the materials should be thoroughly studied individually. From

32

the results of the study the properties should be calculated and then entered

into Ecotect for analysis. This will provide thermal behavior results that relate

closer to the actual conditions on site.

zone material width solar

absorp.

thermal

lag

U value

Spanish

Colonial

roof/ceiling clay tiles 76 mm 0.60 0.2 hrs 5.49

Spanish

Colonialspace mampostera 430 mm 0.53 5 hrs 2.10

Spanish

Colonial

floor tiles on ground 12 mm 0.48 4.6 hrs 0.50

Turn-of-the-

Century

roof tin 2.2 mm 0.48 0 hrs 5.53

Turn-of-the-

Century

ceiling susp. wood 10 mm 0.37 0.3 hrs 4.09Turn-of-the-

Century space concrete block 203 mm 0.60 5 hrs 1.27

Turn-of-the-

Century

floor susp. wood 20 mm 0.60 0.7 hrs 1.26

Tropical

Modern

roof/ceiling reinf. concrete 171 mm 0.90 7 hrs 1.05

Tropical

Modernspace reinf. concrete 223 mm 0.51 5 hrs 1.20

Tropical

Modern

floor slab on ground 100 mm 0.47 4.6 hrs 0.88

! The program requires a digital model in order to calculate the results

[Fig. 6]. These were constructed for each structure individually, with the site

Fig. 5 Table showing the material properties used in Ecotect

Fig. 6 Ecotect model construction

33

and orientation conditions taken into consideration for each example. The

models were built with three main zones roof/ceiling, living space, and floor.

Once the model was completed the different materials were assigned to the

surfaces. Once this was completed the meteorological data for the site was

uploaded into the program. As the final step before the survey was started, an

analysis grid was setup that covered all the spaces of the house [Fig. 7].

! Because the three structured differ greatly in their area, the grids were

sized differently for each. The Colonial structure had a grid of 50x50 cells, the

Turn-of-the-Century house had a grid of 80x80 cells and the Tropical Modern

residence had a grid of 100x100 cells. These grids were then adapted to

form-fit the plan of each of the houses. The individual structures where then

analyzed in terms of the natural daylight entering the spaces, the spatial

comfort, the amount of time interior areas spent within the comfort zone, fabric

conditions, and overall interior temperatures.

! The lighting and comfort analysis grids were setup at two separate

heights, 30cm (1 foot) and 250cm (8 feet), to compare the conditions close to

the floor and at the height of most contemporary ceilings. The zones within

the building were separated in three: the floor, space, and ceiling/roof. The

conditions of these three zones in all three structures where then compared to

gain a better understanding of the impact of materials and design strategies in

space comfort. Additionally to the results obtained with the grid, a series of

Fig. 7 Sizing of analysis grid

34

results were gathered from the analysis section of Ecotect. These consisted

on temperature, performance, fabric, and heating/cooling loads for each of the

houses. The results obtained from Ecotect on each of these categories was

then imported into a graphing software where they were interpreted and

compared and additional graphs were generated to compliment those

generated by the program.

C. Fluent/ CFD

! Fluent was used to carry out the Computational Fluid Dynamics (CFD)

aspect of the research. This program allows for the simulation of air

movement through and around the structure. The mesh for the floor plan and

the necessary sections for the analysis were generated in Gambit and then

imported into Fluent.

! To create the mesh in Gambit, the plan drawings created in AutoCAD

were imported into the program. Once loaded, mesh edges were added to the

volumes, for the floor plans the spacing for the edges was 20. After the

program completed this command, the mesh was laid out [Fig. 8]. Because

the size of the structures varies, the total amount of cells in the mesh varies.

The Spanish Colonial mesh had 250,000 faces, the Turn-of-the-Century mesh

had 320,000 faces and the Tropical Modern had 160,000 faces. For the

sections of all three structures, the number of faces on the mesh ranged

between 35,000 to 50,000. All of these surfaces were further refined in Fluent.

Fig. 8 Creation of mesh in Gambit

35

! To complete the setup process in Gambit, the edge conditions were

specified. For all the plans there were four types of edges, North, South, East,

West, and walls. The walls edges referred to all the lines that represented a

structure. The other four categories referred to the mesh boundaries. In the

sections there were four edge types, top, walls, East and West or North and

South. The walls edges included the building and ground surface. The side

boundaries received their name depending on their orientation on the plan.

Once the edges were specified, the boundary conditions were set. In all of the

drawings, there was one velocity-inlet facing the direction where the wind

would come, usually from the East. The walls were specified as solid surfaces

where no air circulation could pass. All of the remaining boundaries were

specified as pressure-outlets. After this was completed, the mesh was

exported to Fluent where the final refinement was done.

! Once imported to Fluent, the plan mesh for the residences was further

refined in two zones radiating from the center of the selected houses. The first

zone [Fig. 9] was refined with a radius of 2,000 cells and the second zone of

refinement [Fig. 10] was 1,000 cells from the center of the structure. For the

sections, the refinement was done in two rectangular zones, but because of

their varying sizes, the number of cells varied in each example. The

refinement of the mesh near the houses allows the program to provide a more

detailed analysis on the air movement inside and around the structures.

Fig. 9 Mesh refinement of zone 1

36

! Once the mesh was refined, the boundary conditions were revised and

the wind speed was specified. The wind speed was calculated from the

weather data that was obtained for San Juan, Puerto Rico which indicated

that the primary wind direction is from the east-northeast between 60 to 100

from north at a speed of 20-30 km/hr (12-18 mph). The wind in this direction

and speed was recorded in more than 940 hrs, this can be interpreted as the

principal direction of a mainly constant air movement. For the calculations a

speed of 6.9 m/s (15 mph) was used in a direction of x=-1 and y=-0.5.

! After all the boundary conditions were set, the residuals were chosen

and the model was initialized. The next step was beginning the iterations for

each of the drawings individually. The iterations were performed until the

results were converged or stabilized [Fig. 11]. A total of 115,000 iterations

were performed on the plans and 100,000 on the sections. Once the iterations

were complete, the wind direction and velocity vectors were plotted as well as

the pressure contours for the plans and sections of the selected structures.

These plots contain the information necessary to understand the air flow

within and around the buildings and weather the design exploits or hinders the

available natural ventilation available in the sites.

Fig. 10 Mesh refinement of zone 2

37

! The results obtained from this analysis were then compared among the

structures. In order to get the most accurate results for the houses, they were

placed in the urban context that existed around the time of construction this

information was obtained from historical urban plans. The results from this

simulation were also used to help interpret the results obtained in Ecotect.

Since this analysis was only carried out in two dimensions, there is a

possibility for further future analysis of the wind conditions in three dimensions

for all of the structures.

Fig. 11 Example of residuals results after iterations were completed

38

Chapter 5

Ecotect Results

! The three houses were analyzed following the methodology explained in the

previous chapter. A computer model was created for each of the structures that

specified the orientation, climatic conditions and materials used in each of the

examples. Experiments were run on several aspects of the design solutions for each

of the houses were analyzed and the results from these experimentations will be

discussed in detail below.

A. Daylighting Analysis

! The first analysis that was carried out was the calculation of the amount of

sunlight entering the interior spaces of the houses. This proves to be an important

aspect of design as poor natural lighting makes it necessary to have alternative

illumination that produces additional heat. On the other hand, too much exposure

makes the space uncomfortable, plus the direct sunlight also heats up the space.

Interior ideal lighting levels would range between two and five percent. The analysis

were carried out at 30 cm (1 foot) and 250 cm (8 feet) for each of the structures. By

studying the levels at these two heights, the overall lightning conditions for the livable

space can be researched and compared. It should be expected that exterior areas

as well as those near openings should have the highest percentage of natural

lighting levels, and those furthest from the openings should have the lowest. All of

the selected structures have operable louvered windows and in the Colonial and

Turn-of-the-Century examples the doors have operable louvers as well. For the

purpose of this research, the daylight analysis were carried out with all of the

windows and doors open. The results would then present the highest percentage of

daylight available in each of the houses. It should be mentioned that the way the

users control the louvers would make a great difference in reducing the lighting

39

levels. Because of time constraints, and in order to keep the scope of the research

manageable, the user variable was not taken into consideration in the analysis.

