refrigeration

Suggestions on keeping the cook happy
terryk
Posts: 320
Joined: Wed Jan 10, 2007 10:37 pm
Location: Gosford

refrigeration

Post by terryk » Thu Sep 09, 2010 7:08 pm

Hi Paul,

If you are still bent on building your own check out this website

http://www.foamsales.com.au/shop/browse ... =6&next=21

Have a look at the Isoboard range, good prices and you can buy online.

Cheers

terryk

mahnamahna
Posts: 579
Joined: Wed Aug 02, 2006 4:48 pm
Location: Gosford NSW

refrigeration

Post by mahnamahna » Thu Sep 09, 2010 9:07 pm

This gets stranger by the day. I spoke to Australian Urathane and Styrene who make and sell both PUR and Isoboard (styrene) and they told me that by Australian standards, their best insulating board PUR has an R value of 1 (actually 0.96) per inch. And the articles I am reading from the US are suggesting you need an R value of between 20 and 30 depending on application (fridge or freezer) or location (top or bottom of top loading fridge) and the US products have an R value of 5 per inch. Surely this cannot be the same measuring criteria, surely their stuff isnt 5 times as effective per inch. If the measuring units are the same this guy is saying I would need about 500mm of wall thickness. Anyone know if they use the same measurements of R value in the US v AU? If they do not and the equivilent measure is about 5:1 then this stuff is quite reasonably priced and would work out at about $200 per 1200x2400x 100mm sheet so I would need about 5 sheets, and be at about the $1000 worth of foam I had always assumed it would cost. I cannot imagine there are people in Australia making fridges with 500mm walls. Not on 40ft boats!!!



Edit, no it seems we use the same R value scale because Multipanel claim a value of 6.3 per 30mm sheet so about the same as the US measure of 5 per inch. I guess its true, you pay for what you get and there are no cheap alternatives. If you want a wall thickness that you dont have to walk through, you have to pay $7000 for a 200 liter battery powered fridge. Madness.



I think I will be checking out Harvey Normal on the weekend for top load chest freezers that I will turn down real low and use as a fridge or side by side front load fridge and freezers.

Smooth Cruiser
Posts: 583
Joined: Thu May 11, 2006 1:51 am
Location: Brisbane

refrigeration

Post by Smooth Cruiser » Fri Sep 10, 2010 3:13 am

From what I have seen most people building their own fridges use stainless boxes surrounded by fairly cheap polystyrene, sealed and coated, Or they use a stainless box with an outer case and fill the void with expanding foam using a long applicator hose as a nozzle to fill from the bottom and avoid air voids. Most home made fridges I have seen would cost in the low hundreds of dollars not the high thousands. Most domestic fridges would be lucky to have more than 40mm of insulation.



I haven't built one myself though . . . .



Why not phone a custom fridge maker and ask what he would do for you and get a quote off him?

tuskie
Posts: 23
Joined: Sat Jun 05, 2010 3:38 am
Location: Brisbane

refrigeration

Post by tuskie » Fri Sep 10, 2010 3:14 am

Getting pretty technical guys!

I'm sure 500mm of quality insulation is better than 100mm, which is better than 25mm. Likewise, $7,000 will build a great frig/freezer. I'm sure that you're not that keen on a great frig!



I have built many iceboxes and a couple of snap freezers, all out of rigid polyurethane sheet foam (fromFGI) covered with polyester resin and chopped strand mat, bogged, faired and either sprayed with 2 pac or flowcoated. Snaps had 100mm foam and ice boxes, usually 30mm. Main reason that these were custom made was to make most efficient use of an unusual shaped space.

Suggestion:

If the space is regular ("square") perhaps a domestic frig and freezer, preferably with a stainless cabinet, with extra insulation added on sides and bottom. You could run it on 240v through an inverter as 44C is doing or there's nothing to stop you ripping out the 240v compressor and evap plate and putting a eutectic tank inside on the back wall. This would give a professional looking cabinet, high efficiency and cost much less than a custom job.



And you wouldn't be gruntin and swearing trying to get the bloody male mold out from inside your frig liner!

Syhlif32
Posts: 7
Joined: Sat Sep 13, 2008 4:07 pm
Location: Garopaba, Brazil

refrigeration

Post by Syhlif32 » Mon Sep 13, 2010 12:39 pm

I have made a few boxes over the years.

Always with expanding foam ether the 2-component which are the best or the spray one which is the easier to use.

Make the box in plywood or even better make a mold and make a smooth inside for easy cleaning.

Stainless is easy to clean but is also a good heat conductor.



Make sure the box is completely vapor proof, several coats of epoxy on the outside should take care of that.

If you build it in make sure you have access to 3 sides and the top.

There will be air pockets which you need to filled in or you lose efficiency.

Put a vapor barrier on the outside of the insulation or the insulation will get wet.

The box that worked best I made an exact copy of the space it was later placed in. Filled with 2 component foam and filled the air pocket with a spray in foam.

