1. Twa Panel Systems Inc. April 12, 2012
1201 – 4th St.
Nisku, Alberta, Canada P: +1 (780) 955-8757
T9E 7L3 F: +1 (780) 965-8757
www.twapanels.ca
2. Agenda
• Active Beam Origin • Air-side Information
• Active Beam Overview • Water-side Information
• How A.B.’s Function • Capacity
• Construction • Benefits & Limitations
• System comparisons • Applications
3. Active Beam Origin
• Origins in Europe
Radiant Chilled Passive Chilled
Panels Sails Beams
(1950’s) (1990’s) (1990’s)
Perimeter Modular Active
Induction Unit
(1950’s)
Chilled Beams
(2000’s)
4. Active Beam Overview
• High acceptance rate in Europe
• Historically high energy costs
• North American market increasing due largely to:
• Green initiatives
• Increasing energy costs
• Increased installed base (Familiarity & Successful projects)
• Lowering cost due to increasingly competitive market
5. Active Beam Overview
• Hydronic systems use water as the
energy transport medium
• Water has many times the thermal
capacitance as compared to air
7. How A.B.’s Function
A – Duct connection
S/A (primary Air) from the AHU
B – Primary air (P/A) plenum
Static Pressure forms and drives
P/A through nozzles
C – Perforated grille
Room air (Secondary air) is
induced, through grille, into coil
D – Unit mounted coil
2 or 4 pipe coil, cools/heats
the secondary air
E – Mixed air
P/A and secondary air mix
F – Discharge air
Mixed discharge air exits the beam, Coanda is induced to throw the air horizontally
9. Construction Standard Beam
Dimensions:
Width: 1’, 2’
Length: 2’, 4’, 6’, 8’, 10’
Standard Coil
Lengths:
2’, 3’, 4’, 5’, 6’, 7’, 8’, 9’, 10’
Various Nozzle Types
• Induction Ratio
• Acoustics
Discharge Pattern:
1, 2, & 4 - way
Other:
• Frame for Drywall
• Exposed – Coanda Wings
10. System comparisons
Active Beams
• Low Energy Consumption
• Reasonable Acoustics
• Low maintenance costs (No moving parts)
• Cooling Capacity: ~100 – 394 W/m2 (32 – 125 Btuh/ft2)
Versus
Fan Coil Units (FCU)
• Medium/High Energy Consumption
• Reasonable/Loud Acoustics
• Adaptable Solution
• Potential for high maintenance costs
• Cooling Capabilities: ~100 – 200 W/m2 (32 – 64 Btuh/ft2)
Variable Air Volume (VAV) System
• Low Energy Consumption
• Quiet/Reasonable acoustics
• Most efficient all air system
• Cooling Capabilities: ~100 – 200 W/m2 (32 – 64 Btuh/ft2)
Variable Refrigerant Volume (VRV) System
• High Energy Consumption
• Reasonable Acoustics
• Potential for high installation/maintenance costs
• Cooling Capabilities: ~150 – 200 W/m2 (48 – 64 Btuh/ft2)
11. Air Side Information
(Primary Air - Overview)
• Meet all ventilation requirements
• Min. Vent. (O/A requirements)
• Remove 100% of the latent loads (Psychrometrics)
• Induce enough Rm./A to meet sensible loads
**Greatest of these factors sets the minimum air flow rate**
• Higher SAT may be used
• May use heat recovery strategies for increased energy savings
• Decreased AHU & Duct size
• Decrease in fan energy
12. Air Side Information
(Primary Air)
• Majority of energy is saved at the FAN
• Air-side Load Fraction (ALF)
– The smaller the air-side load fraction, the more energy can be saved by
using a chilled beam system
Office Classroom Lobby
O/A Requirement 0.15 0.5 1
(cfm/ft2)
Air Volume (All Air System) 1 1.5 2
(cfm/ft2)
Air-side Load Fraction 15% 33% 50%
14. Air Side Information
(Psychrometrics)
Psychrometric review required to prevent condensation
Standard Procedure:
• Remove moisture from the P/A at AHU
• Dry P/A lowers the space dew point temperature
• To prevent condensate on the coil:
Space dew point temp. < EWT
Not all spaces are suitable for active beams:
• Suitability engineering check - % of Sensible from CFMLatent
15. Air Side Information
(Psychrometrics)
Option 1 Option 2
Primary air dew
48°F 51.5°F
point
Room air dew
55°F 57.8°F
point
Secondary
55°F 58°F
CWT
Dehumidificatio
0.002 lbs/lbDA 0.002 lbs/lbDA
n
RESET FOR ENERGY
SAVINGS!
