Shaping daylight for floating cities

Shaping daylight for floating cities Abhinavv Singh abhinavv@andrew.cmu.edu Carnegie Mellon University School of Architecture

Fig1. Location of Worli Koliwada in Mumbai

Abstract

Floating cities could soon be a prevalent urban typology of the near future due to rising sea levels. Floating communities are imagined as resilient communities that are designed to grow, adapt and stay climate neutral over time. The communities are expected to sustainably harness natural resources to fulfil their needs of energy, food, water and other materials. While these natural resources include sunlight, among others, as an important resource to be harnessed to provide for lighting of indoor and outdoor spaces, there have been scant precedents that propose guidelines for such an important design factor in the realm of floating cities.

How can architects consider the fluid nature of water and its reflectivity in cohesion with design of lighting to change our perception of space?

This study aims to test the aforementioned question in the context of the Koliwada community, native to Mumbai to examine how the existing parameters of lighting design can be utilized for a new urban typology that intends to embrace rising sea levels rather than resisting it. The study has used various daylighting metrics such as Useful Daylight Illuminance (UDI), Continuous and Spatial Daylight Autonomy(sDA) and Annual Solar Exposure (ASE) to help inform the design of housing modules. The study involved 3d modeling using Rhinoceros(Version 6,Robert McNeel), Grasshopper 3D(Robert McNeel) and running simulation tests using Climate Studio(Solemma LLC) for the above parameters on a proposed built typology while also running flow simulations using Autodesk Flow for the topography of the site with an attempt to overlay the outcomes of both tests to better inform design solutions. Results illustrated that factoring in the reflectivity of water while designing a floating house unit can significantly improve the lighting quality of the space.

Introduction

Residing can be defined as relating and adapting to where each one of us chooses to live and the connections we make to the natural and social environment. Worli Koliwada, one of the last swathes of land in Mumbai that have been unaffected by capitalist development, today faces the same preoccupations of all megacities around the world: financial pressure from real estate actors, lack of affordable housing, gentrification and shrinking open space. However, the most pertinent challenge it faces today is the one from imminent inundation due to rising sea levels. This challenge calls for a futuristic vision where the community adapts to this situation and designs their lifestyle to accept sea level rise.

One of the major components of the built environment that would need to be redesigned in response to this situation is housing. The Koliwada built morphology displays an extreme density of housing modules that have been incrementally adapted to accommodate different functions over time. The inorganic evolution of these modules has been driven largely by complex structures of land ownership, increasing pressure on resources due to scant availability of land but most importantly due to an individualistic approach to development which stands in stark contrast to the community’s deeply entrenched principles of sharing and celebrating resources together. The problem lies partly in land being a scarce resource in dense developments and hence it being viewed as a speculative asset but majorly in the pattern of development that has lost its connection to its most prominent surrounding resource, water. Universally, land has been compartmentalized and demarcated to create visible disconnect, the obvious challenges of repeating this pattern on water can prove to be the antidote.

Fig2. Built Morphology of Worli Koliwada against the backdrop of Mumbai’s skyline

Fig3. The mudflats of Mahim Bay Fig4. The edge condition between the Peninsula and the mudflats

This research examines how designing on water can challenge the commodification of resources while also proving to be a tangible factor in improving the qualitative aspect of the design.

Lighting is an integral part of the architectural design process as it helps users comprehend and connect with their spatial surroundings. Designing an optimal home environment is essential for the wellbeing of people since it is the setting for various social and life activities. It has been well documented how lack of efficient daylighting can cause physiological and psychological problems and in certain cases, sickness (Freeman 1993). Studies have also conclusively demonstrated the increased productivity and performance of people when working in spaces with daylight as the primary source of lighting (M. De Carli 2009).

Designing the optimal level of natural light in internal spatial configurations is governed and, in some ways, complicated by several factors that affect the distribution of light, most importantly the built typology. .

