Tag Archives: heat transfer

Defining Humidity Ratio and Relative Humidity

Green Building

Defining Humidity Ratio and Relative Humidity

Originally published on April 4, 2018 by BNP Media through the Building Enclosure Blog. How does a hot-air balloon rise? Fire up the burner and the temperature of the air captured within the balloon increased. The molecules of the air take on the thermal energy and become more excited. The excited molecules create more space between them. As a result, the air expands as its temperature increases. Thus, one pound of air at 80-degrees Fahrenheit (°F) is a larger volume than….

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Thermal Dynamics: Visualizing Sensible Versus Latent Heat

Green Building

Thermal Dynamics: Visualizing Sensible Versus Latent Heat

Originally published on March 12, 2018 by BNP Media through the Building Enclosure Blog. It’s the first law of thermodynamics. The Law of Conservation of Energy states that energy can neither be created nor destroyed; energy can only be transferred or changed from one form to another. This is the foundation of phase change in the physical environment. Molecular activity requires energy. The activity does not just magically happen. Phase Change When a material changes its state or phase (e.g., going….

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The Difference Between Reflectance and Emittance

Green Building

The Difference Between Reflectance and Emittance

Originally published on November 18, 2015 by BNP Media through the Architectural Roofing & Waterproofing Blog. What is emittance? Among the three basic forms of heat transfer – conduction, convection, and radiation – the term emittance refers to a material’s ability to release heat through radiation. The term necessarily refers to the heat exchange at surface of a material because heat exchange through a solid would be conductive and heat exchange through a fluid would be convective. Emittance is the….

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