12V Compressor Refrigerators

[GeorgeRad]

I assume you have capillary electromechanical thermostat which can be replaced with an electronic one. I replaced my ancient capillary thermostat with Isotemp Smart Thermostat and like it a lot. No more clicking, compressor runs at different speeds as necessary and it is more efficient. Isotherm Smart controller is designed for DC controller which you have. I have AC/DC and had to do slight wiring modification, for your Danfoss 101N0212 controller it is plug and play change. https://www.indelwebastomarine.com/int/products/cooling-technology/isotherm-smart-energy-control/

I am not sure if I would add a rear fan for vertical condenser, you could consider “making” a chimney to enhance convection cooling.

If you plan to add/change a fan I used these - https://www.amazon.com/Noiseblocker...rpm/dp/B00WV6ZUHO?ref_=bl_dp_s_web_7597168011 PWM fans are also available.

 

[booster]

I assume you have capillary electromechanical thermostat which can be replaced with an electronic one. I replaced my ancient capillary thermostat with Isotemp Smart Thermostat and like it a lot. No more clicking, compressor runs at different speeds as necessary and it is more efficient. Isotherm Smart controller is designed for DC controller which you have. I have AC/DC and had to do slight wiring modification, for your Danfoss 101N0212 controller it is plug and play change. https://www.indelwebastomarine.com/int/products/cooling-technology/isotherm-smart-energy-control/

I am not sure if I would add a rear fan for vertical condenser, you could consider “making” a chimney to enhance convection cooling.

If you plan to add/change a fan I used these - https://www.amazon.com/Noiseblocker...rpm/dp/B00WV6ZUHO?ref_=bl_dp_s_web_7597168011 PWM fans are also available.

I think if he uses a chimney, whichwill mostly just prevent hot air looping, the added fan would be either at the air entrance or exit of the chimney in the end of the duct to help move the air. Compressor frigs don't exhaust much heat, so convection chimney only will be weak flow.

 

[GeorgeRad]

I think if he uses a chimney, whichwill mostly just prevent hot air looping, the added fan would be either at the air entrance or exit of the chimney in the end of the duct to help move the air. Compressor frigs don't exhaust much heat, so convection chimney only will be weak flow.

My condenser is wrap around the compressor with PC fan moving cooling air across both. I never had problem with my fridge but it is mounted in the aluminum framed galley with no back panel allowing full ventilation. I agree that chimney with a pulling or pushing fan controlled by exit temperature sensor would work well.

 

[eric1514]

The fridge will be going in a Travato that now has an absorption fridge so I have the upper and lower vents in the side of the van that I am going to utilize. They are large enough according to NovaKool's specs to provide adequate air. I plan to create a chimney from the bottom vent to the top vent using rigid foam insulation and seal that area off completely from the inside of the coach.

With Novacool's permission I will either move their fan or add a fan on the same terminals that runs the current fan. That fan runs only when the compressor is on. I've sent them an email. If they nix that, I'll add another fan controlled by a thermostat and not the control module. As was mentioned, I don't expect much air flow through the chimney so I want to force air flow in the bottom vent, across the coils and out the top. The problem, as I mentioned is how to trigger that fan.

I don't see a temp adjustment on the board that Avanti mentioned and I wouldn't know what temp to set it at anyway. The preset thermostat that RowieBowie uses looks like it would work, but it's measuring air temp and not coil temp. I guess that's OK.

 

[eric1514]

Well the installation is 99% complete. I just have to tidy up some wiring and make sure no connections vibrate loose. I took a lot of ideas from the Facebook Travato Group so hat's off to them for pioneering this.

The Novacool R3100 is quite a bit smaller than the Dometic that Winnebago installs and nowhere near as nicely built but so far it seems to hold temperature better and it seems it will hold enough food for the two of us. I mounted it up high in the space the old fridge was in and that leaves a large area underneath for a portable freezer/fridge like an Engel or an Indel-B (Truckfridge) if I find that the Novakool is too small. I would relegate that small chest fridge for drinks and that would leave plenty of room in the Novakool for food and that food wouldn't freeze like it did in my old absorption unit. Right now that space is a large area (23"x18"x16") with a shelf on very heavy duty locking drawer slides that we will use for water (my wife won't drink from the onboard tank) and other stuff. There's 110v+ and 12v on the back wall of that space.

I used the exterior vents that were cut into the van for the Dometic absorption fridge. The vents are far apart and work really well as a chimney. The old refrigerator had no problem cooling, infact it worked too well. If I set it at 36 during the day, it was in the teens overnight. Winnebago put a false wall about 2 inches in from the actual van skin running up and down between the upper and lower vents. It seems to contain insulation. I glued an additional 1 inch of rigid foam with a foil face to the entire length of that wall. I built a shelf to hold the fridge and below that is the large cubby. The back of the cubby and the back of the fridge reduce the area of the chiminy between the vents to about 3 inches by 17 inches which is more than the 30 square inches that Novakool specs. The condensor coils are one side of that chimney and in addtion to the fan that Novakool installs to cool the compressor, I installed another fan that blows directly at the condensor coils in a upward direction. Both these fans run only when the compressor is on. I have one more fan that is installed near the top vent that is controlled by a thermostat down in the chimney set to come on at 90 degrees. I have a switch inside that controls that fan in either manual, auto (thermostat) or off mode. I put a 270ohm resistor inline on one of the thermostat leads to speed the compressor up a notch. It's been really hot here and that helps the fridge keep up in full sun. I have another 690ohm resistor on a lead ready to swap out should I need a little more speed. I'll automate all that later if necessary, but it's $130 I don't want to spend right now.

The Novacool has no on-off switch so I had to install one and the thermostat they supply is silly for a $1000 fridge. I bought a digital one with probe made by Dwyer/Love for $70 bucks. Now instead of turning a dial between 1 and 7, I can set the temp I want to the exact degree and the probe reads the fridge's air temp not the wall temp so it responses quickly and temperature fluctuations are minimal. It doubles as a thermometer. It's also wired to the on/off switch, so you throw the switch on and the thermostat starts and so does the refrigerator.