Insitu fridge requires insulation - what material to use

I once insulated a fridge with polystyrene. When it was later removed, it was as heavy as a plank of wood, having absorbed moisture from the air.
 
A further thought. It seems you can get closed cell polystyrene beads so that reduces effect of water absorbtion. Rather than trying to blow it into the surrounding space from below. If I could manage to get some access to to the hull side of the fridge box by opening the base of the locker at worktop level then perhaps I could pour the stuff in by mixing it in solution with a PVA (like unibond) to make it congeal and restrain it from dissipating into other parts of the hull. (Nigel this is in a Bav 47)
 
superboots said:
If I could manage to get some access to to the hull side of the fridge box by opening the base of the locker at worktop level then perhaps I could pour the stuff in by mixing it in solution with a PVA (like unibond) to make it congeal and restrain it from dissipating into other parts of the hull. (Nigel this is in a Bav 47)
Click to expand...

You mean the two lockers above the fridge? I assumed these were blanked off from the worktop.

Perhaps a small hole and a snake camera (endoscope) would be an idea. This one has LEDs, but if turned off and coupled with a good torch it could be used to check for gaps. Handy for all sorts of things, I bought mine to check the gas pipe run before replacing it.

http://www.amazon.co.uk/exec/obidos/ASIN/B00APCCCFO/dolcetto-21

I'm going to order a couple of bags of beads, and distribute them into my luggage on the next trip in January. A bonus of adding some protection against the baggage gorillas. Just re-read the details on the page in my #18, it seems the delivery charge is per bag (I'm checking), so eBay may be a better bet although the beads are more uniform. They have confirmed it is closed cell, suitable for cavity walls.
 
Last edited:
Even if the worktop extends to the hull - which I doubt - it should be possible to open the base of the locker and take a look at the structure below. I can't pursue this job for a while and don't have a scope but if you do please post the results. I could use quite a few bags as I also have a wall to insulate! I'm also in Kent - but on the other side (ME9)Maybe the stuff could be collected from the supplier?
 
superboots said:
I don't think the compressor is faulty, its all been checked. The fridge box is quite large - about 80 cu ltrs and the fridge is much colder at the end with the element than the other end next to the hull. I have been running it on shore power so not a battery roblem either. Interesting to know from other Bav owners how their fridge works
Click to expand...

I used to have a 38 Ocean and had no real problem with the fridge temperature, but a big problem with the compressor duty cycle. To keep the fridge cool in the summer the compressor would run between 30% and 50% of the time. However, it did produce lots of ice around the evaporator that required defrosting every few days.

There is no doubt the insulation is poor. However, I believe your initial problem is refrigeration, as has been suggested above. How was the compressor "checked"?
 
It depends entirely on your budget.

1) Drill holes throughout the structure of the fridge then have a professional inject the two part polystyrene into the void.


Or

Decide if you can loose internal volume from the fridge compartment as I believe you have mentioned its quite large.
Buy sufficient king span/celotex sheets to clad in internal surfaces of the compartment. Either permanently of temporarily fix them in place.
I personally would fix them temporarily so that the cooling unit could be tested to investigate if its Infact the unit at fault.

The thicker the sheet the better the insulation obviously, but it would be easier, quicker, less invasive a work process and
a solution, the only down side is the loss of internal volume.


Or a combination of both void filling and cladding.
 
robertj said:
Buy sufficient king span/celotex sheets to clad in internal surfaces of the compartment. Either permanently of temporarily fix them in place.
I personally would fix them temporarily so that the cooling unit could be tested to investigate if its Infact the unit at fault.

The thicker the sheet the better the insulation obviously, but it would be easier, quicker, less invasive a work process and
a solution, the only down side is the loss of internal volume.
Click to expand...
I've considered that approach as in some ways it seems simpler than the external insulation - the problem I see with it is how you surface and seal the Celotex once installed
 
The fridge engineer repaired the unit (it was not working) by replaceing the electronic regulator and enlarging the fan on the evaporator (its a Waceo unit) and then checked performance after 24 hours - that was in October. No gauges to see if its fully gassed but close to the evaporator it is quite cold but this rapidly diminishes further away from the evaporator
 
As others have said polystyrene absorbs moisture and loses its insulation value.

Long lasting and perhaps easily forgotten about is cork.

Loose granules have a useful life measured in decades and are safe and simple to use. Thick rigid sheet is also available of course.
 
nigelmercier said:
Not according to the sellers I have spoken to.
Click to expand...
Personal decades long experience in refrigeration says otherwise. The post above mentioning polystyrene becoming as heavy as wood tallies with my own experience.

Rockwool, even when inside a polythene bag has also ended up wet and frozen.

I've not had a problem with cork however.

water-absorption-table.jpg


The graph compares expanded and extruded polystyrene foam performance. The above is for insulation in use for home insulation. Refrigerators are subject to condensation which raises the incidence of moisture absorption. The water absorption figures in the graph are readily exceeded in refrigeration conditions, resulting in greater loss of insulation value.

http://www.polyfoaminc.com/downloads/brochure/Foam-Control-EPS-Water-Absorption-Facts.pdf Further reading on one of the foam manufacturer's websites, extolling the virtues of their offering.
 
Last edited:
Update. I've drilled a 50mm hole in the bottom of the fridge cabinet. I went as close as I could to the edge, but the fridge unit is still in the way of using a wide rigid blow-tube. No matter, I have plenty of old hose I can use.

Using a snake camera to probe the depths was hopeless, but I did look around inside within a few inches of the hole. It seems that the lower shelf has been foamed around the edges, then the fridge unit dropped in place. Hopefully this means no leakage, at least around the base.
 
Our Bav44 fridge has stopped freezing and I suspect loss of gas. The compressor runs continuously and some cold air comes out of the evaporator but not enough to cool anything. The gas was replaced about 5 years ago and the fridge mechanic thought this was pretty normal for the Bav units. A couple of weekends ago I had a crowd on the boat and needed cooling so invested in 2 bags of ice. There was still some ice in the fridge 3 days later which changed my mind about the effectiveness of the standard insulation. Inside daytime temps over the weekend would have been mid to high 30s. We will get the fridge regassed (assuming that is the problem) when the boat is next hauled out for antifoul. One thing the mechanic did was to vacumn all the dust and fluff off the condensor. I was surprised at how much he got .
 
I've had an idea, not sure if it will work, so I will experiment.

Get a batch of beads in a bag that is too big, give them a shake to build up the static, then sprinkle on some Cascamite powdered glue: quantity to be determined. Shake the bag again to distribute evenly.

Now blow beads into the chamber, and allow atmospheric moisture make the glue go off, or inject a small amount of steam into the cavity if necessary.

Has anyone else researched prices of EPS beads, in particular those with a moisture proof guarantee?
 
Last edited:
nigelmercier said:
I've had an idea, not sure if it will work, so I will experiment.

Get a batch of beads in a bag that is too big, give them a shake to build up the static, then sprinkle on some Cascamite powdered glue: quantity to be determined. Shake the bag again to distribute evenly.

Now blow beads into the chamber, and allow atmospheric moisture make the glue go off, or inject a small amount of steam into the cavity if necessary.
Click to expand...
Sounds like an interesting idea - my concern over using the beads is that I don't think the cavity around the cold box is well sealed at the top - I would like some way of keeping at least the top layer of beads in place.
 
Have you thought of filling up the void ( between fridge and hull) with polysterene pellets? to supplement the existing insulation? Foam could be hydroscopic and difficult to remove once there. Pellets can be sucked out with a vacuum cleaner if you don't get the desired results.
 
You must log in or register to reply here.

Share this page

Top