ASHRAE 62.1 Ventilation for Acceptable Indoor Air Qualit (3)
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3/31/2015
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ASHRAE Standard 62.1
TRACE 700™
ASHRAE 62.1: Section 6.2Ventilation Rate Procedure (VRP)
• Prescribes quantity of outdoor air delivered to each zone based
• How to calculate outdoor air flow needed at the system intake
Trane C.D.S. eLearning Tutorial ASHRAE Standard 62.1 and TRACE™ 700
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Learning objectives
• Describe the multi-zone calculation process
• Show how TRACE™ determines system level
• Common questions
Example: Two zone officeCalculate required outdoor air intake VAV reheat system
Block airflow : 2560 cfm
VAV diversity factor:0.8 1600 cfm
25% min stop
exhaustunconditioned outdoor air
sup
ply
air
retu
rn a
ir
VAV
VAV
1600 cfm 25% min stop
zone 1
zone 2
Trane C.D.S. eLearning Tutorial ASHRAE Standard 62.1 and TRACE™ 700
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exhaust
ASHRAE Standard 62.1 Variables
Vpz = 1600 cfmVpz-min = 400 cfm
Vpz = 1600 cfmVpz-min = 400 cfm
outdoor airsu
pp
ly a
ir
retu
rn a
ir
VAV
VAV
Block airflow : Vps = 2560 cfm
Zone Airflow Rates
1. Define Zone Level Parametersa. Define zone airflow rates and distribution effectiveness
a. Ra = Outdoor airflow rate per unit area (Table 6-1)b. Rp = Outdoor airflow rate per person (Table 6-1)c. Ez = Define zone air distribution effectiveness (Table 6-2)
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Trane C.D.S. eLearning Tutorial ASHRAE Standard 62.1 and TRACE™ 700
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3/31/2015
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Zone Airflow Rates
1. Define Zone Level Parametersa. Define zone airflow rates and distribution effectiveness
a. Ra = Outdoor airflow rate per unit area (Table 6-1)b. Rp = Outdoor airflow rate per person (Table 6-1)c. Ez = Define zone air distribution effectiveness (Table 6-2)
2. Calculate Breathing Zone Outdoor Airflow (Vbz)a. Vbz= (Rp x Pz) + (Ra x Az),
where Pz is the number of people and Az is the zone area
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Zone Airflow Rates
1. Define Zone Level Parametersa. Define zone airflow rates and distribution effectiveness
a. Ra = Outdoor airflow rate per unit area (Table 6-1)b. Rp = Outdoor airflow rate per person (Table 6-1)c. Ez = Define zone air distribution effectiveness (Table 6-2)
2. Calculate Breathing Zone Outdoor Airflow (Vbz)a. Vbz= (Rp x Pz) + (Ra x Az),
where Pz is the number of people and Az is the zone area
3. Calculate Zone Outdoor Airflow (Voz)a. Voz = Vbz/Ez
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2
3
Trane C.D.S. eLearning Tutorial ASHRAE Standard 62.1 and TRACE™ 700
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Zone Airflow Rates
Zone 2:• Rp = 5 cfm/p• Ra = 0.06 cfm/ft2
• Pz = 10 people• Az = 500 ft2
• Ez = 1.0 (cooling)
Calculate Vbz and Voz:Zone 1:• Rp = 5 cfm/p• Ra = 0.06 cfm/ft2
• Pz = 30 people• Az = 1500 ft2
• Ez = 1.0 (cooling)
exhaust
OA
sup
ply
air
retu
rn a
ir
VAV
VAV
zone 1
zone 2
Voz = 240 cfm
Voz = 80 cfm
ASHRAE Standard 62.1/TRACE demonstration
1. Area and occupancy ventilation rates: OA required to remove contaminants from people and building materials
2. Zone level efficiency: Effectiveness of zone level outdoor airflow to dilute indoor contaminants
Trane C.D.S. eLearning Tutorial ASHRAE Standard 62.1 and TRACE™ 700
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3. Area and occupancy ventilation rates: Select an appropriate standard 62.1 calculation
ASHRAE Standard 62.1/TRACE demonstration
TRACE™ ASHRAE Standard 62.1 report
Ventilation Parameters
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4. Determine Zone Primary OA Fraction (Zp) for each zone
exhaust
Vpz = 1600 cfmVpz-min = 400 cfm
Vpz = 1600 cfmVpz-min = 400 cfm
sup
ply
air
retu
rn a
ir
VAV
VAV
Zp = Voz/Vpz-min
WhereVozVpz-min
= zone outdoor airflow= minimum expected
zone primary airflow at the design condition analyzed
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OA