! The following images show the results obtained from Ecotect for the lighting

levels for each of the structures. As should be expected, the daylight levels at 30 cm

are higher than those at 250 cm for all three structures. Because of the angle of

incidence of the sunlight, these results are not of any particular importance. The

Colonial and the Turn-of-the-Century structures have similar results since all interior

spaces act as one. The lighting levels inside the house are quite homogeneous

when compared to the results from the Tropical Modern house where there is a clear

difference between the public and private areas of the home.

! All the structures show comfortable lighting levels in the interior spaces at 30

cm, the lowest being 1% in the Colonial house and the highest being 10% in the

Tropical Modern example. For the exterior spaces, the lowest level is 6% in the

Tropical Modern house and 15% would be the highest percentage in the Turn-of-the-

Century building. The lowest percentage at 250 cm for interior spaces is 1.2% in the

Colonial structure, the highest being 6% in the Tropical Modern house. For the same

height, the lowest exterior percentage is 6% for the Tropical Modern and the highest

is 14.8% in the Turn-of-the-Century structure.

Fig. 1 Daylight analysis of the Spanish Colonial structure at 30 and 250 cm

40

! As the analysis results show, the levels for the interior of the Colonial house

are ideal for natural daylighting, but because the percentages are low, these spaces

would need supplemental lighting in overcast days [Fig. 1]. The Turn-of-the-Century

structure also provides natural lighting within the comfort percentage, but unlike the

Colonial house, this example has enough daylight to maintain the spaces in a

comfortable range even in slightly overcast days [Fig. 2]. It should be noted that

these two examples have doors and windows that have louvers and are operable

and adjustable by the user and the adjustment of these objects would have very

noticeable effects on the light available in the spaces.

Fig. 2 Daylight analysis of the Turn-of-the-Century structure at 30 and 250 cm

Fig. 3 Daylight analysis of the Tropical Modern structure at 30 and 250 cm

41

! Unlike the first two examples, the Tropical Modern house, because of its

openness to the exterior areas, has a much higher lighting levels. In Fig. 3 it can be

noticed that there is a clear division between the public and private zones of the

house in terms of the lighting. The bedrooms receive noticeably less light than the

living room, dining room and entrance. The daylight levels in the private areas of the

house range from zero to six percent while the public areas are between six to

fourteen percent. It is clearly noticeable that the public areas of the Tropical Modern

structure would not need supplemental lighting in overcast conditions since the

openness of the design allows for plenty of natural light to enter the spaces.

! Due to the results obtained and discussed above it could be concluded that

the most efficient design for optimum daylighting is the Tropical Modern house. The

attention to orientation, and the ability of the architect to separate public from private

areas using light, separates this design from the others. Care was taken to design an

open house where every room was accessible to natural lighting conditions

according to the activities in their designated areas. Therefore, some spaces are

brighter and others darker to focus on their particular functions. It is remarkable that

by studying the lighting analysis plans the living spaces and the service or support

spaces can be clearly differentiated from each other. The only possible problem with

allowing so much natural light to enter the house is the possibility for elevated

temperatures and heat storage that would make these areas uncomfortable.

B. Thermal Comfort Analysis

! The thermal comfort study was carried out in order to establish the

temperatures found in the interior and exterior spaces of the selected structures. As

with the lighting analysis, this was performed at two heights, 30 and 250 cm. In this

case, the selected heights would indicate the temperature relationship between the

spaces" different heights and the possible relationship between comfort levels and

the exposure of the materials. The comfort band for natural ventilation in Puerto Rico

ranges between 18 to 26C (64 to 79F). The three selected examples were

analyzed by Ecotect and the thermal results were plotted and are presented below. It

should be necessary to clarify that all of the three homes have operable doors and

windows, that, depending on different combinations, could potentially have a great

impact on the air circulation within the structures. The range of possible user

42

adaptations is so extensive that, due to time restraints and to maintain the scope of

the research manageable, were not taken into consideration. For this analysis, the

materials used, as well as their orientation, play a vital role in the temperature

distribution. It is expected that the temperatures at 30 cm are lower than those at 250

cm because the roof is exposed to direct sunlight for most of the day and radiates

part of the stored energy into the interior spaces.

