Hyatt Regency Chicago

West Tower Chilled Water Plant Replacement, Design

West Tower Chilled Water Plant Replacement, Design


Hyatt Regency Chicago is a 1,886,000-square-foot luxury hotel consisting of two towers housing 2,019 rooms, located near Chicago's famous Magnificent Mile. The hotel has 228,000 square feet of flexible function space, including four ballrooms; 63 meeting rooms, and the 70,000-square-foot Riverside Convention Center. The purpose of the project was to replace the existing 1,500-ton chiller plant serving the West Tower of the hotel. The existing chillers and cooling towers were almost 40 years old and past their useful service life. The original chilled water system was constant flow.


  • The project involved the removal of a 750-ton absorption chiller that utilized hot water and a 750-ton constant speed centrifugal chiller. Two 750-ton (nominal) centrifugal chillers with variable frequency drives were installed.
  • The cooling towers, chilled water pumps, and condenser water pumps were also replaced. All were equipped with variable requency drives.
  • A hydronic economizer was added to the system, as the facility requires hydronic cooling year-round.
  • The refrigerant detection system was upgraded to meet current ASHRAE 15 requirements.
  • The chiller plant was automated with new direct digital controls, and flow meters were installed to measure the chilled water and condenser water flows.
  • The owner purchased the the chillers, cooling towers, and hydronic economizer before the design was completed, based on life cycle cost, so the equipment was on site for installation right after the project was awarded.
  • The plant was converted from a constant flow primary chilled water system to a variable primary chilled water system.
  • Condenser water flow matches the number of chillers in operation.
  • Tower condenser water is reset based on ambient wet bulb temperature.
  • The series-counterflow arrangement minimizes chiller lift and hence energy use.
  • A five-micron filtration system for the chilled water loop can be used to backwash the plate heat exchanger on the chilled water side.