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 stoping at any point.
At that time we where 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 on the freezer was a unsufficient lid gasket that never closed. The second thing was water driping under the freezer out of the insulation, what indicates that there is humidity kondensation in the insulation foam, degrading the ability of the foat to insulate at all.
So, I took the chissel, as there was no other way to get to the problem, and chopped the cover off to remouve the old foam insulation.
You can see how bad that worked in video Part one. In this blog I like to focus on the achivements we got by this hell of a work.
After remouving the evaporator, the stainless inner lining basin and the old foam isulation, I installed an outer humidity bock with ALUJET Floorjet Reflex. The membrane is used as a heat-reflecting, cold-seal self-adhesive sealing membrane aginst entering humidity that might kondense in the insulation. This has to be prepared very carefully as any tinest leak would counterfy the hole 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 vaccum insulation has time 4 to 5 the insulating capability that could be achived with foam. We choose these boards because of the given limited space in the ships pantry.
inside the vacuum baord insulation was another 6mm protective layer of foam installed and then the stainless basin inserted. I fixed it all with expansive foam, so that nothing moves when the ship is under sails.
The outer liner of floorjet 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 tubings back, I installaed a DS18b20 temperature sensor that replaces the old thermostat. The attatched 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 dregree 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 icecream 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
If you like to contact us, please feel free to comment or use the comment on YouTube
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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: