Aircon alternative - Cold Tubes

[rruff]

anecdotally, this works.
...If I can find one that is higher power without a huge weight increase, or that can make the ice colder than just frozen that would probably be a better choice, but i think a 400w industrial one is just going to be too big and heavy.

Very cool! I was pondering making ice (freezing homemade packs) for a different reason (to keep food cold!), but I was going to use a 12v compressor fridge for that. But the ice maker might be fine for you. Still think the water pad would be better, though...

Don't worry about about getting the ice colder than frozen... all the energy absorption is in the heat of de-fusion of the ice (ie melting). 333kj/kg to melt vs 1/deg C of temperature change. So cooling the ice 36 deg (20 C) below freezing only increases the cooling capacity 6%.

 

[NatersXJ6]

Are you imagining that the ice maker is modified to make use of the compressor only, or that the ice maker is simply creating the “cold reservoir” for your tube to circulate through? I’ve used those ice makers for several years in my house, and they would probably work well if you removed the ice basket part and just allowed the cubes to drop back into the water reservoir. Figuring out how to maintain the on/off function of the ice maker might be important, but IIRC, the Newair brand I had used a thermal switch not a mechanical one.

 

[rruff]

I think he's planning to make lots of ice during sunny times, which he will use to cool down at bed time.

 

[tanuki.himself]

I think he's planning to make lots of ice during sunny times, which he will use to cool down at bed time.

Exactly. I'll have to take a look at the ice makers available and decide whether to just use the ice container provided as the reservoir or transfer the ice to a more insulated container like a vacuum flask through the day. Marketing i've read for some of them says they will automatically recycle any melt water through the system, so that may make life easier. Effectiveness of the system will come down to storing as much cold as i can and keeping it cold until i want to use it - more ice and less water.

I looked into mattress cold pads but couldn't find many options available over here with just the pads, expensive and i did wonder if the exposed colder surface might attract condensation to the bedding. And i wouldn't fancy making my own for that - don't know what sort of pipe they use to be strong enough to be knelt on repeatedly without the risk of leaks

 

[rruff]

...i did wonder if the exposed colder surface might attract condensation to the bedding. And i wouldn't fancy making my own for that - don't know what sort of pipe they use to be strong enough to be knelt on repeatedly without the risk of leaks

I thought about condensation briefly and decided it was a non-issue. Unlike the radiant cooling method where a large temperature differential is needed, circulating water has a very high heat transfer coefficient... ie very little temperature differential is needed. You should be able to control the cooling rate by how many loops you have in your cooler and the rate of flow.

I don't know what sort of tubing would be best. My first thought would be to try latex. It's tough and very flexible.