A New Concept in Lab Cooling and Ventilation - Cost
and Energy Savings From an Induction System
Vanderbilt MRB-IV: First Research Laboratory Application
of the Venturi-Wedge Cooling System
Thomas C. Fisher, Jr., P.E.,
Phoenix Design Group, Inc
Donald Blair, AIA, Donald Blair & Partners,
Vanderbilt Medical Center currently has a new 366,000 sq. ft. Medical
Research Facility under construction in Nashville, TN. The building
HVAC system utilizes a new concept in laboratory ventilation and
conditioning known as the Venturi-Wedge. This system has significantly
reduced mechanical system first cost in addition to providing a
more flexible and energy efficient system requiring less maintenance
than a variable flow tracking system concept. The Venturi-Wedge
unit is a self-contained 4-pipe unit that receives a constant volume
of preconditioned air from a central air handling system. The medium
pressure air "induces" room air through an enclosed wedge-shaped
plenum under each ceiling-mounted unit and draws the air over an
intertwined heating and cooling coil. Depending upon the load within
the laboratory, the "induced" air is either cooled or
heated by the coils to satisfy room temperature requirements.
This system eliminates the need for providing 100 percent conditioned
outdoor air to cool the laboratories. Outdoor air makeup is provided
by the central air system to meet only the exhaust requirements
of the fumehoods within a Lab Module (at least 6 air changes per
hour). The remaining internal heat loads within the lab modules,
equipment corridors and research alcoves are removed by the supplemental
cooling coil at each Venturi-Wedge. There is no need for expensive
flow tracking controls for each Laboratory and fume hood or the
annual maintenance for calibrating the complex electronic controls.
The application of the Venturi-Wedge to Medical Research Building
IV resulted in a first cost savings of about $2,400,000 in fan capacity,
chiller capacity, sheetmetal distribution and electronic controls.
Phase I of the project (120,000 sq.ft.) was completed in August
2005. The operating costs for the first complete year of operation
should be available in November of 2006.
Recent interest from the medical design community in the Venturi-Wedge
and similar "Chill Beam" systems has placed VUMC at the
technical leading edge in the application of this Concept. The simplicity
of the exhaust hood systems integration and control is felt to offer
considerable infrastructure flexibility as well as yielding lower
first cost and optimum energy cost benefits.
The building utilizes a new concept in laboratory ventilation and
conditioning. The system has significantly reduced system first
costs and provides a more flexible and energy efficient system,
which requires less maintenance than a variable flow tracking system
Thomas C. Fisher Jr. has been in responsible charge
of HVAC engineering projects since 1974 while with Union Carbide
in nuclear research at ORNL and the Y-12 weapons plant. His experience
includes the HVAC systems computer modeling, building energy analysis,
design calculations, design of HVAC DDC controls, equipment specifications,
pipe stress analysis, cost estimating, computer software development,
and extensive experience in inter-discipline coordination.
Other experience includes: Central chilling and boiler plant design,
high-rise building design, convention centers and large assembly
facilities, finite-element simulation modeling for pressurization
control in multi-compartment buildings and atriums, CFD Smoke Control
Simulation, ice and thermal storage design, pipe stress analysis,
and acoustical analysis.
He is thoroughly familiar with DOE Energy Program, CAESAR II, AutoCAD
and Intergraph CADD systems, NIST CFD Modeling and has authored
several software applications. Mr. Fisher is personally responsible
for the design of all HVAC and mechanical systems.
Donald Blair specializes in the master
planning, programming and design of institutional facilities. His
clients include health care, research, educational, and academic
facilities that have complex programmatic and operational requirements.
Projects consist of new buildings, renovations, and adaptive reuse
of existing buildings. 25 years of practice has resulted in a design
focus on maintaining operations, minimizing revenue and customer
loss, planning for disruption of service, accurate phasing, budgets
and other issues critical to the client's business. Donald was formerly
managing director of Perkins and Will NYC office and a partner at
Russo & Sonder Architects.
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