School HVAC The following article was published in ASHRAE Journal, May 2007. ©Copyright 2007 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. It is presented for educational purposes only. This article may not be copied and/or distributed electronically or in paper form without permission of ASHRAE. ‘House Air’ system improves vivarium air quality, reduces energy loads and is architecturally expressed at the Life Sciences Institute. University Laboratory System By Ronald W. Henning, P.E., Associate Member ASHRAE T he University of Michigan is one of the premier research institutions in the United States. In May 1998, the university embarked on a study of the rapidly developing fields of the Life Sciences by forming the President’s Commission on the Life Sciences, which led to the enhancement of collaboration and exchange of ideas across a range of academic and medical disciplines. To achieve the desired collaboration, the northeast corner of the university’s central campus required a physical transformation. As a result, the Life Sciences Institute was created to foster basic and translational research. The Palmer Drive Development is a complex of buildings including the Life Sciences Institute (LSI), the Undergraduate Science Building, and Palmer Commons. It also includes a 1,000 car parking 22 ASHRAE Journal structure; a 100,000 ft2 (9290 m2) plaza and walkway system; and the creation of a pedestrian bridge that spans across a major city thoroughfare. The Palmer Drive Development creates a physical and ashrae.org intellectual “bridge” across what used to be a “chasm” of traditional academic studies, medical research and the education of future scientists. The LSI building presented the challenge of creating the right work environment for the building using a mechanical and electrical system that would be flexible enough to accommodate revisions and upgrades over the life of the building. It was also important that the building met the energy efficiency requirements of the university. Life Sciences Institute The LSI is a 235,000 ft2 (21 831 m2) biomedical research facility consisting of six floors and a mechanical penthouse. The building houses three major funcAbout the Author Ronald Henning, P.E., serves as the chief mechanical engineer for SmithGroup’s Science & Technology Studio in Detroit. Henning won an honorable mention for the 2007 ASHRAE Technology Awards. May 2007 tional groups; 43,400 ft2 (4030 m2) of vivarium space located on the lowest level of the building, 135,000 ft2 (12 540 m2) of laboratory and laboratory support spaces on the third through sixth floors; and 25,000 ft2 (2320 m2) of office/interaction spaces distributed across the second through sixth floors. Major mechanical and electrical spaces are located on the second floor and penthouse floor of the building. ing the operating static pressure of the exhaust system. The two air-handling units serving the laboratory/laboratory support spaces each contain two supply fans and the supply ductwork is cross connected at each of the floors. This cross connection of the supply ductwork provides a common supply duct from the two air-handling units and allows for redundancy in the system with the four total supply fans. One of the four air-handling units serving the vivarium is a Central Plant Heating and Cooling redundant unit and the system can operate at 100% capacity The LSI building in the Palmer Drive Development receives with only three of the units in operation. However, an analysis steam from an existing central power plant at two pressures, 40 of the system energy use indicated that the normal control oppsi and 9 psi (276 kPa and 62kPa). All condensate is metered eration for the system is for all four units to be in operation at and returned to the central power plant. all times. This allows each unit to operate at a reduced capacity Discussions with the university and the initial analysis of the which results in less total operating fan energy than if only three Palmer Drive Development established that a central chilled units were operating at full capacity. water plant that could be expanded to include future buildings The design consideration for the laboratory/laboratory support would be more efficient and cost effective than individual exhaust air systems needed to be flexible and include redundancy. chillers at each building. The The resultant design allowed design resulted in the chiller for a four exhaust fan group for plant being included as part of each of the lab floors and for the Palmer Commons Building the vivarium. Separate exhaust and included multiple electric risers for each floor extend up to the penthouse, through the centrifugal chillers. The plant energy recovery coils and then has a maximum capacity of out to the associate exhaust fan 6,000 tons (21 100 kW) and delivers 42°F (5.6°C) chilled group located on the roof. Each water via a primary-secondsystem was designed to operate ary piping system and through on three of the four fans set at underground tunnels. maximum load with the fourth fan in each group as a