Zones

Zones group spaces that share common HVAC equipment. A zone typically represents all the spaces served by a single thermostat or terminal unit.

Zone Concepts

What is a Zone?

A zone is a collection of one or more spaces that are:

• Controlled together by a single thermostat
• Served by a common terminal unit (VAV box, fan coil, etc.)
• Expected to have similar thermal conditions

Single-Space Zones

Many designs use one zone per space for:

• Maximum control flexibility
• Spaces with varying loads
• Critical comfort requirements

Multi-Space Zones

Combine spaces into zones when:

• Spaces have similar loads and schedules
• Cost constraints limit the number of zones
• Spaces are thermally connected (open plan)

Creating Zones

Automatic Zone Creation

HVAKR can automatically create zones:

1. Click Auto-Create Zones
2. Choose the zoning strategy:
   • One zone per space
   • Group by space type
   • Group by orientation
3. Review and adjust as needed

Manual Zone Creation

Create zones manually:

1. Navigate to Building Model > Zones
2. Click New Zone
3. Name the zone
4. Select spaces to include

Assigning Spaces to Zones

• Drag spaces into zones in the zone list
• Or select spaces and use Assign to Zone
• A space can only belong to one zone

Zone Properties

Zone Name

Use descriptive names that indicate:

• Location (East Wing, Floor 2)
• Function (Conference Rooms, Open Office)
• System (AHU-1 Zone 3)

Space Assignments

The list of spaces in this zone. Shows:

• Space names
• Space areas
• Space loads (when calculated)

Zone Load

The sum of all space loads in the zone. This determines:

• Terminal unit sizing
• Supply airflow
• Heating/cooling capacity

Zone Airflow

Peak Airflow

The maximum airflow required by the zone, based on:

• Peak cooling load
• Minimum ventilation requirements
• Heating airflow (if applicable)

Minimum Airflow

The lowest airflow the zone can receive:

• Ventilation requirements (ASHRAE 62.1)
• Minimum turndown ratio
• Heating airflow in VAV systems

Diversity

When zones peak at different times:

• System airflow may be less than sum of zones
• Diversity factor accounts for this
• Important for central equipment sizing

Zone Types

Interior Zones

Zones with no exterior exposure:

• Cooling-only in most climates
• Dominated by internal loads
• Relatively constant load

Perimeter Zones

Zones along the building exterior:

• Both heating and cooling loads
• Affected by solar and transmission
• Variable loads throughout the day

Special Zones

Zones with unique requirements:

• Conference rooms (variable occupancy)
• Server rooms (high cooling load)
• Laboratories (special ventilation)

Best Practices

1. Match controls - Zones should correspond to control zones
2. Consider orientation - Separate perimeter zones by exposure
3. Account for load diversity - Similar spaces can share zones
4. Plan for flexibility - Future changes may require zone modifications
5. Check ventilation - Ensure zones meet outdoor air requirements