Slate Fridge

[Zebra]

I gave away my fridge on freecycle, as it was noisy and I didn't like it. Now I don't have one.
Until now, the house has really been quite cold and damp, but now it's warm and dry, and the milk is starting to go off.
Once, in a rather eco-build log cabin which I had the privilege to work on, I saw a fridge which consisted simply of a wooden box lined with slate. I would like to try to make one, and am wondering if anyone knows anything about them, whether it is a historical practice, whether slate would be the best material or another type of stone, and how thick the slate ought to be.

 

[Penners]

I don't think a simple slate box is going to offer you much "chilling" benefit. Yes, it will act as a heat sink, and so will delay the warming up of the contents when the weather turns warm, but the opposite will also be true - once warm the slate will take longer to cool down than the surrounding air.

The only type of cost-free, non-fridge container that will offer a slight benefit, in my opinion, is one of those old-fashioned meat safes. They consist of the metal cabinet with a depression pressed into the top panel. You fill this depression with water which then evaporates, causing a modest heat-exchange effect within the cabinet.

Alternatively, make yourself a thickly lined hay box and keep putting in bags of ice, purchased from your local supermarket.

 

[Zebra]

I see, yes.
I've just had a look at fridge alternatives on wikipedia, and it mentions an Australian idea involving evaporation from a hessian cloth, as well as the traditional "iceboxes" that we used to have here.
Anything involving evaporation has the drawback in my case, though, of introducing more moisture into the house, which might not be the best idea. And having to purchase ice daily just transfers the carbon-impact somewhere else, and leads to other types of waste.
A hay box sounds good. I fear however that the temptation to simply eat it might be too great.

 

[Delta]

Could you vent outside, perhaps creating a chimney effect to improve airflow, and increase evaporation. Of course this would probably work best when it is cold outside and warm(ish) in, the times when you probably don't want a draught!

Use a cellar space?

The latent heat from vaporisation is the only thing I can think of to provide real cooling effect.

 

[worms]

Simplest solution is to take your coffee black...

Old dairies used to have slate or marble slabs, zinc mesh windows and a north-facing aspect. I guess in summer it might still have been a bit hit and miss getting the milk to cool from cow temperature quickly enough.

I used to have a meat-safe that sat outside the back door, painted white to reflect sunlight, with slatted sides and zinc mesh screen. No provision for evaporative heat loss, though. But meat doesn't go off as quickly as milk and once it develops a crust it lasts quite well!

As far as I am aware, the normal rule of thumb is that chilled milk should last ten days, but that you should deduct a day for every hour that it remains at room temperature.

 

[Zebra]

There's no cellar unfortunately. The bathroom floor is uninsulated though, and colder than the rest of the house. Perhaps I should keep the milk under the bath.
Oh! Or.... hang on, this could be workable! I'm planning to split the bathroom in half, and have half of it as a sort of utility room. The walls are single skin four and a half inch brick, the floor is uninsulated concrete, and it's the north facing side which will be the utility room. What if I left part of the walls uninsulated, and built a sort of cold larder? I could make a temporary one now, before I commit to doing it for real.
Or dig a hole in the ground outside?...... and have a little winch to take the stuff up and down.... a milk well!
No, I'm getting carried away now.

 

[worms]

Zebra, you are the resident electrical guru, so - peltier unit; heat exchanger from an old laptop; old cool box. Sorted!

 

[livias]

Back in times of yore when I was a student we didn't have a fridge. We had a large bowl of water and put milk and stuff on an upturned dish to keep it from getting wet. Then we draped a muslin cloth over, with its ends in the water. It worked fine, even in summer

I don't think we cared or even thought about evaporation, but could you not put a similar thing outside, but inside a pest-secure box

 

[Penners]

I'm planning to split the bathroom in half, and have half of it as a sort of utility room. The walls are single skin four and a half inch brick, the floor is uninsulated concrete, and it's the north facing side which will be the utility room. What if I left part of the walls uninsulated, and built a sort of cold larder? I could make a temporary one now, before I commit to doing it for real.
Or dig a hole in the ground outside?