4. Determine critical zone (zone with maximum Zd)5
exhaust
Zd = 0.6
Zd = 0.2
sup
ply
air
retu
rn a
ir
VAV
VAV
critical zone
OA
Trane C.D.S. eLearning Tutorial ASHRAE Standard 62.1 and TRACE™ 700
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3/31/2015
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*
TRACE™ ASHRAE Standard 62.1 report
Ventilation Calculation for Cooling Design
Vou = D Σall zones Rp Pz + Σall zones Ra Az, where D represents the occupancy diversity within the system
Assume D =1 Vou = 320 cfm
4. Determine uncorrected OA intake (Vou)6
exhaust
Vbz = 240 cfm
Vbz = 80 cfm
sup
ply
air
retu
rn a
ir
VAV
VAV
OA
Trane C.D.S. eLearning Tutorial ASHRAE Standard 62.1 and TRACE™ 700
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TRACE™ ASHRAE Standard 62.1 report
System Ventilation Requirements
Xs = Vou/Vpswhere Vps is system primary airflow (VAV block airflow)
4. Determine Average Outdoor Air Fraction (Xs)7
exhaust
sup
ply
air
retu
rn a
ir
VAV
VAV
OA
Vou = 320 cfmVps = 2560 cfm (fan block)Xs= 0.125
Trane C.D.S. eLearning Tutorial ASHRAE Standard 62.1 and TRACE™ 700
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3/31/2015
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TRACE™ ASHRAE Standard 62.1 report
System Ventilation Requirements
Ev = 1+Xs‐Zd‐max = 1+0.125‐0.6 = 0.525
4. Determine system ventilation efficiency (Ev): Table 6‐3 or App. A
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exhaust
Vbz = 240 cfm
Vbz = 80 cfm
sup
ply
air
retu
rn a
ir
VAV
VAV
OA
Equation A‐1
Trane C.D.S. eLearning Tutorial ASHRAE Standard 62.1 and TRACE™ 700
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Vot = Vou/Ev = 320/0.525 = 610 cfm 23.8% OA at cooling design (610 cfm/2560 cfm)
Vot = 610 cfm
4. Find outdoor intake flow (Vot): 9
exhaust
sup
ply
air
retu
rn a
ir
VAV
VAV
OA
TRACE™ ASHRAE Standard 62.1 report
System Ventilation Requirements
Trane C.D.S. eLearning Tutorial ASHRAE Standard 62.1 and TRACE™ 700
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3/31/2015
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TRACE and ASHRAE Standard 62.1
Common Questions
• Why is my system 100% OA?
• Why does my ASHRAE multi-zone spreadsheet does not match the TRACE 700 output?
• Why does TRACE calculate Zd using Vpz-min?
Resolving 100% OA • Set Max Vent Allowed (Max Zd) in Create Systems>Advanced• Increase VAV min in critical zone in Create Rooms>Airflows
Trane C.D.S. eLearning Tutorial ASHRAE Standard 62.1 and TRACE™ 700
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3/31/2015
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ASHRAE Standard 62.1Lesson 2: Program Methodology100% OA
Max Zd = 75%
Pros
Reduce OA cfm• Reduced outdoor air
cfm
• Reduced ventilation load
Cons
Increased airflows• Increased minimum stop
• Increased fan power
• Increased reheat loads
Max Zd
Trane C.D.S. eLearning Tutorial ASHRAE Standard 62.1 and TRACE™ 700
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Note: These values are for the 2 zone example
Impact of Zd-max on Vot and Vpz-min
TRACE and ASHRAE Standard 62.1
Common Questions
• Why is my system 100% OA?
• Why does my ASHRAE multi-zone spreadsheet does not match the TRACE 700 output?
• Why does TRACE calculate Zd using Vpz-min?
Trane C.D.S. eLearning Tutorial ASHRAE Standard 62.1 and TRACE™ 700
©2015 Trane. All rights reserved.
3/31/2015
15
TRACE and ASHRAE Standard 62.1
Common Questions
• Why is my system 100% OA?
• Why does my ASHRAE multi-zone spreadsheet does not match the TRACE 700 output?
• Why does TRACE calculate Zd using Vpz-min?
Trane C.D.S. eLearning Tutorial ASHRAE Standard 62.1 and TRACE™ 700
©2015 Trane. All rights reserved.
3/31/2015
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Additional resources
• TRACE™ 700 User’s Manual
• TRACE online (F1) help
• Trane.com/EN
• Trane.com/ContinuingEducation
phone I 608.787.3926
fax I 608.787.3005
email I [email protected]
Web I www.tranecds.com
contact us
Trane C.D.S. eLearning Tutorial ASHRAE Standard 62.1 and TRACE™ 700
©2015 Trane. All rights reserved.