Energy Efficient Vivariums

Energy Efficient Vivariums
Peter Rumsey, P.E., Rumsey Engineers, Inc
Glen Berry, NCARB, Design for Science
Why Vivariums?
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Rapid Growth in Vivarium Construction and Use
High Energy Intensity – Typically 1.5 to 2.5 more
energy intensive than traditional labs
„ High Steam Usage
„ High Air Change Rates
Criterion #1: Guide for the Care and Use of
Laboratory Animals
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Excellent reference manual for planning and design of
vivarium facilities.
The Guide was written in 1996.
Page 32: “The guideline of 10-15 air changes per hour
has been used for secondary enclosures for many years
and is considered an acceptable general standard.”
The Guide does not mention ventilated cage racks, as
they did not exist as a tried/tested/proven product for
animal holding in 1996.
Criterion #2: NIH Design Guidelines
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Another excellent reference manual for the planning and
design of vivarium facilities.
Published in 2003
Does acknowledge ventilated cage racks as an
acceptable form of housing rodents.
Page F.70: “The air-handling system design should
comply with the requirements described in the Guide for
the Care and Use of Laboratory Animals.”
Page F.71: “If microenvironments are employed for
animal holding, the minimum ventilation requirement
may be reduced to 10 air changes per hour plus the sum
of the microenvironment airflow.”
Concept #1: Understand the difference between
primary and secondary barriers.
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science laboratories: The chemical fume hood is the primary
barrier, and is the primary method of capture and containment
of volatile chemical fumes.
BSL3/4 labs: The biological safety cabinet is the primary
barrier, and is the primary method of capture and containment
of airborne pathogens.
vivaria: the ventilated cage rack is the primary barrier of
rodents, and is the primary method of controlling air change
rate, temperature, and humidity of the housing environment.
In all of the above, the room is the secondary barrier, and
should always be thought of as such. The room cannot and
should not provide the same level of capture/containment as
the primary barrier.
Building Basics
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Location – 30 miles south of San Francisco on coast
Size – 115,000 sf – 15,000 s.f. vivarium on ground
floor (~50 double sided 144 count cage racks)
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Purpose - Biomedical Research
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Cost – approximately $610/sf
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Minimum LEED Silver and 30% energy savings
Lab Space – Daylight Simulation
Vivarium
Vivarium Floor Layout
„~15K sf
Mechanical
„Basement Floor
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Cage Wash Area
Holding Rooms
Loading
Dock
Open Cage Racks
Ventilated Cage Racks
Concept #2: The secondary barrier (the room) envelope
does not need to provide the same level of capture and
containment as the primary barrier.
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Then (Lab planning and design): 10-12 air changes per
hour
Now: 6 air changes or 1 cfm/sf with even lower rate for
unoccupied mode.
Then (vivarium planning and design): 10-15 air changes per
hour
Now: still 10-15. Has not addressed the role of the ventilated
cage rack as the primary barrier.
Perhaps we can allow the equipment to solve the energy
consumption problem, by reducing the effective envelope
for which the air change rate is required. Similar to the
function of a chemical fume hood or biological safety cabinet……
HVAC Systems
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Dedicated AHU – 40,000 CFM
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Chilled Water System
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Two fans one for
redundancy
One 300 ton – peak use full
building
One 100 ton – peak use
vivarium only
Generator - 600 kW
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Back-up for all Vivarium
uses except steam
AHU, Lights, Chiller, Pumps,
Open Cage versus Ventilated Cage
Air Change Rates
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Typical Open Cage Rack Holding Rooms
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15 to 20 Air Changes per hour (approx. 3-4
cfm/sf)
Ventilated Cage Rack Holding Rooms
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10 air changes per hour (approx. 2 cfm/sf)
Vivarium Options Considered In Schematic
Design
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Option 1 - All Open Cage Racks in Holding Rooms
„ AHU:
49,000 cfm
„ AHU and Chiller Costs:
$613k
Option 2 – 50% Open Cage Racks/50% Ventilated
Cage Racks
„ AHU:
40,000 cfm
„ AHU and Chiller Costs: $482k
Option 3 – 100% Ventilated Cage Racks
„ AHU: 36,000 cfm
„ AHU and Chiller Costs: $442k
Vivarium Options Costs
Option
All Open Cage Racks
50% Open / 50%
Ventilated
All Ventilated Cage
Racks
Vivarium HVAC
Costs
$819,000
$723,000
$663,000
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Selected
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Option
CFD Analysis
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Purpose Determine Optimal Placement of
Supply and Return Diffusers in Open Cage
Rack Rooms
CASE A
Return
Supply
CFD Results – 1000 cfm, 55 deg F
CASE B
Return
Supply
CFD Results – 1000 cfm, 55 Deg F
CASE C
Return
Supply
CFD Results – 1000 cfm, 55 Deg F
CFD Results – 850 cfm, 55 Deg F
STEAM SYSTEM ANALYSIS
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Getinge Cage
Tunnel Washer
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Cage and Rack Washer
Steam Load Summary
Equipment
Tunnel Washer
Cage & Rack Washer
Regular
Steam
Peak
2400
600
Ave
-
Clean
Steam
Peak
-
Ave
-
Medium Sterilizer
(26 x 37.5 x 60")
LSR Sterilizer
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-
335
800
185
450
Autoclave - 1st floor
-
-
60
56
Autoclave - 2nd floor
-
-
60
56
Medium Autoclave - 3rd
floor
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-
335
185
Autoclave - 4th floor
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-
60
56
Autoclave
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-
60
56
Autoclave
Glasswasher (future)
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60
300
56
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3000
-
2,070
1090
TOTAL
Comments
1000 lbs/hr dryer
Can find alt. equip 10% lower
steam, such as Getinge
700LS
10% additional savings
possible
10% additional savings
possible
Can find alt. equip 10% lower
steam, such as Getinge
700LS
10% additional savings
possible
10% additional savings
possible
10% additional savings
possible
60% OF STEAM DEMAND IS IN THE WASHERS
Tunnel Washer
Manufacturer
High Pressure
Steam Use
(lbs/hr)
Steam
Requirements if
supplemented
with 140 deg F
Hot Water
Getinge
1200
600 - 950
No
IWT Technoplast
661
Not recommended
No
LYNX
1400
Not recommended
Yes
Steris
1300
Not recommended
Yes
Can use low
pressure steam
Cage and Rack Washer
Manufacturer
High Pressure
Steam Use
(lbs/hr)
HP Steam
Requirements if
supplemented
with 140 deg F
Hot Water
Getinge
800
400
Yes
IWT Technoplast
600
Not recommended
No
LYNX
1200
600
Yes
Steris
1400
Not recommended
No
Can use low
pressure steam
Other Strategies for Lower Energy Use in
Vivariums
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Improved venting strategies for ventilated cage rack
systems
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Improved fans on ventilated cage racks
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Unoccupied or lower occupancy turn down
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Autoclaves improvements
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Low energy lighting
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Demand Controlled ventilation
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Others??
Conclusion (food for thought)
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Let the primary barrier (fume hood, BSC, ventilated
cage rack) define the envelope for air change rate
and environmental controls. Reduce the secondary
barrier (the room) air change rate to lower levels
that save energy and still provide a safe working
environment.
Animal Holding Rooms:
„ Use Ventilated Cage Racks
„ Room - 6+ air changes per hour occupied
„ Room - 4+ air changes per hour unoccupied
Thank You
www.RumseyEngineers.com
www.designforscience.com