Found that 5-6 inches in the bottom, 4-5 inches on the sides and 2-3 inches on the top worked well in the tropics for a refrigerator with a small freezer compartment.



On the catamaran we had I bought a new Isoterm front loaded unit.

They do use a little more power even with extra insulation on the sides an bottom, but my wife liked in better felt that fruits and vegetables lasted longer than in the top loading units that I made on our mono hulls.



The 2-component need to be mixed in small quantities as is goes of rapidly, lots of fun to watch, except if it pushes up you box and you have to cut it out and start again



Bjarne

44c
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Location: Hervey Bay, Qld

refrigeration

Post by 44c » Mon Sep 13, 2010 5:14 pm

Smooth Cruiser wrote:From what I have seen most people building their own fridges use stainless boxes surrounded by fairly cheap polystyrene, sealed and coated, Or they use a stainless box with an outer case and fill the void with expanding foam using a long applicator hose as a nozzle to fill from the bottom and avoid air voids. Most home made fridges I have seen would cost in the low hundreds of dollars not the high thousands. Most domestic fridges would be lucky to have more than 40mm of insulation.

I haven't built one myself though . . . .

Why not phone a custom fridge maker and ask what he would do for you and get a quote off him?


The BOX mght not cost much, but the refrigeration gear does. Even a basic compressor-condenser-evaporator set up will cost around $1200.



If you go for a eutectic system it will cost more.



And then, being "marine" it won't be reliable, but because it cost so much up front, you won't just replace it when it breaks down, you'll have to get it repaired by a marine refrigeration mechanic (ie an EXPENSIVE refrigeration mechanic).



Household type fridges won't be as efficient, but they usually run with zero problems for decades. And they are cheap, so if it does eventually fail, you just chuck it and buy another. And for very little money, you get a nice looking, well finished fridge, with door storage, veggie drawers, wine racks, stainless steel door, interior light...... or you can pay much more, and have something home-made.....



Inverters are getting cheap, and instead of investing a lot of money in a "marine" (= expensive and unreliable) fridge, I invested it in more solar panels, which usually are good for 20 years or so.

mahnamahna
Posts: 579
Joined: Wed Aug 02, 2006 4:48 pm
Location: Gosford NSW

refrigeration

Post by mahnamahna » Thu Sep 16, 2010 7:26 am

44c wrote: The BOX mght not cost much, but the refrigeration gear does. Even a basic compressor-condenser-evaporator set up will cost around $1200.

If you go for a eutectic system it will cost more.

And then, being "marine" it won't be reliable, but because it cost so much up front, you won't just replace it when it breaks down, you'll have to get it repaired by a marine refrigeration mechanic (ie an EXPENSIVE refrigeration mechanic).

Household type fridges won't be as efficient, but they usually run with zero problems for decades. And they are cheap, so if it does eventually fail, you just chuck it and buy another. And for very little money, you get a nice looking, well finished fridge, with door storage, veggie drawers, wine racks, stainless steel door, interior light...... or you can pay much more, and have something home-made.....

Inverters are getting cheap, and instead of investing a lot of money in a "marine" (= expensive and unreliable) fridge, I invested it in more solar panels, which usually are good for 20 years or so.


If I had a dollar for every time I have changed my mind on this issue, I could buy a top line fridge and not blink.



My issue with household fridges is 2 fold.



First I have galley up, so I dont have the height for a full height domestic house fridge. My only option for under bench height is bar fridge and bar freezer side by side pidgeon pair. And this has 2 inherent problems first is that bar fridges are nowhere near as efficient as household fridges because they are designed to keep bottles of drink cold, not a variety of foodstuffs. And they are not particularly spacious, but as a chest box of 400mm x 600mm deep is my alternative I can hardly complain about that, and of course the other issue is I want a freezer big enough to hold more than a couple of ice block trays so will need the pidgeon pair freezer which means running 2 inefficient units to get the utility I need in an under bench form factor.



So assuming I allow for buying a pair, each is about $400 so I am up for $800 for the units. Then I need a massive inverter to cope with start up loadings, and of course a deeper battery bank and solar/wind/genset to keep up with the load consumed by 2 separate units.



Second is that whilst I agree that household fridges do offer years of robust service, that is in a home, not on a moving boat in a high salt environment. Not sure given all the issues in the previous paragraph pertinent to my requirements, that I am terribly confident that a household unit will cut it.



And of course I have already all but ruled out paying close to $7000 to build my own eutectic system or $5500 for a condensor plate system.



No I am going to have to bite the bullet and buy this little beauty.







http://www.isotherm.com/en/index.html?fixframe=1&



Isotherm cruise 200 (150 liter fridge, 50 liter freezer under bench unit). It comes in s/s front but Jo is not a fan of s/s appliances, thinks they are very hard to keep clean and fingerprints are the main culprit so we will go for the plain front version. Its a bit cheaper than the s/s anyway. I have a friend that will buy me one on his account so at trade they are about $2800. But it ticks all my boxes. So I have my fridge. A bit more expensive than domestic units, and way cheaper than making my own even if it wont quite be as efficient, but it is a beautiful unit, purpose made and fulfills our needs. My only concern is the spillage of energy that front loaders are but this is by far the best option given my galley up restrictions.

tuskie
Posts: 23
Joined: Sat Jun 05, 2010 3:38 am
Location: Brisbane

refrigeration

Post by tuskie » Fri Sep 17, 2010 5:05 am

Hi Paul,

That's a nice fridge, a reasonable price and a good compromise. I can't see any reason why efficiency can't be improved by adding extra insulation around and below these standard fridges.