The word typology has been derived from the word type which is defined by Cambridge International Dictionary of English as ‘a particular group of things or people sharing similar features and forms a smaller division of a larger set’ (P.Procter 1995). The built form of the Koliwada is densely packed, interspersed at several places with small courts and open spaces. These spaces act as the community drivers, hosting daily fishing and religious activities (Rupali Gupte 2007). The typical Koliwada house in such a settlement consists of a multifunctional living space with several small rooms, a kitchen and often a toilet. The houses are modified to grow incrementally in a vertical fashion as the number of inhabitants increases thereby creating a dense cluster where the lower levels are often deprived of adequate sunlight

The current built morphology of the Koliwada is extremely dense with majority of the units constructed with a concrete framework of beams, columns and floor slabs. The partition walls are constructed with locally sourced mud bricks and finished with lime plaster. The houses are poorly equipped to adapt to an incremental framework with tarpaulin and asbestos sheets acting as the roofing material for temporary enhancements. The unplanned incremental growth and industrial material palette result in an extremely brutalist built environment and creates indoor and outdoor spaces in dire need of better living conditions including quality of light in spaces. The above studies help in identifying the macro and micro level interventions required to respond to this problem. Further studies would involve developing a housing unit module with buoyant technology to be developed in Mahim Bay. The material palette of the housing unit would include locally sourced bamboo, which is recognized for its lighter material mass, but higher tensile strength compared to steel.

Fig5.1,5.2. The real estate actors impacting the built morphology

Fig5.3,5.4. Unplanned Incremental housing

Daylight is one method to offer healthy lighting in buildings; it is efficient in terms of energy, rich in short-wavelength light and obtainable much of the time at great concentrations (Veitch 2007). When the process of design comprises daylight-strategies integrated into the building design process in the primary design phases, significant positive results can be attained. It is also important to understand the vivid qualities of water to factor it into the design process and how an illumination experience can be created by lighting the structures in and around it. Light reflected from water can dance and undulate on the surfaces creating a sense of motion and drama in the spatial setting. The specific water conditions need to be factored into the design by using it as the ground plane while running simulations in ClimateStudio. The combined role of both daylighting and water have governed the methodology of design in this research.

This study uses the following daylight metrics to inform the design of a new typology of Koliwada housing:

Useful Daylight Illuminance (UDI):

A dynamic climate-based metric is the UDI which measures the amoun another dimension on what is considered adequate daylight to work in and overheating issues. The thresholds proposed being below 100 lux a to dark and above 2000 lux would lead to visual and/or thermal disco of the year when illuminance lies within one of the three illumination ra Nabil 2001). It provides information not only on useful daylight levels, b of glare or unwanted solar gain.

Annual Sunlight Exposure(A

It is defined as the cumulative amount of vis or the direct illuminance considering the sun is used to describe how much of space recei (glare) or increase the cooling load. This me specified illuminance level, 1000 lux, for at l the sky. (Y. Elghazi 2014) (Illuminating Engin

Metrics Spatial Daylight Autonomy (sDA):

Spatial Daylight Autonomy describes how much of a space receives sufficient daylight, which for residential and commercial spaces must achieve (sDA 300 lux / 50% of the annual occupied hours) for at least 55% of the floor area. It calculates the percentage of analysis points that exceeds a specified Illuminance level (300 lux) for at least 50% of the total occupied hours from 8am-6pm over the year. (IES 2012)

nt of illuminance on a horizontal work plane. It adds n, added as an upper threshold so as to avoid glare and above 2000 lux, where below 100 lux would be omfort. UDI is the percentage of the occupied hours anges: 0-100 lx, 100-2000 lx, and over 2000 lx (A. but also on excessive levels that could be the cause

ASE):

sible light incident on a point of interest over the course of a year, n only. Annual light exposure is measured in lux hours per year. ASE ives too much direct sunlight, which can cause visual discomfort etric calculates the percentage of the analysis points that exceeds a least 250 hours of the occupied hours without any contribution from neering Society & The Daylight Metric Committee 2013)

Methods 1. Mapping

the impact of sea level rise to formulate the design strategy of the floating modules

In order to assess the impact of sea level rise on the Worli Koliwada peninsula, a series of simulations are conducted on a 3d model of the site generated using Rhinoceros (Version 6, Robert McNeel) with ArcGIS Pro (Esri) data acquired from the Mumbai Metropolitan Regional Development Authority (MMRDA). Using the predictions from the Intergovernmental Panel for Climate Change (IPCC) (al 2016), a terrain mapping procedure helps construct the regions of the peninsula that are likely to be submerged by 1 feet sea level rise by 2030 and 2 feet sea level rise by 2050.