16. Air Side Information
(Psychrometrics & Climate Regions)
Legend:
■ Easy , Application of active beam products is natural
■ Medium , Application of active beam products requires some additional design
to control building moisture
■ Difficult, Application of active products is more difficult and humidity must be
carefully considered
17. Air Side Information
(P/A Design Parameters)
Typical Design Conditions (Cooling):
S/A Space
TDry Bulb: 55 - 65 F TDry Bulb: 75 F
TWet Bulb: 53 - 57 F TWet Bulb: 64 F
TDew point: 52 F TDew point: 58 F
R.H.: 55%
ΔGr = 13.64 Gr/lb
Typical Design Conditions (Heating):
S/A Space
TDry Bulb: 65 F TDry Bulb: 70 F
R.H.: 50%
QL = 0.68*CFM*ΔGr Qs = 1.08*CFM*ΔT
18. Air Side Information
(Space Over Cooling)
• Maintain reasonable dew point control
• Meet 100% of latent load under Peak Design conditions
• Infiltration
• Maximum occupancy
• Other sources of moisture
• Limit over-cooling
• Keep air-side load fraction low
• Reset air temperature
• CHWS Shut-off control or EWT reset
• VAV for fluctuating occupancy
19. Air Side Information
(Air Velocities & Thermal Comfort)
ASHRAE Std. 55
• Occupied Zone
• ΔT and Air velocity determine
Thermal Comfort
• 80% Occupancy Satisfaction
• Radiant Affect
Active Beams
• Higher discharge air temp.
• Highest air velocities are at
the perimeter of the space
21. Air Side Information
(Plenum Air Pressure Drop)
250
1.00”
230
0.93”
• Fan Static is higher
210 • Less penalty then high air flow
0.85”
Plenum Pressure [Pa]
190
• Can correlate pressure and air flow
0.77”
• Air volume is difficult to measure
170
0.69” K 60A
150
0.60” K 60C • Measuring pressure is easy and
130
0.52”
reliable
K 60D
110
0.44”
K 60B • Pressure is the common factor
90
0.36”
70
• Plenum and ducting should be
0.28” Primary air [l/s] sealed
50
0.20” 0 5 10 15 20 25 30 35 40
CFM 10 21 32 42 53 64 74 85
22. Air Side Information
(Acoustics)
45
40
2’x8’ – Larger Nozzles Chart reports
35 acoustic values
LwA [dB(A)]
without room
30 attenuation
effect
25
2’x8’ – Smaller Nozzles Active beams can
20
be very quiet!
15
0.4 0.6 0.8 1 1.2 1.4
Plenum Pressure [“w.c.]
23. Air Side Information
(Air Side Controls)
• CAV primary air flow is
typically simple with
Total capacity
orifice plate “Iris” type
dampers.
• Varying the plenum
pressure yields a non-linear
capacity response. Tight
control with variable
plenum pressure is typically
impractical.
Static pressure
24. Air Side Information
(Air Side Controls)
• Occupancy Valve may solve
the issue of over-cooling a
Total capacity
space with un-tempered
primary air.
• Plenum static pressure
range (0.3”-1.2” w.c. max)
• VAV modulation range is low
with active beams
Primar y air volume
25. Air Side Information
(Possible Dampers)
Iris Dampers –
(angled multi-leaf
blades)
Pressure independent –
butterfly type
Iris Dampers
26. Air Side Information
(Common Design Pitfalls)
• Two Air-side Design Concerns:
1) Psychrometrics (Cooling only)
2) Preliminary Design based on DOAS system
27. Water Side Information
(Overview)
• Coil responsible for majority of the sensible load
• Cooling & Heating
• Design requires:
• Water flow rate
• Circuit pressure drop
• Temperatures (EWT, LWT)
• Increase in pump size and pump energy
• Fan Energy vs. Pump Energy = Net energy savings
28. Water Side Information
(Water Design Parameters)
• Active Beam Cooling:
• EWT temperature, typically between 56 – 62 F
• Secondary CHWS loop required
• Psychrometrics – (Condensation control)
• Generally EWT = 1 – 2 F above SPACE dew point temp.
