SOLAR GARDEN SHADE
VISION Our problem was to address LIGHT in the Glass House, by Phillip Johnson, in a new location - Tapachula, Mexico. Tapachula has a tropical climate, ranks last in GDP per Capita in Mexico, and is currently experiencing a humanitarian crisis. An executive order from Trump trapped migrants and refugees in Mexico, many of which live on the street of Tapachula. Because of this, it was important that our system not only block light and heat, but also address the psychosocial problem of an energy inefficient modernist building existing in the midst of a crisis. We are calling this system Solar Garden Shade. The name reflects the use of solar power, green façade elements, and the ability to move back and forth like a standard shade over a window. This modular green wall panel system transforms the glass house, both internally and externally, while being minimally intrusive to the landmarked building’s assembly. The panels are dynamic, moving in response to the sun, therefore creating optimal shading at all times of the day, even when there is no one there to move them. Each module has its own motor that is powered by a solar panel. The whole system runs along a track that fits snuggly into the parapet of the building, concealing the messy mechanical elements from view. Our use of plants comes from our desire to maximize cooling effects, capitalize on the psychosocial effects of green walls, and create an opportunity for edible plantings that could help feed the displaced migrant population. - Liza Otto, Sam Richman, and Mimi Liebenberg
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CONTENTS
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SOLAR GARDEN SHADE
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40
12
44
18
50
30
58
Tapachula, Mexico
The Glass House
Peer Review Articles
Case Studies
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Schematic Design
The Substrate
Operating System
Environmental Analysis
Solar Garden Shade
TAPACHULA, MEXICO Site Context Temperature Precipitation Annual Wind Rose Psychrometric Chart
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Site Context
Despite its ecological and cultural wealth, Chiapas struggles economically. Chiapas has the lowest GDP per capita and the lowest literacy rate in of all of Mexico’s 32 states. The state’s economy relies mostly on agriculture, and its tropical climate and mountainous geography make permanent infrastructure a challenging undertaking. Tapachula is a border city along a major migrant route through Central America. It is the temporary home for tens of thousands of refugees hoping to reach the United States. Refugees in Chiapas are largely from the Northern Triangle Countries but many come from South America, the Carribbean, and Africa. The Solar Garden Shade is a triple bottom line response to these important social, economic and environmental factors.
TAPACHULA, MEXICO
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Temperature
Comfort Zone
Design High & Low
Average Temp
Extreme High & Low
110 100 90 80 70 60 °F
50 40 30 20 10
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Source: Climate Consultant Source: Climate Consultant
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Precipitation
Sunny
Partly Cloudy
Overcast
Precipitation
30 25
days
20 15 10 5 0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Source: Metroblue
Source: Meteoblue
TAPACHULA, MEXICO
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Annual Wind Rose
0-3 mph
NNW
3-7 mph
7-12 mph
N 2500
>12 mph
NNE
2000
NW
NE
1500 1000
WNW
ENE
500 0
W
E
WSW
ESE
SW
SE SSW
S
SSE
Source: Meteoblue Metroblue Source:
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Psychrometric Chart
Relative Humidity
100%
80%
60% .028
.024
.020
.012
Humidity Ratio
.016
.008
.004
10
20
30
40
50
60
70
80
90
100
110
Dry-Bulb Temperature, Deg. F
EPW Location: San Jose, GU, GTM Latitude/Longitude: 13.92deg North, 90.82deg West Data Source: SWERA 786470 WMO Station Number, Elevation 6ft
Source: Climate Consultant
TAPACHULA, MEXICO
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THE GLASS HOUSE Floor Plan West Elevation South Elevation
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The Glass House
Architect: Phillip Johnson Location: New Canaan, CT Date: 1949
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1’
4’
8’
Floor Plan
1’
4’
8’
THE GLASS HOUSE
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West Elevation
1’
4’
8’
1’
4’
South Elevation
1’
4’
8’
The Glass House, or Johnson House, is an influential work of modern architecture. It demonstrates principles of structural simplicity, clean lines and enacts a system of classical proportions. Transparency is used to create a connection to the building’s natural surroundings. Although it is praised for its aesthetic and material qualities, the building’s detailing and energy performance are widely criticized. If the Glass House were to be located in Tapachula, Mexico, the large amount of 1/8” = 1’ glass and lack of proper ventilation would create an uncomfortably hot interior for most of the year.