Recognizing the unique topographic coastal edge conditions of the peninsula, the study also involves visually mapping and plotting the mudflats created in the shallow Mahim Bay to the east. The waters of the Bay recede to a distance of 150 m during low tide which occurs twice daily. This condition presents an opportunity to explore the construction of buoyant housing modules in the Bay as a less hostile environment for habitat compared to the Arabian Sea on the west.

The mudflats are part of a larger network of delicate ecology that requires a sensitive intervention. This research looks at designing a buoyant housing module that can be constructed by the community itself using locally sourced materials such as bamboo. Bamboo, as a material, provides an opprtunity for quick, light weight construction that can adapt to the rising sea levels but can also act as agency for community skill building. Studies have shown that Bamboo provides high tensile strength, comparable to steel, but it also has an advantage of an impermeable layer on the outside which protects it from rotting due to water, which is a major problem for all organic materials (Discoveries 2018). The study considers bamboo’s performance in the realm of lighting design and its impact on the qualitative aspects of the space.

Fig6.1,6.2. Using terrain mapping to gauge 1 feet v/s 2 feet sea level rise

Fig6.3,6.4. Mapping predictions of 2 feet v/s 4 feet sea level rise by 2100

Mahim Bay

Arabian Sea

Mudflats

Fig7.1,7.2. Mapping the edge conditions and results of flow simulation

Highest elevation 10 feet

Fig7.3,7.4. Schematic sections on site overlayed with flood prone regions to identify vulnerable houses to be rebuilt as buoyant units on the mudflats

Methods

The second part of the mapping exercise involves recognizing the housing clusters which are most threatened by the possibility of being submerged and can be potentially relocated on the mudflats as part of the floating city typology.

A flow simulation script generated in Grasshopper(Version 3d, Robert McNeel) utilizes the base mesh of the Rhino 3d model to approximate the flow of water on site. Based on the contour data from ArcGIS, a permutation of highest and lowest points on site are chosen as an input for the script. The simulation calculates the maximum distance between the points based on the topography of the mesh and generates the flow lines for water.

Schematic sections are cut through the site at a constant distance of 50 m to overlap with the previously generated flow simulation shown in fig 7.2. These sections are used to understand the topographic conditions wherein water runoff from within the sea combines with flood prone low-lying regions to create a unique flood watershed network. The data from the simulation exercise are mapped out to determine the units that would require rehabilitation in the future. Green connections are designed to connect the two distinct edge conditions of the coast interacting with the Arabian Sea and the Mahim Bay as shown in diagram 7.5 These green connections are extended as physical links towards the new floating typology

Fig7.5. Green connections extended as bamboo pontoons which connect the peninsula to the buoyant units on the mudflats

The Buoyant Unit

The buoyant unit is designed as a living entity that supports the livelihoods of the Koli community and the individual families that would reside in them. A cluster of units are arranged around a water courtyard that would act as a social congregation space but also fucntion as an aquaponic farming system.

The water courtyard arrangement allows for sufficient space between the units that results in increased access to sunlight.

Physical access to these culsters has been designed though a network of bamboo pontoons that stay afloat on top of barrel and boat sections. The submerged aquaponic system consists of freshwater mussels submerged in the water to acts as both fish fodder and an organic cleansing element.

A front and back system of access to each individual unit helps design openings that can allow maximum sunlight inside the space.

A pitched roof system with a bamboo truss is introduced for several reasons. The sloping roof is meant to increase the rainwater harvest that can be collected in the barrels under the pontoon but most importantly, the form of the roof isused for weather protection, increasing the sectional volume of the space and using it to reflect light off the surface of the water underneath.

