Tag Archives: Energy

The Basic Forms of Heat Transfer

Green Building

The Basic Forms of Heat Transfer

Originally published on September 6, 2019 by BNP Media through the Building Enclosure Blog. Heat always flows from substances of a warmer temperature to substances of a cooler temperature. Heat (thermal energy) will be exchanged in an environment until a common temperature (equilibrium) is achieved. This equalizing of temperature in an environment is caused by a combination of three basic types of heat transfer: conduction, radiation, and convection. Conduction Conduction is the transfer of vibrating energy between adjacent molecule (Fig. 1)…..

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Revisiting the Insulating Effects of Green Roofs

Green Building

Revisiting the Insulating Effects of Green Roofs

The Simon Skjodt International Orangutan Center, which opened at the Indianapolis Zoo in May 2014 features an 8,000-square foot extensive green roof. Architect: Browning Day Mullins Dierdorf. Photograph by Daniel Overbey. Originally published on June 12, 2019 by BNP Media through the Building Enclosure Blog. One of the consequences of blogging is the peer review of the internet. I am always happy to take comments. I value the dialogue because of the learning involved and it reaffirms that what I….

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Clarifying Slab-on-Grade Insulation in ASHRAE Standard 90.1

Green Building

Clarifying Slab-on-Grade Insulation in ASHRAE Standard 90.1

Originally published on April 8, 2019 by BNP Media through the Building Enclosure Blog. Slab-on-grade insulation. It seems like it should not be so complicated. Yet, slab-on-grade insulation can be arranged in a number of configurations, each with pros and cons. One arrangement may be more conducive to maintaining a continuous thermal barrier from a wall down through its foundation but it allows unsightly exposure along the building perimeter. Another configuration may better conceal the insulation yet it allows an….

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Gauging the Impact of Exterior Shading using the Projection Factor

Green Building

Gauging the Impact of Exterior Shading using the Projection Factor

Originally published on February 15, 2019 by BNP Media through the Building Enclosure Blog. The solar heat gain coefficient (SHGC) is a ratio that defines the amount of solar energy that reaches a glazing assembly (including both the glass and frame) with the amount that gets through to the inside. It represents the ability of a glazing assembly to resist heat gain from direct solar radiation. A high SHGC indicates poor resistance. That means most of the solar radiation arriving to the window or….

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Why the 2018 IgCC is Critical to the Future of Green Building

Green Building

Why the 2018 IgCC is Critical to the Future of Green Building

Originally published on January 23, 2019 by BNP Media through the Building Enclosure Blog. It has been nearly half a decade since the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), the American Institute of Architects (AIA), the International Code Council (ICC); the Illuminating Engineering Society (IES); and the U.S. Green Building Council (USGBC) signed a memorandum to better align green building goals through ANSI/ASHRAE/ICC/USGBC/IES Standard 189.1, the International Green Construction Code (IgCC), and the LEED certification system. For years, these groups had been working on their owner green building….

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Clarifying Energy Simulation Aided Design: A Look at ASHRAE Standard 209

Green Building

Clarifying Energy Simulation Aided Design: A Look at ASHRAE Standard 209

Originally published on September 5, 2018 by BNP Media through the Building Enclosure Blog. ANSI/ASHRAE Standard 209-2018, Energy Simulation Aided Design for Buildings Except Low-Rise Residential Buildings is the product of a half-decade of inertia within the building design and construction community toward leveraging energy modeling a design tool through a project. Standard 209 outlines the minimum requirements for providing energy design assistance using building energy simulation and analysis. To this end, the standard defines a range of minimum criteria from energy modeling requirements,….

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How to Make Building Energy Models More Accurate

Green Building

How to Make Building Energy Models More Accurate

Originally published on August 13, 2018 by BNP Media through the Building Enclosure Blog.   I’m asked regularly about the discrepancies between modeled and measured building performance. At first blush, one might suspect that the building energy model (BEM) itself contains bad information. That notion could very well be correct! BEM inputs require a certain level of synthesis, interpretation, and assumption. But there are many other reasons why the BEM results may vary significantly from measured performance outcomes on a completed project. In basic terms: Actual weather in….

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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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