RIBA Lubetkin Prize 2013

Two giant biomes designed by Wilkinson Eyre Architects – the Flower Dome (1.2 hectare) and the Cloud Forest Dome (0.8 hectare) – display plants and flowers from the Mediterranean-type climatic regions and Tropical Montane (Cloud Forest) environments and provide an all-weather “edutainment” space within the Gardens.

• The Cooled Conservatories, designed by Wilkinson Eyre and located in Bay South, are home to two glass biomes – the Flower Dome (cool dry biome) and Cloud Forest (cool moist biome).

• The Conservatories are an amalgamation of architecture (Wilkinson Eyre), structural ingenuity (Atelier One) environmental engineering (Atelier Ten) and landscape design (Grant Associates).

• They are an iconic feature of the Gardens that showcase the application of sustainable energy solutions and tell the story of plants and their intimate relationships with man and the ecosystem. At the same time they offer a spectacular visual and spatial experience for the visitors.

• The Flower Dome replicates the cool-dry climate of Mediterranean and semi-arid sub tropical regions like South Africa and parts of Europe like Spain and Italy. The Cloud Dome replicates a cool-moist climate found in Tropical Montane regions between 1,000 to 3,500 metres above sea level, such as Mt Kinabalu in Sabah, Malaysia, and high elevation areas in South America.

• About 226,000 plants from every continent except Antarctica expect to be featured in the conservatories. Many of these species face the threats of climate change and habitat loss brought about by human activities. It is hoped that displaying them in the conservatories will help to promote awareness of the wonders of nature and the value of plants to Man and the Environment.

Key Statistics About The Flower Dome

Footprint: 1.2 hectares (approx 2.2 football fields)
Plantable area: 4,570m2 including 848m² of planting space in the Flower Field
Façade:
Overall surface area: 16,000m²
No of glass panels: 3,332 glass panels of 42 varying shapes and sizes
Height:
Floor to top of glass: 35m
Floor to top of structure: 38m
Volume: 195,000m³ (approx. 75 Olympic swimming pools)
Temperature: 23ºC to 25ºC
Humidity: 60% to 80%
Capacity: 1,400 people
Features:
• Plants from the Mediterranean and semi-arid subtropical regions, complemented by changing displays in the Flower Field to reflect different seasons and festivals
• An indoor event space spanning 2306m² that can accommodate up to 1,000 people
• Two food and beverage spaces totalling 1,119m² in area

Key Statistics about The Cloud Dome

Footprint: 0.8 hectares (approx. 1.5 football fields)
Plantable area: 6,000m2 including 3,800m² of vertical planting space on the Cloud Mountain
Façade:
Overall surface area: 12,000m²
No of glass panels: 2,577 glass panels of 690 varying shapes and sizes
Height:
Floor to top of glass: 54m
Floor to top of structure: 58m
Volume: 153,000m³ (approx. 60 Olympic swimming pools)
Temperature: 23ºC to 25ºC
Humidity: 80% to 90%
Capacity: 1,200 people
Features:
• Plants from Tropical Montane regions between 1,000 to 3,500 metres above sea level
• A 35-metre-tall man-made mountain (The Cloud Mountain) with waterfall

Energy Efficient Cooling Technologies

To optimise energy efficiency, the following key architectural and engineering strategies were implemented:
• Minimising solar heat gain while allowing maximum light for plants
This is achieved through the use of spectrally selective glass and light sensor operated shadings.
• Cooling only the occupied zones
The process of thermal stratification is applied to ensure cool air settles at the lower occupied zone and warm air is allowed to rise and vented out at high levels. This is enhanced by ground cooling, which are chilled water pipes cast within the ground slabs.
• Efficient de-humidification in the cooling process
A liquid desiccant system will be used to achieve greater energy savings in the cooling process. The cooling process is de-coupled into first de-humidifying of the air with a liquid desiccant (i.e. lithium chloride) and then cooling of the dry air. This reduces the need to over-cool the air in order to remove its moisture as in a conventional air-conditioning system.
• Generating energy and harnessing waste heat on
Electricity is being generated on site to run the electric chillers that produces chilled water to cool the Conservatories. Waste heat is captured in the process to regenerate the liquid desiccant. This co-generation of energy is achieved by the use of a Combined Heat Power (CHP) biomass steam turbine. A steam turbine will be incorporated to produce electricity and waste heat from biomass. This is mainly horticultural waste from the Gardens and other NParks horticultural operations. This reduces dependency on the electric grid for the cooling of the Conservatories.
• NParks had earlier commissioned an energy modelling study to ascertain the environmentally sensitive energy requirements of the conservatories. The study showed that, by applying the cooling technologies, the energy consumption for the conservatories is comparable to that of an average commercial building in Singapore of the same footprint and height, normalised to a 24-hour cooling period.
• This suite of technologies can achieve at least 30% savings in energy consumption, compared to conventional cooling technologies.