Openings in the walls and the pontoon are designed accordingly and tested through simulations to check how they use the fluid and reflective nature of the water underneath to affect the quality of light in the space

Bamboo roof

Bamboo framework

Bamboo walls

Bamboo pontoons

Images: Lazar Belic

Boat sections for buoyant systems as well as the storage of harvested water and collection of waste water

Aquaponic farming system

Fig8 Exploded diagram showing system design of the buoyant units

Setting up for Simulations

The Koliwada housing sizes on the mainland are used as ametric to determine the size of the floating units. The units are typically 15 feet x 20 feet in size with the pontoons around being 30feet x 30 feet. The roof is kept at a constant pitch angle of 45degree from a centre median. The window to wall ratio (WWR) is varied between 20% to 40% to test for different fenestration permutations. In order to recreate the setting and the depth of a waterbody, an open box is modelled to be placed under the surface of water and assigned a dark material which allows for accurate simulations

20 feet

15 feet

30 feet

30 feet

Fig 9.1 Plan layout of the house and pontoon 45 deg 14 feet

11 feet Custom water material created Trough created to simulate depth

Fig 9.2 Section

To run the simulations in climate studio, each surface is assigned to a seperate layer in Rhino3d. Each layer is assigned a specific material as shown in figures 9.3-9.8. A custom water material is created to act as the surface of the water as shown in Figure 9.4.

Fig9.2-9.8. Setting up different opaque and transparent materials with different visual transmittance and reflectance values

Simulation Iterations

The first five s run with an in

Iteration 1: Opening facing geographic north. WWR: 30% sDA achieved: 0% ASE a

Iteration 2: Opening facing geographic north. WWR: 20% sDA achieved: 18.8% AS

Iteration 3: Opening facing geographic north. WWR: 25% sDA achieved: 100% AS

simulations use water as the ground pane. A singular simulation was nbuilt ground material in climate studio to compare the two conditions

achieved: 15.4% Outcome: Not desirable for no sDA and ASE>10%

SE achieved: 0% Outcome: Not desirable for low sDA

SE achieved: 1.7% Outcome: Not desirable for possibility of extreme glare

Iteration 4: Opening facing geographic north. WWR: 23% sDA achieved: 94% ASE

Iteration 5: Opening facing geographic north. WWR: 23% sDA achieved: 53% ASE

Iteration 6 Ground plane: Opening facing geographic South. WWR: 23% sDA a

E achieved: 0% Outcome: Not desirable for possibility of extreme glare

achieved: 0% Outcome: Not desirable for low sDA

achieved: 75.2% ASE achieved: 7.7% Outcome: desirable

Results

The results for the simulations helped determine the design of a unit with a window to wall ratio of 23% .The final module included a fenestration on the south facade with an additional skylight fenestration on the south side of the pitch roof.

A favorable Spatial Daylight Autonomy (sDA) value of 89.7% and Anual Solar Exposure (ASE) value of 7.7% helped gain 4 credits.

The simulation also revealed favorable numbers of 75.2% sDA and 7.7% ASE for the unit with an outdoor ground plane displaying that the unit would perform well in both conditions though the reflective quality of water improves its daylight performance considerably

Iteration 7 Water plane: Opening facing geographic South. WWR: 23% sDA achieved: 89.7% ASE achieved: 7.7% Outcome: extremely desirable

Illuminance

March 21 10.30 am

March 21 12.30 pm

June 21 10.30 am

June 21 12.30pm

Sept 21 10.30 am

Sept 21 12.30 pm

Dec 21 10.30 am

Dec 21 12.30 pm

March 21 2.30 pm

March 21 4.30 pm

June 21 2.30 pm

June 21 4.30 pm

Sept 21 2.30 pm

Sept 21 4.30 pm

Dec 21 2.30 pm

Dec 21 4.30 pm

March 21 10.30 am

June 21 10.30 am

Sept 21 10.30 am

Dec 21 10.30 am

Annual Solar Glare

The Annual Solar Glare simulations provide sensor data in view of 8 different directions. The red spaces represent the percentage of occupied space that experiences more than 5 hours of disturbing glare. Blinds and other forms of weather protection can be used to reduce the percentage of glare in these spaces.

