Most of us are familiar with air conditioners, the white units mounted near the ceiling that contribute so much to our everyday comfort. In larger buildings and facilities, chillers are also a well-known part of the cooling infrastructure. But the idea of District Cooling Systems is less widely known. Even though they play an increasingly important role in carbon emission reduction for HVAC System designs.
What is a District Cooling Systems (DCS)
A District Cooling Systems (DCS), is a regional cooling network that distributes cooling energy usually through chilled water, from a central source to multiple buildings within a dedicated region, through a network of underground pipes. In some rare cases, the medium could also be some other materials (Depends on country / regions) for better efficiency or cost-effectiveness.
From that, individual facility users could purchase chilled water from the network and directly enjoy the cooling provided, without needing to install their own chiller plant. One successful example in Hong Kong includes the Kai Tak District Cooling Networks, where a majority of the facilities within the region enjoy cooling from the network.
What are the benefits?
The DCS brings a lot of benefit to not only the facility users, but also to the regional neighbourhood within the cooling district as well.
Energy Savings with District Cooling Systems
From an energy perspective, the Hong Kong Electrical and Mechanical Services Department (EMSD) reports that district cooling systems (DCS) use about 35% less electricity than traditional air‑cooled air-conditioning systems, and around 20% less than individual water‑cooled systems that rely on cooling towers. This improved efficiency directly supports carbon emission reduction for HVAC System operations at the district scale.
From the user’s point of view, the need for a dedicated chiller plant is effectively removed, along with its associated energy use. This helps reduce both operating costs and the environmental impact. In addition, because DCS relies on a central plant, energy-saving measures can be implemented more easily and consistently than in a scenario where individual chiller plants are spread across multiple buildings. A single efficiency upgrade can improve the overall system COP and benefit every building connected to the network.
Environmental Sustainability with Cooling Systems
Today, carbon footprint is a major concern, especially for owners and operators of large buildings. A chiller plant typically accounts for around 40% of a building’s total operational energy consumption, and the emissions associated with extensive installation or replacement works add even more to its environmental impact. As a result, the chiller plant is often one of the largest sources of greenhouse gas emissions in a building.
Many of these impacts can be significantly reduced by integrating with a District Cooling System (DCS). In line with the energy savings mentioned earlier, the overall emissions associated with cooling can also be substantially lowered.
Enhancing Economic Viability with District Cooling Systems
District Cooling Systems also help reduce upfront capital costs for consumers, as there is no need to install chiller plants in individual buildings. By eliminating the chiller plant at the building level, owners can avoid significant investment in equipment, plant rooms, and associated infrastructure.
| Chiller Plant | District Cooling Systems | |
| Installation Cost | Water - Side Air- Side | Air - Side |
| Operation & Maintenance Cost | Water - Side Air- Side | Air - Side |
| Repair & replacement cost | Water - Side Air- Side | Air - Side |
| Risk | Higher | Lower |
The table above highlights the additional costs that clients or building owners incur to install, operate, and maintain their own chiller plants. This leads us to the next part of the discussion: what happens if you choose to join the DCS network instead? What benefits can you expect as a participant in a District Cooling System?
What comes next?
One of the most noticeable differences between a traditional chiller plant and a DCS is the space you gain. Without the need for a chiller plant room and rooftop cooling towers, these areas can be freed up and repurposed for more valuable uses.
The rooftop, in particular, can become a valuable asset for urban sustainability initiatives. It can host rooftop gardens that produce local crops and herbs or simply provide a green, relaxing space for occupants. It can also accommodate small-scale solar or wind installations that generate renewable energy and help reduce the building’s overall energy demand.
This, in turn, helps mitigate the urban heat island effect and reduces the risk of microbial contamination by removing cooling towers. The additional greenery also offers habitat and resting spots for local species in an otherwise concrete-dominated environment, enhancing both biodiversity and the overall liveliness of the surrounding area.
Should You Choose District Cooling Systems Over a Chiller Plant?
Given all the benefits discussed, the answer is yes. In regions with significant heating demand, there is an additional advantage: the plant can be designed to supply hot water as well, creating a District Heating and Cooling System (DHCS) that provides both cooling in summer and heating in winter for the surrounding area.
The applications and potential adaptations of DCS are extensive. Many of the systems we operate at Veolia around the world are designed with unique features to address the specific challenges of their local environments. If you’d like to explore some of these examples.