Hospital Hvac Design

1
Copyright Materials
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distribution, display and use of the presentation
without written permission of the speaker is
prohibited.
© 2006
2
Learning Objectives
• The learner will identify benefits of incorporating
sustainable design in healthcare facilities.
• The learner will identify average, US-based
hospital energy usage.
• The learner will identify typical HVAC systems
used in hospitals.
• The learner will identify HVAC systems and
technologies that can be used to improve energy
consumption and help achieve energy and
carbon goals.
Hospital HVAC Systems 6/22/08
Paul Switenki - PE, Associate
Hospital HVAC Systems 6/22/08
Benefits of Sustainable Hospitals – Client Satisfaction
Hospital HVAC Systems 6/22/08
Benefits of Sustainable Hospitals - Employees
Hospital HVAC Systems 6/22/08
Benefits of Sustainable Hospitals - Earth
Hospital HVAC Systems 6/22/08
Average Hospital Energy Consumption
Hospital HVAC Systems 6/22/08
Energy Strategy
Hospital HVAC Systems 6/22/08
UCSF Mission Bay Medical Center
Hospital HVAC Systems 6/22/08
Energy Strategy
Hospital HVAC Systems 6/22/08
Air Handling Systems
HVAC – Air Handling Systems
Hospital HVAC Systems 6/22/08
Air Handling Systems
Air Handling Unit
(AHU)
HVAC – Air Handling Systems
Hospital HVAC Systems 6/22/08
Air Handling Systems
Duct
Inlets/Outlets
Terminal Unit
HVAC – Air Handling Systems
Hospital HVAC Systems 6/22/08
All Air Systems
Constant Air Volume – Base Case
SA
EA
EA
75 hp
30 hp
105 hp
Air Handling Unit Fan Energy (assumes 40,000 cfm per AHU)
EA SA
P
P
CAV w/
Reheat Coil
OA
Hospital HVAC Systems 6/22/08
Constant Air Volume – Base Case
Pros:
• Tried and tested system
• Straightforward controls
• Lowest first cost
Cons:
• Maximum flow 24/7
• Fans at maximum HP
• Simultaneous cooling/reheat
All Air Systems
EA SA
CAV w/
Reheat Coil
Hospital HVAC Systems 6/22/08
Reducing Air Flow
Ventilation Minimum
2 ACH (CMC)
6 ACH (AIA)
Up to 15 ACH
Patient Room - Load vs. Ventilation
Solar + Internal Loads
Hospital HVAC Systems 6/22/08
Sizing Drivers - Loads
Load-dominated Areas
Patient Rooms
Imaging
MRI
CT Scan
Radiology
Fluoroscopy
Lounges
Nourishment/Food Prep
Hospital HVAC Systems 6/22/08
All Air Systems
Constant Air Volume – Base Case
OA
SA
EA
EA
75 hp
30 hp
105 hp
Air Handling Unit Fan Energy
EA SA
P
P
CAV w/
Reheat Coil
Hospital HVAC Systems 6/22/08
All Air Systems
Variable Air Volume - Boxes
OA
SA
EA
EA
60 hp
20 hp
80 hp
Air Handling Unit Fan Energy
EA SA
P
P
VAV w/
Reheat Coil
Hospital HVAC Systems 6/22/08
All Air Systems
Variable Air Volume – Boxes
OA
SA
EA
EA
60 hp
20 hp
80 hp
Air Handling Unit Fan Energy
EA SA
P
P
VAV w/
Reheat Coil
VAV
Hospital HVAC Systems 6/22/08
All Air Systems
Variable Air Volume – Boxes
OA
SA
EA
EA
60 hp
20 hp
80 hp
Air Handling Unit Fan Energy
EA SA
P
P
VAV w/
Reheat Coil
VAV
Hospital HVAC Systems 6/22/08
All Air Systems
Variable Air Volume - Valves
Air Handling Unit Fan Energy
OA
SA
EA
EA
60 hp
20 hp
80 hp
EA SA
P
P
VAV
VAV
VAV
RHC
Hospital HVAC Systems 6/22/08
All Air Systems
Variable Air Volume - Valves
Pros:
• Tried and tested system - labs
• Adjusts to meet load
• Lower average fan BHP