Is the freezer large enough? If not, for longer legs you could use something like an Engel fridge: reasonable efficient and totally unkillable. When not needed it can be turned off and easily stored.



I picked you for a "must make-it man" (don't take that as an insult) so the idea of buying a ready made took me by surprise. If that's the way you want to go, did you consider the drawer type compressor fridges and freezers? I know some serious offroad caravaners who swear by their Vitrifrigo fridges, but don't know anyone with one in their boat.



These are modular (can have 2 freezers and 1 fridge for example) and won't spill all the cold out when opened.



VITRIFRIGO STAINLESS STEEL DRAWER REFRIGERATOR



Width: 607mm

Height: 830mm

Depth: 542mm

Weight: 55kg

Power: 12/24v

Capacity: 165 litres





Vitrifrigo DW180 Internal Compressor

165 Litre Compressor Cooled RV Refrigerators. (DW180) $2,899.00



Cheers Mark

PS. I personally have had some disappointing experiences with Waeco fridges, so wouldn't recommend them.

mahnamahna
Posts: 579
Joined: Wed Aug 02, 2006 4:48 pm
Location: Gosford NSW

refrigeration

Post by mahnamahna » Fri Sep 17, 2010 6:28 am

tuskie wrote:Hi Paul,
That's a nice fridge, a reasonable price and a good compromise. I can't see any reason why efficiency can't be improved by adding extra insulation around and below these standard fridges.
Is the freezer large enough? If not, for longer legs you could use something like an Engel fridge: reasonable efficient and totally unkillable. When not needed it can be turned off and easily stored.

I picked you for a "must make-it man" (don't take that as an insult) so the idea of buying a ready made took me by surprise. If that's the way you want to go, did you consider the drawer type compressor fridges and freezers? I know some serious offroad caravaners who swear by their Vitrifrigo fridges, but don't know anyone with one in their boat.

These are modular (can have 2 freezers and 1 fridge for example) and won't spill all the cold out when opened.

VITRIFRIGO STAINLESS STEEL DRAWER REFRIGERATOR

Width: 607mm
Height: 830mm
Depth: 542mm
Weight: 55kg
Power: 12/24v
Capacity: 165 litres


Vitrifrigo DW180 Internal Compressor
165 Litre Compressor Cooled RV Refrigerators. (DW180) $2,899.00

Cheers Mark
PS. I personally have had some disappointing experiences with Waeco fridges, so wouldn't recommend them.


Mark, I only insist on making things if it is cheaper than not. I have a saying, time I have money I dont. However, if making it is no cheaper or as seems the case here more expensive (even if more efficient in use) then I have no issue paying for off the shelf units.



The Vitrifrgo looks nice and about the same price as the unit I am looking at, except the unit I am looking at is 200 liter compared to 165 for the unit above. So far this is still my favorite. The freezer is deceptively large. It is after all 50 liters, but it is tall deep but narrow. Jo asked if it would be big enough to freeze a fish such as a mahi mahi, and I reckon it would be. It about 550mm deep front to back, about 220mm wide (and about 800mm high). Our home freezer is 70 litre and rarely if ever full. Its wide enough to get a tub of icecream in and high enough that you get a number of shelves. And deep enough that you could put a pretty big fish (If I catch fish bigger than 500mm with their heads off I will cut it in half and be about as happy as a bloke could be). And the fridge is larger than I was going to have in the one I was building. 150 litres is plenty of fridge.



I agree with your idea of insulating a box that the fridge would go in in order to increase its efficiency and will probably do that. And I do like your idea of an engel or other portable freezer as an extra for when people are on board etc. Good idea.



Cheers, Paul

Jim
Posts: 691
Joined: Fri May 19, 2006 8:25 am
Location: Cairns

refrigeration

Post by Jim » Fri Sep 17, 2010 5:08 pm

I think there is too much being made about how much the upright fridges spill cold air. Understand the fridge is usually quite full which reduces the amount of cold air space inside, so when the door is opened not all of that air will come out and if you don't have kids onboard (a good way to stuff up a good boat trip) then the amount of time the door is open will be reduced. The food inside does not instantly heat up, so it is just the air space we are talking about. Like I said earlier in this section the advantages of an upright far outweigh the disadvantages in my opinion. If you want to watch a power loss then watch the amp gauge when someone is having a shower or when lifting the anchor, nothing compared to a fridge.

I compensated with bigger solar panels, 2 x 250w (should have got three) where most boats you see around have 2 or 3 x 80w and because of their size they put in some charge even when overcast.

Jim.

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