Both of those ideas are based on the heat-sink concept, but I reckon they could be more effective than the slate box because they use a much larger heat sink - the concrete floor and the ground.

You need to be aware, however, that neither of them will be anything like as effective as a fridge.

For your milk needs, it might be best to bulk-buy UHT milk in the smallest sized container possible. The milk will keep a long time unopened, and with small containers you'll use them up quickly once you've opened them.

Lecture alert: the refrigerator is perhaps one of the most important contributors in the world to human health and food security. Its electricity consumption is small and its benefits are enormous. Why would you voluntarily deprive yourself of this important device?

 

[davidbrac]

years ago l was without a fridge for a while and used the stream by the side of the house to keep my milk cool

 

[Penners]

That's a good solution, but I don't know how many tumbling streams there are in Snorbans!

 

[plasticpigeon]

I think it is possible to make something that cools down something inside it a bit, but it will need to make use of evaporation. I think something like a porous clay pot with water inside it where the water can evaporate from the surface might cool things a bit. I can't see why a slate lined wooden box would cool anything.

http://en.wikipedia.org/wiki/Pot-in-pot_refrigerator

 

[Penners]

There is some evidence that evaporative cooling was used as early as the Old Kingdom of Egypt, around 2500 B.C. Frescos show slaves fanning water jars, which would increase air flow around the porous jars and aid evaporation, cooling the contents

So there you go, Zebra, there's your answer: porous water jars and a slave or two.

 

[88v8]

In our previous house I fitted a stone shelf in one of the cupboards. It was always cold and helped to cool anything sat on it. A supplement rather than a substitute for a fridge, though.

The old fridge we inherited here was noisy and rusty. We bought a Liebherr. Much quieter.
One can also get olde-looking fridges, not cheap though.

You want a silent fridge?
http://www.ebay.co.uk/itm/Electrolux-Gas-Only-Fridge-/121346727667?pt=UK_Campervan_Caravan_Accessories&hash=item1c40d41ef3
Less decrepit versions may be available.

Ivor

 

[Penners]

a stone shelf in one of the cupboards

I'm afraid the same principle applies as Zebra's earlier suggestion of a slate box. As the weather warms up, the stone shelf will stay cooler than the air for a while, but it will achieve equilibrium in due course. Then, when the weather cools down, the stone shelf will stay warm longer than the air.

 

[philpjuk100]

Back in times of yore when I was a student we didn't have a fridge. We had a large bowl of water and put milk and stuff on an upturned dish

students!, milk!!, we used to keep our beer cold in the bath!.

 

[Zebra]

Thank you all for your tips! Penners I suppose, if all ese fails, then a new, efficient fridge and solar panels out of sight on the flat roof is an option.
In any case I can report that my temporary cold larder (three layers of bricks in a U shape against the cold bathroom wall with a piece of ply on top) has kept the milk a little cooler than room temperature. It's not bad for now.
Worms I'm afraid I'm only your common-or-garden house-bashing/commercial spark, not someone who tinkers with bits of electronics, but I will look into it!

 

[Flyfisher]

if you don't fancy worms' suggestion of making a peltier module coolbox from the basic parts then you could look for such things in caravan and camping shops. We used to have a small one that was powered from a 12v car lighter socket until FF junior borrowed it for uni.

Incidentally, peltier modules are fun devices and can also be used to make those 'thermal fans' that work from the heat of a woodstove. Basically, if you put a temperature difference across them then generate a small voltage but if you put a voltage across them they generate a temperature difference, which can be used for cooling things. They cost about £4 each on ebay, so not very expensive to experiment with.

 

[CliffordPope]

There used to be clay pots designed for standing over a milk bottle in a saucer of water. (Old milk bottles with the wider necks and wax card tops, not the more recent narrower version with tinfoil).

I think it was standard practice to drape damp cloths over perishables.

Or of course you had an ice-house in the grounds, and your servant brought up ice daily for keeping the dairy cool or making icecream. A large icehouse filled in winter with crushed ice from your lake would supply ice all year.

 

[Penners]

What with fanning the clay pots and carrying in the ice, your servants are going to busy, Zebra.