400: Improving Insulation on Fridge & Freezer

[b_rodwell]

I have 2 fridges and a freezer. Not surprisingly I have a high energy demand to keep them going. The experts tell me that it is a good idea to upgrade the insulation on these units and this has a significant impact on the amount of energy required.

What different ways are there to do this on a Lagoon 400. I am particularly interested in hearing of ways that are not a complete rebuild of the boxes.

Thanks

Brian

[SV THIRD DAY]

Hi Brian
To wrap your head around the concept, a good rule of thumb is that if you double the Rvalue of your box insulation, you can cut your daily power usage in Half. So insulation is indeed a big deal.

The majority of us don't want to tackle a box reinsulation job, so we take the best "easy way" that can still make a big difference, which is adding ridgid foam insulation panels to the inside walls of your box. A good choice goes by the trade name of RMax and is sold at Home Depot in 4ftx8ft sheets in varrying thicknesses for about $20. Cut the panels to fit tightly in your box and seal the cut edges with foil tape. You can leave it raw for a quick "how much does it help test" and then cover it with a FRP or plastic wall board also from Home Depot for cheap.

Some like Blue Board, but the Rmax (polyisocyanurate) has a 1/3 better Rvalue, so it wins in my book.

Not only does this approach increase the Rvalue of your box, but is shrinks the box volume, so your refrigeration system wins on two fronts!

Oh the other good way to deal with refrigeration systems sucking your power down is to just add on more solar! I know that can sound like a smart ass answer, but solve the power problem by just making more!!

[tuskie]

Yep, Brian, I've also got 3 Vitrifrigo units that consume Amps at a rapacious rate. I'm a bit sorry that I didn't bite the bullet straight after i purchased my boat (used) and consign them to a much more apt function as artifical reefs. Fine examples of Italian engineering! Replacing the "friggios" with a properly insulated fiberglass cabinet and a water cooled eutectic system would have paid dividends over time.

The insulation is inadequate in thickness and quality. Condensation forms on the outside because of thermal leak but also seems to waterlog the foam itself, particularly in the door. This would further reduce efficiency.

I looked at glueing extra foam to the base and sides, but didn't think that the units could then fit back in to the recesses. I was also concerned that the metal cabinet would rust due to trapped water.

What i did achieve was to improve ventilation around the compressors and condensers. The heat build up in this space is considerable when they are running hard, which is most of time in our climate. The heat can be felt on the outside seat back through the padding. I replaced the plastic vents near the saloon door with larger models and attached 12 volt computer fans to exhaust through these vents. Another fan was added behind the slots in the wood cabinet side to blow in air. The fans were supposed to be able to be run off the compressor wiring but this caused overload issues, so instead of installing relays, etc. I just activate manually via a concealed toggle switch when required. This keeps the temperature around the fridge and freezer much lower and also dries condensation.

The other thing to do is adjust the doors to be sure the seals are not leaky. This is a fiddly job. Use a sheet of paper and make sure that it doesn't easiy slide at any part of the opening. You may need to bend the door if it is out of shape.

Good luck and cold beer.

[woodenboats]

Look for aerogel and stuff alike.

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