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Meeting ASHRAE Fundamentals, Standard 55 & 62.1 with Chilled Beams Displacement Ventilation.
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ASHRAE Standard 62.1-2009Space Ventilation for Non-residential Occupancies
Ventilation
for Acceptable
Indoor Air Quality• Classifies occupied spaces
• Sets ventilation requirements based on size and occupancy
• Sets guidelines for demand control ventilation
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ASHRAE Standard 62.1-2009Space Ventilation for Non-residential Occupancies
Conventional Method• Ventilate the space according to ASHRAE 62-2009
• Use Ventilation Rate or IAQ Procedure to determine OA requirements using table 6-1
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ASHRAE Standard 62.1-2009Space Ventilation for Non-residential Occupancies
Conventional Method• Ventilate the space according to ASHRAE 62-
2009 • Use Ventilation Rate or IAQ Procedure to
determine OA requirements using table 6-1
• Make Corrections for Zone Air Distribution Effectiveness using Table 6-2
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ASHRAE Standard 62.1-2009Space Ventilation for Non-residential Occupancies
Conventional Method• Ventilate the space according to ASHRAE 62-
2009 • Use Ventilation Rate or IAQ Procedure to
determine OA requirements using table 6-1
• Make Corrections for Zone Air Distribution Effectiveness using Table 6-2
• Make Corrections for Multiple-Zone Recirculating System using Table 6-3
Zp=Voz/Vpz
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ASHRAE Standard 62.1-2009Space Ventilation for Non-residential Occupancies
Conventional Method• Ventilate the space according to ASHRAE 62-
2009 • Use Ventilation Rate or IAQ Procedure to
determine OA requirements using table 6-1
• Make Corrections for Zone Air Distribution Effectiveness using Table 6-2
• Make Corrections for Multiple-Zone Recirculating System using Table 6-3
Zp=Voz/Vpz
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ASHRAE Standard 62.1-2009Space Ventilation for Non-residential Occupancies
Conventional MethodOur Goal is to Reduce the Amount of Treated Air Traveling Through theBuilding• 62.1 Dynamic Reset a.k.a. CO2
Ventilation• How does the Outdoor Air know
where to go?
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ASHRAE Standard 62.1-2009Space Ventilation for Non-residential Occupancies
Goal: Reduce the Amount of Conditioned Air Traveling Through the Building
-So how else can we reduce the treated air???
Free Cooling Hours for 54F & 69F
0
500
1000
1500
2000
2500
3000
54F 69F
5am-4p
m Mon-
Fri
Displacement
18“ x 18“
Air Duct
1“ diameter
Water Pipe
Chilled Water
(above the dew point)
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ASHRAE Standard 62.1-2009Space Ventilation for Non-residential Occupancies
Goal: Reduce the Amount of Conditioned Air Traveling Through the Building
-So how else can we reduce the treated air???
Displacement
Displacement Terminal QLI Disp. Term w/ Coil Active Chilled Beam
Chilled Water
(above the dew point)
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ASHRAE Standard 62.1-2009Space Ventilation for Non-residential Occupancies
Ideally get to a…
DOAS• The system is simplified.
• Constant Volume
• No return air.
One Step Further…
DOAS w/ CO2 Sensor• The Fresh Outside Air goes where
it’s need.
• More Complicated due to VAV
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Implementing ASHRAE Standard 62.1While Not Abusing ASHRAE Standard 55 &
Fundamentals
Near/Adjacent Zone
No comfort zone
High Airflow / Draft
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ASHRAE Standard 55-2009Thermal Comfort Guide
• Defines “Occupied Zone”
• Factors affecting thermal comfort
– Metabolic rate– Clothing (insulation)– Air temperature and speed– Radiant effects– Humidity
• Defines acceptable conditions
• Goal is occupant satisfaction levels 80% or higher
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ASHRAE Standard 55-2009Occupied Zone
• Defines “Occupied Zone”
Occupied zone definition– Not within two (2) feet of a wall
– Between the floor and the head level of the predominant space occupants
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ASHRAE Standard 55-2009Thermal Comfort Guide
• Defines “Occupied Zone”
• Factors affecting thermal comfort
– Metabolic rate– Clothing (insulation)– Air temperature and speed– Radiant effects– Humidity
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Occupant Thermal ComfortBasic principles
SHG = Metabolic RateClothing
Convective transfer to surrounding airRadiant transfer to cooler surfaces
Dependent on temperature of surfaces
Independent of air conditions
Dependent on orientation of surfaces
Effected by air speed
Dependent on air conditions
Thermal comfort achieved when heat out is equal to heat generatedThermal comfort achieved when heat out is equal to heat generated
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ASHRAE Standard 55-2009Thermal Comfort Guide
• Defines “Occupied Zone”
• Factors affecting thermal comfort
• Defines acceptable conditions
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ASHRAE Standard 55-2009Cooling Operation Comfort Range
65 70 75 80 85
0.012
0.014
0.013
0.011
0.010
0.009
0.008
0.007
50
55
60
57
Operative Temperature, °F
Hu
mid
ity
Ra
tio
, L
bs
Wa
ter
pe
r L
b D
ry A
ir
Sp
ac
e D
ew
Po
int
Te
mp
era
ture
, °F
50%
RH
45%
RH
55%
RH60%
RH
Cooling Operation Comfort Window
Cooling Operation Comfort Window
Assumes 1.0 Clo, 40% Tu and ≤ 40 FPM mean velocity
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ASHRAE Standard 55-2009Thermal Comfort Guide
• Defines “Occupied Zone”
• Factors affecting thermal comfort
• Defines acceptable conditions
• Goal is occupant satisfaction levels 80% or higher
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ReturnReturn
Ankle Level
Displacement Supply Air
Near Zone
Neck Level
Thermal Plume
ASHRAE Standard 55-2009 & Fundamentals
Lets Start with Displacement Ventilation
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Near/Adjacent ZoneAdjacent zone is defined as the region adjacent to the terminal discharge in which terminal velocities exceeding 0.2 m/s (40 FPM) may be found that are 71F or below.
It is indicated by the dimension L0.2 as shown.
To avoid draft complaints, stationary space occupants should not be located within this region.
No comfort zone
L 0.2
ASHRAE Standard 55-2009 & Fundamentals
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Occupied Zone
Ele
vati
on
Max. 5oF
TE
TS
Ankle Level TA
TR
Stagnation Layer
Stratification Zone
Supply Layer
ASHRAE Standard 55-2009 & Fundamentals
Near/Adjacent Zone
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Occupied Zone
Ele
vati
on
Max. 5oF
TE
TS
Ankle Level TA
TR
Stagnation Layer
Stratification Zone
Supply Layer
ASHRAE Standard 55-2009 & Fundamentals
Comfort Chart – Ankle Region
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Occupied Zone
Ele
vati
on
Max. 5oF
TE
TS
Ankle Level TA
TR
Stagnation Layer
Stratification Zone
Supply Layer
ASHRAE Standard 55-2009 & Fundamentals
Comfort Chart – Neck Region
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Adjacent Zone Comparison (Face size of 24x48")Trox Titus Halton Price
0 2 4 6 8 10 12 14 16 18
150 cfm
225 cfm
300 cfm
370 cfm
Flow
Length (ft)
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So why is there such a difference between manufacturers? Nozzles VS
Perforated
Adjacent Zone Effect
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Tag Model Size CFM Max Adjacent Zone @ 10F DT-1 INC 24x48 225 6ftDT-2 INC 24x48 150 5ftDT-3 INC 24x48 300 8ft
Displacement Terminal Schedule
Include the Max. Allowable Adjacent
Zone in the Schedule
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ASHRAE Standard 55-2009 & Fundamentals
Now Lets Look at Active Chilled Beams
Discharge to Room
Ducted primary air
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Room sees two slot linear diffusers, nothing more!
Room sees two slot linear diffusers, nothing more!
ASHRAE Standard 55-2009 & Fundamentals
What is an Active Chilled Beam?
It‘s a Diffuser!
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ASHRAE Standard 55-2009
• Defines “Occupied Zone”
• Factors affecting thermal comfort
– Metabolic rate– Clothing (insulation)– Air temperature and speed– Radiant effects– Humidity
• Defines acceptable conditions
• Goal is occupant satisfaction levels 80% or higher
Now Lets Look at Active Chilled Beams
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Mixed Air SystemsMixed Air Systems
OCCUPIED ZONE
T150
T100
T50
T50
T100
T150
ASHRAE Standard 55-2009
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ASHRAE FundamentalsCooling Operation Comfort Range
Acceptable to 80%
Dissatisfaction Criteria 5% to 15% recommended limit
15% for draft (mixed flow)
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Part 1 – Chilled Beam
The primary air via a diffuser (Beam)•Provides fresh air requirement•Controls temperature•Controls humidity
Room Airflow
Active Chilled BeamsActive Chilled BeamsMixed Room Air DistributionMixed Room Air Distribution
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Part 1 – Chilled Beam
What does a diffuser do? • Delivers fast cold (or hot) air to the space• It directs the discharge• Makes use of the Coandă effect• Reduced velocity by mixing• Changes temperature by mixing
What does a diffuser do? • Delivers fast cold (or hot) air to the space• It directs the discharge• Makes use of the Coandă effect• Reduced velocity by mixing• Changes temperature by mixing
Room Airflow
Active Chilled BeamsActive Chilled BeamsMixed Room Air DistributionMixed Room Air Distribution
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Room Airflow
Part 1 – Chilled Beam
Beam vs. diffuser• Increases volume, Example: assume 60% water 40% air
• 100 cfm by diffuser, 40 cfm @ beam but with induction ratio of say 4:1, = total air discharged is 40 x 4 + Original 40 = 200 cfm
• If we work on 1cfm/SF and room Height of 10’• 100 cfm = 6 ac/hr, 200 cfm = 12 ac/hr (room air movement)
• The increased discharge temperature helps but the higher volume throws further in a ‘more active space’.
Beam vs. diffuser• Increases volume, Example: assume 60% water 40% air
• 100 cfm by diffuser, 40 cfm @ beam but with induction ratio of say 4:1, = total air discharged is 40 x 4 + Original 40 = 200 cfm
• If we work on 1cfm/SF and room Height of 10’• 100 cfm = 6 ac/hr, 200 cfm = 12 ac/hr (room air movement)
• The increased discharge temperature helps but the higher volume throws further in a ‘more active space’.
Active Chilled BeamsActive Chilled BeamsMixed Room Air DistributionMixed Room Air Distribution
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ASHRAE Standard 55-2009
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Sel
ecti
on S
oftw
are
4 or 2 pipe beam
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Input Beam Length and Nozzle Type
Sel
ecti
on S
oftw
are
Input Primary air, Room and CWS Temperatures
Input Water Flow Rate (s)
Input Primary Airflow Rate
Input Beam Mounting Details for Local Velocity Predictions
Output: Sensible from Water, Air and
Total
Output Waterside,
Airside Pressure drop
and noise
Output: Sensible from
Water, Air & Total
38
Room Airflow
Part 1 – Chilled Beam
Beams must be selected for comfort, not just BTU’s
The selection programs will also show you that as you increase the cooling but maintain the cfm volume, the throw increases.
Beware of any proposition that half the number of beams for a given design when no throw data or statement on comfort is offered.
Beams must be selected for comfort, not just BTU’s
The selection programs will also show you that as you increase the cooling but maintain the cfm volume, the throw increases.
Beware of any proposition that half the number of beams for a given design when no throw data or statement on comfort is offered.
Active Chilled BeamsActive Chilled BeamsMixed Room Air DistributionMixed Room Air Distribution
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Active Chilled Beam Velocities
• ASHRAE and AHRI working to establish testing and rating standards– Sensible cooling capacities– Aerodynamic performance (throw data) – Acoustical performance
• Many manufacturers do not catalog throw or velocity data
• One proposes selections with discharge airflow rates > 100 CFM/LF – Results in T100 values of 20 to 25 feet– Requires minimum diffuser separation of 50 to 60 feet for ADPI ≥ 80
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ASHRAE Fundamentals & Standard 55
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ASHRAE Fundamentals & Standard 55
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Designing Chilled Beam Systems for Thermal Comfort
Thank You!
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