A case study on electricity and chilled water production of a gas district cooling plant

Abstract

The paper presents the study on the production of electricity and chilled water of a gas district cooling (GDC) plant. The plant was designed as a cogeneration and GDC plant. The electricity was generated by two 4.2 MW gas turbines. The chilled water was produced by the combination of two unit absorption chillers and four unit electric chillers. The absorption chiller and electric chiller capacities are 1250 RT and 325 RT respectively. Electricity generated was supplied to the user as well as for in-plant consumption The designed standard was to operate the two turbines during the day and only one turbine during the night. While the absorption chillers were to be operated during the day, the electric chillers were to operate during the night for charging the thermal storage tank. The chilled water from the storage tank was designed to supplement the chilled water requirements during the day. From the analysis of two weeks operating data, one week for year 2004 and one week for year 2005, it was noted that variations occurred in terms of turbine operating hours and the chillers operating hours from that of the designed values. Preliminary findings indicated insufficient capacities of the electric chillers and the thermal storage tank were the main reason to the variations.