Headway In Hospitality
The University of Central Florida's Rosen College of Hospitality Management is located in what might be the largest learning laboratory in the world for hospitality and tourism - Orlando. The satellite campus was designed as a city within a city and boasts some impressive amenities, but the HVAC design work that went into it is also worth a look.
Orlando is truly a vacation Mecca. The city's International Drive is at the epicenter of the vacationing mayhem, with a truly vast selection of hotels, restaurants, shopping venues, and plenty of tourist attractions. So when local hotelier Harris Rosen donated $18 million for the construction of a state-of-the-art hospitality college, International Drive was an ideal location. It also helped that Rosen (who owns over 15,000 hotel rooms on the strip) donated the 30-acre site for the project, which was actually to serve as a satellite campus of the University of Central Florida (UCF) - and that his financial donation was matched by the State of Florida.
This 150,000-sq-ft school is about 15 miles from the UCF campus and was designed and constructed to support the department's goal of becoming the world's premier hospitality management school. The idea of locating the school apart from the campus and next to world famous theme parks and venues was that it would foster relationships between the school and hospitality industry leaders.
The school was designed by prominent Orlando architect, Helman Hurley Charvat Peacock/Architects, Inc., which brought Orlando-based GRG Consulting Engineers, Inc. on to serve as the design engineering firm. Since the program teaches students how to manage all aspects of venues ranging from restaurants and bars to hotels and theme parks, its facility presents inherent HVAC design challenges.
City Within A CityThe facility has its own library, bookstore, theater, and dorms (which are currently under construction). Two large classrooms are wired to facilitate "distance learning" sessions anywhere in the world. Several specialty spaces, not typically found at other academic institutions, required extraordinary HVAC design consideration.
For example, one of the three kitchens (called food labs) in this building has 16 grease hoods. "These teaching stations are intended to operate independently from each other as dictated by class size. Since about 25% of the makeup air to each hood is preconditioned at the AHU, the variable number of hoods in use at one time created a building pressurization challenge," explained Walter V. Brennan, Jr., P.E., and project manager, with GRG.
If all hoods were to be operating at the same time and there wasn't enough outside air introduced at the AHU, then the kitchen would become excessively negative. If only half the hoods were operating and there was too much outside air being introduced at the AHU, then the kitchen would become excessively positive. "To address this problem, a variable outdoor air damper was utilized. Its position is modulated based on the static pressure differential between the kitchen and the adjacent space," Brennan explained. "In this manner, if the kitchen becomes too negative due to all the hoods being on, more outdoor air is introduced to the space to maintain the slight negative pressure with the adjacent training dining room," Brennan added.
Vintage Problem SolvingAnother HVAC challenge facing the GRG team was the wine/sensory lab. A unique feature of this space is its walk-in wine storage room. Depending on the products being stored, the temperature and humidity in this space needs to vary from 68° to 78°F and 40% to 100% rh. To provide this environment, a dedicated fancoil unit was selected to control the temperature while a wall-mounted space humidifier was furnished to modulate the humidity.
To serve the cooling needs of these different types of spaces, two HVAC systems were considered - individual DX packaged units vs. a central chilled water plant. While the DX option offered a lower first cost, the chilled water system was ultimately selected for other reasons including acoustical concerns, high percentages of outdoor air, and lower maintenance costs, Brennan said.
Still, costs were a challenge. While there was solid funding for the project, its focus leaned more toward first-cost savings as opposed to operating cost minimization. University management also sought an integrated HVAC system/control vendor. As a result, air cooled chillers with a variable primary pumping arrangement were selected. After a bidding process, GRG specified two 500-ton Trane RTAC air chillers and 12 rooftop T-Series units, along with 99 VAV single duct terminal units and six fan-powered terminal units.
The variable primary pumping system, which was relatively new around the time of installation (December 2003), provided the energy efficiency and flexibility of a primary/secondary system and eliminated a set of pumps. However, it did require a considerable amount of sequencing. The Trane Tracer Summit™ system monitors the flow and makes decisions based on flow, but the sequencing was essential to the system's success.
