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Nova Kool 12-24 VDC/110 VAC Fridge
#1
I’m going to look at a used “off grid” fridge tomorrow. Anyone have experience with these:
http://www.novakool.com/products/two_doo...0_9000.htm
 It’s only $200 so I can’t afford not to check it out. 
 The Nova kool website says the 9.1 sq ft model is designed to vent out the front. That’s nice as vans and buses don’t have fridge vents in the side like RVs. RV fridges vent out the back up and out a roof vent usually. 
 The website says it also has a Danfoss compressor. 
  I had to chuckle at the “$1000 for a cold beer” thread. A new one is not an option for me. These models are more like $1600. It came off a boat which makes me think it might have been switched off most of the time. Unless it was a liveaboard.  The seller plugged it in to 110 for me and texted me a picture of the thermometer a few hours later. It was down to 32 degrees F on as 50 degree day. 
 The Nova Kool website also says placing 2” of foam insulation on the sides will halve the energy usage and reduce run time. 
 Thanks
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  • American Nomad Patriot (03-17-2019)
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#2
Good Luck! 

TJB
                           My Heart Is Good............But Oh This Mouth
                              I'M NOT HERE   Cool   YOU DIDN'T SEE ME
                                            I AIN'T DONE ......YET
                                                           TJB
                              
                                 
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#3
Novakool use s a large passive fanless condenser. Where most danfoss fridges use a smaller condenser with attached fan.

Either way condenser ventilation is very important. And danfoss controllers allows for .5 amps of fans to be switched on with compressor. Exhausting the heat can drastically improve efficiency.
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  • rvpopeye (03-03-2019), American Nomad Patriot (03-17-2019)
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#4
Thanks, SW and TJB. 
 It looked good so I bought the fridge today. I’ll check if it has a danfoss controller. A auxiliary fan on the condenser makes a lot of sense. So a 6 watts (0.5 amps at 12 volts) fan is the magic power number to look for if it has the danfoss controller. Are you saying a passive condenser has no controller at all ?. I’m assuming the controller is mainly for the compressor but can also turn on a fan. Thanks
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  • American Nomad Patriot (03-17-2019)
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#5
I managed to look under this 9.1 cubic foot Nova Kool fridge and it has a fan and danfoss controller. It’s designed to blow the heat out from under it and into the space. That would be good in boats and vans generally. Even a little heat and circulation helps reduce mildew growth. 
 I had a Nova Kool half this size years ago and it did not have a fan.
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  • Texjbird (03-04-2019), American Nomad Patriot (03-17-2019)
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#6
All danfoss have a rectangular controller and it can power upto 0.5 amps of fans.

I used noctua nf-f12 pushing air through condenser for less noise and better performance than fan the fridge came with.

Later switxhed to noctua a12x15 which is even quieter mounted to push air through.

With with 10awg.

Is yours compressor a bd35f oe bd50?
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  • Roadtripp (03-15-2019)
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#7
(03-04-2019, 08:33 AM)sternwake Wrote: All danfoss have a rectangular controller and it can power upto 0.5 amps of fans.

I used noctua nf-f12 pushing air through condenser for less noise and better performance than fan the fridge came with.

Later switxhed to  noctua a12x15 which is even quieter mounted to push air through.

With with 10awg.

Is yours compressor  a bd35f  oe bd50?
Sorry, I was gone for a while. The Danfoss compressor is a bd35f. It has a rectangular controller.  It says it runs from 110 volts, or 12-24 volts. Thanks
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#8
Does the controller have a finned heatsink on its backside? Eary models of this compressor did not and they had premature heat related failure issues which were solved by the addition of this heatsink

Replacement compressor controllers are about 300$, so it is worthwhile to insure they are not getting too hot, and they are basically bathed in compressor and condenser heat. Exhausting the heat from this cooling system area is very beneficial not only to effieicncy of the unit, but the compressor and controller lifespans as well.

Since the controller can power 0.5 amps of fans, and 120mm fans such as the Noctua NF-f12 draw only 0.05 amps and are very efficient at pushing air through a restriction, such as a condenser, there is a lot which can be done to insure good efficiency, low fan noise and long compressor and controller life.

Also keep in mind the fans which come with most compressor fridges are cheapo sleeve bearing fans that have poor CFM and static pressure ratings, and make a lot of noise and consume more amperage than needed to do the job.

The fan which came with my Vitrifrigo consumed 0.12 amps and was rated about 72 cfm. it was mounted to pull air thrugh the condenser and was pretty loud. When I moved the Noctua Fan to the other sideof the condenser so it was pushing air through it, not only could I no longer hear the fan, but each time the compressor cycled on thereafter, instead of it running for 5 minutes and 30 seconds or so, it was down to 4 minutes 50 seconds. So the Noctua NF-f12 0.05 amp fan pushing air was much more effective at removing conenser heat, and did so for 60% less energy consumption of the fan, and reduced duty cycle too.

Do not overlook the importance of compressor fridge cooling unit ventilation. Huge gains to be had here with a well ventilated unit compared to one stuffed on a cabinet with a few passive vents, and which is allowed to recycle preheated air through the condenser over and over. The danfoss's abilty to power upto 0.5 amps of fans makes it simply to upgrade and add fans switched on and off with the compressor to exhaust this heat, and the minor load of any additional fan is more than made up with shorter duty cycle.
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  • rvpopeye (03-16-2019)
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