redundant unit. This would allow the Design Considerations systems to be maintained with The building ventilation system is designed so that each of no loss in capacity or operation the three major function groups on any of the lab floors. in the building can operate inThe air-handling units ‘House air’ system minimizes exhaust and energy use. dependently of each other for serving the office/interaction maximum flexibility. There are two air-handling units (25,000 spaces, are return air type units and use enthalpy control to cfm [11 798 L/s] each) for the office and general building areas; modulate the outside air dampers, in addition to CO2 (carbon two air-handling units (135,000 cfm [63 706 L/s] each) for the dioxide) monitoring. Using the CO2 monitoring allows units laboratory and laboratory support spaces; and four air-handling to adjust the amount of outside air being introduced into the units (25,000 cfm [11 798 L/s] each) to serve the vivarium spaces whenever CO2 rises above the prescribed limits. space. All the air-handling units are variable air volume type All motors for the air-handling units, as well as the main with chilled water cooling coils, pumped hot water heating chilled water and heating hot water pumps, are operated through coils, minimum 65% efficient filters and steam humidifiers to variable speed drives. maintain proper relative humidity levels within the space. Two separately pumped perimeter heat systems divide the The laboratory/laboratory support and vivarium air-handling building into north and south zones to match the major buildunits are 100% outside air design with glycol runaround energy ing exposures. Each perimeter system water temperature is recovery coils in the air-handling units and in the respective controlled, based on the outside air temperature, via a high exhaust streams for these systems. A bypass around the exhaust limit override at each above-grade floor on the south zone. A side energy recovery coils allows the exhaust air to bypass the separately pumped hot water heating system provides reheat coils whenever the energy recovery system is not active, reduc- to the VAV supply valves. May 2007 ASHRAE Journal 23 Figure 1: Typical open holding animal room control system. A heat recovery system is part of the design to reduce heating loads in the winter and electric cooling loads in the summer on the 100% outdoor air systems. A pumped glycol runaround coil loop was determined to be the best option due to space constraints because of the distance between airstreams and cross contamination concerns with the laboratory exhaust. Annual Advertisement formerly in this space. 24 ASHRAE Journal ashrae.org May 2007 Advertisement formerly in this space. May 2007 ASHRAE Journal 25 savings are estimated to be $144,000 based on 2001 energy rates with an average airflow of 200,000 cfm (94 380 L/s) for the laboratory and 75,000 cfm (35 392 L/s) for the vivarium. The resulting simple payback on the increased project cost was just over six years. benefit of not requiring maintenance staff to enter the vivarium space and was designed to improve the quality of space for the staff and animals, while minimizing energy consumption and maintenance expenses for the systems with the highest operating cost in the building. The ventilated animal holding cages are Vivarium Space Design directly connected to the building’s HVAC LSI’s vivarium uses a house air system system, with laboratory airflow control that is believed to be the first operational valves controlling the supply and exhaust Iris Dampers system of its kind in the U.S. University air. Each supply control valve includes criteria established the vivarium design a reheat coil to control the discharge air to be based on a ventilated cage rack systemperature into the animal cages within tem. The house air design was compared the racks. An exhaust air valve is also conagainst the manufacturer’s system that nected to the rack to ensure a slight negative Inline Thermostat Reheat Coil included individual supply and exhaust pressure at the cages. Valve fans placed on top of each cage rack to This system also minimizes the quantity ventilate the individual cages in the rack. of ventilation air required in the animal holdThe supply fan would generally draw ing room, since a specific quantity of air is delivered to and extracted from each rack, room air as the ventilation air for the Figure 2: Barrier rooms. rather than turning over large volumes of animal cages and the exhaust fan would either discharge back into the room or to an exhaust duct. The room air as required with traditional design approaches. It also house air system eliminated the fan noise in the rooms, has the allows the room temperature to be controlled by the technicians Advertisement formerly in this space. 