Ventilation Leads Kerry's Recipe For Success
The Kerry Center is a three-building innovation and technology center on a 124-acre site with reclaimed prairie near Beloit, WI. The 250,000-sq-ft campus, which includes offices, laboratories, and manufacturing for a consumer foods group, seamlessly integrates contemporary architecture with lean design principles and state-of-the-art sustainable technologies to position the international company as a global business leader in the 21st century.
The project is not only LEED®-certified, but the Kerry Center was also designed to meet Energy Star requirements. In addition, the project received one of the highest incentives from Wisconsin Focus on Energy for a single project - $225,000. In this high-performance, sustainably designed facility, overall energy use is 27% better than code and 15% better than ASHRAE 90.1, 2004.
To achieve energy efficiency and these high percentages was a complex process. HGA Architects and Engineers (HGA) worked with the client to meet the needs of not only corporate offices but also of facilities for research and development, which require considerable building exhaust ventilation to control the migration of odors from food ingredients and cooking processes. The challenge was to provide energy-efficient mechanical systems incorporating significant outdoor air ventilation requirements.
THREE BUILDINGS OF INCREASING COMPLEXITYThe Kerry Center complex includes three buildings, each one more complex in its energy use and air handling and ventilation requirements. The four-level 72,000-sq-ft Administrative Office Building was fairly straightforward, yet the square footage was reduced during pre-design by using lean principles to streamline work processes and lessen unnecessary square footage before construction.
The four-story, 90,700-sq-ft Laboratory Building (Building C), is composed of half offices and half laboratories. Here, the mechanical systems challenges included cross-contamination and odor migration since employees in the labs are involved with tasks from baking brownies to creating flavorings with volatile compounds and more complicated chemistry.
Finally, the 76,000-sq-ft Technology Center (Building D) is a manufacturing plant also used for research and development. Its challenge was incorporating HVAC systems and steam for cooking, chilled water, and exhaust; meeting USDA requirements for ventilation and cleanliness; planning for heavy energy and other utility use loads; and programming in flexibility for the company as its needs change over time.
Moreover, all of the buildings on campus are connected, meaning that without proper venting systems, odors and contamination could potentially migrate from one building to another.
BOILERS AND CHILLERSKerry Center’s heating system, as well as the water system, consists of steam boilers. Steam is provided for research and development processes in the technology center (or pilot plant), hot water heating, and domestic water heating. Steam is converted to hot water for all building heating needs. Chilled water is provided for research and development processes in the Technology Center and all building cooling needs.
There were no firm answers on load requirements, because Kerry’s research and development areas need to accommodate future equipment and technologies related to food and ingredient manufacturing. So we started with systems that properly and efficiency handle minimum loads, and planned in systems and flexibility to accommodate future developments.
Two 125-psi steam boilers were installed: one 400 bhp and one 200 bhp with provisions for a future 400 bhp, 125-psi steam boiler. Also installed was one combination condensate surge and deaer-ator boiler feed unit, which was sized for the future total boilers.
For hot water, two shell-and-tube steam-to-water heat exchangers were installed, sized for future building additions, for generating hot water from the steam plant. The system also includes two 1,000 gpm pumps with provisions for a future third pump. Each pump is sized for half of the future heating loads, providing N+1 redundancy when the third pump is installed and creating one pump for standby.
The system also incorporates two 500-ton chillers with provisions for a third chiller and two 1,200 gpm chilled water supply (CHWS) pumps with provisions for a third pump. Each of the pumps is sized for 1.5 chillers providing N+1 redundancy when the third pump is installed, creating one pump for standby. All pump motors on the hot water heating and chilled water cooling systems are controlled with VFDs to reduce pump motor energy requirements.
The chillers also feature a free-cooling mode during the winter months. A refrigerant migration feature, controlled by temperature and phase changes within the chiller, allows for chilled water without actually turning on the chiller. As a result, the Kerry Center’s 500-ton chiller produces about 100 tons of free cooling during the winter to serve various process cooling loads throughout the complex, including the 40° rooms for food storage and the numerous large walk-in coolers and freezers.
The condenser water system includes an indoor sump for a condenser water system, sized for future cooling load of 3,000 tons; two condenser water supply (CWS) pumps for the cooling tower water system with provisions for a third pump; and two cooling towers mounted on the roof of the central plant with provisions for a third tower.
All hot-water heating piping, piping for chilled water, and terminal coils are based on a low-pressure drop to reduce pump horsepower for energy efficiency. Both the hot water heating and chilled water cooling systems utilize variable primary pumping, with two-way control valves for energy efficiency.
The steam boiler system isn’t the most cost-efficient for the office building. Simple and inexpensive rooftop units are low, first-cost solutions that are done all the time on office buildings. However, the client recognized the value of extending the central chilled water and hot water systems to serve the air-handling systems for the office structure.
AIR-HANDLING SYSTEMSJust as the whole campus is on a central steam boiler system, centralized AHU ventilation systems were provided to the greatest extent possible, to ensure the fans ran with higher efficiency (as compared to that of less centralized and smaller systems). The use of variable volume, 100% dedicated OA intake, and exhaust air-handling systems which incorporate energy recovery made it possible to provide odor control for good IAQ, while reducing the high-energy consumption typical with heating and cooling 100% outdoor air.
