Air-con not needed to cool a building

SINGAPORE – Hotter days on the horizon are set to stretch demand for cooling indoors. Air-conditioning is an energy guzzler that contributes to global warming when it emits planet-warming refrigerants.

Cooling alone accounts for 40 per cent to 60 per cent of a commercial building’s total energy use in Singapore.

Nearly 50 buildings in Singapore have adopted alternative cooling methods that safeguard workers’ comfort while reducing energy use.

Alternative cooling technologies that do not rely solely on air-conditioning can reduce a building’s energy use for cooling by up to 48 per cent.

These are a few technologies:

1. Hybrid cooling

• Air-conditioning – set at a higher temperature between 25.5 deg C and 27 deg C – is paired with fans.
• Fans increase air movement, which helps the body release heat more easily through the skin.
• Hybrid cooling is the most widely used alternative cooling method as there is no need for major retrofits. To date, 26 buildings have adopted this, including The GEAR, Kajima Corp’s regional headquarters, and Temasek Shophouse.

2. Radiant cooling

• A room can be cooled through panels on its ceiling. Heat naturally moves from warmer objects to cooler surfaces. This system removes heat by circulating chilled water through panels, pipes or surfaces, absorbing heat and keeping temperatures of surfaces below room temperature.
• A network of pipes carrying chilled water draws heat away to cool the building via radiation and natural convective air movement.

3. Active chilled beams

• Cooling and ventilation are provided through ceiling-mounted systems called active chilled beams.
• Each beam contains coils that carry chilled water.
• Fresh air that has been cooled and treated is pushed through small nozzles in the beam. This fast-moving airflow draws warmer air in the room across the cold water coils, cooling it down before the air sinks to reach people in the room.

A study that the Building and Construction Authority commissioned in 2024 identified that these newer cooling technologies can help high-performing green buildings save up to 80 per cent of their energy use, up from 72 per cent now.

This last-mile gap of 8 percentage points calls for technologies that are more novel in nature, or require higher upfront investments, planning and design.

Following the study, upcoming office tower The Clifford at Raffles Place will be piloting another cooling method for the building’s retail space. This method is called passive displacement cooling, which involves leveraging the natural rise of warm air.

Cooling coils near the ceiling will cool the warm air, which then sinks to the floor. This creates a continuous cycle.

This marks the first time such cooling technology is being tested for a retail environment in Singapore. It is more common in office and classrooms elsewhere.