Conclusion

Our experience of spaces is greatly infuenced by the quality of light in the space. The floating house typology offers an interesting and novel opportunity to experiment with design and add another parameter to the qualitative aspects of lighting design in spaces. Combining local materials with vernacular construction techniques can help communities save on construction cost, generate revenue through skill building and develop better ownership of the houses, however it is the perceptual experience in the housing units that stands to influence their lives the most.

The design of buoyant units can be greatly optimized by including daylight as an important design parameter. The design can be iterative and scalar since it functions at the cluster scale and can be grown across the entire Worli Koliwada peninsula coast. Replicating the module design across different Koliwada’s across the city could impact the lives of several people in the Koli community presently threatened by sea level rise.

A resilient Koliwada network in Mumbai

Bibliography A. Nabil, J. Mardaljevic. 2001. “Useful Daylight Illuminance: A Replacement for daylight factors.” In Energy & Buildings, by O.Walkenhorst C.F.Reinhart, 905-913.

Ali, Et. 2016. IPCC. April 11-13. Accessed April 10, 2020. https://www.ipcc. ch/srocc/.

B. Iason, A. Stephanie Jenny, H.ludvig. 2017. “Innovative solutions for good daylighting for low energy use in multi family buildings.” Swedish Energy Agency Project.

Christoph Reinhart, Oliver Walkenhorst. 2001. Energy and Buildings.

Freeman, H. 1993. Mental Health and high rise housing. London: Chapman and Hall.

Discoveries, Engineering. 2018. “Why Bamboo is stronger than steel reinforcements?” Civil Engineering Discoveries. December 02. Accessed April 2020. https://engineeringdiscoveries.com/2018/12/02/why-bamboo-ismore-stronger-than-steel-reinforcement/.

Heubner, Stefan. 2019. Academia. Accessed February 2020. https://www. academia.edu/40047784/UN_Climate_Action_Sustainable_Floating_Cities_Yale_Global_.

IES. 2012. IES spatial daylight autonomy and annual sunlight exposure.

New York: Illuminating Engineering Society of North America.

2013. “Illuminating Engineering Society & The Daylight Metric Committee.”

IPCC. 2020. Intergovernmental panel on climate change. Accessed February 2020. https://www.ipcc.ch/srocc/.

Lu, Denise. 2019. New York Times. October. Accessed February 10, 2020. https://www.nytimes.com/interactive/2019/10/29/climate/coastal-cities-underwater.html.

M. De Carli, V. De Giuli, R. Zecchin. 2009. “Optimization of daylight in buildings to save energy and to improve visual comfort.” Eleventh International IBPSA Conference. Glasgow.

Majeed, Mohammed Nadheem. 2019. “Impact of Building Typology on Daylight Optimization Using Building Information Modelling.” Journal of Daylighting 189.

P.Procter. 1995. Cambridge International Dictionary of English. New York: Cambridge University Press.

Rai, Shailendra. 2016. “Fishermen Livelihoods and Climate Risk: A Study of Uran Koliwada, Raigad, Maharashtra.” Academia. Accessed February 11, 2020. https://www.academia.edu/40956714/Fishermen_Livelihoods_ and_Climate_Risk_A_Study_of_Uran_Koliwada_Raigad_Maharashtra.

Rupali Gupte, Prasad Shetty. 2007. Housing Typologies in Mumbai. Mumbai, London: CRIT. vaharney, Apekshita. 2019. Accessed 2020. http://citizenmatters.in/mumbai-new-coastal-projects-affect-environment-12384.

Veitch, J.A. 2007. “Lighting to your good health.” Arkitekten 9 60-63.

Acknowledgements This study has been performed under the guidance of Professor Azadeh Omidfar Sawyer, PhD, LEED AP, Assistant Professor at Carnegie Mellon University as part of coursework for the class 48692-A Shaping Daylight.

Author Information:

Abhinavv J Singh, Registered Architect- Council of Architecture India, Credential ID CA/2018/91## LEED Green Associate, Credential ID 11344### Bachelor Of Architecture, Mumbai University 2017, Master of Urban Design Candidate, Carnegie Mellon University 2020