High-Level Integration for a High-Tech Office
For high-tech, mission-critical companies like Townsend Analytics Ltd. of Chicago, a specialist in computer applications for Web-based finance, the ideal office is one where integrated building systems produce the right environment both for equipment and personnel. For its 11,000 square feet of space on the 19th floor of Chicago's 100 South Wacker building, the company was looking to integrate...
By ANIL AHUJA, P.E., General Manager Exelon Services Westchester, Ill.
For high-tech, mission-critical companies like Townsend Analytics Ltd. of Chicago, a specialist in computer applications for Web-based finance, the ideal office is one where integrated building systems produce the right environment both for equipment and personnel. For its 11,000 square feet of space on the 19th floor of Chicago's 100 South Wacker building, the company was looking to integrate electrical, lighting and heating, ventilation and air-conditioning systems to ensure the highest possible reliability of equipment—and a pleasant atmosphere for people.
The design challenge was to develop a versatile signature space using integrated, off-the-shelf components. Technical program requirements included a 24-hour, seven-days-a-week operating data center with a raised-floor operations room and mechanical, electrical and telephone rooms. The space also needed the typical amenities found in a high-end, high-technology setting: private offices, meeting rooms, open offices and a pleasing reception area. In fact, the design called for a nautical/island theme, which chronicles the sailing adventures of Townsend Analytics while nodding to its aptly named strategic partners Archipelago and Terra Nova.
Resolving the integrated system requirements, however, was the first challenge for the project team. Townsend Analytics required power and cooling support infrastructure for future expansion of its data center. A 12-inch raised floor and an exposed ceiling were desired to ease future installations of cable ladder and rack-mounted equipment for network and power wiring. This interior design constrained available ceiling heights and required creative lighting and acoustical designs to meet the functional criteria of other office spaces.
Hoping to plan and construct the offices and data center in an aggressive two-month schedule, the company settled on design/build project delivery to meet the client's ongoing business needs. Engineer and construction manager ESD Construction Inc., and the architecture firm ASD Inc., both of Chicago, were retained for the design/build delivery, working with Townsend Analytics' operations manager to meet design criteria and continuously monitor changing business needs.
Off the shelf
In the first phase of design development, the team investigated "off-the-rack" interior systems that would meet the proposed design motif. A suspended ceiling system was chosen that offered images of "clouds and sand drift" and could be suspended 10 inches from the deck to meet acoustic and lighting considerations in areas with video-display terminal (VDT) workstations.
Standard 40-watt, 3,000-Kelvin fluorescent tubes were tied to the ceiling grid on the suspended "clouds" to provide soft, glare-free uplight, and matching color-rendition task lights were specified for the VDT workstation areas. An L-shaped soffit with cutout corners was built over the walkways to look like clouds; this feature also offered a means for air return and special lighting fixtures.
Installed on the soffit are standard, off-the-shelf 100-watt halogen downlights with a suitable color rendition. Flexible track lighting was used for accents and to represent thematic celestial bodies, and the tracks were positioned to create a soft ambient glow without glare. Blue blown-glass wall sconces were installed on the furred columns and perimeter walls, and the conference rooms were lighted with blue and purple fixtures that fit the theme.
A rippling, undulating ceiling form was created in the entry area and in the operations room by the use of metal curves in the suspended-ceiling system with rope lights built into the edge spline and flexible track lighting on the center spline. This configuration helped bring needed task lighting to the space without taking up desk area and—not coincidentally—the concept met code requirements for egress lighting.
After meeting the aesthetic needs of the work space, attention was focused on the technical challenges of delivering uninterruptible, reliable power and cooling 365 days a year. For the former need, three 150-kilovolt-ampere parallel redundant uninterruptible power-supply (UPS) systems were installed. For the latter, a system consisting of four 50-ton packaged air-cooled chillers with a building central plant and tie isolation valves was developed. The chilled-water piping was conceived with redundant risers in separate shafts and designed to install in a loop around the core with isolation valves at risers and every "T" to isolate leaks and offer flexibility for future tie-ins of cooling units.
