#efficiency

Tech Tips:

Ain’t No Fooling With Free Cooling (Tales of the Economizer)

This article was written by Gary McCreadie from “HVAC know it all.” You can learn more about Gary and his tips and growing community on Facebook and LinkedIn. What is an economizer? Simply put, it is a mechanical device designed to reduce energy consumption, whether it be fuel, electricity, or other. According to Wikipedia, the first […]

Cleaning Condenser Coils Still Matters

There was a story that came out recently based on an ASHRAE study performed by David Yuill from the University of Nebraska. The study appeared to indicate that condenser coil cleanliness makes no difference on system performance and efficiency. Those of us who have worked in the field know that coil cleaning matters because most […]

Q&A – How to Learn Superheat & Subcooling – Short #191

In this short podcast episode, Bryan answers an audience member's question and explains how to learn superheat & subcooling, two fundamental aspects of the HVAC/R trade. You can submit questions of your own at https://www.speakpipe.com/hvacschool. Saturation is when a substance is in the liquid and vapor state in the same place. Eugene Silberstein likes to […]

How to Save Energy with Grocery Store Refrigeration

This podcast episode focuses on practical ways to save energy with grocery store refrigeration systems, with Matthew Taylor from Kalos Services sharing insights from both a technician and business owner perspective. The hosts emphasize that proper, consistent operation and preventing short cycling of compressors can have a major impact as the largest power consumers. […]

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In this short Q&A podcast, Bryan answers a listener-submitted question about apps for doing proper loads. Fred specifically asks about apps or charts that can help an HVAC contractor determine the insulation value of a home without assuming numbers or drilling into walls during load calculations.

Load calculations account for all the ways that BTUs can enter or leave a home: conduction, convection, and radiation. Insulation prevents heat transfer via conduction, so it’s important to the load calculation process. High-end HVAC design software like Wrightsoft and Kwik Model 3D will have these features built into them (based on the age and location of the home). ASHRAE’s handbook also has tables and data with R-values and U-factors to help you out with Manual J load calculations.

RED Calc is an app that allows you to calculate a wall’s R-value with measurements, including surface and air temperatures indoors and outdoors. This RED Calc software is available through the U.S. Department of Energy, as is REScheck. The DOE insulation fact sheet is also quite valuable, as are The Engineering Toolbox and materials straight from the insulation manufacturers.

The best way to get a comprehensive load calculation is to have a lot of tribal knowledge about how houses are built in your area, analyze energy bills, and combine tools like RED Calc with building performance tests.

RED Calc is available through the U.S. DOE at https://basc.pnnl.gov/redcalc. REScheck is available at https://www.energycodes.gov/rescheck.

ASHRAE’s resources are available at https://ashrae.org/technical-resources.

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