The Secret Cooling Network Hiding Under Singapore’s City Centre | Singapore Hour

Key Concepts

• District Cooling System (DCS): A centralized system that produces chilled water and distributes it to multiple buildings for cooling, offering efficiency gains over individual building-level systems.
• Thermal Energy Storage (TES): Utilizing ice production during off-peak hours to store cooling capacity for use during peak demand, reducing energy costs and grid strain.
• Chillers: Machines that remove heat from a fluid (water in this case) to provide cooling. Different sizes are used for optimal efficiency.
• Ground Floor Area (GFA) Bonus: Incentives offered to building owners in Singapore for adopting district cooling or hosting DCS facilities.
• Life Cycle Cost Savings: The total cost of ownership over the lifespan of a system, including initial investment, operation, and maintenance.

Singapore’s Underground Cooling Network: A Detailed Overview

Introduction: The Need for Cooling in Singapore

Singapore’s tropical climate necessitates extensive cooling solutions. Rather than relying on individual air conditioning units in each building, the city has implemented a large-scale district cooling system (DCS) centered around Marina Bay, operating largely unseen beneath the surface. This system is crucial for maintaining comfort and enabling the city’s vibrant urban life.

The Marina Bay District Cooling Plant: Infrastructure and Operation

The core of the system is a plant extending 25 meters underground, one of the world’s largest underground cooling facilities. Engineers, like Ching E, manage the aggregation of cooling demand across 27 buildings – offices, hotels, and malls – located above. The plant utilizes 18 chillers to achieve the same cooling capacity that would traditionally require 27 individual chillers.

The system cools water to 4°C, circulating it through a network of pipes to the connected buildings. A key efficiency strategy involves utilizing a mix of large and small chillers. This approach allows for a 30-40% difference in size and cooling capacity between the chillers, optimizing performance to meet fluctuating demand.

Thermal Energy Storage: Leveraging Off-Peak Power

A significant component of the system is thermal energy storage (TES). The plant freezes up to 60 megawatt-hours of ice during periods of low power demand and lower electricity prices. This stored ice provides cooling capacity when demand – and electricity costs – are high. This equates to enough cooling to power 5-6 medium-sized buildings. The system dynamically switches between chiller operation and ice melting based on electrical price spikes, further reducing costs.

Real-Time Monitoring and Maintenance: Ensuring Reliability

The network is equipped with sensors that continuously monitor every pipe and pump. These sensors detect anomalies, such as abnormal vibrations in the chillers, indicating potential maintenance needs. Data is updated every few seconds, enabling remote control and monitoring. The system’s design prioritizes rapid response to faults, with strategically placed ladders for quick access to equipment. This proactive approach has resulted in nearly 20 years of uninterrupted operation. Approximately 15,000 cubic meters of chilled water – enough to fill six Olympic-sized swimming pools – are circulated hourly through a 5km-long common services tunnel.

Underground Infrastructure and Space Optimization

The 5km tunnel isn’t solely dedicated to cooling; it also houses potable water pipes (from PUB, Singapore’s national water agency) and electricity cables from the power grid. Moving cooling equipment underground frees up approximately 25,000 square meters of space above ground, allowing for valuable rooftop amenities like the F&B outlets and infinity pool at Marina Bay Sands. Harsha highlights that this space saving is a direct result of the underground infrastructure.

Economic and Environmental Benefits

Approximately 30-40% of Singapore’s electricity consumption is attributed to cooling. District cooling offers significant benefits, including 10-20% life cycle cost savings. Furthermore, building owners adopting DCS or hosting facilities receive a bonus in Gross Floor Area (GFA), incentivizing participation. Combined, these benefits can lead to 30-50% life cycle cost savings over a 30-year period.

Future Expansion and Challenges

Despite its success, the underground network faces space limitations. Future expansion requires careful optimization of existing space. Installing new, large-scale chillers necessitates a unique approach: the chillers are delivered in disassembled components and reassembled within the plant. Currently, one ice tank can typically fit 60-80 ice coils and can power a mid-sized building. By 2030, the plan is to extend the network to cool up to 50 buildings, utilizing six district cooling networks.

Operational Expertise and Adaptability

The Marina Bay system serves as the foundation for Singapore’s district cooling expertise. The team has developed the ability to operate multiple plants and manage water flow efficiently across a complex network. The system’s adaptability extends beyond buildings; it has been successfully deployed for outdoor events, such as National Day parades, utilizing return water from buildings to provide outdoor cooling and improve overall system efficiency.

Quote: “When we see people sightseeing or enjoying their leisure activities in the Marina Bay area, feeling cool and comfortable, we really feel proud of the work because not only is the system smart and green, but people actually enjoy the cooling solutions provided by our underground district cooling system.” – A representative from the cooling plant team.

Conclusion: A Sustainable Cooling Solution

Singapore’s underground district cooling network represents a sophisticated and sustainable approach to urban cooling. By centralizing cooling production, leveraging thermal energy storage, and prioritizing efficiency, the system reduces energy consumption, lowers costs, and frees up valuable urban space. The ongoing expansion and adaptability of the network demonstrate Singapore’s commitment to innovative and environmentally responsible infrastructure.