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New-Gen Brushless Inverter Refrigerator Compressors - Mike Mas

Hey Guys - For the past 3-4 years, I’ve been keeping my eye some new refrigerator technology which is finally in production. This technology called “Adaptive Energy Optimization” or AEO, is the first major change to take place with refrigerators in decades.

What this means for Us - Instead of using a conventional single speed compressor to pump refrigerant to cool the interior of the refrigerator, this new generation of “Digital Inverter” compressors instead incorporates a variable speed brushless electric motor allowing the compressors motor to run at seven different speeds for both improved performance as well as amperage economy. This is big news for the RV market since nearly every coach is now equipped with residential refrigerators instead of he more costly 3-way refrigerator which has the ability to run on propane, 12 volt DC or 120 AC.

This inverter technology was developed by - A company called Haier a large refrigeration corporation which was first released in Europe. Soon after, Samsung purchased this technology and rights to offer a new line of digital refrigerators to their customers. Aside from being very efficient and quiet, these new R600a refrigerant pumps draw less than half the current of conventional compressor making them very very suitable for RV’s, since they are powered using, flooded, AGM or lithium batteries, where conventional refrigerators would deplete even a large bank of AGM batteries in a day or so.

Our 2018 Newmar New Aire shown below - Has the similar size Whirlpool french door refrigerator requiring 6 amps when running, quite a contrast to the Samsung using half the current with the same features and space. I also included the spec plate from the refrigerator.







In Contrast - I included a image below of our new Renegade’s galley equipped with the new Samsung Digital Inverter refrigerator. This large French Door refrigerator only draws 2.79 amps at full load virtually extending our run time to 200% of a conventional refrigerator. I also included the an image of the refrigerator and spec plate showing full load at 3 amps.










How it Works - Powering the compressor motor is an special inverter technology. Aside from offering a new efficient mechanical design, the compressor is able to run at seven different speeds, allowing it to run slower requiring less amperage and more frequent avoiding high current starts. The average Digital inverter compressor consumes 46% less power than a conventional compressor. The image below shows my amperage obtained while the refrigerator is running.



If drawing less than 3 amps wasn’t enough, it only gets better since as the refrigerator approaches set temperature, the compressor begins slowing down to only 20% of its speed, allowing the system much more efficient with current as low as only 1 amp.

Traditional Refrigerator Compressors - Operate using a basic “on and off” technology. They turn on to get cold, then shut down once the temp is reached. This method of turning on and off is not efficient since it requires high surge current on each start cycle, plus the food temperature can vary 3-4 degrees between cycles.
Using digital Inverter technology, the compressor slows its speed prior to reaching the set food temperature, which shortens the off-cycle time allowing the food to remain within only 1 degree of set temperature.

Quick Cooling - Our Samsung Digital also incorporates a “Quick Cool” feature which is selectable on the front panel which actually doubles the compressors speed (200%) allowing the refrigerator to cool its contents down in only a few hours. This feature is handy when your getting ready for a trip and turn on the box, since it cools it down twice as fast as a conventional refrigerator.

Perfect for All-Electric RV’s - Since our new Renegade like many other coaches is “All Electric” using a diesel fired hot water and heating system, there’s is no longer a propane tank, preventing the use of a 3-Way fridge for owners like myself who which to extend our “off-the grid“ time. Having a refrigerator like the the Samsung Digital is definitely a step in the right direction for preserving our house batteries.

Other Positives - Topping the list of digital refrigerators is the compressors are almost dead quiet. There’s an absence a the traditional “Plunk” sound as the compressor starts or stops. Another plus is these inverter units use a slow “soft start” protocol, so there’s an absence of high amperage when starting the compressor. therefore, the compressor restarts at a slow speed, then increases speed slowly until it reaches the processors demand.

Victron Inverter - I’ll be helping a friend install a small size Haier digital 7.5 cu ft refrigerator in his Winnebago van in the next month or so. Since larger inverters waste more current to operate, I chose a small Victron Energy 375 watt inverter to run his digital refrigerator. This inverter is very affordable at only $120. It’s compact size allows mounting in tight locations. This inverter will be powered with a bank bank of AGM’s and two solar panels therefore it will easily power the fridge with some reserve. I’ll snap a few images and short story during the project. Keep in mind digital inverter refrigerators come in many sizes so your not limited in size making it very suitable to smaller size Class B and B+ RV’s.



Residential Refrigerator Interior Heat - Regretfully, unlike our “3 Way refrigerators” which vent their heat outside the coach through large vents, all residential refrigerators to include the Digital models from Samsung and Haier still vent their condenser heat into the interior of the coach.




Perfect Timing for Lithium - This new efficient digital Inverter technology is a welcome solution for those who demand a compressor type refrigerator, or for the owner who has an “All Electric” RV where there is no option for a propane 3 way refrigerator. With limited roof space for panels on B / B+ vans for solar, these low current digital compressors makes it possible to power even a large 3 door refrigerator yet still have enough power to charge your batteries for running your refrigerator at night.
Most important, the timely release of these digital inverter units provides a workable solution for manufactures to run refrigeration from either AGM or lithium batteries.



Digital Inverter Compressors for AC use - These same digital inverter compressors are now available in split air condition systems for home and office. Hopefully, companies such as Dometic will soon adapt this technology. These same inverter compressors are now being used extensively for split unit air conditioners, cutting electric bills to less than half. Just the other day, I sat down with few engineer friends at Martin Marietta in Atlanta. When we crunched some efficiency numbers using high SEER numbers of digital inverter air conditioning compressors, we concluded a 1500 btu air conditioning roof unit would only draw 6.7 amps. The beauty of inverter compressor for AC units is the pump could run almost continually at only 20% speed, keeping the coach within 1 degree of its set temperature. Once the AC unit begins to reach temperature the entire AC unit would draw only around 2 amps.



Improved roof Air Conditioners - Presently the older Dometic AC units like the one in my Leisure B+ rated at 15K btu, draws a massive 18-20 amps. However to show the way roof AC units have improved, our two Dometic Mach 10 heat pump AC units in our Renegade, are very efficient and quiet and only draws 10-12 amps, in fact, during a test last week, I was able to run both of my Mach 10’s air conditioners in our Renegade on a single 3012 Freedom inverter, how’s that for efficiency!

Stay Safe - Mike Mas
rvvolt.com

On a side Note - I’ll be installing a “state of the art” Lithium system in cooperation with Renegade which I’ll document in a an in-depth story and video - Regards!