Building-supplied chilled-water temperature and differential pressure across the supply and return channels is monitored. In case of trouble—temperature or flow—with Townsend Analytics' chilled-water system, the tie isolation valves are commanded to open after sensing the proof of building chilled-water availability. This set-up maintains continuous chilled-water flow to the computer room air-conditioning (CRAC) units. Upon re-establishment of chilled-water flow, the isolation valves are automatically closed to provide reliable flow to CRAC units.
To further improve reliability, the chiller plant is designed with redundant chillers and pumps. The chillers are enabled and sequenced based on supply and return temperature. The two lead chillers and pumps are run continuously; the pumps and chillers are rotated in sequence to equalize run time and maintain reliable standby.
Equipment cabinet versatility
In the data center, equipment cabinets were designed as double cabinets to minimize cost and to house either rack-mount or shelf-type equipment by changing the cabinet guts. Wire management within the cabinets is also flexible, with both vertical and horizontal raceways for organization. Each cabinet can also handle four 4-inch fans, four 10-inch fans and two blower fans to deliver air from the four CRAC units. Space temperature and humidity is continuously monitored.
Exterior window condensation in the winter months is controlled through a window supply-fan system. When the outside temperature is below 30°F and when the wet-bulb temperature is within 3 degrees of the room dew-point temperature, the fan is started and heating washes down windows through high-throw supply grills in the perimeter soffit.
A unique feature of the integrated systems for the Townsend Analytics installation is its ductless heating and cooling system. The raised floor is used as a supply-air plenum.
The space is provided with a small mechanical room housing two variable-frequency-drive CRAC units, one being redundant. The units are equipped with an integral, standalone controller that is integrated with the building supply-air system. The integral controller stages the cooling, reheat and humidifying cycles. During "building-on" hours—weekdays 8 a.m. to 6 p.m.—this allows the company to conserve energy and use building-supplied air conditioning, which is a condition of the lease agreement.
The mechanical room is designed as a building air-mixing box (see Figure above). When the building supply-air temperature and static pressure are within acceptable levels, the building supply-air damper in the mechanical room is modulated to underfloor supply air as needed for redistribution by the CRAC units. The CRAC units modulate air volume to maintain adequate pressure under the raised floor. During this operation, the building return-air dampers are open and the zone's outside air, heater and fan is turned off.
When building supply air is colder than needed, the supply-air damper is closed. The return air is mixed in the mechanical room and injected into the return of the variable-air-volume CRAC units. When building air is unavailable, the building supply- and return-air dampers are closed. The outside-air damper for Townsend's floor is opened and a make-up air fan is turned on. The outside air make-up heater then maintains a minimum outside-air intake temperature, allowing economical 24-hour air conditioning and use of building air when available.
The air-distribution grills on the raised floor are low-draft square boxes. The building perimeter uses modular fan-powered terminal units with electric reheat to take care of building skin losses and to maintain comfort conditions in the office spaces.
The building UPS system is continuously monitored for current, voltage, watts and frequency to maintain power quality and reliability, and all critical power-system panels are equipped with transient-voltage surge suppressors to maintain power quality.
In addition, all access to the space is secured through a card-reader security system to maintain business process secrecy. In this way, the entire space can be expanded for data center, operations or communication rooms as required in the future.
For companies like Townsend Analytics, this kind of installation represents an ideal balance of building-system integration and comfortable, contemporary surroundings. Their state-of-the-art client applications for the financial services sector demand reliable, efficient building services, not unlike the power and cooling systems used by most data centers. In part, these goals are achieved by carefully integrating the new components together.
Best of all, Townsend Analytics' clients—individual traders, television stations, online companies, corporations and brokerage firms—can enjoy the benefits of the systems in a contemporary environment suggestive of clouds, islands and stars.
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