Thursday, May 24, 2018

Phenolic Foam Insulation Revisited

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Can we put to bed the corrosion concerns with this insulation?
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A particularly well thought-out and thorough question from longtime GBAGreenBuildingAdvisor.com reader Aaron Birkland on the pH of phenolic foam and its possible corrosive nature prompted me to follow up my original blog on Kingspan’s Kooltherm rigid insulation.

Aaron has two main questions:

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from Building Science http://www.greenbuildingadvisor.com/blogs/dept/building-science/phenolic-foam-insulation-revisited

Wednesday, May 23, 2018

How to Read Manual J Reports

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If you know what to look for, it’s easy to check for accuracy
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When you enter the world of building science — whether through building a house, becoming a home energy rater/building analyst, or just hanging out in cyberplaces like this — everyone talks about the importance of getting actual heating and cooling load calculations based on ACCA Manual J. A great number of HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building. contractors sell and install oversized equipment with air distribution systems that don't work because these contractors base their choices on rules of thumb.

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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/how-read-manual-j-reports

Wednesday, May 9, 2018

Proper Sizing Isn’t the Real Reason for HVAC Design

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Yes, size matters, but another factor matters more
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Many people seem to think HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building. design means you get a load calculation (Manual J in the ACCA protocols) so you know what size system to put in. Hey, that's a great start. It's way better than just using a rule of thumb or Manual E (for eyeball).

But there's so much more to real HVAC design than simply finding out how much heating and cooling a building needs when it's at design conditions. And we might as well start with the fact that my first statement is incorrect: The load calculation does not tell you what size system you need.

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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/proper-sizing-isn-t-real-reason-hvac-design

Thursday, April 26, 2018

Understanding and Measuring Mean Radiant Temperature

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Mean radiant temperature, a major component of thermal comfort, is easy to measure
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All the way back in 1993, one of my first research projects at the NAHBNational Association of Home Builders, which awards a Model Green Home Certification. Research Center was assessing the performance of radiant ceiling panels for the Department of Energy’s Advanced Housing Technology Program. (The final report was titled “An Evaluation of Thermal Comfort and Energy Consumption for the Enerjoy Radiant Panel Heating System.”)

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from Building Science http://www.greenbuildingadvisor.com/blogs/dept/building-science/understanding-and-measuring-mean-radiant-temperature

Wednesday, April 25, 2018

Sweaty Southern Slabs

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Here’s why wet concrete and stone in winter are common along the coast
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If you live anywhere in a warm, humid coastal area, you're no doubt familiar with wet concrete in winter. Some days you walk outside and find the carport slab is soaking wet. How did it happen? Did rain blow into the carport? If it's not rain, is it moisture from the ground that came up through the concrete? Could it be condensation from the water vapor in the air? Let's take a look.

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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/sweaty-southern-slabs

Wednesday, April 11, 2018

HVAC Design Requirements in the International Building Codes

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A look at what the codes actually require for load calculations and duct design
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Building codes, especially those related to energy efficiency, have improved a lot over the years. With building enclosures, this has made a big difference. We now have more insulation, less thermal bridgingHeat flow that occurs across more conductive components in an otherwise well-insulated material, resulting in disproportionately significant heat loss. For example, steel studs in an insulated wall dramatically reduce the overall energy performance of the wall, because of thermal bridging through the steel. , and tested air barriers. On the mechanical side, the improvements are significant — reduced duct leakage and mechanical ventilation in airtight homes — but there's still a gap between some code requirements and what's being installed.

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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/hvac-design-requirements-international-building-codes

Wednesday, March 28, 2018

Converting Heating and Cooling Loads to Air Flow Needs

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Here’s how Manual J software takes your inputs and gives you both the BTU/hour and cfm needed for each room
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When you embark on the project of educating yourself about building science, one of the first things you encounter is the concept of heating and cooling loads. Every building has them. (Yes, even Passive House projects.) That's why we do heating and cooling load calculations. We enter all the details of the building, set the design conditions, and get the heating and cooling loads for each room in the building.

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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/converting-heating-and-cooling-loads-air-flow-needs