The Energy Spot

By Riisipuuro (Own work) [CC-BY-SA-3.0 (www.creativecommons.org/licenses/by-sa/3.0) or GFDL (www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons

Sometimes its necessary to find the heat loss or heat loss savings from insulating/re-insulating a wall. Here is a method for calculating the loss.

Above is what would be considered a common stud wall. I didn’t include dimensions for stud spacing to keep it general. Commonly they would be 24in or 36in on-center (O.C.). I also didn’t include stud height. You could assume commonly 96in to 120in (8-10ft). For the most part, height and width are rough numbers because it seems this calculation is done after the fact.

Continue reading “Finding Energy Loss Through A Wall (Heat Flow)” »

By NOAA (http://www.hpc.ncep.noaa.gov/noaa/noaa.gif) [Public domain], via Wikimedia Commons

If you need to quickly weatherize data (account for weather changes in billing) you can do it simply by creating a scatter plot. After the scatter plot is created you just need to add a trendline. The equation the trendline gives you a way to compare your data year-over-year, taking into account weather changes.

x= Cooling Degree Days per Month

y= Monthly Consumption (kWh)

Note: This is not a multi-variate regression, so it does not take into account other important data like number of billing days per month.
Continue reading “How to Quickly Weatherize Billing Data” »

By By Aaron Logan (from http://www.lightmatter.net/gallery/albums.php) [CC-BY-1.0 (www.creativecommons.org/licenses/by/1.0)], via Wikimedia Commons
Deemed energy savings figures must always be taken with a bit of skepticism. This is because these figures were reached with making certain assumptions. Sometimes these assumptions are reasonable, sometime they’re not. Before using any deemed figure you should read the whitepaper’s list of assumptions and calculations to verify you agree with how the figures were reached.

Below is a list of locations where you can find deemed energy savings figures. Click the name to follow the link.

Southern California Edison (SCE) Whitepapers on Deemed Energy Savings

Continue reading “Where to Find Deemed Energy Savings” »

By Mark Ahsmann (Own work) [GFDL (www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0-2.5-2.0-1.0 (www.creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

What is it? What does it do? How does it affect me?

California Assembly Bill (AB) 1103 was approved on October 12, 2007 and requires two important things.

The first is it requires Gas and Electric utilities to record 12-months worth of usage data for every one of their non-residential customer buildings in a format compatible with EPA’s Energy Star Portfolio Manager.

Continue reading “Assembly Bill 1103” »

Here is an Excel spreadsheet that shows the savings associated with a solar system at different rates and different escalations. This is not a detailed pro forma, but gives a quick idea whether the terms of a solar power purchase agreement (PPA) are viable.

Solar & Utility Rate Comparison

By NASA Langley Research Center (NASA-LaRC) (nix.ksc.nasa.gov)[see page for license], via Wikimedia Commons

Sometimes its necessary to find the amount of energy entering or leaving a space. For this the mass flow equations come in handy. Here are the general and common equations for calculating the BTUs per Hour entering a space.

General Eq.: 

Continue reading “Air Heat Flow” »