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8’
Eirik Johnson Photography
THE GLASS HOUSE
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PEER REVIEW ARTICLES How Plant Choice Influences Cooling Properties Designing Urban Parks that Ameliorate Climate Change Edible Green Infrastructure
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How Plant Choice Influences the Cooling Properties of Green Walls By Ross W.F. Cameron, Jane E. Taylor, Martin R. Emmett 2013 “What’s ‘cool’ in the world of green facades?” This research studied the use of wall shrubs and climbing plants to reduce air temperature adjacent to, and the surface temperature of, brick walls.
Benefits of Green Walls: 1. Promote biodiversity 2. Reduce run-off 3. Improve air quality 4. Attenuate noise 5. Support psychological well-being 6. Improve aesthetics 7. Mitigate heat island effect 8. Are important because of global warming and urban expansion.
How Plants Provide Cooling: 1. Shading (most effective) 2. Evapo-transpiration 3. Modifying air flow 4. Absorbing solar radiance
Green Walls
Living Walls
Bio-Walls
Plants are rooted in the ground or in pots and the shoots grow up the side of the building (wallshrubs or vines).
Roots into the wall or have cells of substrate that are supplied with water and nutrients.
Designed to improve indoor air quality and humidity and are composed of microorganisms or primitive plants.
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Factors to Consider for Green Walls 1. Plant Species: - canopy cover - moisture availability - seasonality 2. Soil moisture content
Drawbacks of Green Walls: 1. Wasteful of water 2. Wasteful of nutrients 3. Wasteful of energy to pump irrigation water through system.
Materials: 1. Brick wall sections separated by polystyrene to thermally isolate 2. Constructed on concrete slab 3. Weather station and data logger 4. Potted evergreen plants, all the same soil Variables: 1. Potted plants 2. Pot+media (to ascertain heating/cooling effects of the pot/damp media) 3. No pot or plants
Wall temperature as affected by vegetation type.
Findings: - The air at the vegetated walls was significantly cooler than the air adjacent to the non-vegetated. The pot+media treatment was not significantly cooler than the bare wall. This suggests plants’ ability to distribute cooling moisture vapor around a wall. - Instact stems leave the wall significantly cooler than excised stems. - The form of cooling (shade vs. evapotranspiration) and the degree of cooling can be influenced by plant choice. - Increased density of canopy results in greater degree of cooling.
Mean reduction in wall temperature
Procedure: - Walls were irrigated wtih 4L of water/day. - Non-plant pots and bare walls were ‘irrigated’ with equivalent volumes of water per day.
Stachys
Fuchsia
JasminumHedera
Reduction in wall temperature attributed to planted troughs with derived values for shade (Tp) evapo-transpiration (TPet), and evaporation (Tm).
Lonicera Prunus
LSD
TP
Tpet
Tpsh
Tm
PEER REVIEW ARTICLES
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Designing Urban Parks that Ameliorate the Effects of Climate Change By Robert Brown, Jennifer Vanos, Nayasha Kenny, and Sandra Ienzholzer 2015 “How can landscape architects and urban planners design parks that will have the greatest cooling effect on people during hot summertime weather and during the heat gains predicted in the coming years due to climate change?� Terminology
Research Questions
Park Cool Islands (PCIs): Air temperatures in parks are typically cooler than the surrounding urban environments and the cool air can extend downwind into neighboring areas.
1. What are the effects of thermal sensation of reduction of air temperature from Park Cool Islands?
Parameters Air Temperature, Short Wave Radiation, Wind, Humidity Changes
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2. What are the effects of on thermal sensation of reduction of solar radiation by various species of trees and solid structures? 3. What are the effects on thermal sensation of reductions and increases in wind speed?
