Hyatt Regency Atlanta

Boiler and Chiller Plant Renovation

Boiler and Chiller Plant Renovation - Atlanta, GA

Overview

A major utilities reconfiguration was based on a central plant assessment completed several years earlier by G/BA. Phased projects resulted in major improvements to this 1,260-room luxury hotel in Atlanta's city center, encompassing about 1.5 million square feet in three towers.

The prior configuration consisted of one chiller room, one mechanical room with an additional chiller and a low-pressure steam boiler plant, and a third mechanical room containing a high-pressure steam boiler plant. The two chiller plants were consolidated into a single plant, and the two steam boiler facilities were consolidated into a single low-pressure facility. Overall energy use for the hotel has dropped from 123,000 MMBtu/yr to 110,000 MMBtu/yr, a 10.6% decrease. Reductions represent an annual electrical cost savings of $103,900, plus measured gas cost savings of $52,930 for the first 10-month period following completion of the boiler plant project. The renovation conserves water and also removed equipment with CFC refrigerants that contributed to ozone depletion.

Awards

Source Award
2014 Excellence in Engineering Award, ASHRAE Illinois Chapter.

Features

Chiller Plant

  • Two existing chiller plants were consolidated, and a plate heat exchanger hydronic economizer was incorporated.
  • Two new chillers (500 ton and 800 ton), plus condenser and chilled water pumps, were added to the existing 1,000-ton unit. The chillers were prepurchased based on a life cycle cost analysis. All pumps were equipped with variable frequency drives. The new variable-primary chiller configuration corrected a previous problem where the most efficient chiller could not be equally loaded in certain scenarios.
  • The hydronic economizer provides non-mechanical cooling during spring, fall and winter months when mechanical cooling was previously needed.
  • The system was converted to a variable-primary chilled water flow. Piping was reconfigured to correct existing flow deficiencies and to allow for more efficient operation. Chilled water system control optimizes energy efficiency.
  • Features include condenser water reset based on ambient wet bulb; variable-primary chilled water distribution; chilled water temperature reset; continuous calculation of plant operating efficiency for benchmarking; cooling tower de-ice mode (used with the hydronic economizer); condenser water flow reset based on the number of active chillers and load.

Boiler Plant

  •  The low-pressure and high-pressure plants were consolidated into a single low-pressure boiler plant. The earlier chiller plant reconfiguration cleared space to allow new steam boilers to be installed in the low-pressure boiler plant. The high-pressure plant was kept on-line for domestic hot water production until the low-pressure plant became fully operational; it was then removed, and the space was re-purposed for a new emergency generator.
  • Four new 300-hp flexible-tube steam boilers were installed, along with a new boiler feedwater system (including four feed pumps), a chemical treatment system, and upgraded ventilation and heating for the room. Controls include automated boiler sequencing, oxygen trim control, and boiler integration to the BAS.
  • Boilers were shipped in knockdown form for field assembly in order to be rigged to the boiler room. Distribution piping was re-configured, and pressure-reducing stations were removed to allow for the elimination of high-pressure steam.