Case study

Gardens By The Bay Sustainable Strategies on Passive Design and Energy Efficiency

Asian Architecture ARC 2234

Project 1:Case Study

Gardens by the Bay Sustainable Strategies on Passive Design and Energy Efficiency

NAME: Choo Ai Lin

STUDENT ID: 0317253

LECTURER: Mr Koh Jing Hao

ARC2234 ASIAN ARCHITECTURE Page 1


Table of Content Page

Abstract

1.0 Introduction

2.0 Principles of Sustainable Building Design

3.0 Passive Design Solution

4.0 Methods to Cool and Maintain the Interior Temperature

5.0 Benefits of Using Displacement Air Supply System

6.0 Energy Efficient Building Material

7.0 Conclusion

8.0 References


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Abstract

The purpose to study the implementation of sustainable architecture is to identify and understand the sustainability features and workings of a self-sufficient design that supports an energy-efficient and passive design. The Cloud Forest of Gardens by The Bay comprise the advance stage of environmental design and sustainable development principles. Singapore's Gardens by the Bay feature the world's largest climate-controlled greenhouses which this is an integral part of a strategy by the Singapore government to transform Singapore from a "Garden City" to a “City in a Garden” and the aim is stated to raise the quality of life by enhancing greenery and flora in the city. In assisting the validation of research, literature reviews and research based on various sources regarding the passive design and the sustainability features of Gardens by the Bay were conducted. In order to provide a wider variation of research, the sustainable building materials, innovative passive and active environmental strategies for living conditions within the conservatories and the method of technical system that makes the conservatory suitable for displaying the collections of plants on earth was integrated into sustainable architecture. Design by Andrew Grant Associates, Gardens by the Bay is one of the best representations of sustainable design as it proves how sustainability and landscaping could come together. The Cloud Forest Dome which is one of the conservatory that simulate the mountainous tropical region condition where the air temperature was low during the day and cooler at night but with humidity levels that approaching saturation throughout both day and night. (Bellew & Davey,2012) The energy systems of The Cloud Forest works to reduce heat gain with selected material, cool and maintain the dome by using displacement air supply system and generate heat and electricity by using waste wood. These sustainability features of The Cloud Forest will explain how implementation of sustainable architecture with passive designs and energy efficiency can support the massive glasshouse.



1.0 Introduction

Figure 1: Gardens by the Bay (Source: Trends,2012)

The Singapore Gardens by the Bay which located in Marina Bay is a main project in delivering the Singapore Government’s vision of transforming Singapore into a ‘City in a Garden’. Architect Wilkinson Eyre was called upon to design this centrepiece of ambition.

The focal point of of Gardens by the Bay is the 2 conservatories which are The Flower Dome and The Cloud Forest. They are the 2 largest climate-controlled glasshouses in the world. The Flower Dome consists of a cool dry conservatory while The Cloud Forest has a cool moist conservatory. (Rus. M , 2012) Each of them has its own character but both explore the horticulture of those environments most likely to be affected by climate change. (Sheppard. C, 2012)

The Cloud Forest highlights the relationship between plants and the planet, showing how the warming of the cool tropical cloud forests will threaten biodiversity. (Rus. M , 2012) The purpose of this project is to communicate to the Singapore community the urgency and importance of environment sustainability with its linked message of its value of biodiversity conservation arose from the need to expand the footprint of the city. (Bellew & Davey, 2012)



This paper will investigate on the Sustainable Strategies on Passive Design and Energy Efficiency of The Cloud Forest in Gardens by the Bay by responding to the following question:

1. What are the principles of a sustainable building design?2. How to integrate passive design in this building?3. How to cool and maintain the temperature of the conservatory?4. What are the benefits of using displacement air supply system for air conditioning?5. Which energy efficiency building materials are used in The Cloud Forest?

2.0 Principles of Sustainable Building Design

Building construction and operations can have wide-ranging direct and indirect impacts on the environment, society, and economy. To balance the needs of these areas, the field of sustainable design use an overall way to harmonize needs and establish a design which benefits in each ways.

The aim of sustainable designs is to avoid reduction of critical resources to prevent environmental degradation caused by facilities and base installation throughout their life cycle. (WBDG, 2013) Therefore, it is important to create a building with passive designs and energy efficiency.

