Hilton Palm Springs reduced energy demand by 48 percent with enhanced automation and associated technology.

Using a combination of enhanced automation strategies and energy efficient equipment, Hilton Palm Springs sheds demand during high cost periods. Since 2000, the resort has reduced peak demand by 275 kW, while increasing customer satisfaction.

PROBLEM:
Operating a 205,000 square foot hotel in the California desert is a challenge. The Hilton Palm Springs is faced with keeping guests comfortable through wide temperature extremes (the highs eclipse 120 degrees Fahrenheit in the summer and the lows dip into the 30’s during in the winter) while managing high energy costs. In addition to 260 customer rooms, the hotel also maintains 18,000 square feet of meeting space with constantly changing occupancy levels.


SOLUTION:
Hilton Palm Springs has been a progressive user of enhanced automation for over two decades, dating back to its first installed energy management system (EMS) in 1984. It has recently upgraded to a third generation EMS to stay current with advancing technology. The new system is linked to programmable thermostats throughout the hotel and is on a pulse meter that monitors real-time energy use through a new energy information system (EIS).

From a centralized computer, the building engineers establish start/stop set points that correspond to occupancy levels in the meeting rooms. For example, at the beginning of each week a building engineer enters the weekly meeting schedule into the system, and the EMS then regulates the HVAC to match occupancy periods. The operator sets a target room temperature, and the system determines and sets the necessary ramp up time needed for the HVAC system to reach a desired setpoint. The Hilton complements this load shedding strategy with a procedure to shift peak energy demand from the ice machines, dishwashers, and in-house laundry to non-peak time periods.

The Hilton has improved its overall HVAC and EMS capability by upgrading two 140-ton chillers with optimizing equipment and by retrofitting all 1/4 to 30-horsepower motors with high efficiency motors and installing variable frequency drive evaporator motors in the walk-in coolers.

The EMS and HVAC improvements reduced the Hilton’s average electric demand by over 275 kW, nearly 50 percent of the total load at the Palm Springs resort. The weekly demand curves compare a preretrofit week (August 6 –12, 2000) to a post-retrofit week (August 1-7, 2004) with similar climate and occupancy conditions. The gray bars indicate the on-peak highest energy cost from noon to 6PM, Monday through Friday.

BENEFITS:
Hilton’s energy management strategies have helped cut the overall average building demand (kW) by 48 percent compared to pre-retrofit levels. The Hilton can now optimize comfort levels for building occupants while reducing energy costs.

The EMS has streamlined maintenance operations by providing a centralized location to adjust room environments. Prior to the upgraded EMS, building engineers would have to physically monitor several meeting rooms at once, often interrupting ongoing meetings. Now they can monitor and control all room temperatures through a convenient centralized computer—freeing up staff time and reducing comfort complaints from meeting participants.

The energy trending data from the EIS—particularly kW, kWh, and cost data—has become an important tool for Hilton’s building engineers to track and analyze building performance. They have used this data to justify new energy improvements such as chiller optimization, using solar water heaters for the 110,000 gallon swimming pools and installing two 140 kW cogeneration units with a 50-ton absorption chiller to generate power during peak period. The chiller optimizer alone saves $36,000 annually with improved temperature set points based on outside air temperature and return water temperature.
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"The energy management system allows my engineers to control meeting room temperatures from a centralized location, freeing up their time and eliminating the need to disturb meetings already in progress.  As energy prices fluctuate, it’s especially important to fully understand and have control over the building’s energy performance.  Enhanced automation allows us to do that."
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TECHNICAL INFORMATION:
Hilton Palm Springs uses a Honeywell Light Commercial Building Solution (LCBS) energy management system to integrate all its heating, ventilation, and air conditioning equipment. The LCBS is combined with the Honeywell LonSpec configuration software, which allows operators to control set points and monitor real-time and archived energy trends. The LonSpec software communicates with Honeywell’s T7300 Communicating Commercial Programmable Thermostat as part of the building’s open direct digital control (DDC) automation system. The DDCs are a networked system of microprocessorbased controllers connected to devices that monitor and control the building’s HVAC equipment.

Hilton Palm Springs takes advantage of three primary start/stop functions of the system to reduce its energy demand. First, the EMS is programmed to start up the HVAC system one hour prior to a meeting’s start time in order to reach a desired temperature level. Conversely, the system ramps down the HVAC as the meeting is scheduled to end. Secondly, the system can tell if the one-hour start up time will be insufficient (based on indoor and outdoor temperatures) and will pre-condition the space to reach the desired set-point before the meeting starts. This function acts as a safety net for the hotel and guards against comfort complaints. The third function allows the operator to set upper and lower temperature boundaries for different building zones. This keeps the hotel within a comfortable temperature band and protects the system against large localized demands.

The Hilton installed a Millennium Series Chiller Optimizer with ELECTRA software on their two 140-ton chillers to add further efficiency performance to the HVAC system. The Optimizer has achieved 37 percent electricity savings on the chillers by fine tuning energy levels based on 5-minute interval testing of outside temperature, chilled water supply, and return water temperature.
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Arnold Schwarzenegger, Governor
Joseph Desmond, Chairman
Jackalyne Pfannenstiel, Vice Chair
Commissioners: Arthur H. Rosenfeld, Ph.D, James D. Boyd, John L. Geesman,
B.B. Blevins, Executive Director
Free resources are available from the California Energy Commission at: www.energy.ca.gov/enhancedautomation/

* Chiller Optimizer® is a registered trademark of Energy Optimization LLC