• Active Beam Heating:
• EWT temperature, typically between 100 – 120 F
• Secondary HWS loop required
• Minimum flow rate per circuit = 0.45 to 0.65 GPM
• Prevent laminar flow (more important for cooling)
29. Water Side Information
(Piping Design)
Water system pressure control
• Variable speed pump and
differential pressure sensor
• Reduces energy by lowering
pump loading
• Maintain constant pressure
• Can cause imbalances in the
system when not at full flow if
pressure independent flow
control valves are not used
30. Water Side Information
(Piping Design)
Direct return
• Length of pipe varies from supply
header to return header for each
unit
• Change in pressure drop from one
circuit to another, affects flow rates
• Use balancing valves or circuit
setters
• Can cause imbalances in the
system when not at full flow if
pressure independent flow control
valves are not used
31. Water Side Information
(Piping Design)
Reverse return
• First supplied, last returned
• Zone or array is self-balancing
• Number of balancing valves can
be reduced
• Additional pipe length required
• May require pressure
independent flow control valves at
mains for zone take off
32. Water Side Information
(Piping Design)
Parallel piping
• Used exclusively for chilled
beams
• Reduced pressure loss
• Lower flow rates to achieve ΔT
• Better temperature distribution
and response
33. Water Side Information
(Water Side Controls)
On/Off valve Turbulent flow
• Inexpensive
Secondar y Capacity
• Adequate control
• Flow remains turbulent
• Req’d for mix mode ventilation
• Small & large zones
Laminar
Proportional control valve flow
• Expensive
Water gpm
• Advanced control not required
• Flow becomes laminar (cooling) 0
0 50
0.22 100
0.44
• Potential for searching
Minimum flow rate per circuit
= 0.45 to 0.65 GPM
34. Water Side Information
(Common Design Pitfalls)
• Three water-side Design Concerns:
1) Use of Glycol as the operating fluid
• Especially in cooling
2) Not considering Pressure independent flow control valves
• Especially with large hydronic systems
• Modulating valves
• Variable frequency drive pumps
3) Valve & Entrapped air noise
35. Capacity Overview
Air Side:
• 100% Latent energy capacity, increase by:
• Increasing ΔGr between P/A & Rm/A
• Increasing air flow rate
• Minority of sensible capacity, increase by:
• Increasing ΔT between P/A & Rm/A
• Increasing air flow rate
Water Side:
• Majority of sensible capacity, increase by:
• Increasing ΔT between water & Rm/A
• Increasing water flow rate
Total Capacity = Air capacity + Water capacity
36. Capacity vs. Air Volume
40
A-DT 8
A-DT 10
35
B-DT 8
B-DT 10 • Increasing air flow rate and
C-DT 8
30
C-DT 10
D-DT 8
pressure:
D-DT 10
Air Volume [l/s]
• Significant Increase in Capacity
25
20 • Increasing GPM in turbulent
flow:
15
• Marginal Increase in Capacity
10
Secondary Capacity [W]
5
100 200 300 400 500 600 700 800
Typical sensible range is approx. 250 – 1500 BTUh/Ft
37. Capacity
(Performance Data)
• Applicable standards:
• EN 15116: Chilled Beams
• ASHRAE/AHRI - SPC 200
• When choosing a manufacturer, ensure they
test to an applicable standard!
38. Active Beam Benefits
• Significant Fan Energy savings
• lower overall S/A
• Increased air circulation with high thermal comfort
• Smaller AHU & Ductwork
• Lower floor-floor heights
• Good retrofit applications
• Significant reduction of riser space
• Low maintenance requirements
• Can be integrated with other energy saving systems
• Geothermal, ERV’s, Enthalpy wheel…etc
• Water side free cooling may be an option
39. Active Beam Benefits
• Spaces may be zoned
• Increased Comfort
• Reduced energy consumption
• Individual space temperature control (LEED Compliant)
• Quick response time
• Low to Reasonable Acoustics
40. Active Beam Limitations
• Potential for higher first cost
• Increase in pump energy
• Small Compared to Fan Energy Savings
• Limited air-side free cooling
• Limited VAV modulating range
• High importance for building humidity control in Cooling
• Dehumidification at the AHU is required
• May require a building envelope upgrade
• May require more sophisticated controls for humidity control
• May not be acceptable for all spaces, based on latent loads
41. Commercial
Applications Office spaces
Data centers
Shops/Stores
Sensible and Latent energy drive suitability
Institutional
Labs
Higher the sensible - the greater the energy savings Lecture Theatres*
Lower the latent - the easier it is to control the dew point temperature
of the space (Required due to no condensate pan) Government
Schools
Hospital**
Spaces with: Airports
• High sensible loads & low latent loads Clinics
• Ideal
Other
• High sensible loads & high latent loads
Child care facilities
• May be suitable with careful examination
*Occupancy may produce high
• Low sensible loads & high latent loads latent requirements
• Would not be recommended for use with chilled beams **Some areas such as surgical
suites do not allow room air to
be induce or circulated through
the HVAC equipment
Not a silver bullet, each space should be individually
reviewed to determine suitability
