Upgrading our onboard refrigeration

This project came up when we realized that the main energy draw from our service batteries was used to keep the beer cold.

We noticed that the freezer refrigeration compressor was working 24 hours a day without stopping at any point.

At that time we were in Europes south, with cold water of about 16 to 18 degrees Celsius around us. By that the cabin temperatures, with the freezer inside the cabin, never got so hot like they are in the tropics.

The first bad things we saw in the freezer was an insufficient lid gasket that never closed. The second thing was water dripping under the freezer out of the insulation, what indicates that there is humidity, condensation in the insulation foam, degrading the ability of the foot to insulate at all.

So, I took the chisel, as there was no other way to get to the problem, and chopped the cover off to remove the old foam insulation.

You can see how bad that worked in video Part one. In this blog,like to focus on the achievements we got by this hell of a work.

After removing the evaporator, the stainless inner lining basin and the old foam insulation, I installed an outer humidity bock with ALUJET Floorjet Reflex. The membrane is used as a heat-reflecting, cold-seal self-adhesive sealing membrane against entering humidity that might condense in the insulation. This has to be prepared verycarefully as any tiniest leak would counterfeit the whole work.

In this outer liner was a layer of polyurethane foam boards placed to align the case for the main insulation, the vacuum insulation boards. These vacuum insulation has time 4 to 5 the insulating capability that could be achieved with foam. We choose these boards because of the given limited space in the ship’s pantry.
Inside the vacuum board insulation was another 6mm protective layer of foam installed and then the stainless basin inserted. I fixed it all with expanded foam, so that nothing moves when the ship is under sails.
The outer liner of forget was then closed to the upper rim of the stainless insert, using butyl rubber sealing tape. We installed also inside the freezer lid the same style of insulation. The lid got a new magnetic freezer gasket. On the opposite side, at the rim of the stainless insert was a magnetic stainless metal stripe installed. With this setup the lid is forced by the integrated magnet to seal perfectly.
When I set the evaporator and compressor tubes back, I installed a DS18b20 temperature sensor that replaces the old thermostat. The attached new controller loggs the main data of the installed freezer and fridge.

Now, after using this freezer in the tropics, we are very satisfied with its performance. We cool it down to –19 degree Celsius and get cabin temperatures around +30 degrees Celsius. That results in a temperature difference of about 50 degrees!
We logged operating times of 58% ON and 42% OFF, and that in the tropics. Remember before, the freezer was 100% ON all day long when not in the tropics and the ice cream was still melting.

Some technical data for the nerds:

• operating temperature freezer: – 19 C
• operating time per day 58% in tropical conditions, long time data log
• compressor watercooled, maximum temperature at 28 degree C watertemperature 33 C
• vacuum board thickness 40 mm
• Freezer, Freezer compressor, Fridge, Fridge compressor and Raw-water-intake temeprature controlled
• controller with CANbus and NMEA2000

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We published two videos about this topic on YouTube, this bog is part 2.

The first Video is under this link: