Mark Jefferson Science Complex
Renovation, addition; Mark Jefferson Science Complex; Peter Basso Associates
Engineering firm: Peter Basso Associates
2013 MEP Giants rank: 78
Project: Mark Jefferson Science Complex
Address: Ypsilanti, Mich., United States
Building type: School (college, university)
Project type: Other
Engineering services: Automation & Controls, Code Compliance, Electrical/Power, Fire & Life Safety, HVAC, Lighting
Project timeline: February 2008 to February 2013
Engineering services budget: $31.13 million
MEP budget: $31.13 million
The HVAC system for the new Mark Jefferson Science Complex is projected to save over 40% of the energy required for a conventional ASHRAE baseline system. The existing Mark Jefferson building's HVAC system was a constant volume, reheat system. This type of system provides the same volume of air to each space, 24 hours a day, 365 days a year, regardless of whether the building is occupied or unoccupied. Laboratory HVAC systems are notorious energy consumers. These systems use large quantities of outdoor air. This outdoor air is used for heating and cooling of the spaces, to provide minimum air change rates for dilution of airborne contaminants, and as makeup air for fume hoods and other exhaust sources within the laboratories. Recirculation of this air in laboratory spaces is prohibited by code, so all air supplied to the laboratories must be exhausted.
An ASHRAE compliant laboratory HVAC system—the baseline system for energy comparison purposes—is a 100% outdoor air, variable air volume, reheat system. This type of system varies the supply air volume to meet the cooling or ventilation requirements of the space. When the ventilation requirements exceed the cooling requirements, heat must be added to prevent overcooling of the space.
The HVAC system designed and installed for the new Mark Jefferson Science Complex handles HVAC quite differently. This innovative system type decouples the heating and cooling function from the ventilation function, and handles both in a very efficient manner. Ventilation—the required air change rates and the makeup air required for fume hoods—is handled with a dedicated outside air unit with dual energy recovery.
The dual energy recovery functions are (1) to exchange energy between the exhaust air stream and the incoming outdoor airstream, thereby significantly reducing the energy required to heat and cool the incoming outdoor air; and (2) in the cooling mode, to transfer some of the heat from before the cooling coil (precooling the entering air) to after in the cooling coil, reheating the air to a neutral temperature dry air for supply to the spaces. This dramatically reduces reheat energy. The air supplied by this unit handles the ventilation and the latent cooling requirements of the spaces. Heating and sensible cooling of the spaces is handled by hot water and chilled water hydronic terminal equipment. Instead of increasing the airflow to rooms, beyond what is required for ventilation, to provide additional cooling, as is done with a traditional variable air volume reheat system, chilled beams provide cooling with chilled water on a room-by-room basis. By handling the heating and cooling function with hydronic terminal equipment, airflow rates, duct systems, fan sizes, and the associated fan energy were significantly reduced. Accordingly, the space required above the ceiling for ductwork was reduced significantly.
Unique features of the custom, dedicated outdoor air unit included heat pipe technology energy recovery devices. These devices transfer heat efficiently without any moving parts and without required maintenance. The wrap-around heat pipe at the cooling coil was designed with a bypass so that during noncooling periods of time, when it is inactive, the air bypasses the coil bank and saves fan energy.