A hotel’s success in the hospitality industry is measured by the quality and value of its guests’ experience, and that requires the hotel to deliver consistently flawless service and reliable comfort at a competitive rate. Managing energy consumption and associated costs — while improving environmental sustainability — are among the significant operational challenges. Not only are hotels operational 24/7/365, they are typically characterized by considerable load diversity over 24 hours.
In January, EMCOR Services Mesa Energy Systems (“EMCOR Services Mesa”) was part of a team that successfully met these challenges at the Hilton Los Angeles Universal City Hotel, which completed an overall building system upgrade undertaken and announced as “transformational” of the facility into a sustainable destination hotel. Located at 555 Universal Hollywood Dr., in Universal City, CA, the Hilton Los Angeles/Universal City is a block away from the entrance to Universal Studios Hollywood and minutes from Hollywood. The 23-story, 502,200-sq-ft hotel has approximately 500 guest rooms, and it includes a 16,000-sq-ft ballroom and 32,000 sq ft of meeting space.
EMCOR Services Mesa was chosen to be part of the multidiscipline Los Angeles County Commercial PACE (Property Assessed Clean Energy) Program project development team selected by Hilton and coordinated by sustainability firm ReNewAll. Los Angeles County PACE financing was used to fund $7 million in sustainability upgrades for the Hilton project, making it the largest C-PACE project in the U.S. to date. C-PACE programs are available to property owners to pay for building improvements that save energy, and EMCOR Services Mesa was chosen as the mechanical contractor on the project, in part, because of its knowledge and familiarity with the C-PACE program.
Overall, Hilton has stated it anticipates the project to yield estimated annual energy savings of $800,000, of which the company stands to save more than 2 million kWh and $300,000 in savings on electricity consumption from a new high-efficiency chiller system and building automation system — realizing a simple payback on investment in just 3.7 years — plus significant reductions in environmental impact from greenhouse gas emissions.
EMCOR Services Mesa’s scope of work included the replacement of both existing constant speed, centrifugal chillers with two high-efficiency 450-ton centrifugal, variable-speed-driven chillers; VSD to serve condenser water and chilled water pumps; chilled and condenser water piping, including required pipe trim; central plant DDC and optimization; and an ASHRAE 15 ventilation system upgrade.
The project included energy-efficient glass and LED lighting, as well as water-conservation measures (including 500 low-flow shower heads and the replacement of 250 bathtubs with showers), which are projected to yield savings of $28,000 and conserve more than 2.8 million gallons of water a year.
EMCOR Services Mesa also completed an extensive, fast-tracked HVAC retrofit for the entrance foyer and ballroom under a separate contract in time for a ribbon-cutting ceremony on January 28, 2014, featuring a speech by Los Angeles Mayor Eric Garcetti in recognition of Hilton’s completion of the project.
HILTON LOS ANGELES UNIVERSAL CITY HOTEL AT A GLANCE
Existing vs. New Chiller Systems (Installed By EMCOR Services Mesa Energy Systems, Inc.)
Building Size/Hours of Use:
- Hotel floor area: 502,200 sq ft
- Weekly operating hours: 168 hrs.
Existing cooling system: Two 475-ton constant speed CVHE centrifugal chillers (manufactured in 1982):
- Fan coil units; AHUs
- 562-ton maximum cooling load
- 4,195-MBh maximum heating load
- Constant speed pumping system, both circuits
- Legacy controls
- Annual energy consumption: 8,986,150 kWh
New cooling system: Two 450-ton high-efficiency centrifugal chillers with factory mounted VSDs (0.369 kW/ton NPLV):
- Fan coil units, AHUs
- 562-ton maximum cooling load
- 4,195-MBh maximum heating load
- Variable speed pumping, VPF, with automatic control isolation valves
- Web-based, native BACnet DDC system
- Revised energy consumption: 6,947,159 kWh
Estimated anticipated annual energy savings: 2,038,911 kWh Simple payback on investment: 3.7 years
Solving the Load Diversity Challenge
Compared with other commercial buildings, hospitals, and data centers, where loads are fairly constant over operating hours, hotels are characterized by load diversity due to the fluctuations in occupancy of guest rooms, use of restaurant and lounge facilities, conference and meeting spaces and ballrooms, etc. In addition, hotels typically use extensive glass on their facades, and the older glass technologies often found in existing hotels typically contribute to significant heat gain. The Hilton Los Angeles/Universal City Hotel was no exception in these respects.
In fact, when an existing conditions inspection was performed in autumn 2012 in preparation for submission of a bid proposal, the chiller plant was running at a light load. An inventory of all the components and a rough calculation of efficiency revealed that the existing plant was operating at greater than 2.0 kW/ton, whereas EMCOR Services Mesa strives for a chiller plant system design that meets a performance goal of 0.5 kw/ton on average. The discrepancy between existing and optimal performance at the Hilton was not surprising given that some of the equipment was 30 years old. In fact, one of the chillers had experienced a recent catastrophic motor failure. The Hilton was renting a temporary chiller at a cost of approximately $20,000 a month to meet its hospitality service standards for its guests.
Fast forward to the following August, when Hilton awarded the mechanical contract to EMCOR Services Mesa, the company repaired the existing chiller, providing spare parts at no cost from the inventory of similar chillers in its warehouse. Technicians got the damaged chiller up and running in approximately three weeks, enabling Hilton to return the temporary chiller months before completion of the mechanical upgrade.