• Less reheat
• Less drafty
Cons:
• More terminal units (x 2)
• Assembly required
• More complicated controls
EA SA
VAV
VAV
RHC
Hospital HVAC Systems 6/22/08
Decoupling Ventilation
Ventilation Minimum
2 ACH (CMC)
6 ACH (AIA)
Up to 15 ACH
Patient Room - Load vs. Ventilation
Solar + Internal Loads
Hospital HVAC Systems 6/22/08
Chilled Ceiling
SA
EA
T
out
T
in
~ 60
0
F
Hydronic Systems
Hospital HVAC Systems 6/22/08
Passive Chilled Beams
SA
EA
Hydronic Systems
Hospital HVAC Systems 6/22/08
Active Chilled Beams - Ceiling
SA
EA
Hydronic Systems
Hospital HVAC Systems 6/22/08
SA
EA
Active Chilled Beams
5 hp pump
CAV
Hydronic Systems
Hospital HVAC Systems 6/22/08
Hydronic Systems
Active Chilled Beams
Pros:
• European Healthcare
• Minimal ceiling space requirements
• Simple air and chilled water controls
• Recent US Offices, Laboratories, Universities
• Minimal rooftop/mechanical room space requirements.
Cons:
• Higher first cost
• Higher maintenance costs
• User unfamiliarity
Hospital HVAC Systems 6/22/08
Hydronic Systems
Constant Air Volume & Active Chilled Beams
OA
SA
EA
EA
40 hp
15 hp
55 hp
Air Handling Unit Fan Energy
P
P
CAV
SA
EA
5 hp
Hospital HVAC Systems 6/22/08
Minimum Ventilation (2-6 ACH)
Peak Cooling Loads (9-15 ACH)
• Mechanical Space
• Duct Sizes
• Shaft Sizes
• Ceiling Space Coordination
Hydronic Systems
Physical Impacts
Hospital HVAC Systems 6/22/08
Air Only: VAV Air Only: CAV
Chilled Beams w/CAV
Life Cycle Cost Analysis
Hospital HVAC Systems 6/22/08
Life Cycle Cost Analysis
Hospital HVAC Systems 6/22/08
Indirect Evaporation Chilled Beam (Active) 100% Outdoor Air, Constant Volume C3
Air-to-Air HX Chilled Beam (Active) 100% Outdoor Air, Constant Volume C2
Runaround Loop Chilled Beam (Active) 100% Outdoor Air, Constant Volume C1
Indirect Evaporation - 100% Outdoor Air, Variable Volume B3
Air-to-Air HX - 100% Outdoor Air, Variable Volume B2
Runaround Loop - 100% Outdoor Air, Variable Volume B1
Indirect Evaporation - 100% Outdoor Air, Constant Volume A3
Air-to-Air HX - 100% Outdoor Air, Constant Volume A2
Runaround Loop - 100% Outdoor Air, Constant Volume A1-Base
Energy Recovery Local System Central System Option
Life Cycle Cost Analysis
Hospital HVAC Systems 6/22/08
Hospital Life Cycle Cost Analysis
-$8,000,000
-$6,000,000
-$4,000,000
-$2,000,000
$0
$2,000,000
$4,000,000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Years
T
o
t
a
l

S
a
v
i
n
g
s
A2 A3 B1 B2 B3 C1 C2 C3
Chilled Beam
(Active) w/IE
Chilled Beam
(Active) w/HX
Chilled Beam
(Active) w/RL
100% OA
VAV w/IE
100% OA
VAV w/HX
100% OA
VAV w/RL
100% OA
CAV w/IE
100% OA
CAV w/HX
100% OA
CAV w/RL
Central
System
6
55 yrs
C3
5
25 yrs
C2
T3
17.1 yrs
C1
T3
17.1 yrs
B3
T1
12.5 yrs
B2
T1
12.5 yrs
B1
8
never
A3
Similar to
Base
A2
Base A1
Rank Option
Life Cycle Cost Analysis
Hospital HVAC Systems 6/22/08
Hospital Life Cycle Cost Analysis
-$5,000,000
-$4,000,000
-$3,000,000
-$2,000,000
-$1,000,000
$0
$1,000,000
$2,000,000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Years
T
o
t
a
l

S
a
v
i
n
g
s
Chilled Beams
Life Cycle Cost Analysis
Active Chilled Beam System
First Cost: $ 4,000,000
Maintenance Cost: $ 55,477
Annual Energy Savings: $ 259,112
20 Yr Life Cycle Savings: $ 773,837
