ANSI/ASHRAE standard 62.1 defines zone air effectiveness (Ez) value as a measure of how effectively the zone air distribution uses the supply air to maintain the acceptable air quality in the breathing zone.

When the 'Ventilation Rate Procedure' option is selected for 'Ventilation Calculation Type' input, the 'Outdoor Zone Outdoor Airflow (Voz)' uses the People and Area Outdoor Air Rate and is calculated as:

Voz = Vbz/Ez

Where,

Vbz = Breathing zone outdoor airflow (defined by equation 6.2.2.1 within ASHRAE standard 62.1)

Ez = Zone air distribution effectiveness

Looking for Ez options available in loadmodeling.tool? Check out this article

The system types are listed below along with their Ez value. These are used for calculations on baseline and optimization pages.

The IAQP calculation also utilizes these same Ez values when performing Baseline and Optimization.

System Types

Ez Value

CAV w/ Reheat, with Gas Boiler, and Packaged DX

0.8

CAV w/ Reheat, with Electric Boiler, and Air Cooled Chiller

0.8

CAV w/ Reheat, with Electric Boiler, and Packaged DX

0.8

CAV w/ Reheat, with Electric Resistance, and Water Cooled Chiller

0.8

CAV w/ Reheat, with Electric Resistance, and Air Cooled Chiller

0.8

CAV w/ Reheat, with Electric Resistance, and Packaged DX

0.8

CAV w/ Reheat, with GSHP, and GSHP

0.8

CAV w/ Reheat, with ASHP, and Water Cooled Chiller

0.8

CAV w/ Reheat, with ASHP, and Air Cooled Chiller

0.8

CAV w/ Radiant, with Gas Boiler, and Packaged DX

1

CAV w/ Radiant, with Electric Resistance, and Packaged DX

1

CAV w/ Reheat, with ASHP, and Packaged DX

0.8

CAV w/ Reheat, with Electric Boiler, and Water Cooled Chiller

0.8

CAV w/ Reheat, with Gas Boiler, and Air Cooled Chiller

0.8

CAV w/ Reheat, with Gas Boiler, and Water Cooled Chiller

0.8

DOAS w/ FCU, with Gas Boiler, and Water Cooled Chiller

1

DOAS w/ FCU, with Gas Boiler, and Air Cooled Chiller

1

DOAS w/ FCU, with Electric Boiler, and Air Cooled Chiller

1

DOAS w/ FCU, with Electric Boiler, and Water Cooled Chiller

1

DOAS w/ FCU, with Electric Resistance, and Water Cooled Chiller

1

DOAS w/ FCU, with Electric Resistance, and Air Cooled Chiller

1

DOAS w/ FCU, with ASHP, and Water Cooled Chiller

1

DOAS w/ FCU, with ASHP, and Air Cooled Chiller

1

DOAS w/ FCU, with GSHP

1

DOAS w/ Induction, with Gas Boiler, and Air Cooled Chiller

0.8

DOAS w/ Induction, with Gas Boiler, and Water Cooled Chiller

0.8

DOAS w/ Induction, with Electric Boiler, and Air Cooled Chiller

0.8

DOAS w/ Induction, with Electric Boiler, and Water Cooled Chiller

0.8

DOAS w/ Induction, with Electric Resistance, and Water Cooled Chiller

0.8

DOAS w/ Induction, with Electric Resistance, and Air Cooled Chiller

0.8

DOAS w/ Induction, with ASHP, and Water Cooled Chiller

0.8

DOAS w/ Induction, with ASHP, and Air Cooled Chiller

0.8

DOAS w/ Induction, with GSHP, and GSHP

0.8

DOAS w/ Radiant, with Gas Boiler, and Air Cooled Chiller

1

DOAS w/ Radiant, with Gas Boiler, and Water Cooled Chiller

1

DOAS w/ Radiant, with Electric Boiler, and Water Cooled Chiller

1

DOAS w/ Radiant, with Electric Boiler, and Air Cooled Chiller

1

DOAS w/ Radiant, with Electric Resistance, and Water Cooled Chiller

1

DOAS w/ Radiant, with Electric Resistance, and Air Cooled Chiller

1

DOAS w/ Radiant, with ASHP, and Water Cooled Chiller

1

DOAS w/ Radiant, with ASHP, and Air Cooled Chiller

1

DOAS w/ Radiant, with GSHP

1

DOAS w/ VRF, with Electric Boiler, and Cooling Tower

1

DOAS w/ VRF, with Gas Boiler, and Cooling Tower

1

DOAS w/ VRF, with Ground Source

1

DOAS w/VRF

1

DOAS w/ WSHP, with Electric Boiler, and Cooling Tower

1

DOAS w/ WSHP, with Gas Boiler, and Cooling Tower

1

Natural Vent, with Gas Boiler, and Direct Expansion

1

Natural Vent, with Electric Boiler, and Direct Expansion

1

Natural Vent, with Electric Resistance, and Direct Expansion

1

Natural Vent, with ASHP, and Direct Expansion

1

Natural Vent, with ASHP, and No Cooling

1

No Mechanical System

1

Single Zone, with Gas Boiler, and Packaged DX

0.8

Single Zone, with Gas Boiler, and Air Cooled Chiller

0.8

Single Zone, with Gas Boiler, and Water Cooled Chiller

0.8

Single Zone, with Furnance, and Direct Expansion

0.8

Single Zone, with Furnance, and Packaged DX

0.8

Single Zone, with Furnance, and Air Cooled Chiller

0.8

Single Zone, with Furnance, and Water Cooled Chiller

0.8

Single Zone, with Electric Boiler, and Air Cooled Chiller

0.8

Single Zone, with Electric Boiler, and Water Cooled Chiller

0.8

Single Zone, with Electric Boiler, and Packaged DX

0.8

Single Zone, with Electric Resistance, and Water Cooled Chiller

0.8

Single Zone, with Electric Resistance, and Air Cooled Chiller

0.8

VAV w/ Radiant, with Gas Boiler, and Water Cooled Chiller

1

VAV w/ Radiant, with Electric Resistance, and Water Cooled Chiller

1

VAV w/ Radiant, with ASHP, and Water Cooled Chiller

1

VAV w/ Reheat, with Gas Boiler, and Packaged DX

0.8

VAV w/ Reheat, with Gas Boiler, and Water Cooled Chiller

0.8

VAV w/ Reheat, with Gas Boiler, and Air Cooled Chiller

0.8

VAV w/ Reheat, with Electric Boiler, and Air Cooled Chiller

0.8

VAV w/ Reheat, with Electric Boiler, and Water Cooled Chiller

0.8

VAV w/ Reheat, with Electric Boiler, and Packaged DX

0.8

VAV w/ Reheat, with Electric Resistance, and Air Cooled Chiller

0.8

VAV w/ Reheat, with Electric Resistance, and Packaged DX

0.8

VAV w/ Reheat, with Electric Resistance, and Water Cooled Chiller

0.8

VAV w/ Reheat, with ASHP, and Water Cooled Chiller

0.8

VAV w/ Reheat, with ASHP, and Air Cooled Chiller

0.8

VAV w/ Reheat, with ASHP, and Packaged DX

0.8

VAV w/ Reheat, with GSHP

0.8

Related Articles:

  1. System Type

  2. What is ASHRAE 62.1?

  3. Optimization and Bundles

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