The air-handling system for the Administrative Office Building includes two 50,000 cfm roof-mounted VAV AHUs with chilled- water cooling and hot-water heating coils. Multiple units provide partial backup redundancy in the event a unit is being serviced.
The Laboratory building includes two air-handling systems, with multiple units to provide partial backup redundancy if a unit is being serviced. A 55,000 cfm indoor VAV AHU, with hot water heating and chilled water cooling coils, serves the office spaces.
Two 30,000 cfm, 100% outdoor air and exhaust AHUs with energy recovery wheels, hot water heating, and chilled water cooling coils serve all of the laboratory research spaces. This separate system ensures air goes through the labs just once. This strategy was chosen to prevent odor migration and cross-contamination from the lab portion of the building to the nearby offices, since the lab activities vary from simple baking to experimentation with heavy chemistry.
The Technology Center includes rooms with different temperature and humidity requirements and rooms with extraordinary cleaning and sanitation requirements for FDA compliance. Each suite may require its own complicated system of steam, hot water, and nitrogen. Each suite has a wash-down mode for its walls and floors, stainless steel countertops, and ductwork, with control sequences so the room can go 100% exhaust during cleaning mode and water can be drained out of the room. A system was created to control the number of rooms being cleaned at one time, and the number of rooms is limited to six.
To accommodate these requirements, the Technology Center was provided with three 30,000 cfm, 100% outdoor air and exhaust AHUs with energy recovery wheels, hot water heating and chilled water cooling coils. Again, multiple units provide partial backup redundancy in the event an AHU has been switched off for servicing.
In addition, all AHU supply and exhaust fan motors are controlled with VFDs to reduce fan motor energy requirements. Total energy wheels recover up to 80% of the energy from the exhaust airstreams. The energy recovery wheel motor is controlled with a VFD to maintain energy recovery wheel effectiveness.
OTHER SUSTAINABLE STRATEGIESTo complement the high efficiency heating, cooling, and air-handling systems, direct digital building temperature controls were incorporated to provide users with the flexibility to adjust building parameters to achieve the most efficient operation. In addition, conserving energy consumed by the interior lighting system, while maintaining adequate ambient illumination, was the key focus of our lighting specifications. This approach not only lowered lighting operating costs but reduced cooling loads as well.
For the office and lab spaces, a lighting design was specified that uses high-efficiency lamps (high lumens per watt) and luminaries with high-quality optics (which allowed us to use fewer units). These decisions resulted in a connected lighting load of .81 W/sq ft for the office and laboratory spaces, which surpasses ASHRAE design standards by 29%.
Rooms dedicated to the research and development of food products require high levels of ambient lighting with an average maintained illumination of 70 fc. The lighting solution for these labs and workspaces included enclosed USDA-rated luminaries equipped with high-output fluorescent lamps in conjunction with high-reflectance walls. The overall connected lighting load for the technology center is 1.1 W/sq ft, surpassing ASHRAE design standards by 16%.
Single-occupant offices, single-occupant toilet rooms, storage rooms, janitor closets, and other enclosed rooms of less than 1,000 sq ft were designed with ceiling-mounted PIR/passive acoustic, dual technology occupancy sensors to automatically control lighting. Local dual-level or multi-level switching in work and office areas allows occupants to select their own lighting levels for various tasks and applications.
Selected conference rooms have architectural preset dimming systems. Lighting in open offices, corridors, waiting areas, lobbies, technology center areas, and other large or unenclosed public spaces is controlled by a programmable, time-based lighting control panel system. Through the campus, wherever possible, the architectural design provides access to natural lighting, to encourage less use of electric light.
The project’s architects also massed the buildings so they shade each other, and specified white, reflective PVC roofs that reduce heat in the buildings and on the surrounding microclimate of the prairie. Water-efficient plumbing fixtures reduce wastewater and potable water demand. Inside the buildings, low-VOC emitting materials, adhesives, primers, and paint reduced indoor air pollutants. Materials with recycled content, local and regional provenance, and Forest Stewardship Council certification ensured the client’s sensitivity toward its employees and the environment was reflected inside the buildings, as well as outside in the natural prairie setting.
COMMISSIONINGHGA’s team provided Kerry Center with LEED® prerequisite commissioning on the project. HGA completed commissioning work in March 2009, which included commissioning more than 600 pieces of equipment and performing more than 100 functional performance tests. The results: 95% of all commissioning issues were corrected prior to occupancy, netting the owner a return on the commissioning investment of 900%.
One of the largest green buildings in the Upper Midwest, Kerry Center incorporates numerous energy-efficient systems that contributed to its LEED registration and an Energy Star design that surpasses 76% of buildings in its class. The sustainable design strategies incorporated into the Kerry Center, with its complex and complicated heating, cooling, and air-handling requirements, has positioned the international food company as a global business leader in the 21st century. ES