While fewer components are needed to deliver chilled water to the facility, the control of those components was complex and critical. GRG, which also served as the commissioning agent for the project, played a key role in getting the system running. "HVAC commissioning was crucial to the success of this project. Without commissioning, the system wouldn't have likely performed as intended from the day the owner moved in," Brennan said.
Another positive aspect of the building's HVAC system control is that UCF facility management staff is able to control the entire system from the main campus, which results in further staffing savings.
Desiccant Unit Allows Staff And Customers To ‘Have It Their Way'Too hot for employees, too cool for customers, and too much moisture in some areas: that was the scenario playing out at an Orlando area Burger King restaurant. The 3,400-sq-ft eatery was originally built in 1985 and remodeled in August 2004. It has seating for 99 diners, and a total of roughly 60 people man the location's three shifts.
While the building's 5-ton straight DX rooftop unit was adequate for maintaining the thermostat settings, customers frequently complained that conditions felt cool and damp, and employees complained that floors remained wet after mopping. It was apparent the existing equipment could not control the humidity.
Hold The HumidityA high people load coupled with a full operation kitchen usually equates to humidity concerns for most high-volume fast food restaurants. In many cases, turning down the thermostat is not enough to ensure that indoor comfort conditions are satisfied. This is the problem that was presented to PowerCold ComfortAir Solutions, Inc., (PCS) a D-B firm located in Largo, FL, with offices across the United States. PCS became involved with the project after Buz Alexander, manager of construction services for Burger King Corporation, U.S. restaurants, agreed to accept the company's proposal to test their new desiccant unit at the location.
In order to determine exactly what was happening in the space, monitoring and recording instruments were placed in the building on a 24/7 basis. After 30 days of monitoring, it was found that the humidity levels ranged from 65% rh to as high as 79% rh, and although the thermostat was set to 72°, the temperature ranged from 72° to 80°, depending on the time of day.
PCS, which is a licensed engineering firm with extensive experience in the new and retrofit restaurant business, determined that a single desiccant dehumidifier would rectify the space condition problems. Burger King agreed to conduct a field test of the proprietary PowerCold HVAC system in August 2004. The 1,000-cfm unit, with a 3-ton supplemental cooling system, replaced the existing rooftop unit. The restaurant had the usual contingent of multiple DX packaged rooftop units, ranging in size from 5 to 7.5 tons.
The existing rooftop unit was removed, a down-flow curb adaptor was installed to accept the new desiccant unit, and electrical and sheet metal connections were made. The installation which was performed by PCS, proceeded smoothly, taking about six hours to complete, with the majority of the work completed while the restaurant was closed.
After the installation was completed, management was instructed to set the thermostats at 78°, up from 72° where they were previously set. PCS president Bob Yoho explains that thanks to the low humidity, the higher temperature doesn't present any problems, yet he's quick to note that it's best if the Burger King employees are unaware of the high temperature, lest they be concerned about the perceived heat.
Monitoring and recording of drybulb and humidity conditions continued in the space. The temperature was now being held between 78° to 80°, with humidity levels consistently between 45% to 50% rh, with the capability of operating below 40%. At 78° and 80°, both the staff and customers were comfortable and the space was dry. The restaurant's manager, Vanessa Lozada, reported that the system has performed exceptionally. "We don't have to mess with the thermostat at all, it works just fine. We've had no issues whatsoever," she said.
A Whopper Of A Usage DropAccording to a recent report from the utility company, the building's kWh usage for August 2003 was 57,440, compared to only 50,120 for August 2004. Additionally, the building's use of peak hour electricity dropped from 40,960 kWh to 34,840 during that same period.
"The three points to realize from this application are that by reducing the overall humidity, the people are more comfortable; the power savings come from raising the thermostat; and by recirculating the air 24 hours a day, the restaurant is maintaining the same humidity, so there's a lower moisture level in the air," said Yoho. The lower tonnage also is probably more correctly matched to the actual load and is more efficient comfort-wise, with less cycling, he added.