Locations
Thermal Comfort Model
Kuala Lumpor, Malaysia (Tropical): Weather: Hot and Humid Hottest Month: March Clothing: Salwar-Kameez Cloud Cover: Cloudy Average Summer: 30.1c
COMFA Model: Allows for a variety of landscape modifications to be tested individually or in tandem by providing a detailed output of the magnitude of each element in the human energy budget.
Lahore, Pakistan (Dry): Weather: Hot and Dry Hottest Month: June Clothing: Salwar-Kameez Cloud Cover: Mostly Sunny Average Summer: 35
Human Energy Budget:
Kyoto, Japan (Warm): Weather: Hot and Humid Hottest Month: August Clothing: Shorts & T-shirt Cloud Cover: Mostly Cloudy Average Summer: 28.8c Alice Springs, Australia (Desert): Weather: Hot and Dry Hottest Month: February Clothing: Shorts & T-shirt Cloud Cover: Partly Cloudy Average Summer: 31.9c Toronto, Canada (Snow): Weather: Hot and Humid Hottest Month: July Clothing: Shorts & T-shirt Cloud Cover: Mostly Sunny Average Summer: 23.0c
EB (W m^-2)=M+Rabs-C-E-L EB = Energy Budget M = Metabolic Heat Production Rabs = Solar and Terrestrial Radiation Absorption C = Heat Loss from Convection E = Evaporation L = Emitted Terrestrial Radiation from a Person Outside Estimation of total radiation absorbed by standing person in typical summer clothing: Total Radiation = Effective Area of Standing Person x ((Incoming Ground Reflected Solar Radiation Absorbed by Human + Absorbed Atmospheric and Ground Surface Longwave Radiation) /Outer Surface of the Body) *assumption of grass covered ground surface
PEER REVIEW ARTICLES
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Energy Budget Modeling
Sensitivity Testing for Variables
1. Hottest month of each year based on 30 yr climate averages.
Air temperature: 1-6c @ 1c intervals
2. During heat waves. 3. During heat waves projected to occur in the future due to climate change.
White: no heat stress danger Light Grey: heat vulnerability Dark Grey: likely sunstroke and heat exhaustion Darkest Grey: extreme danger
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Wind Velocity @ 3pm and 3am: -80%, -40%, 0%, +60%, +200% Transmissivity of Radiation: 50%100% @ 10% intervals
Results Findings: For all climates during the summer and heat waves, cooling from wind was minimal. In extreme heat it even increased energy budgets minimally. In some areas of high humidity wind helps with heat loss through evaporative cooling, but even this is minimal compared to other methods. Findings: PCI have a modest cooling effect. In the most extreme temperatures people still ran the risk of heat exhaustion. PCIs coupled with canopies that provide shade are the most effective.
Findings: The more hours of direct unshaded sun in a climate, the higher the magnitude of cooling from shade. Shading interventions also lower the temperatures of the ground and thus it’s absorption by humans. By far the most effective strategy for cooling.
PEER REVIEW ARTICLES
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Edible Green Infrastructure: An Approach and Review of Provisioning Ecosystem Services and Disservices in Urban Environments By Alessio Russo, Francisco J. Escobedo, Giuseppe T. Cirella, Stefan Zerbe 2017 “A novel concept that intertwines environmental, social, + economic benefits that increases food security and decreases transportation distance and can play a vital role in the justification for green space conservation + utility.� Terminology
Objectives
Ecosystem Services (ES) Provisioning: food and water production Regulating: climate and disease control Supporting: nutrient cycles and o xygen production Cultural: spiritual and recreational production
1. Identify different typologies of urban EGI
Ecosystem Disservices (ED) Ecosystem function that results in negative impacts on human wellbeing Edible Green Infrastructure (EGI) A sustainable network of food components and structures within an urban ecosystem that are managed and designed to provide provisioning ES rather than cultural and regulating ES
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2. Synthesize findings on ES, ED, and EGI from relevant literature 3. Provide technical guidelines regarding design, planning, and management of sustainable EGI
Edible Urban Forests
Allotment and Community Gardens
Edible Forest Gardens
Domestic Gardens
Historic and Botanical Gardens, Parks
Edible Green Roofs, Vegetable Raingardens
School Gardens
Edible Green Walls and Facades PEER REVIEW ARTICLES
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Edible Green Walls and Facades Description Research is limited and recent Installed on high profile buildings to add visual effects to the urban landscape Can accommodate vertical urban farming, aesthetics, efficient thermal performance, daylight penetration, and interior environmental control Holistic approach offering food, housing, and sustainable solutions Facade design found in skyscraper exoskeletons and reshaped skin to support Ecosystem Services Provisioning: Food production, medicinal resources Regulating: Carbon sequestration, air pollution, stormwater runoff reduction Supporting: Biodiversity, soil fomation Cultural: Aesthetic, stress reduction Ecosystem Disservices Installation costs
