As temperatures rise, so does the use of air-conditioners. Today, there are over one billion air-conditioning units in the world – a number that is expected to increase to 4.5 billion units by 2050.
These electrical appliances consume large amounts of energy—which contributes to carbon emissions—to bring temperatures down. Cooling systems typically make up about 40 to 50 per cent of a building’s total energy consumption. In Singapore, electricity consumption in buildings and households contribute to approximately 20 per cent of the country's overall annual carbon emissions.
Air-conditioners can also leak potent greenhouse gases that exacerbate climate change – leading to even higher temperatures. Air-conditioners commonly use hydrofluorocarbons (HFCs) as refrigerants, which are 116 to 12,400 times more efficient at trapping heat than carbon dioxide.
A more efficient way to cool — District cooling
District cooling is a modern and efficient way to provide air-conditioning for a network of buildings, where chilled water is supplied from centralised cooling plants through an underground network of insulated pipes. The benefits of district cooling include enhanced energy savings, lowered lifecycle costs, and reduced carbon emissions.
However, district cooling systems are usually used in greenfield developments, where it is integrated into the design of the development from the start.
In highly developed cities like Singapore, majority of land has been built up and individual building owners are already equipped with their own chiller plants.
Can the concept of district cooling still be applied in such brownfield settings?
A distributed district cooling network in Tampines Eco Town
To find out, Temasek and SP Group did a feasibility study involving 14 buildings in Tampines Central, Singapore, using a novel Distributed District Cooling (DDC) concept.
The results are promising:
- Moving to the DDC network would save the 14 buildings approximately 5,321,432 kWh of energy a year, or 17 per cent of the BAU energy consumption – enough to power 1,665 three-room HDB households.
- The annual average carbon emissions reduction from reduced energy consumption and refrigerant use would be 2,475 tCO2e, or an 18 per cent reduction from the BAU scenario – equivalent to taking 2,250 cars off the roads per year.
- Building owners in the network would also enjoy long term economic value of S$130 million over 30 years, from savings on energy, maintenance, and equipment replacement costs; and potential earnings from leasing out freed-up chiller plant space.