! For all three selected examples, the temperature relationship between the

readings at 30 and 250 cm is very similar, the latter being slightly higher than the

lower. The average temperature at a height of 30 cm in the Colonial house is around

27C (81F), in the Turn-of-the-Century structure it is around 30C (86F) and in the

Tropical Modern example the average is 28C (82F). Although all the temperatures

are over the comfort zone, the Colonial and Tropical Modern structures present the

most comfortable conditions. The temperatures at 250 cm for the Colonial and

Tropical Modern houses have no significant change from those at 30 cm. However,

in the Turn-of-the-Century house there is a four degree temperature difference.

!

Fig. 4 Thermal comfort analysis of the Spanish Colonial structure at 30 and 250 cm

43

! Out of the three structures, the one with the best performance is the Colonial

house. The analysis for this structure [Fig. 4] shows that the temperature close to the

interior walls can be as low as 15C making this area the coolest of the examples. It

can be argued that due to the great thickness of the walls, 50 cm (20 inches), it has

great thermal storage. It can then be concluded that since the interior partition walls

never receive direct sunlight they are always maintained at a lower temperature than

the surrounding spaces. Additionally, the structure only has three exterior surfaces

that are exposed to the sun, the north and south walls and the roof. These could be

Fig. 5 Thermal comfort analysis of the Turn-of-the-Century structure at 30 and 250

Fig. 6 Thermal comfort analysis of the Tropical Modern structure at 30 and 250 cm

44

two of the major contributing factors that help maintain comfortable temperatures in

the interior spaces.

! The analysis results of the Tropical Modern [Fig. 6] house show that the

temperature distribution throughout the spaces remains constant and slightly over

the comfort zone. A combination of overhangs and paving materials allows the

structure to balance the possible heat gains to maintain comfortable conditions.

Where the temperature seems to shift and be slightly higher are the areas where

there are no shading devices protecting the surfaces from direct heat gains from the

sun. In these spaces the architect placed individual stone pavers or grass to help

control the temperatures.

! Noting that the Turn-of-the-Century house had the highest temperature at 30

cm and at 250 cm it can be concluded that this is the poorest performer for thermal

comfort [Fig. 5]. One of the most noticeable aspects of the temperature distribution is

in the front porch and the veranda surrounding the interior courtyard. Usually these

areas served as transition spaces from the exterior to the interior of the structure. It

can be clearly seen in the analysis results that these spaces do actually act as such.

They are slightly cooler than the exposed areas and slightly warmer then the inside

spaces. In order to gain a better understanding and establish what elements of the

construction and design affect the temperature distribution it would be necessary to

analyze the conditions in the floor, space, and ceiling/roof. The detail look into the

relationship between the materials and temperatures in the spaces with the outside

conditions could prove to be extremely relevant to the performance of the structures.

C. Temperature Distribution

! In order to better understand the temperature distribution within the structures

and its relation to the outside conditions, it would be necessary to compare the

materials and their relation to the temperature profiles for the floor, space and the

ceiling/roof. For this, different zones were setup in Ecotect so the analysis graphs

would present the comparison of the temperatures in the three areas. By comparing

the performance of the individual zones, conclusions could be drawn on the impact

of design strategies on the spatial comfort. The data from the previous analysis was

taken into consideration in order to establish the temperature distribution. Because of

this, the present analysis is of outmost importance for the examination of the

45

efficiency of the structure. Design strategies, location, orientation, materials, air

circulation, and other data is used by Ecotect to provide accurate results for each of

the structures. Once the simulation is complete, the results indicate the amount of

time that each of the areas spends in the comfort zone.

! From the result graphs obtained from Ecotect, clear differences can be

noticed in the way the three structures react to temperature fluctuations. The floor

and the spaces in the Colonial house seem to follow a similar pattern within in the

comfort zone [Fig. 7]. The roof, on the other hand, follows a pattern very similar to

that of the ambient temperature. The roof is partially located outside of the comfort

zone towards the end of the day. This can be due to the constant exposure to the

sun throughout the day and the thermal absorption by the traditional roofing

materials. It could be concluded that the ceilings of the Colonial houses have a hight

between 3.5 to 5 meters in order to permit for the hot air to rise and allow for an air

gap to help insulate the livable space and keep it cooler than the top area. The

results from the thermal comfort analysis show that there is a temperature difference

from 30 to 250 cm, indicating that the height of the Colonial structures may have

played an important part in the climatic control of the spaces.