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Guidelines for Edible Green Infrastructure Contamination Do not grow crops less than 10 meters from busy roads using buildings and large masses of woody vegetation as barriers between crops and roads Planning Designate zones for EGI based on site history, existing soil properties, and proximity to pollution Take into account context-specific geographic, social, and economic requirements Reporting Need for more region-specific education tools, information on products, and best agriculture practices and techniques to promote urban agriculture worldwide Literature availability in many languages, particularly developing nations
PEER REVIEW ARTICLES
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CASE STUDIES The Via Verde Project Biodiversity Green Wall and Edible Green Screen
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The Via Verde Project
Cola de Zorro
Peperomia Variegade
Peperomia Verde
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The Via Verde project covered ~1,000 of the concrete columns surrounding Mexico City’s beltway with vertical gardens. The company claims that environmental benefits include: enough oxygen production for 25,000 people, annual 27,000 tons of toxic gas reduction, 10,000 kilograms of heavy metal filtering per year, acoustic isolation, reduction of the urban heat island effect, and preservation of biodiversity. They’ve also linked these benefits with stress reduction, even going as far as to claim it improves work productivity, improves intelligence, and decreases mental illness.
The panels are made of a steel alloy. The insulators, which separate the garden from the architectural elements, are made of polyalumium, and the plants are embedded in a textile substrate made of recycled plastic.
The micro-spraying irrigation system is a mix of nutrients that support plant development and treated rainwater.
The automated system is also monitored and otherwise controlled through an app. This system uses analytics to verify the functionality of each green wall panel daily.
CASE STUDIES
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Biodiversity Green Wall, Edible Green Screen, and Water Harvesting Demonstration Project
The Biodiversity Green Wall, Edible Green Screen + Water Harvesting Demonstration Project is a research project at the College of Built Environments. The creators are attempting to understand and verify how a green façade can “ecologically contribute to the built environment.” Research into green walls is still new, and they want to understand if they can really produce biodiversity, edible plantings, and energy savings. In pursuit of biodiversity, they used 500 plants, and 23 species, most native to the area. The edible green screen contains hops and kiwi vines. The system is made up of a permeable textile and an aluminum frame surrounded by LED lights. They hope that by using two 750-gallon rainwater harvesting cisterns for irrigation they will decrease the impact of storm water on the surrounding area. For ease of care and sustainability, the panels are mounted on a manually operated pulley systems controlled from the 2nd and 3rd floor.
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The Biodiversity Green Wall will provide vertical habitat and increase building performance
The Green Wall is designed on a manual pulley system for ease in research and maintenance from the adjacent balcony
A Water Harvesting System will capture, reuse and cleanse roof runoff for use in the Green Wall irrigation
Solar Panels will be installed in phase II to offset 100% of electrical needs for the project
An Edible Green Screen will explore the efficacy of vertical surfaces to support local food production
The existing garden below will provide seating for reflection and restoration opportunities with vertical nature
Existing rainleader drains runoff from 23,630 SF roof
Irrigation is pumped up to green wall panels, planted with low water need and native plants
Rainleader extension diverts roof runoff to cisterns
Cisterns to hold ~2,100 gal, or 21 waterings to assist in dry season
Overflow directs excess water back to the storm drain
CASE STUDIES
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SCHEMATIC DESIGN Climate Consultant Suggestions Preliminary Sketches
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Climate Consultant Suggestions
Use plant materials (bushes, trees, ivy-covered walls) especially on the west to minimize heat gain (if summer rains support native plants growth.)
