A district cooling system allows the building owner to eliminate their on-site chiller operation and maintenance. By doing this, the building owner no longer needs to purchase utilities related to air conditioning, operate and maintain chillers, and replace chillers at the end of their life cycles. Because of the high efficiencies that district cooling systems operate at, and their ability to utilize waste energy sources such as Treated Sewage Effluent (TSE), the building owners can expect more stability in their energy costs into the future.
The conversion from conventional cooling systems to a district cooling system entails the removal of on-site chiller plants, and heat rejecting condensers, from individual buildings, noise and mechanical vibrations, as well as thermal plume and waste heat pollution can be significantly reduced.
When considering converting to district cooling the building owners need to conduct a building survey, which will collect sufficient data to establish a technical concept and associated costs to convert the building from a conventional system to a district cooling system. Generally buildings running a central cooling system benefit from the conversion a lot more than buildings that run individual electrical units, such as split units, as central cooling systems require less conversion costs.
Another important part of the building survey is to gather sufficient data and information to determine the buildings’ thermal peak loads and energy requirements.
A building’s peak load is a very important calculation. The district cooling system has to be designed to provide enough capacity to deliver each building’s peak thermal needs during peak days. If the system is under-designed, the customer will not be happy with the system, as the building’s occupants will obviously be uncomfortable during peak weather periods. If the system is over-designed, then the capital costs to deliver the cooling will be too high and could affect the economics of the entire project.
The building’s energy consumption must be determined, based on historical usage. In estimating future cooling requirements, it is important to take into account the energy conservation impact of the conversion to a district cooling system.
The connection of a building to district cooling also offers improvement to the reliability and flexibility of the service. Compared with conventional centralized air-conditioning systems, district cooling systems are built with standby cooling capacity, to ensure that cooling is always available, at the central plant. Distribution systems are also generally designed with multiple loops or other back-ups to provide additional reliability in distribution.