Buildings use resources generate waste and give out harmful emissions. Hence, architects and builders face a unique challenge to meet demands for new facilities that are able to secure, healthy and productive while minimizing their impact on the environment.

There are 6 basic principles for sustainable design. That is by optimizing site potential, optimize energy use, protect and conserve water, optimize building space and material use, enhance indoor environmental quality (IEQ) and lastly optimize operational and maintenance practices. (WBDG, 2013) The Cloud Forest of Gardens by the Bay had fulfilled all the six principles of sustainable design.



3.0 Passive Design Solution

The Cloud Forest structures have been designed with sustainability as a starting point with every consideration given to passive climate control techniques. A computer-controlled shading system and carbon neutral cooling technologies have been integrated into the fabric of the building to efficiently maintain the climate within the conservatory. (Bellew & Davey, 2012)

The giant gridshell framework protected by a series of 28 steel ribs or arches, anchored at the base and the arches deflect and absorb the strong winds, protecting the glass beneath. The customised glass panels, each weighing approximately 320kg, incorporate metal oxide adjusted to a level to achieve the right amount of light transmission. The ribs at ground level are also painted off-white to reflect light and heat. (Bellew & Davey, 2012, p.42)

However, a retractable shading system will be arranged between the arches during hot weather to reduce heat loss and maintaining the indoor temperature. 8m x 10m of rolled triangular sails will be hidden within the arch structure and these will spread out as a shading device.

Process of rolled triangular sails concealed the dome

Figure 2 :Gardens by the Bay (Source: Archdaily,2012)

Biomass boilers are applying in this conservatory for heat supply. It is considered to be close to carbon neutral that making a significant improvement to the energy rating of The Cloud Forest by giving out minimum amount of smoke while boiling. This heating system will reduce the energy that use to heat up the building and will also cut down the carbon footprint therefore contribute Singapore to move to a low carbon environment.

The Cloud Forest make us of the primary energy which is the waste wood sponsored by The National Parks Board to provide energy to cool the conservatory at the energy site centre. 3 millions of waste wood were used monthly. The reuse of waste wood is used to drive the Combine Heat and Power (CHP) system.

K.W. (2012, June 19) stated that ash from the boiler will be re-used in the garden while heat from the Combine Heat and Power unit will be used to regenerate a liquid desiccant. These desiccants will be used to remove moisture from the fresh air supply. This helps cut power consumption, dry air requires far less energy to cool it than moist air does.


Heat detectedShading between arches conceal the glasshouse


Renewable Energy- Automatic Pellet Feed Boiler

Figure 3: Biomass heating system (Source: NorthStar Energy, 2011)

Generally, wood pellets or other biomass products are put into a chamber where an electric probe burn the material. Microprocessor then monitors the combustion using thermostats in the flue gasses as a result adjustments are made automatically to the fuel supply and the fan speed. (NorthStar Energy, 2011)

Then, heat is transferred from the combustion gasses to the water used in the central heating system when hot gasses are passed through a heat exchanger. The hot water is then circulated around a standard central heating system. (NorthStar Energy, 2011) Hence the biomass heating system is a renewable heating system which only requires minimum energy.

Figure 3 shows that the rainwaters are collected from the roof by using gutter to transfer it to the filtration system underground. The rainwater then will store and transfer for plant irrigation and to the manmade waterfall. After cleaning and filtering, the clean water was sent to the reservoir for daily usage.


Waste wood is use to provide cooling and power energy to the biomes.

http://www.northstarenergy.co.uk/biomass_boilers/how_biomass_boilers_work/



Figure 4: The Gardens (Source: Gardens by the Bay, 2012)

The environmental diagram showing sustainability cycles that incorporates the water, energy and materials cycles


4.0 Methods to Cool and Maintain the Interior Temperature

Despite the efficiency of the high performance glass and the use of external shades during times of high solar gain. Hence, there remain a significant amount of solar and other heat gains into the biomes that needed to be offset through the introduction of cooling in various form.

The first method is the use of a displacement air supply system which involves introducing the conditioning air at low level within the occupied zone to limit the volume of the building that requires conditioning thereby reducing energy usage and plant capacities.

