Whiteworm cooler

[Ptarmigan]

In the Grindal worm thread Ronnie Lee said >
"If I had the same low temp from where you are, I'll probably attempt whiteworms too"
and also said >
"Just share the information and experience with those around you... "

Absolutly agreed :-)
I wish my problems were the same as yours, my old bones dont like the damp-cold English winters, :-( one of the happiest times of my life was when I lived in Brazil where the temperature varied from hot to very hot.
But I digress, sorry.
Anyway, my information for you is the evaporation cooler, have you met this device before?
In the days long ago, before fridges, my Grandmother used to tell me :-) , food would be kept cool in the summer months by placing the food container inside a larger box and the whole thing would be placed in a shallow tray filled with water. A cloth or other absorbent material would then be placed over the box and dangle down into the water.
I think you can probably guess the rest ! :-- As the water evaporates from the cloth the latent heat of evaporation is carried away and the box with its food inside all cools down.
I believe BoyScouts and GirlGuides do similar when on camp.
But it only works well if the general humidity is not too high, I wonder if Singapore is both hot & humid ?

I wonder if that might help ?
Malcolm.

[RonWill]

I wish my problems were the same as yours, my old bones dont like the damp-cold English winters, :-( one of the happiest times of my life was when I lived in Brazil where the temperature varied from hot to very hot. But I digress, sorry.

Ok Malcolm, thank you for that insight but I think another word for 'damp-cold' would be 'frigid'! My bones aren't that old but they still creak occasionally!

But back on topic :wink: ...

I did a Google search and the hits returned pointed to 2 main items;
A evaporative cooler that looks like a portable air-conditioner, but using basically a powered fan, water and filter material. How it works...

The other was a cooler for CPUs in a computer... and I don't think that's what we're looking for.

FWIW, as far as I can remember, we had a refrigerator in the home and it's a little vague (hard actually) to imagine life without one. About 34 odd years back, we have relatives living in kampongs* in the rural, undeveloped areas of then infant Singapore, and they kept leftovers in a wooden cupboard with fine mesh at the door. That's to allow ventilation and keep the flies out but not keep cool!

As the water evaporates from the cloth the latent heat of evaporation is carried away and the box with its food inside all cools down.

Questions;

Is there water inside the box as well?

I presume that this box had no lid but draped over by a cloth? How thick or thin is this cloth supposed to be? How about an old cotton-T?

If it did work, considering that all natural elements are favorable, how many degrees do you think it'll lower from ambient surroundings?

I believe BoyScouts and GirlGuides do similar when on camp.

I was neither but do camp out, and there's wasn't anything we brought that needed 'chilling'.

But it only works well if the general humidity is not too high, I wonder if Singapore is both hot & humid ?

According to this site;
TEMPERATURE:
Diurnal** range: Minimum 23 to 26 deg C and Maximum 31 to 34 deg C
Extremes: Minimum of 19.4 deg C and Maximum of 35.8 deg C

RELATIVE HUMIDITY:
Diurnal range in the high 90's in the early morning to around 60 % in the mid-afternoon.
Mean value is 84%
During prolonged heavy rain, relative humidity often reaches 100 %.
So is humidity too high?

Let see if time allows me to rig up a prototype, shoot some pics and check the inside temp against the ambient. It sounds like a fairly simple contraption, so... d*mn if I can restore a turntable but not diy a cooler!

If I can drop the temp to between 24~25º Celcius (75~77º Fahrenheit), I'll holler for some whiteworm starter. If not, I'd better go look for that used dorm fridge.

*Kampong is a Malay word for small village. Yes, we used to have these...

**Diurnal = Relating to or occurring in a 24-hour period; daily.

[Ptarmigan]

I did a Google search and the hits returned pointed to 2 main items;
A evaporative cooler that looks like a portable air-conditioner, but using basically a powered fan, water and filter material.

Oh, that is a bit "high tech" ! I didnt know that they came with fans as well !!

Questions;
Is there water inside the box as well?

No, not needed. The water is only there to keep the cloth wet.

