Sign In / Sign Up

sign in / sign up

Air-Based Solar Thermal Collectors

 

Air-based solar thermal collectors use air as the heat transfer medium to capture and distribute solar energy. They are an efficient and low-cost solution for improving indoor air quality and reducing heating demands in buildings. These collectors are categorized into transpired and non-transpired types based on their design and operation.

 

1. Transpired Solar Collectors

 

  • How They Work:
    • A dark perforated absorber captures solar energy.
    • Fans draw air through the absorber’s small perforations, warming it as it passes through.
    • The warmed air is collected in a cavity between the absorber and the building wall and then distributed through the building.
  • Key Features:
    • Installed on the south-facing wall of a building for optimal sunlight exposure.
    • Acts as part of the building envelope, improving thermal performance.
  • Advantages:
    • Improved Air Quality: Filters incoming air, removing pollutants and delivering pre-heated fresh air indoors.
    • Energy Efficiency: Reduces the need for conventional heating systems, lowering energy costs.
    • Durability: Often made of long-lasting materials like aluminum or steel, ensuring minimal maintenance.
  • Applications:
    • Commonly used in commercial, industrial, and institutional buildings for ventilation and space heating.

2. Non-Transpired Solar Collectors

 

  • How They Work:
    • Similar to transpired collectors but without perforations.
    • Air is drawn across the collector’s surface and heated directly by solar radiation before being distributed indoors.
  • Key Features:
    • Can be integrated into building designs, such as shading devices or louvers.
    • Suitable for applications where direct ventilation is not required.
  • Advantages:
    • Flexible Design: Often integrated into architectural elements like aluminum louvers, doubling as shading devices.
    • Low Cost: A simpler design reduces installation and maintenance costs.
  • Applications:
    • Ideal for pre-heating air in HVAC systems or providing supplemental heating in buildings.

3. Advantages of Air-Based Solar Collectors

 

  1. Improved Indoor Air Quality:
    Air-based systems bring in fresh, filtered air, reducing indoor air pollutants while maintaining comfortable temperatures.
  2. Energy Savings:
    By pre-heating air, these systems reduce reliance on traditional heating systems, cutting energy costs significantly.
  3. Low Maintenance:
    With no liquid to freeze or leak, air-based collectors require minimal maintenance compared to liquid-based systems.
  4. Architectural Integration:
    Components like aluminum louvers can serve dual purposes, acting as both shading devices and solar collectors, blending functionality with design.

4. Design Considerations

 

  • Orientation:
    South-facing walls are preferred for maximum solar exposure.
  • Material Selection:
    Durable materials like aluminum or steel are used for absorbers and louvers to withstand environmental stress and prolong lifespan.
  • Integration:
    These systems can be integrated into building envelopes, reducing installation costs and improving overall energy efficiency.