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South
Minimize or eliminate west facing glazing to reduce summer and fall afternoon heat gain.
Orient most of the glass to the north, shaded by vertical fins, in very hot climates because there are essentially no passive solar needs.
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Preliminary Sketches
Green Geodesic Dome
Manually Hoisted Planters
Extended I-Beam Trellis
SCHEMATIC DESIGN
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THE SUBSTRATE
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Plant Specifications for Shading Panel Climbing High light tolerance Wind tolerance Edible
1
Climatic Specifications for Plants Direct sunlight Precipitation Drainage
1
2
3
4
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Passionfruit Maturity: 18 months Light: full sun Water: 3-4 days per week
2
Malabar Spinach Maturity: 2 months Light: full sun Water: 7 days per week 3 Grapes Maturity: 3 years Light: full sun Water: 1 day per week Nasturtium Maturity: 2 months Light: full sun Water: 2 days per week
SOLAR GARDEN SHADE
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Wide horizonal bars in the top half of the trellis provide shade during the growth period and allows the plant to grow thicker as it reaches maturity
Half growth
Full growth
The open structure of the bottom half of the trellis provides enough space for the trunk to grow to support the 10’ height of the plant
THE SUBSTRATE
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OPERATING SYSTEM System Diagram System Details
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System Diagram
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The panels move along the façade while minimally effecting the landmarked building’s construction. They simply rest in a track that is fastened to the roofing substrate and hang over the façade.
The weight of each panel is counterbalanced with the other panels that hang around the building, so the track can be very simply screwed into the roof.
Each unit has a solar panel with an integrated solar tracker that powers a motor. The motor turns wheels that roll along the track. Each panel has its own mechanical system but they are programmed together when working in multiples.
The bottom of the panel has a rubber tire nested behind the planting trough that allows the panel to roll against the façade with minimal friction but maximum pressure. The user is encouraged to tend to the plants frequently, so the panels are highly interactive. The mechanical system can be bypassed whenever the user would like and push them manually from side to side.
OPERATING SYSTEM
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System Details
Scale: 1/2” = 1’ GARDEN SHADE SOLAR 48
Solar panel and integrated sensor Responsive motor L track fastened to roof
Aluminum track frame
Trellis wire steel cable cross bracing
Corten steel trough
12” diameter tire C Channel fastened to brick facade
Scale: 1-1/2” = 1’
OPERATING SYSTEM
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ENVIRONMENTAL ANALYSIS Lighting Analysis Panel Position on North Elevation Natural Lighting
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Lighting Analysis Because Tapachula is always too hot for the Glass House, it requires almost complete coverage in order to keep it comfortable. By analyzing the Sun Shading Chart from climate consultant we identified some flexibility for movement within the design. As you can see in the diagram to the right, the North West corner gets some shade, predominantly in the winter. We used this to make assumptions on how to situate the building and designed two positions for the North facing panels. Position 1, situates the panels all the way to the West to block the constant sun from that side, and position 2 has then equally spaced along the North and slightly open on the South allowing for natural sunlight to fill the space evenly. The Sefeira energy response curves, to the right corroborate these assumptions.
Jun - Dec
10 11
9
8
9
16
17
7
18
10 11
9
12 13
8
9
20
15 16
8
7
6
21 14
10
17
7
Sun Shading Chart
25000
140
24000
135
23000
130
22000
125
21000
120 0
Annual Electricity Demand & EUI
SOLAR GARDEN SHADE
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Dec - Jun
145
-150
20
15
8
7
6
21 14
10
26000
20000
52
12 13
150
115
19
18
Pos. 1
Pos. 2
N
Under/Over
Jul 21
Dec 21
Daylight
Annual
No Panels
ENVIRONMENTAL ANALYSIS
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Panel Position on North Elevation
Position 1: maximum shade
Position 2: balance of shade and natural light
Position 3: maximum natural light
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N
Natural Lighting
N
Summer Solstice
Winter Solstice
ENVIRONMENTAL ANALYSIS
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56
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N
Interior View
ENVIRONMENTAL ANALYSIS
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