Payback: 17.1 Years
Hospital HVAC Systems 6/22/08
Hospital Life Cycle Cost Analysis
-$5,000,000
-$4,000,000
-$3,000,000
-$2,000,000
-$1,000,000
$0
$1,000,000
$2,000,000
$3,000,000
$4,000,000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Years
T
o
t
a
l

S
a
v
i
n
g
s
VAV System
Air Only: VAV
Life Cycle Cost Analysis
VAV System
First Cost: $ 4,600,000
Maintenance Cost: $ 8,250
Annual Energy Savings: $ 357,404
20 Yr Life Cycle Savings: $ 3,092,290
Payback: 12.5 Years
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Thank you!...Questions?
Hospital HVAC Systems 6/22/08
Unused Slides – Supporting Info
Hospital HVAC Systems 6/22/08
Recirculating
Simple AHU
100% OA
Simple Ductwork
Good IAQ
AHU Configuration Options
HVAC – Air Handling Systems
Hospital HVAC Systems 6/22/08
Energy Recovery – Runaround Loop
HVAC – Air Handling Systems
Hospital HVAC Systems 6/22/08
Energy Efficiency Options
HVAC – Air Handling Systems
Hospital HVAC Systems 6/22/08
HVAC – Air Handling Systems
Air Handling Unit
Components
Filters
Pre-filters (30-65%)
Final-filters (90-95%)
HEPA (99.97%+) ?
Coils
Cooling
Heating
Energy Recovery
Humidifiers
Attenuators
Fans, Motors & VFDs
Hospital HVAC Systems 6/22/08
HVAC – Air Handling Systems
Air Handling Unit
Components
Filters
Pre-filters (0.5”)
Final-filters (1.0”)
HEPA (1.5”) ?
Coils
Cooling (0.8”)
Heating (0.5”)
Energy Recovery (0.5”)
Humidifiers
Attenuators
Fans, Motors & VFDs
Hospital HVAC Systems 6/22/08
HVAC – Air Handling Systems
Air Handling Unit
Components
Filters
Pre-filters (0.5”)
Final-filters (1.0”)
HEPA (1.5”) ?
Coils
Cooling (0.8”)
Heating (0.5”)
Energy Recovery (0.5”)
Humidifiers
Attenuators
Fans, Motors & VFDs
Hospital HVAC Systems 6/22/08
HVAC – Air Handling Systems
Air Handling Unit
Components
Filters
Pre-filters (0.3”)
Final-filters (0.8”)
HEPA (1.0”) ?
Coils
Cooling (0.5”)
Heating (0.3”)
Energy Recovery (0.3”)
Humidifiers
Attenuators
Fans, Motors & VFDs
Hospital HVAC Systems 6/22/08
6 ACH
CAV: Sunny Day, No Diversity
North Facade
All Air Systems
15 ACH
South Facade
12 ACH
East Facade
15 ACH
West Facade
Total = 50 ACH
Hospital HVAC Systems 6/22/08
6 ACH
North Facade
All Air Systems
6 ACH
South Facade
6 ACH
East Facade
6 ACH
West Facade
Total = 24 ACH
Overcast, Cold Day with Diversity
Hospital HVAC Systems 6/22/08
Solutions for Patient Rooms
•Dual Vertical Chilled Water Coils
•Chilled Beam Cavity Part of Room
In-Room Chilled Surface Rather Than
External Re-Circulating Equipment
Room
Plenum
“ Noncentral Recirculating Air Handling System”
CMC 408.2.4
•MERV 1 Filter
•Ceiling Mounted Active Chilled Beams
Hospital HVAC Systems 6/22/08
Solutions for Patient Rooms
•Dual Vertical Chilled Water Coils
•Chilled Beam Cavity Part of Room
In-Room Chilled Surface Rather Than
External Re-Circulating Equipment
•Coil Condensate Trays
Condensate Captured and Removed
•Supply Air Does Not Traverse Chilled Beam
Coil
Supply Air Traverses Filter Banks 1, 2 & 3
CMC 408.1.5
•Ceiling Mounted Active Chilled Beams
Hospital HVAC Systems 6/22/08
Chilled Beams - Active
Hydronic Systems
Condensation
Shower is major source of room moisture
Override ceiling valves - Room dewpoint
Comfort conditions maintained?
