Satellite Utility Plant 2 Expansion

Texas A&M University

Shah Smith & Associates, Inc. was retained by Texas A&M University to undertake the design to expand the West Campus Utility Plant No. 2. Currently, the plant includes three-1330 ton chillers. Two 500 HP rental boilers are brought in each winter to supplement the heat provided from the West Campus Plant No. 1. To meet the additional heating and cooling requirements, SSA designed the addition of two-2250 ton chillers with room for a third chiller of the same size and the permanent installation of 2 – 500 HP heating water boilers.

Critical to the success of this project was the control of Plant No. 2 in parallel with Plant No. 1. As originally designed, both plants were configured with primary/secondary chilled water pumping systems. TAMU had experienced hydraulic problems with the system for many years affecting pumping and differential temperature.  SSA evaluated the system and demonstrated that the problems in primary/secondary pumping, starting and stopping of chillers is determined by the magnitude and direction of flow in the decoupler (plant bypass). When two primary/secondary plants operate in parallel, the decoupler flow is not an indication of load on the plant. SSA recommended converting Plant No. 2 to primary only pumping, which would allow Plant No. 1 to operate in primary/secondary mode, and start and stop chillers based on the decoupler flow.

The existing 15 kV electrical equipment was expanded to serve the new expansion. Each chiller is served by a dedicated transformer.

The existing Emerson WDPF II distributed control system was expanded to incorporate the new equipment and implement sequences of operation.