! The results for the Turn-of-the-Century structure indicate that the temperature

fluctuations of the different zones are in direct reaction to the changes in the ambient

conditions [Fig. 8]. The profile for the floor almost mimics the changes of the exterior

temperatures. The roof profile also fluctuates in such a way that the peak time spent

at one temperature is similar to that of the floor and ambient. However, the interior

spaces seem to spend most of the time within the comfort zone before heating up

Fig. 7 Temperature distribution for the Spanish Colonial structure

46

during the day and going over. The graph generated by Ecotect provides important

information on the amount of time the structure spends at a particular temperature.

No sharp peaks, as in the Colonial and Tropical Modern examples, indicate that the

structure is constantly responding to the changes in the environment and reacting in

such a way that almost mimics the fluctuations. Unlike the Colonial house, all three

zones warm up enough during the day to be over the comfort zone. This can be an

indication of uncomfortable temperatures and, when compared to the results of the

thermal comfort analysis [Fig. 5], it is a clear indication of overheating of the

structure.

! For the Tropical Modern house, the result patterns seem to be a combination

of the results obtained in the other two structures [Fig. 9]. Here the space and the

ambient temperature curves seem to be almost identical. This would be a very clear

indication that the fluctuations in the environment have direct effects on the

temperature in the interior spaces. The floor temperature curve is identical to that

obtained in the Colonial structure. It clearly shows that most of the time the floor is

found well inside the comfort zone. The roof seems to react to the ambient

fluctuations, but is mainly located outside of the comfort zone. This can be attributed

to the material used in the design of the roof, reinforced concrete. This material

absorbs the heat from the sun throughout the day and slowly releases it at night

making it radiate temperatures outside the comfort zone. When these results are

compared to those of the thermal comfort analysis [Fig. 6], it can be concluded that,

although the interior spaces react to the ambient fluctuations, it is mostly within the

comfort zone.

Fig. 8 Temperature distribution for the Turn-of-the-Century structure

47

! To better understand the relationship between the ambient and building

temperatures, the interior and exterior temperatures for six different days were

compared. The days used were the average hottest day, average coolest day,

windiest day, least windy day, brightest and most overcast days. The temperatures

obtained were then graphed and compared in each of the structures to better

understand the results. These graphs should provide a better insight at the behavior

of the structures and their reaction to the environment, taking into consideration the

design strategies.

! The results for the Colonial house [Fig. 10] provide a much better

understanding of the way the building works in the tropical climate. The graphs

clearly show that, although the exterior temperatures seem to rise during the day and

peak around one in the afternoon before coming down, the temperature inside the

structure seems to remain constant and mostly within the comfort zone. This reaction

from the house materials is very interesting and rather unexpected. Because of the

thickness of the walls, it would be thought that the thermal storage would be great

and when released at night would deem the spaces too warm. As can be clearly

seen the night temperatures are not low enough to render the use of thermal mass

necessary, but as these and the other results show, the thickness of the Colonial

walls do not seem to work as other walls with large thermal storage. In order to

better understand the thermal properties of the mampostera walls it would be

necessary to sample and use meters to measure the temperatures of the wall

throughout the day. Because of the time constraints presented with this research this

Fig. 9 Temperature distribution for the Tropical Modern structure

48

was not possible, but would be necessary for future analysis and study of the

behavior of Colonial construction in the warm Caribbean climate.

! Contrasting the results from the Colonial house, the temperatures of the Turn-

of-the-Century structure fluctuate greatly during the day [Fig. 11]. What is interesting

about the way this building reacts is that during the peak hours where the ambient

temperature is at its highest, the temperatures within the house are actually lowered.

This find was unexpected and compared to the other structures, it shows that the

ceiling/roof design was the most efficient solution out of the three that were studied.

The Turn-of-the-Century house has a double surface roof construction where the

part that is exposed to the outside is not the same surface that is visible from the

inside. The two-pitched roof is made of corrugated metal sheets with a large

ventilated air gap before the tongue-and-groove ceiling. This air gap provides the

best insulation from the exterior heat during the peak heat hours when the sun is at

its highest position in the sky. In contrast to the high efficiency of the ceiling/roof

design, the graphs show very poor performance from the fabric of the structure. It is

clearly visible that the house is quickly heated once the sun comes out. In all of the

days that were studied, the house had a higher temperature than the ambient. The

temperatures then become slightly lower during midday when the roof overhangs

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