26 ASHRAE Journal ashrae.org May 2007 Advertisement formerly in this space. working in the room since the temperature within the animal cages is controlled independently. A manifold of racks in a room on a common supply and exhaust air valve enables each project to be able to use conventional air valves, which reduces cost, while providing improved temperature control and monitoring. This approach reduces maintenance costs, and allows for maintenance access from outside the holding areas, while maximizing space use within the rooms. Another positive feature of the scheme is that it eliminates the need for two bio-pack fans on top of each rack—one for supply and one for the exhaust from the cages. Without the fans, the racks are lighter and easier to move, reducing the potential for workrelated injuries. An additional benefit is that both room noise and noise in the racks are reduced. The elimination of any fan noise within the animal holding rooms improves the environment for the animals. The system also provides better isolation between the room and the air in the animal cages, resulting in a cleaner, more odor-free environment, making the vivarium staff much happier with their working conditions. It is clear that the animals also like this innovation. Based on over one year of operation, the reproductive rate for the animals in this vivarium is considerably higher than other vivariums on campus. Laboratory/Laboratory Support Space Design Advertisement formerly in this space. All laboratory and laboratory support spaces are provided with tracking VAV supply and exhaust air valves to maintain a proper negative pressure relationship with adjoining office and corridor areas. Fume hoods for the laboratory spaces are located in alcoves adjacent to the open laboratory spaces. This creates a localized area for control of the fume hoods that is separate from the open laboratory spaces. The fume hoods were designed as VAV-type with sash position sensors to control the exhaust airflow through the hoods. Operations and Maintenance All major pieces of equipment such as the lab exhaust fans, air-handling unit supply fans and pumps have some level of redundancy to allow maintenance to occur without having to shut down services to the facility. The equipment rooms were designed with appropriate space to allow the proper maintenance of all equipment. All equipment is monitored by the building management system for runtime status to ensure proper maintenance can be maintained. The static pressure drop across all filters is monitored to ensure proper service and replacement of filters is maintained. 28 ASHRAE Journal ashrae.org May 2007 Environmental Impact The LSI was evaluated against Leadership in Energy and Environmental Design ® (LEED) 1.0 criteria during the design process to see how well the university’s design guidelines for laboratories fit the goals of sustainability. The university required that satisfaction of any LEED criteria would need to be accomplished within the project budget and schedule. If pursued, LSI would have come within a few points of certification, even though LEED 1.0 was not designed for a complex research laboratory. This is a significant accomplishment for a laboratory building designed to maximize the research space within the facility. The following sustainable design concepts were included as part of this effort. • A heat recovery system is part of the design, signif icantly reducing the amount of heat loss. This HVAC system also meets laboratory safety criteria of passing through the building only once. • Sustainable growth wood is used for much of the project’s woodwork, including the extensive wainscoting in virtually all of its public areas. • The project is located within a rehabilitated “brown field” site, creating a well-used complex on what was once an underdeveloped impervious surface parking area. • The facility includes 20 major exhaust fans on the roof, thereby not increasing the perceptible noise to the 4,000 occupants of the residence halls located within 500 ft (152 m). Conclusions The university and its stakeholders invested in the creation of LSI, the state-ofthe-art research facility, in consideration of the emerging field of life sciences. To entice potential scientists to join the fledgling organization, the institute need- ed to present an image of permanence and longevity. In addition, the design of the laboratory spaces was unique to other campus facilities, making them more attractive to potential supporters. In addition, the university is currently tracking nine technologies that may lead to patents and/or licensing agreements with the pharmaceutical industry. The technologies range from new research techniques, to cell, gene and protein interaction, to possible therapies. After only two years in operation, the results are impressive. Overall, the investment of $96 million in the Life Sciences Institute is paying dividends for the students, faculty and staff of the university, resulting in more jobs for the region and an economic shot in the arm for the State of Michigan. The university believes it made a very cost effective forward moving decision with their research into the life sciences and with its decision to build this facility. Advertisement formerly in this space. May 2007 ASHRAE Journal 29
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