Ventilation Systems Design

Ventilation Systems

• Types of Ventilation Systems:
  • Natural Ventilation: uses natural forces (wind, temperature differences) to circulate air
  • Mechanical Ventilation: uses fans and ducts to circulate air
  • Hybrid Ventilation: combines natural and mechanical ventilation
• Ventilation System Components:
  • Air intakes and outlets
  • Ducts and fans
  • Filters and humidifiers (optional)
• Ventilation System Design Considerations:
  • Building orientation and layout
  • Climate and weather patterns
  • Occupant density and activity levels
  • Indoor air quality (IAQ) and pollution control

Heat Transfer

• Heat Transfer Modes:
  • Conduction: direct heat transfer between objects in physical contact
  • Convection: heat transfer through fluid motion (air or water)
  • Radiation: heat transfer through electromagnetic waves
• Heat Transfer Mechanisms:
  • Insulation: reduces heat transfer through materials
  • Ventilation: removes heat through air circulation
  • Shading: reduces heat gain through shading devices
• Heat Transfer Units:
  • Watt (W): unit of power
  • Joule (J): unit of energy
  • Kelvin (K): unit of temperature

Thermal Comfort Indices

• Thermal Comfort Indices:
  • Predicted Mean Vote (PMV): predicts occupant thermal comfort based on air temperature, humidity, and air movement
  • Predicted Percentage of Dissatisfied (PPD): predicts percentage of occupants dissatisfied with thermal comfort
  • Thermal Sensation Vote (TSV): measures occupant thermal comfort on a scale from -3 to +3
• Thermal Comfort Factors:
  • Air temperature
  • Humidity
  • Air movement
  • Radiant temperature
  • Clothing and activity levels
• Thermal Comfort Standards:
  • ASHRAE Standard 55: thermal comfort standard for commercial buildings
  • ISO 7730: thermal comfort standard for indoor environments

Ventilation Systems

• Natural Ventilation uses natural forces such as wind and temperature differences to circulate air.
• Mechanical Ventilation uses fans and ducts to circulate air.
• Hybrid Ventilation combines natural and mechanical ventilation.

Ventilation System Components

• Air intakes and outlets are components of ventilation systems.
• Ducts and fans are used to circulate air in ventilation systems.
• Filters and humidifiers are optional components in ventilation systems.

Ventilation System Design Considerations

• Building orientation and layout are considered in ventilation system design.
• Climate and weather patterns are considered in ventilation system design.
• Occupant density and activity levels are considered in ventilation system design.
• Indoor air quality (IAQ) and pollution control are considered in ventilation system design.

Heat Transfer

• Conduction is a mode of heat transfer that occurs through direct contact between objects.
• Convection is a mode of heat transfer that occurs through fluid motion (air or water).
• Radiation is a mode of heat transfer that occurs through electromagnetic waves.

Heat Transfer Mechanisms

• Insulation reduces heat transfer through materials.
• Ventilation removes heat through air circulation.
• Shading reduces heat gain through shading devices.

Heat Transfer Units

• Watt (W) is the unit of power.
• Joule (J) is the unit of energy.
• Kelvin (K) is the unit of temperature.

Thermal Comfort Indices

• Predicted Mean Vote (PMV) predicts occupant thermal comfort based on air temperature, humidity, and air movement.
• Predicted Percentage of Dissatisfied (PPD) predicts the percentage of occupants dissatisfied with thermal comfort.
• Thermal Sensation Vote (TSV) measures occupant thermal comfort on a scale from -3 to +3.

Thermal Comfort Factors

• Air temperature is a factor in thermal comfort.
• Humidity is a factor in thermal comfort.
• Air movement is a factor in thermal comfort.
• Radiant temperature is a factor in thermal comfort.
• Clothing and activity levels are factors in thermal comfort.

Thermal Comfort Standards

• ASHRAE Standard 55 is the thermal comfort standard for commercial buildings.
• ISO 7730 is the thermal comfort standard for indoor environments.