From there, the conditioned air rises easily into the user's zone and as the air moves through the room, it gains heat from users, equipment and lighting. Then, it continues to move upward until it is exhausted out of the space through open windows or be extracted and re-circulated. Displacement ventilation also allows the air conditioning to be supplied at 18˚C rather than 12˚C, which would be the norm for a conventional conditioning system and this elevated supply temperature results in saving the energy.

Figure 5: Raised Access Floor (Source: Architectural Record, 2010)

Figure 5 shows that fresh air is drawn in from outside through air intake louvers and shafts concealed within the embankment planting. Diffusers integrated into the vertical surface of the planter beds anti-displacement diffuser terminals placed in beds throughout each biome deliver air at low velocity into the lowest space at lowest level. (Bellew & Davey, 2012, p.44)

Next, to absorb and remove the incident absorbed solar radiation in the biomes, the method of radiant cooling in the pathway in pathways and pavements are also being used. This reduced the amount of heat gain to distribute by the air systems and reduce mean radiant temperature for occupants to improve human comfort. (Bellew & Davey, 2012, p.44)


Air flow adjusted to

suit individual needs

Air exhausted out will be re-circulated

Displacement air supply system in The Cloud Forest

Cool air delivers from low level


Umbilical Walkways Floating Walkways

The two types of walkways used for radiant cooling are the umbilical walkways and the floating walkway. Air supplies are distributed above the floor structure of the umbilical walkway. They adapt to gradients and usually apply an individual or continuous vent. While the floating walkways is a fixed walkway that is adaptable to surrounding changes and continuous low profile vents are used. (Bellew & Davey, 2012, p.30)

In addition, The Cloud Forest Dome requires extremely high levels of moisture to duplicate the cool humidity of high attitude cloud forest. At the high levels, the air requires to be supplied at more than 100% relative humidity. Hence, the uses of direct evaporative humidification are installed within the space to provide the very high humidity levels which provide additional moisture to the atmosphere at the same time enhance the cooling performance. These systems are largely installed within the planting on the aerial walkways that extend from the mountain.

The Cloud Forest Mountain shrouded in mist

Figure shows that the misters allowed the moisture to be directly injected into the space to keep humidity level high but also to form part of the visitor show by creating a visible fog bank inside the building.


Visible fog created


The Cloud Forest has a 35-metre tall mountain which covered in lush vegetation envelop the world’s tallest indoor man-made waterfall in order to cool and maintain the indoor temperature therefore showcases the plant life from tropical highlands up to 2000m above the sea level.



5.0 Benefits of Using Displacement Air Supply System

Figure Green Building Guideline for design (Source: Architectural Record, 2010)

Displacement air supply system will minimize the solar heat gain. The conservatory was fitted with double glazing with low-E coating that allows optimal light in for plants but reduces a large amount of solar heat. At sunny day, the automatically open sensor-operated retractable sails will provide shading for plants. (Trends, 2012)

In addition, this air conditioning system will cool only the occupied zones. The Conservatories apply the strategy of cooling only the lower levels so that it can reduce the volume of air to be cooled. This is achieved through thermal stratification which the ground cooled by chilled water pipes which cast within the floor slabs to enable cool air to settle at the lower zone while the warm air rises and is vented out at high levels. (Trends, 2012)

Lastly, the advantage of this system is to generate energy and draw out waste heat. Electricity is generated on-site to run the chillies that cool the Conservatories but at the same time, waste heat is captured in the process to regenerate the liquid desiccant. This energy is generated by the use of a Combined Heat Power (CHP) steam turbine that is fed by horticultural waste from the Gardens and other parks around Singapore. (Trends, 2012) The CHP system will reduce the dependency on the electrical grid.


Minimize heat gain

Cool only the occupied zone

Generating energy and harnessing waste heat


6.0 Energy Efficient Building Material

The choice of double glazing is important to prevent heat loss in the conservatory. The

double glazing of The Cloud Forest will have a low emission coating on the inner surface of

the glass. This is to ensure more sunlight which is about 65% into the building but only only

35% solar heat was transferred. In this case, double glazing which is the main building

material used to allow maximum lighting into the building with a minimum heat transfer.


Cool Air(long wave radiation reflected the cold air back to the interior)

Insulated Glazing(reduce heat transfer)

- In The Cloud Forest, double glazed glass is where it assists in keeping air conditioned spaces cooler for longer time, cutting down on energy bills and improving comfort.

