The 16-story central atrium at Compuware headquarters features a 14-story waterfall.
Compuware headquarters is helping transform seven city blocks in downtown Detroit. Meanwhile, its HVAC system is helping transform tenants' expectations of comfort and flexibility into reality.
These condenser water pumps provide cooling for secondary equipment used to serve retail spaces and computer systems.
How would you like to land this Design/Build job: A $400 million, 16-story, 1 million sq.ft. building that includes space for 4,000 employees, an 8,000 sq.ft. data center, a 16-story central atrium with a 14-story waterfall, 60,000 sq.ft. of retail space, a 38,000 sq.ft. fitness center, a day care facility with 18 classrooms, a full-service cafeteria with kitchen, and an attached 12-story parking deck.
This project, in the form of a new world headquarters for computer software manufacturer Compuware Corporation, became a showplace for the skills of Plymouth, MI-based Mechanical Professional Services, a fully owned subsidiary of Limbach Facility Services LLC.
Compuware headquarters is the anchor building in a seven-block development plan that's revitalizing downtown Detroit. The majority of the employees who will call it home have been relocated from scattered, suburban offices into the new, consolidated setting.
Mechanical Professional Services is a 23-year-old, 15-person HVAC design and engineering firm that provides services for the Detroit branch of Limbach Facility Services. It is one of 11 Limbachowned firms across the country.
The challenge for Mechanical Professional Services' design team was to provide a mechanical system that not only accommodated the office spaces and amenities in this multi-function building, but also provided flexibility to easily accommodate future space renovations and suit the changing needs of a dynamic technology company. The resultant mechanical systems are highly flexible, innovative, reliable, energy efficient, and help ensure a high level of indoor environmental quality.
The judges for this year's Design/Build Awards commented that Mechanical Professional Services was lucky to have a client that not only wanted the best, but also was willing to pay for it. That's true, but it's also a double-edged sword: Mechanical Professional Services was under pressure to produce a system that lived up to Compuware's expectations.
Compuware's chairman and CEO, Peter Karmanos Jr, was one of the founders of the company back in 1973. "Peter Karmanos had a vision of what he wanted this building to represent, as it's a visible symbol of the pride he feel for his company," says Thom Barry, vice president of Mechanical Professional Services. "But it's not as if we didn't have budgets. In fact, we were brought in to make sure nothing got gold-plated. He wanted a great system based on a cost basis that made sense."
Barry explains that his company was able to land the HVAC design contract based on its existing relationships with the general contractor, developer, and the engineering firm that was doing the conceptual engineering for the entire building.
"They needed our estimating abilities, and also wanted to have a peer review of the initial building designs from an HVAC contractor's point of view," Barry says. "That allowed us to get involved with the project early, which was one of the keys to its success."
With the goal of designing a highly flexible, reliable, and energy-efficient mechanical system, Mechanical Professional Services' design team considered numerous system designs. The designs tested included a conventional, overhead variable air volume (VAV) system; a quasi-dual duct VAV air system; floor-by-floor air handling; an underfloor air system; a low-temperature air system without underfloor air; a district chilled water system; a thermal storage system; and absorption chillers.
In the final analysis, the system chosen to meet and exceed the needs of the customer was a hybrid design that blends a centralized, low-temperature (46F) primary air system with an underfloor system, along with electric centrifugal chillers.
The underfloor air distribution system, on a 15-in. raised floor, is extremely flexible, allowing Compuware to quickly and easily modify office space layouts to accommodate changing project requirements. The adjustable diffuser provided in each cubicle can be moved to suit a new office layout simply by moving a 24-in. X 24-in. access floor tile in which the diffuser is located, while continuing to provide individual occupant control in the new location.
In addition, the underfloor system was designed to allow for a high degree of redundancy. Upon failure of any one of the six primary air handling units, the remaining units can compensate (at reduced total capacity) through common connections via the underfloor plenum on each floor. Similarly, if one of the six vertical fan/mixing units on each floor were to fail, the remaining units could compensate via the common underfloor supply plenum. A spare chiller was also provided, allowing for full cooling capacity even in the event of failure of a chiller.
Nuts and Bolts
The primary air handling equipment, chillers, and pumps are located in a mechanical penthouse at Compuware's headquarters.
Low temperature supply air is generated by six VAV air handling units. This low-temperature, primary supply air is ducted down through shafts and connects to the inlets of six vertical fan/ mixing units (VFMUs) on each office story. Each VFMU is located in a separate mechanical closet, and each includes a primary air inlet, filtered recirculated air inlets, a downflow supply fan with variable frequency drive, and sound attenuators. The VFMUs mix the low-temperature primary supply air with re-circulated air from the ceiling plenum, and discharge 62F to 65F air into the underfloor supply plenum, maintaining a low positive pressure (0.05-in. w.g.) below the raised floor.
The supply diffusers in the raised access floor are designed to mix the air only in the occupied zone (the area below and approximately six ft. above the raised floor). A portion of the office equipment and occupant heat gain, all of the non-radiant lighting heat gain, and all of the exterior wall conduction from more than six ft. above the finished floor affects the air temperature only in a stratified zone above the occupied zone. This results in return air temperatures of 78F to 80F, while the occupied zone is maintained at 75F during summer operation.