I presume that this box had no lid

The outer box is only there as a means of support for the cloth. (It does not have to be a box, it could be just an open framework.) It can have a lid, if it has no lid then the cloth might sink into it, otherwise you could place struts across the top to support the cloth. And the inner box is only there to keep the food ( worm culture !) dry, because underneath (inside) the cloth the air will be 100% humidity.
Let me try a different description or idea or form :-
Imagine you go camping and erect your cloth tent in the middle of a shallow * pond ( yea, I know, pretty stupid huh !? but stay with me :-) )
Then you put your sun-lounger style camp bed inside the tent and crawl in on top. The camp bed keeps you out of the water. the tent cloth soaks up water and as it does so it evaporates and a gentle breeze outside carries the water vapour and its heat away. So you and the air inside the tent become cold. Now think small tent and whiteworm box inside.
(* edit later, I should have said - a shallow small pond - else if it was a wide pond it would conduct warmth from outside back into the tent !
A circular, anular trough would work very well even )

but draped over by a cloth? How thick or thin is this cloth supposed to be? How about an old cotton-T?

Yes, draped over and surrounded by the cloth. I dont think the thickness matters much, as long as it can soak up and evaporate the water. Is that what I would call a T-shirt ? Yes that would do, or perhaps an old towel.

how many degrees do you think it'll lower from ambient surroundings?

At a temperature of about 30C for example, and a humidity of 60% I think you could expect about a 6C drop, down to 22C inside the box/tent. Does that sound good ?
If the humidity was higher, in the morning 90%, the drop is much less. Only about 1.5C at 30Cambient. but your morning is cooler anyway so,,,
at 22Cambient and 90% the drop would be about 1C so inside the box would be 21C.

RELATIVE HUMIDITY:
Diurnal range in the high 90's in the early morning to around 60 % in the mid-afternoon.
Mean value is 84%
During prolonged heavy rain, relative humidity often reaches 100 %.
So is humidity too high?

Hmmm, it is a bit too high in the morning and mean. However that 60% is quite good in the afternoon (see above)
I am not sure if it will all be worth it ??? a bit marginal perhaps, worth a try though ???

by the way, you could look up metological, meteorl, oh botherrrr, weather sites ! and search on "wet and dry bulb thermometers", "dew point" "relative humidity" etc to get an idea of what is going on and see some charts for working out the temperature drop.
And with two thermometers, one with a dangly bit of cloth (wick) round its bulb and the bottom end of the cloth in a pot of water, you could set up a simple experiment.

Malcolm.

[Ptarmigan]

some charts for working out the temperature drop

Here is a nice chart http://www.uswcl.ars.ag.gov/exper/rhtable.htm
Down the left side is Tdb (temp. of dry bulb) which is your ambient temperature.
In the chart body are the %humidity values.
And across the top are the temperature drops below ambient which would be expected inside the cooled chamber.
Hope that helps,
Malcolm.

[RonWill]

Let me try a different description or idea or form :-
Imagine you go camping and erect your cloth tent in the middle of a shallow small pond... <snip>

I get a pretty clear picture now but danged if that contraption will actually work!

At a temperature of about 30C for example, and a humidity of 60% I think you could expect about a 6C drop, down to 22C inside the box/tent. Does that sound good ?

Oh YES it does Malcolm and I'd be quite happy if it touches 24ºC... at least I have a chance at the whiteworms, even though the survival and reproductive rate may only be marginal.

And with two thermometers, one with a dangly bit of cloth (wick) round its bulb and the bottom end of the cloth in a pot of water, you could set up a simple experiment.

That should be easy replicate and thanks for the idea. However, in this case, the wick is touching the bulb, while the draping-cloth doesn't touch the culture box. I'd suspect the difference to be substantial... then what?

As for the linked chart, I'm not a number-cruncher and cannot relate to it. Mostly a hands-on person, I'll just go ahead with the experiment and hope for favorable results which might just encourage me to buy some starters.

[Ptarmigan]

I get a pretty clear picture now but danged if that contraption will actually work!

hehee ! We will all be as surprised as you if it does :-)
I can imagine that if it does then 100's of Grandmother's Coolers will be being constructed all round Singapore and by other hot Killi keepers elswhere !

I'll just go ahead with the experiment

That is the bottom line of course and the only bit that matters !