Energy, Payback, and Environmental Analyses Project Big Savings
In preparing the bid proposal, the EMCOR Services Mesa engineering team performed a comparative energy analysis of the existing chiller plant and two alternative upgrades — two 450-ton chillers versus two 475-ton chillers. (See sidebar for details of the existing and new chiller systems.) The Hilton’s utility rates were built into the model to provide an estimate of annual operating costs and savings. The analysis took into account the integrated energy conservation measures (ECMs), in particular, retrofitting with Smart Glass in public areas and window tinting on the guest tower to reduce solar heat gain and a lighting retrofit and installation of ECM motors on guest room fan coils to further reduce the internal load. As a result, the design was able to downsize the York replacement chillers by 10%— from 475 tons to 450 tons.
As part of the proposal, the EMCOR Services Mesa team also included the results of an analysis using the Energy Star Building Label Benchmarking Tool. With a building floor area of 502,200 sq ft and an average of 168 operating hours a week, the 450-ton York chiller system is projected to save over 2 million kWh of electricity annually. At an average blended rate of 15 cents per kWh, the Hilton stands to save approximately $300,000 annually on the cost of electricity.
In fact, the new chiller equipment exceeds the minimum energy-efficiency standards of the California 2010 Green Building Standards Energy Code (California Code of Regulations, Title 24, part 11). As a result, the Hilton was able to realize the maximum rebate on the purchase of the new chiller equipment.
The team also shared the results of their environmental impact analysis, which showed a potentially significant reduction in the impact of three greenhouse gases with implementation of the high-efficiency chiller system, specifically: carbon dioxide (CO2) reduced by 3,872,810 lbm/yr; sulfur dioxide (SO2) reduced by 1,052 gm/yr; and nitrous oxide (NOX) reduced by 3,449 gm/yr.
A Closer Look at the Chiller and Control Systems
In seeking a solution that went well beyond simply replacing aging equipment, the engineering team developed a chiller strategy that takes advantage of the hotel’s inherent load diversity: an open drive chiller system with variable-speed technology and a 10-to-1 turn-down ratio to save energy in partial-load operation.
The new system involved replacement of four existing VFD motors serving the cooling tower fans and space heating hot water pumps with four new 460V 3-phase ABB VFD motors (two 30-hp and two 40-hp). The new VFD drives were selected because they have BACnet capability to enable integration with a new HVAC controls and building automation system. EMCOR Services Mesa is a factory-authorized representative of ABB with factory-trained ABB start-up technicians. The team installed all of the components necessary to provide a variable pumping system for the central plant, including differential pressure transmitters, automatic control valves, flow meters, and Btu meters, which are required to support the variable pumping strategy.
The HVAC controls and building automation system were selected for monitoring and control of the central plant mechanical equipment. The new Schneider system utilizes BACnet open protocol networking that facilitates interoperability between different devices, such as VFDs, boiler controllers, and chiller controllers. The team developed the algorithm for the automation system to implement the variable sequence, as well as the graphical user interface. Building operators interface with the system utilizing a local graphical workstation and a standard internet browser from remote locations such as employee homes.
The team used three control strategies to maximize energy efficiency, facilitate more accurate and reliable control, and maintain guest comfort: DDC, chilled water reset, and hot water reset. DDC utilizes proportional, integral, and derivative action for optimum control speed and tight control accuracy. Chilled water reset reduces the demand on the chiller system by adjusting the chilled water set-point to a higher temperature based on demand and outside air temperature. Hot water reset reduces the demand on the boiler system by adjusting the heating hot water set-point to a lower temperature based on demand and outside air temperature. The boiler system can also be locked out based on outside air temperature.
EMCOR Services Mesa provided project management for the mechanical retrofit and building automation system to facilitate coordinated project delivery. The company self-performed the engineering, mechanical system upgrade, ventilation/refrigerant monitoring system upgrade, building automation system, sheet metal, startups, and commissioning. Its partners performed the piping and electrical installations as well as crane and rigging work.
Saving the Big Day
Hilton Los Angeles/Universal City’s owner advisory board approached EMCOR Mesa to quickly solve a difficult problem. The owners had scheduled a ribbon-cutting ceremony for January 28 featuring a speech by Los Angeles Mayor Eric Garcetti. The event included a 200-guest luncheon in the Sierra Ballroom. Unfortunately, the ballroom and its soaring 40-ft-high foyer had long been plagued by heating and cooling problems. The advisory board wanted to assure their guests’ comfort at this salutary event.
The EMCOR Services Mesa team came up with a solution, expediting engineering, equipment selection, procurement and delivery, installation, and commissioning to ensure the event’s success. The team isolated, demolished, and removed hot water piping to remove five existing VAV boxes and associated pneumatic control valves. The team provided and installed five new fan-powered VAV boxes with reheat coils, associated ductwork, and five new DDC hot water control valves; new hot water piping with shut-off valve, circuit setter, strainer, and connections to the new reheat coils; and associated electrical power. The team performed pressure testing, air and water balancing, and startup commissioning of the system and controls.
During the event, EMCOR Services Mesa supported Hilton Los Angeles/Universal City Facility Manager Steve Thompson’s presentation with a large-screen view of the building automation system’s graphical user interface showing live operational and energy consumption data. Team leaders also led guests on a tour of the central plant.
After a successful event, a member of the Hilton Los Angeles/Universal City Hilton advisory board commented, “EMCOR saved the day for us.” As a result, the owners asked EMCOR Services Mesa to develop mechanical and control solutions for another section of the ballroom, the banquet areas, front entry area, bar, and buffet areas.
The team finished its part of the project, completing it approximately two months ahead of schedule — in just 110 days — and within budget. A follow-up energy analysis performed by EMCOR Services Mesa Energy Systems after six months of operation demonstrated that the project is performing as projected.
Just as a hotel’s success in the hospitality industry is measured by the quality and value of its guests’ experience — requiring the hotel to deliver consistently flawless service and reliable comfort at a competitive rate — so, too, is a mechanical services company.