Effects of pumping station configuration on the energy performance of district cooling systems

Abstract

In this paper, a hypothetical district representing the typical urban districts in Hong Kong was considered and a district cooling system model was designed for this district. Mathematical models were tailor-designed for all the major district cooling system equipment to simulate the effects of changing the pumping station’s configuration on the energy performance of the district cooling system. The measures included the use of multiple pumping stations and an unequal number of pumps in each station. In view of the vast number of pumping station combinations possible for analysis, a hydraulic gradient evaluation method was adopted to assist a quick assessment and exploration of those combinations that would be technically feasible. Furthermore, the energy performance of all these technically feasible combinations was evaluated to identify an optimum design that would lead to the lowest electricity consumption.

Practical application: In a district cooling system where there is only one main pumping station for distributing chilled water to all the buildings in the district, the chilled water flow rate and pressure head are very high. Adding booster pumping stations can help to reduce pressure head, pump size and hence power demand of the main pumping station. In this paper, the effects of different pumping station configurations on the energy performance of a district cooling system were investigated. The configuration that could mitigate the impacts of a low delta-T on the energy performance of the district cooling system was also identified.