Space Cooling » District cooling

Savings

The final energy savings of district cooling schemes, if any, are highly dependent on the system design and equipment used. Generally speaking, there are no final energy savings for standard district cooling systems using CHCP, in fact they will tend to use more final energy. However, the potential benefits of district cooling using CHCP come when the energy system as a whole is examined. The figure below presents the potential primary energy savings from a district cooling system using CHCP compared to conven-tional air conditioners with a SEER of 2.5 and 3.5.

Energy savings

District cooling system savings potential and economic benefits
As can be seen, the results are highly sensitive to the overall efficiency of the electricity generation system. When the overall efficiency of delivered electricity is low, district cooling delivered by CHCP systems can provide significant primary energy savings per unit of cold supplied. However, only the most efficient CHCP systems will save primary energy when the efficiency of electricity generation is high. CHCP systems with high electricity-to-heat ratios and double-effect absorption chillers therefore yield the highest primary energy savings.

Data on the total costs of district cooling networks using CHCP systems are difficult to obtain. From the consumers’ point of view, investment costs are usually significantly lower, as no plant room is required and no heat rejection systems are required, in addition to saving on the chiller equipment and installation. This has to be balanced by the cost of connecting to the district cooling system. Investment costs are therefore lower, but the levelised cost of cold provided will depend on the charges for chilled water from the district cooling company.

To date district cooling systems supply almost exclusively commercial buildings. They are suitable for meeting large cooling loads, not for comfort cooling in small residential dwellings. Given that district cooling systems must compete with the least cost conventional cooling solution for a building (taking into account equipment costs, operations and maintenance costs, fuel costs, and the cost of finance) district cooling tariffs are usually negotiated to deliver a lower cost than that equivalent. Where district cooling is taken up, it is therefore because it is a more economic means of cooling.