Classification Ventilation Systems

Overview

Engineering reference data for Classification Ventilation Systems in HVAC systems.

Key Formulas

Sensible Heat

$Q = \dot{m} c_p \Delta T$

Heat causing temperature change.

Latent Heat

$Q = \dot{m} h_{fg} \Delta\omega$

Heat causing moisture change.

COP (Cooling)

$COP = Q_c / W$

Coefficient of performance.

Variables

Classification by Function

Ventilation systems can be categorized based on their primary operational function:

• Ventilation: Supply and evacuation of air to maintain atmospheric climate according to requirements.
• Climate Control: Supply and evacuation of air to maintain temperature and atmospheric climate.
• Heating or Cooling: A recycling system designed to supply the building with necessary heat or cooling.
• Combined System: A system that integrates two or more of the functions above.

Classification by Distribution

Distribution strategy defines how air is managed across a building:

• Centralized: A single, central plant supplies and extracts air for the entire building.
• Decentralized: Each room or area has its own dedicated ventilation unit.
• Combined: Utilizes both centralized and decentralized systems.

Classification by Ventilation Principle

This classification is based on the airflow pattern within a room:

• Displacement Air Flow: Air moves slowly through the space, typically with vertical air movement.
• Mixed Air Flow: Air is supplied at high velocity to promote mixing with the room air.

Both principles can be implemented using either:

• CAV (Constant Air Volume): Delivers a constant airflow rate.
• VAV (Variable Air Volume): Modulates the airflow rate based on demand.

Common System Types

• Single-Zone Constant-Volume System
• Single-Zone Constant-Volume System with Reheating
• Multi-zone System
• Induction Unit System
• Variable-Air-Volume System
• Dual-Duct System

References

• Original Source