Condensation eliminated?
Computational Fluid Dynamics (CFD) model would
consider:
Shower = rate of increase in humidity level
Ceiling = rate of surface temperature change
Room = warmest resulting average temperature
Filtration
MERV 1 possible
Hygiene
Antimicrobial coating
Hinged coil and/or access panel for cleaning
Similar to finned-tube baseboard heating
SA
EA
Hospital HVAC Systems 6/22/08
Active Chilled Beams – Under Window
EA
SA
Hydronic Systems
Hospital HVAC Systems 6/22/08
Hydronic Systems
Hospital HVAC Systems 6/22/08
Sizing Drivers - Ventilation
Ventilation Rates
ASHRAE Standard 62
1,000 s.f. assembly area = 395 cfm
Hospital HVAC Systems 6/22/08
Sizing Drivers - Ventilation
Ventilation Rates
ASHRAE Standard 62
1,000 s.f. assembly area = 395 cfm
AIA Guidelines (2006)
Air change rate based on contaminant dilution
1,000 s.f. waiting room = 2,000 cfm
California Mechanical Code (2007)
1,000 s.f. waiting room = 2,000 cfm
Hospital HVAC Systems 6/22/08
Sizing Drivers - Loads
Ventilation-dominated Areas
Waiting
Laboratories
Clean Utility
Soiled Utility
Corridors
Exam Rooms
Isolation Rooms
Kitchens
Toilets/Baths/Lockers
Hospital HVAC Systems 6/22/08
Sizing Drivers - Ventilation
Ventilation Rates
ASHRAE Standard 62
300 s.f. office = 35 cfm
Hospital HVAC Systems 6/22/08
Sizing Drivers - Ventilation
Ventilation Rates
ASHRAE Standard 62
300 s.f. office = 35 cfm
AIA Guidelines (2006)
Air change rate based on contaminant dilution
300 s.f. patient or exam room = 270 cfm
California Mechanical Code (2007)
Differentiates between 100% outdoor air and
recirculating systems.
300 s.f. patient room = 90 cfm
Hospital HVAC Systems 6/22/08
Sizing Drivers - Ventilation
Ventilation Rates
ASHRAE Standard 62
300 s.f. office = 35 cfm
AIA Guidelines (2006)
Air change rate based on contaminant dilution
300 s.f. patient or exam room = 270 cfm
California Mechanical Code (2007)
Differentiates between 100% outdoor air and
recirculating systems.
300 s.f. patient room = 90 cfm
Cooling = 650 cfm
Hospital HVAC Systems 6/22/08
•Reduction of 6 x 40,000 cfm AHU’s
•Reduced ductwork ~ 15%.
•Reduced average CAV box size ~50%.
•Reduced run-around energy recovery system.
•Two beams per patient room.
•One 3-way valve, circuit setter and manual isolation valve set per patient
room.
•One set of manual isolation valves per beam.
•Added horizontal, reverse-return CHW loops ~ one per tower per floor.
•Generator savings not yet accounted for.
•Electrical system savings not yet accounted for.
Chilled Beam (Patient Towers) Cost Differentials
Hospital HVAC Systems 6/22/08
1 2
3
4 5
6
Life Cycle Cost Analysis