Double glazed glass consists of two panes of glass with a gap in the middle which enable sunlight to be reflected back to the surroundings. The two pieces of glass and an insulated frame are sealed together as one unit while the gap in the middle is usually a vacuum and sealed tight. (Double Glazing Info, 2010)

Usually, a certain amount of Argon gas, which is a naturally occurring inert gas, is inserted between the panes of glass. Argon gas has a higher density than the surrounding air and this reduced heat energy to be transmitted into the conservatory. The gas also acts as a barrier reducing heat loss as well as heat absorption in the building.

Figure 6:Roof & Frame Glass (Source: Conservasolve, 2009)



The conservatory uses low-e glasses for the glass facades because the solar rays passes

through the glasses as short wave and goes through the glass to be absorbed by the interior

of the building. From Double Glazing Info (2010), most of the longer wave heat energy is

reflected back into the building exterior while the low-e glass filter out most of the heat

wave and reduce the interior heat gain.

The combination of low-e glass and insulated glazing can ensure a better heat insulation for

the building improving the thermal comfort of The Cloud Forest. The glass can minimize the

loss of the cool air in the interior that passes through the double glazed glass. This glass is

chosen not only maintain interior temperature but also reduce external noises.

- The main structural members were deliberately placed outside the glazing to help with shading (Source: Glass Network, 2011)


7.0Conclusion

The success of this grand enterprise rest on the total understanding of the intent of the project, the creativity and professional talent and skill brought in achieving the technical and aesthetic aspirations and passion- driven effort of the architect to translate dream into reality. (Bellew & Davey, 2012) The most important is they let people know the effects of climatic changes on the world’s plant species, the importance of maintaining a sustainable environment and also to survey the main questions on how the building stands and how environmental control is maintained within the spaces.

References

1. Bellew, P., & Davey, M. (2012) Green House, Green Engineering: Environmental Design at Gardens By the Bay. Singapore: Oro Editions.

2. ArchDaily.(n.d.). Gardens by the Bay / Grant Associates. Retrieved April 17, 2014, from http://www.archdaily.com/254471/gardens-by-the-bay-grant-associates/

3. Sheppard, C. (2012). Gardens by the Bay by Grant Associates and Wilkinson Eyre Architects. Retrieved April 17, 2014, from http://www.dezeen.com/2012/06/19/gardens-by-the-bay-by-grant-associates-and-wilkinson-eyre-architects/

4. Arup. (n.d.). Gardens by the Bay South. Retrieved April 18, 2014, from http://www.arup.com/projects/flower_dome.aspx

5. Rus, M. (2012). I Like Architecture. Retrieved May 2, 2014, from http://www.ilikearchitecture.net/2012/10/singapore-gardens-the-bay-wilkinson-eyre-architects/

6. Sheppard, C (2012). Detail Daily The architecture and Design Blog. Retrieved May 10, 2014, from http://www.detail-online.com/daily/5515-5515/

7. WBDG Sustainable Committee, (2013). Sustainable. Retrieved June 10, 2014, from http://www.wbdg.org/design/sustainable.php

8. Trends (2012). The sky's the limit – Gardens by the Bay from Commercial Design Trends, Volume 2814. Retrieved June 10, 2014, from http://trendsideas.com/Article16828/NewZealand/book=861

9. Double Glazing Info (2010). Air or Argon Gap. Retrieved June 12, 2014, from http://www.double-glazing-info.com/Choosing-your-windows/Air-or-Argon-gap

10. Dr. Tan, K.W. (2012, June 19). Gardens by the Bay by Grant Associates and Wilkinson Eyre Architects. Retrieved June 12, 2014, from dezeen magazine website: http://www.dezeen.com/2012/06/19/gardens-by-the-bay-by-grant-associates-and-wilkinson-eyre-architects/


http://www.double-glazing-info.com/Choosing-your-windows/Air-or-Argon-gap

http://trendsideas.com/Article16828/NewZealand/book=861

http://www.wbdg.org/design/sustainable.php

http://www.detail-online.com/daily/5515-5515/

http://www.ilikearchitecture.net/2012/10/singapore-gardens-the-bay-wilkinson-eyre-architects/

http://www.ilikearchitecture.net/2012/10/singapore-gardens-the-bay-wilkinson-eyre-architects/

http://www.arup.com/projects/flower_dome.aspx