Increased energy efficiency results from the high airside temperature differential of the lowtemperature primary air system, resulting in lower primary airflows and less fan energy than a traditional 55F system. Fan energy savings also are achieved through the avoidance of low-pressure secondary ductwork thanks to using the open, underfloor plenum for air distribution.
The overall airside temperature differential for the primary air distribution system is 33F (46F supply air temperature and stratified 79F return air temperature). Compared with a traditional overhead supply air system having a typical 20F airside temperature difference (55F supply and 75F re-turn), the low temperature primary air system requires 40% less airflow, and therefore much less fan horsepower, than a traditional system.
The fan energy savings remain significant despite being partially offset by the reduced chiller efficiency caused by operating at the cooler chilled water temperatures required by the 46F primary air, and the decreased duration of full cooling by the airside economizer.
Mechanical Professional Services estimates that Compuware's underfloor system provides $163,200/yr. in energy savings ($0.183/sq.ft. of office space) when compared with a conventional, variable volume, overhead air distribution system with 55F supply air.
An Innovative Solution for the Perimeter
Providing an effective perimeter comfort system is a common, significant challenge for underfloor air distribution systems. The solution provided for Compuware by Mechanical Professional Services is innovative and effective.
Series-type fan-powered boxes with electric heating coils were installed in the ceiling plenum of the story below the floor they serve. Supply air from the underfloor plenum of the floor being served was ducted down through the subfloor to the inlet of the fan-powered boxes. The boxes also have inlets for return air from the ceiling plenum in which they are located. Discharge air from the boxes was ducted to individual supply air diffusers located along the exterior wall.
The fan-powered boxes are equipped with GE ECM motors to allow reduced airflow and reduced fan energy usage off-peak. The underfloor supply/return air mixture at each box is modulated based on heating/cooling demand from the room temperature sensor, as is the speed of the motor and the output from the box's electric heating coil.
Energy savings are achieved through the use of variable airflow, and also by the ability to recover energy from stratified return air in the ceiling when perimeter heating is required. The solution was cost-effective upfront, too, as it allowed largecapacity fan-powered boxes to be placed in the ceiling below, instead of the much greater number of lesser-capacity boxes that would have been required had they been placed within the underfloor plenum.
Comprehensive Controls and a Clear Vision
The building's comprehensive management system integrates DDC controls for the HVAC system with lighting control, power monitoring, fire alarm, security, and elevator systems. Limbach Company was chosen as the building automation system integrator for the facility and was tasked with integrating multiple systems and providing a singleuser interface. Limbach was able to seamlessly integrate systems from multiple manufacturers, each using different communications protocols and dedicated front ends, into a unified network with browser access.
Among the features of the control system:
- Occupancy sensors for HVAC systems in conference rooms and private offices, which provide $15,700/yr. in cost savings.
- Integration of the air conditioning units that serve Compuware's data center into the central energy management and control system. Coupled with free cooling coils in the data center units, the integrated control systems provide approximately $17,800 in energy savings each winter.
Steve Marquardt, director of facilities, Compuware Corporation, says Mechanical Professional Services was an integral part of what he calls "one of the best office buildings ever constructed."
"Thom Barry is one of the sharpest people I have ever seen in the industry," Marquardt says. "His expertise, insight, and wit made his presentations come alive. There were a variety of people involved in the project, and he was able to speak to all of them with a clear vision.
"The vision was to give the end user — our employees — the ability to control their own environ-ment, and the system has delivered everything we hoped it would."
It wasn't easy. "Underfloor systems are notoriously difficult to commission, and they don't work very well if you have high swing loads," says Mechanical Professional Services' Barry. "You really have to babysit them to get them right, and we did: we spent six months commissioning this project."
In the end, though, it was all worth it. Barry says two aspects of the project in particular make him the happiest.
"The professional building management company that's leasing the building has told us it has had onetwelfth the environmental complaints that it would expect to get on a building this size," he says. "That, and seeing pride of ownership on the face of Peter Karmanos, really stand out in my mind."
Winner at a Glance:
COMPANY: Limbach Mechanical Professional Services, Plymouth, MI
PROJECT NAME/LOCATION: Compuware headquarters, Detroit, MI
TOTAL COST: $38,000,000
KEY CUSTOMER CONTACT: Steve Marquardt, director of facilities, Compuware Corporation
NOMINATION SUBMITTED BY: Thom Barry, vice president, Limbach Mechanical Professional Services
THE PROJECT TEAM: Thom Barry, engineering design; David Brentzel, conceptual plant design; Preston Wallace, account manager; Peter Furlan, project manager; Pierre Sirois, project engineer; Ron Schmidt, controls; Tim ward, temperature controls design; Phil Hapeman, commissioning; and the team at Peter Basso & Associates, Troy, MI
BUILDING MANAGEMENT: Hines Corp.
PRODUCTS KEY TO SUCCESS: