Fridge sink fitting coolers - views?

[gregcope]

Hi,

Considering replacing a leaking Sink drain skin fitting with a Skin fitting that also acts as a heat exchanger for a fridge compressor so that I can get better fridge power efficiency (and replace a leaking fitting!).

Like this one;

http://www.isotherm-parts.com/sp-cooled-c-4_10_60_65/

Any views on;

1. This approach?
2. This particular product?
3. Any other products or ideas?

Ta

 

[David2452]

It's a Webasto product so I've fitted a couple, it does mean one less hole so has to be a good thing. The air cooled ones seem to work well enough in the UK if in a well ventilated site though.

 

[Hadenough]

No answers sorry but we liveaboard and are planning along the a same lines. I didn't get round to it this winter but the slight increase in ambient outside temperature recently has already started to cycle our air cooled compressor noticeably more frequently and I am referring to overnight temperatures when we are not heating the boat. The water temperature on our mooring is currently 5 to 7 degs less than air temperature. I will be interested in feedback.

 

[KenMcCulloch]

What a very cunning design. We have an older water cooled Isotherm fridge with slightly complicated plumbing involving a second seacock to admit cooling water, a pump to circulate it, and a tee in the sink drain to discharge the cooling water. It's much more efficient than an air cooled fridge. Most of the locker under the sink is taken up with all the pipe work, the combined skin fitting and heat exchanger is a lot simpler. Go for it.

 

[Twister_Ken]

I have it. Works for me.

 

[charles_reed]

It's a Webasto product so I've fitted a couple, it does mean one less hole so has to be a good thing. The air cooled ones seem to work well enough in the UK if in a well ventilated site though.

When the water temperature reaches 28C it's totally inadequate. Air cooling OK up to 42C but definitely needs adequate ducting. I have a 140mm computer fan instead of the tiny one which came (and failed) with the unit and ducting up from the heat-exchanger unit to an exhaust grille.
In fact it's stocked by both Webasto and ASU Isotherm. As neither produce the main refrigeration components themselves I assume it's a 3rd party item.

 

[charles_reed]

No answers sorry but we liveaboard and are planning along the a same lines. I didn't get round to it this winter but the slight increase in ambient outside temperature recently has already started to cycle our air cooled compressor noticeably more frequently and I am referring to overnight temperatures when we are not heating the boat. The water temperature on our mooring is currently 5 to 7 degs less than air temperature. I will be interested in feedback.

I'd suggest you look first to your box-insulation, before looking at water-cooling and then @ optimising the passage of air from the heat-exchanger, both far cheaper and less labour intensive.

I've used my unit in the Med for the last 11 years and it never cycles more than once in 60', though @ 40C it's on for twice as long as it is @ 20C.

 

[owen-cox]

When the water temperature reaches 28C it's totally inadequate. Air cooling OK up to 42C but definitely needs adequate ducting. I have a 140mm computer fan instead of the tiny one which came (and failed) with the unit and ducting up from the heat-exchanger unit to an exhaust grille.
In fact it's stocked by both Webasto and ASU Isotherm. As neither produce the main refrigeration components themselves I assume it's a 3rd party item.

No It is manufactured by Isotherm.

 

[geem]

Hi,

Considering replacing a leaking Sink drain skin fitting with a Skin fitting that also acts as a heat exchanger for a fridge compressor so that I can get better fridge power efficiency (and replace a leaking fitting!).

Like this one;

http://www.isotherm I met a few pe...ooler option if I was going for water cooled.

 

[robmcg]

Good luck with just getting the sink cooler bit. No one would sell me just that bit, only as part of a full kit. Still air cooled as a result! :ambivalence:

 

[David2452]

Good luck with just getting the sink cooler bit. No one would sell me just that bit, only as part of a full kit. Still air cooled as a result! :ambivalence:

Do you still want one? if so PM me.

 

[Vanilla]

Hi,

Considering replacing a leaking Sink drain skin fitting with a Skin fitting that also acts as a heat exchanger for a fridge compressor so that I can get better fridge power efficiency (and replace a leaking fitting!).

Like this one;

http://www.isotherm-parts.com/sp-cooled-c-4_10_60_65/

Any views on;

1. This approach?
2. This particular product?
3. Any other products or ideas?

Ta

I have this one on my boat in the UK. Been very happy with it. An earlier poster talked about smell from it but this has not happened in my case. Would have one again if/when I change boat.

Vanilla

 

[BrianReynolds]

Hello
Yes but how much for a replacement?. I was quoted a ridiculous price for the hull fitting alone.


Brian

 

[MASH]

It wouldn't be hard for a reasonably skilled hobby metalworker to make a skin fitting like that.

 

[Spirit of Glenans]

My worry would be that it would be affected by galvanic corrosion, as normal through-hulls are. If you have to replace it every few years as a result of de-zincification the costs mount up.

 

[vyv_cox]

My worry would be that it would be affected by galvanic corrosion, as normal through-hulls are. If you have to replace it every few years as a result of de-zincification the costs mount up.

That was most definitely a problem with early production ones. There was quite a cocktail of metals in them. Seemed to improve with later ones but there has been mention of an anode in another thread, apparently very difficult to replace.

 

[BrianReynolds]

Hi Vyv
I ordered a replacement anode from the stand at the boat show £20. Might prove difficult to get the old one off tho. Brian

 

[Maninita]

When the water temperature reaches 28C it's totally inadequate. Air cooling OK up to 42C

I don't understand this comment. Why would water cooling ever be less efficient than air cooling? We have both an Isotherm SP fridge and a separate SP freezer here in Singapore where the water temperature is consistently between 28 and 29C. The fridge is on 24/7 and works well and reliably, even with the seacock closed. When on the dock, the air temperature inside the boat is normally between 35-38C during the day and I very much doubt that an air cooled refrigerant loop would continue to work as well day in day out in those conditions.

The Isotherm supplied SP hull fitting is DZR brass but as others have mentioned also has an anode. This is an extract from Isotherm's SP installation instructions. "Isotherm SP has a skin fitting in direct contact with the sea water and has as standard a zinc anode. The brass in the fitting is dezincification and salt water resistant as well as the Cu/Ni condenser pipes and the soldering silver." Our anodes have been replaced any without problems.

The main issue that concerns us is keeping the fitting and the internal refrigerant coil clean and free from marine growth.:ambivalence: