Tag Archives: psychrometrics

The Psychrometric Chart Explained

Green Building

The Psychrometric Chart Explained

Originally published on June 13, 2018 by BNP Media through the Building Enclosure Blog. It is one of the intimidating charts for any building design professional: the psychrometric chart. At first blush, the “psych chart” looks very complicated. There are layers of axes and curved reference lines. However, a closer examination will reveal that – at its essence – the chart is visually conveying the answers to two related questions: How much sensible (dry-bulb) heat is in the air? (See….

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Dry-Bulb Temperature, Wet-Bulb Temperature and Enthalpy

Green Building

Dry-Bulb Temperature, Wet-Bulb Temperature and Enthalpy

Originally published on May 9, 2018 by BNP Media through the Building Enclosure Blog. There is energy in the air all around us. Some of it exists in the form of thermal energy that one can sense – heat in air that impacts one’s perception of thermal comfort. But there is also an energy embodied in the vapor present in the air. While this “hidden” heat is not experienced as warmth, it certainly has a bearing on thermal comfort as….

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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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Visualizing Weather Data Using Climate Consultant

Green Building

Visualizing Weather Data Using Climate Consultant

Originally published on December 28, 2015 by BNP Media through the Architectural Roofing & Waterproofing Blog. The U.S. Department of Energy’s Office of Energy Efficiency & Renewable Energy (EERE) provides public access to long-term climate data for over 2,100 locations throughout the world in formats suitable for the publicly-funded EnergyPlus whole-building energy modeling software. These files are chock-full of hourly weather data of 30-year averages for temperature, humidity, wind speeds, and much more. For residential projects and other skin-load dominated….

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