Winter Test on DQ Freezer Gives Solid Results

Good Place to Stop for a Treat

 
     About half way between where the skeptical brothers live and where I live is tiny Nelson, Missouri.  As such, the Fast N Friendly fuel and ice cream shop is a perfect place to stop for whatever I need, and I do every time.  All that ice cream takes a lot of freezer power and all that freezer power takes a lot of electrical power.  

    The owner knows this and has used IceCOLD before.  So he wanted some for this store and also wanted to try out AireServ's new Onset data loggers.  They spent a crazy amount of money for this rig, but it sure is nice.  

     I was thrilled because it's another shot at a winter freezer test where evaporator capacity improvement and compressor power improvement can be "parsed out" of the data. That turns me on but the owner is all about saving money.  Kevin only ran the logger for a week with the catalysts installed, but the system was already showing results.  The owner got what he wanted, I got what I wanted and Kevin got a Blizzard to go.  

Better than Expected Results

   This is the total power for the entire system.  A reading of 20 represents 2.0 kW.  The first thing you see is that the condensing unit actually cycles off after IceCOLD installed.  The reading of 7 is just the freezer's interior fans.  Prior to the injection of the catalysts, the compressor rarely stopped. The reasons turned out to be two-fold.  The IceCOLD did improve capacity as expected.  The second and less obvious reason is the scrubbing of oil fouling from the inside of the tubing.  A side benefit is that the particulates sticking to that goo are removed as well.  From the data we can see that the liquid solenoid valve was also leaking a small amount of refrigerant, causing the compressor to occasionally kick on and back off, wasting energy and shortening the compressor's life.

   The chart below shows the second reason, the increased cooling power developed by the system because of the catalysts.  We're seeing the results at the most expensive part of the system cycle, the cooling down after a system defrost.

 Initially, we saw a 30% capacity improvement that resulted in a 7 minute reduction in the "cool-down" period.  So, what about power consumption?  Beginning at the very first moment, power was cut for the "entire system" by 12% even though the outdoor temperature went up.  By day seven, power went down even further as the outdoor temperature rose even further.  I believe his savings this summer will further improve on this record.