I could go on about charts, and touching bulbs ( the cloth touches the air inside and the air touches the whiteworm box, so they are still connected thermally) and all sorts, but I wont go on about it all, and I'll shut up for a bit till we get the good news from you

good luck,
Malcolm.

[RonWill]

Malcolm, if you're still with us...

I've rigged up 'ol granny's cooler and had it running for some weeks now. With 2 cheap thermometers that gave about the same ambient readings, I shoved one inside the cooler and had constantly gotten an average of 2ºC lower (or 26ºC against 28ºC ambient)... not all that impressive but it was better than nothing and doesn't require any DC current!

'Ol granny's cooler is rigged up from used polyfoam box, a drink serving-tray and old coat hangers, bent and reshaped into a teepee/tent-like contraption. Pieces of hangers were secured with masking tape for some frame rigidity and the 'teepee' cover was an old holey army towel (knew the d*mn thing would come in handy someday).

Evaporation, as we all might have expected, was quite high and required topping up every alternate days. Was doing fine in my study room until I brought it outside and the recent strong winds toppled over the light contraption. Still, I suspect better results can be achieved if the cooler was place somewhere with good air circulation.

Am in the midst of doing that page, aptly titled "Malcolm's Grandmother's Cooler"... hey, credit where credit is due Just gimme more time to retake some pics and trust me to think up some corny commentaries.

If and when we see 100's of these coolers sprouting around our little island, rest assured that you'd be the first to be blamed!

[Ptarmigan]

Hi Ron, yes I'm still here, lurking (*) and reading with interest. Thanks for the update on your cooler experiments, hmmm, as you rightly say, 2deg is not very impressive, quite disappointing in fact :-(
I had intended doing some experiments myself(**) soon when the weather warms up, it is supposed to be spring here but today it turned back to winter and began snowing again, grrr ! So I'll be relying on you to be chief experimenter for a little while yet I think !! It is warmer in my fish-room of course but the humidity is too high and it would not be a fair test.
I think you are right to expect better results in a place with good air circulation and it will be interesting to see your pictures and webpage
I trust that you were being somewhat disrespectful to your old holey army towel and that its holeyness wasnt so great as to allow the air/wind to blow right through it from the outside to the inside, hahaa !

rest assured that you'd be the first to be blamed!

Eeek,,, Malcolm dons javamoss headdress and tries to hide disguised behind piece of bogwood :-)

(*) just lurking because I dont have anything to offer by way of killi interest yet. I'm currently engaged in a battle with the dreaded whitespot in my two big tanks of tetras and angels. Fortunately my small tank of cardinals is OK at the moment.
(**) in the interests of science ! because I dont actually need a cooler, however if you could come up with an idea for a warmer that does not need an energy input I would like to hear about it !!
PS. We can not blame Grandmother - she went to the big fish house in the sky a long time ago

Best wishes,
Malcolm.

[RonWill]

So I'll be relying on you to be chief experimenter for a little while yet I think !!

When that lights up, let me know what else I can try.

I was wondering about something... if the contraption relies on evaporation to 'take away' the heat, perhaps a thinner cloth might work better and oh... no disrespect intended to that 'holeyness' of a towel, which could have gone into the bin eons ago, but I'll admit it's somewhat thick for the job.

BTW, spare that headdress if you find those moss and send it to Kwek Leong :wink:

(**) in the interests of science ! because I dont actually need a cooler, however if you could come up with an idea for a warmer that does not need an energy input I would like to hear about it !!

If we want to be anal about it, wind and convection can be considered as 'energy sources'. In your case, how about reflected light to warm things up?... urm, as in a parabolic design or say, solar panels??

[Ptarmigan]

if the contraption relies on evaporation to 'take away' the heat, perhaps a thinner cloth might work better

I think surface area is the main important thing. The greater the wet (damp) area exposed to the outside air the greater will be the evaporation, so thickness should not matter. Which makes me think ,,, how much of your towel is remaining wet ? How well is soaking up water ? Ideally the whole towel right up to the top should be wet. If the water is rising up only a few cm and the rest of the towel is dry then the cooling effect will only be small, also the outside warmth will be able to get through the dry bit to warm up the inside volume of air and partly offset the cooling effect of the wet bit.

Malcolm.