But energy usage aside, the main objective of providing a more comfortable environment for employees and customers, at a reasonable cost with little or no down-time, was accomplished. The entire unit changeout occurred in one day and utilized the existing 5-ton air distribution system and its power supply, eliminating all but minor work in the occupied restaurant space.
Low Sodium Highlights Oceanside MenuThe Bubba Gump Shrimp Co. is a casual, high-volume theme restaurant based on the movie Forrest Gump, with locations throughout the United States and Asia. When plans were being drawn up for the opening of a new location in Daytona Beach's Ocean Walk, Orlando engineering firm Peninsula Engineering Inc. (PEI) was presented with numerous concerns and challenges.
PEI had been asked to participate on the project by Morris Architects, and designed the shell building, a combined six-story and four-story building with 121,380 sq ft. The Gump restaurant comprises nearly 10,000 sq ft of the building. This particular project was overseen and coordinated for MEP, by PEI principal Don Stewart. The shell building is a pre-cast/poured-in-place structure with six 12-ft, floor-to-floor height levels on one side and four 12-ft, floor-to-floor levels across an open breezeway which serves as an egress between the building and access to the beach. The floor heights were determined in an effort to keep the building under the 75-ft level, which would have made it subject to high-rise codes, etc.
Super SaltyOne of the most pressing concerns with the new location concerned its proximity to the ocean. Since the restaurant is right on the beach, salt spray paves the way for serious corrosion problems. In addition to potential corrosion issues affecting the building's condenser water loop, which is black steel, there were also concerns about the gas piping to the building.
"Originally, the biggest concern was with a gas supply pipe that was being run underground, or under slab, to the building's exterior," said Matt Clark, with manufacturer's representative, The Spirit Group. PEI had specified black steel pipe for inside the building, but outside they figured they needed something different.
Gas-Tite's corrugated stainless steel tubing (CSST) was specified for all piping with the exception of the manifolds built in the kitchen, to help prevent the sandy Florida underground environment from corroding the pipe. "There is no dirt here in Florida. When that sand becomes wet, corrosion could be an issue with iron pipe," explained Sam Leo, of PEI. Clark and his firm got involved in the project when PEI asked for suggestions of alternative piping materials for the exterior.
The base building was designed around water source heat pumps with a closed loop serving all floors, and a plate-and-frame heat exchanger was specified to help prevent saltwater from getting into the cooling towers. Additionally, the building features two 1,650-gpm house pumps in lead-lag configuration that provide the total flow for the heat pumps serving the tenant spaces, two 270-ton cooling towers with three 825-gpm pumps, and one 850 MBtuh boiler with a 70-gpm inline pump.
Bubba Gump is located on the first floor, served by 20 heat pumps for a total of 70 tons, 8,540 cfm tempered air for the makeup at the hood and 8,775 cfm grease exhaust.
When Height Is An IssueAccording to Doug Kramer, a mechanical designer with PEI, the firm was aware from the beginning that the ceiling height would be an issue. With the 12-ft, floor-to-floor levels, there wasn't much room for ductwork, and since the building was poured in place, there was even less room to work with.
In addition to height problems, the structure has 36-in. beams throughout with 18-in. pre-cast joists. The ceiling needed to remain accessible so that the rough-sawn wood and exposed piping theme of the restaurant would be visible. This worked out well since another restaurant is located above Gump's, and the sanitary waste cast iron piping was able to be run exposed across the ceiling.
All the heat pumps were located between joists and framed in, which didn't allow for ductwork, so PEI designed supply plenums with registers. "Outside was also a problem because the building was constructed to provide access only through the perimeter beams (36-in.) at 20-ft intervals," said Kramer. All the exhaust and makeup air fans and refrigerant condensing units are located on the sixth floor roof, which is also the roof of the THX-rated theater. The theater's management required approval of all equipment installations on the roof, due to potential sound transmission into the theater.
"We only had one shaft [30 sq ft] in the area that had been allotted to Bubba Gump's for all exhaust, makeup air, and refrigerant line [for coolers] to the roof, which had a structural beam through it on the fourth floor, with no access through the top four floors due to the theater occupying these floors," Kramer said. Four exhaust ducts and one makeup air duct plus the refrigerant piping (about 12 sets of pipes total) are run to the roof via one 30-ft shaft.
Gump was the first tenant space completed after the base building and anchor tenant (the theater). "Basically, we took the tenant drawings and started hunting for water source heat pumps that would fit into soffits around the space. We looked at everything, trying to find manufacturers that were not too exotic. First cost was critical, along with future maintenance," Kramer said.
They selected Addison and Mammoth units. However, all soffits had to be modified to accommodate the units and supply/return plenums. They also specified Captiveair exhaust fans with sidewall discharge for general exhaust and utility upblast for grease exhaust, and a Greenheck makeup air unit with condenser water tempering coil. All of the equipment is concealed from view by the penthouse, which services the building house systems. ES
Retrofits Help Office Building Tenants Stay WiredThe Colonial Building located at 400 International Parkway in Heathrow, FL, is a 100,821-sq-ft, four-story commercial building that was built in 1995 and currently houses tenants such as Allstate Insurance's claims group and Business Objects Americas, which develops software to help companies track, manage, and understand their businesses. Like many older commercial buildings, the Colonial faced some issues in terms of providing tenants with the temperature and humidity parameters required for computer server or IT rooms.
System BackgroundThe building's existing HVAC system, which was installed during the building's construction, is a Carrier Corporation VAV system. It includes Carrier Central Station AHUs with inlet guide vane control for control of the air volume produced by the large air handlers. The inlet guide vanes on these units regulate each air handler's volume of air that is distributed into the ductwork system.
The ductwork system is constructed with several VAV units and fan-powered terminal units (FPUs) which provide zone control for the different offices and rooms. These units are equipped with dampers and electric heaters that control the tenants' space temperature requirements by controlling the volume of air delivered to each zone for accurate cooling control, and recirculate the air from the space, reheating the air to provide for reheat control.
Cooling is provided to the AHUs by means of chilled water produced by four Carrier 30 Series air cooled chillers, which deliver 44º water into the building's AHUs. Exhaust fans and outside air fans provide for the large change over of fresh air required for the building's occupancy. The building's HVAC system control requirements are provided by Carrier's Comfort Network, a DDC system which monitors and controls all aspects of the HVAC system and other processes required for the building.
The system controls the 420 tons of air conditioning required to maintain the cooling requirements produced by the building's computer systems, electrical systems, and thermal loads. "It's controlled from a desktop computer and alerts the owner of problems before the building's tenants are even aware of them," says Carrier's Matt Thompson. The system has served the building admirably.
Smooth Upgrade To SavingsIn the spring of 2004, the building's owner, Colonial Properties Trust (CPT), needed to add new terminal units for a tenant change on the third floor. Upon discussion with Thompson, CPT decided to upgrade all the terminal units located on the third floor to Carrier's Comfort ID controller because the old controllers within the building were dated and were still available through Carrier, but were soon to be discontinued. Carrier performed the retrofit of all the terminal units and programmed them per Allstate's requirements. Since the original control system was manufactured by Carrier, the retrofit to the new controls proceeded seamlessly.
Additionally, CPT decided to install two new Sanyo split duct systems for supplemental cooling in the computer rooms in December 2004. That installation was performed by Irvine Mechanical.
The new supplemental system provides significant energy savings, since the entire building system can be shut down after 6 p.m. and the computer room's temperature and humidity remain constant. "Installing the system is a money and energy savings move because the supplemental system keeps the temperature and moisture constant when chiller is shut down," said Irvine's president Robert Irvine.