Skip to main content

refrigeration cycle

Efficiency by Baby Steps and Giant Bounds

By Energy Rant 2 Comments
This post features concepts everyone can use to identify terrific savings opportunities, even if you did not take beloved calculus and thermodynamics. Let’s review a general hierarchy of typical energy efficiency families: 1. Shut it off 2. Slow it down, set it back (temperature, etc.) 3. Reduce waste 4. Retrofit or replace with efficient equipment Those are all wonderful and probably capture over 98% of portfolio savings. Even newer programs like behavioral, retro-commissioning, and strategic energy management merely pursue these items. What’s left? Smart design. I.e., 5. Don’t be stupid Or for the glass half full message, it would be...
Read More

Is Energy Recovery Always Good? No.

By Energy Rant No Comments
Last week we introduced exergy and at least one application of it in a building. First, let me make something very clear, for the refrigeration cycle, if I’m cooling beer or freezing leftovers, the heat that is sucked out of those masses is rejected somewhere else. For refrigerators and freezers, it is rejected to the room in which they exist. For air conditioning, most commercial refrigeration, and all industrial refrigeration, it is rejected outside – unless, it is captured for useful heating. Commercial HVAC For commercial HVAC, if CONsultants don’t think holistically about the entire heating and cooling needs, and...
Read More

Duct Leakage; The Results Are In

By Energy Efficiency, Energy Rant 5 Comments
About two years ago, I wrote Duct Leakage Chaff, which explained that residential duct leakage is a mole hill, a red herring, a boogeyman.  I recently reviewed a report[1] that nails my assertions from June 2013. The program evaluation (residential HVAC tune-up) was thorough, likely expensive, but worthwhile.  Too often, not just in evaluation, but any professional service industry, contracts go to the low-ball bidder.  The low-ball bidder either uses the tactic because it’s the only weapon they have, they don’t understand the challenge of doing a decent job (ignorance), or providing actionable value simply isn’t that important to them....
Read More