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All Things Centralised Cooling: Technical Insights Revealed

SP group cooling

The effects of climate change and global warming are highly apparent. This has rendered sustainability efforts to become a social responsibility rather than a desirable goal. In line with the sustainable development agenda efforts created by the UN, organisations far and wide are encouraged to promote sustainability practices with the implementation of more green policies. 

Working towards a greener future requires the involvement of each and every single individual. SP Group does its part by providing a suite of sustainable energy solutions for customers. Our latest masterplan lies in the development of an eco-town in Singapore – Tengah, where lifestyles are driven by technology and sustainability efforts. Some technological elements introduced in this eco-town include eco boards, which will provide residents with a quick view of their block’s total electricity and water usage, electrical vehicle charging and the use of solar energy, generated from photovoltaic panels on the HDB rooftops. The main focus of this eco-town however, is the integration of a Centralised Cooling system, similar to other district cooling projects done in Singapore.

What is Centralised Cooling?

Centralised Cooling utilises district cooling concepts coupled with the use of energy efficient, eco-friendly technology that replaces inefficient conventional cooling methods. The cooling production needs of the individual homes are centralised to a highly energy efficient modular chiller plant at the rooftop instead of individual condenser units at the aircon ledges.

How does it work? – An Overview 

​​Centralised cooling revolves around using water as an effective cooling medium to remove heat from the homes and utilises more energy efficient technology like magnetic bearing compressors in chillers for the production of chilled water. These magnetic bearing compressors are also quieter, more reliable, and eco-friendlier as compared to conventional lubricant oil compressors.

Chilled water produced by these energy efficient chillers are circulated to the indoor fan coil units (FCUs) within the homes at Tengah through chilled water pipes. Within the individual FCUs, a fan blows air through these chilled water pipes to provide cold air to the spaces within the home. This iterative process removes heat from the homes and transfers this heat to the chilled water circulating back to the chiller for cooling down.

The Chilling Process 

The Chilling Process

As shown in the above diagram, chilled water produced by the chiller is circulated to the homes through the chilled water pipes (depicted in blue) using a chilled water pump. Cooling towers shown at the top reject the heat absorbed from the homes through condenser water circulated within the condenser water pipes (depicted in green) using a condenser water pump. The process of transferring heat from the chilled water in the evaporator of the chiller to condenser water in the condenser of the chiller is achieved through the refrigerant cycle.

The Refrigerant Cycle 

The Refrigerant Cycle

The 1st step in the refrigerant cycle is compression and the Compressor is a piece of equipment within the chiller that increases the pressure of the working gas. Low pressure, low temperature refrigerant gas enters the compressor and leaves the compressor as high pressure, high temperature refrigerant vapor.

The Condenser is the 1st of the two of heat exchangers used in the refrigerant cycle. High pressure, high temperature refrigerant vapor from the compressor goes through the condenser where heat is removed from the hot gas vapor through heat exchange using condenser water until the gas vapor condenses into a saturated liquid. After condensing, this high-pressure refrigerant liquid is routed to the Expansion Valve.

The role of the Expansion Valve is to reduce the pressure of the liquid refrigerant and because of this reduction in pressure, part of the refrigerant will boil and create a two-phase liquid and vapor mixture.

The two-phase liquid and vapor refrigerant mixture then enter the 2nd heat exchanger known as the Evaporator. The liquid and vapor mixture absorb heat through heat exchange of the return chilled water within the evaporator and leaves the evaporator as low pressure, low temperature refrigerant gas. The refrigerant gas is then sent back to the compressor where the process restarts.

Chilled Water Loop

Chilled Water Loop

Chilled water produced by the chiller is circulated to the FCUs within the homes through insulated pipes and pumps. This is also known as the chilled water loop.

The chilled water loop is a closed loop system with chilled water in the pipes continuously being circulated and recycled for use. This results in minimal wastage of water and eliminates the potentiality of any environmental contaminations and impurities including dust and bacteria into the chilled water. At the same time, the chilled air produced within the homes does not come into contact with the chilled water directly.

Ultimately, though the technicalities and mechanics of a Centralised Cooling system may seem complex, it is this attention to the smallest of details that ensures unparalleled effectiveness and the best results for Tengah residents and this Tengah new town masterplan.  

Benefits of centralised cooling

From enjoying greater cost savings to empowering energy efficiency and more importantly, contributing to a more ecological landscape, Tengah residents can expect a myriad of benefits in store for them when choosing Centralised Cooling. 

Quality and Reliability

Tengah residents will benefit from best-in-class service and maintenance support packages offered by SP and Daikin.

Proven Concept

This same concept has been proven since 2006 by SP’s district cooling system which provides cooling to buildings across Marina Bay such as the MBS Integrated Resort, One Raffles Quay and the Marina Bay Financial Centre.


The Centralised Cooling System is a smart and highly efficient cooling technology, enabling residents to save money and the planet by leading an eco-friendlier lifestyle.

Condenser-free and Hassle-free

As rooms are cooled by chilled water supplied by a chiller plant on the rooftop, the need for condensers is eliminated which also means less maintenance required.


The smart remote controller allows residences to control their aircon anytime, anywhere. More advanced than conventional remotes, pre-cooling of homes is also made possible.

Cost Savings and Energy Efficient

Tengah residents can look forward to enjoying cool air-conditioning with up to 30% life cycle savings as compared to conventional air-conditioning systems.

MyTengah App

To give residents greater control and a more comprehensive understanding of their Centralised Cooling systems, MyTengah App is introduced. Residents can be better involved in their household utilities consumption, intelligently control their Centralised Cooling usage, browse and purchase energy efficient appliances, and much more.

Advocating climate change and encouraging an effective movement in ecological efforts and activities require teamwork. Centralised Cooling is just one of the many ways in which individuals can play their part and residents are highly encouraged to sign up as it benefits users and promotes a greener landscape. Visit Tengah Singapore HDB to find out more!  

Written By: Steve Seah, Director, Sustainable Energy Solutions

Oct 01 2021


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