retrofit a water cooler to a bed cooler?

Has anyone done this?  

It would be along the lines of cool-the-person-not-the-room, and $1000 things like "sleepme" mattress toppers that cool your sleeping temperature.  In the summer this could be really nice, our summer nighttime temperatures have not been very cool.

I think all that would need to happen (after getting permission to take apart the cooler very permanently) would be to remove whatever is inside the water cooler for cooling the water, and attach to its terminals a 1/4" hose of a certain length.    (And keep the refrigerant from escaping.).

This is beyond my immediate capacity but maybe someone else will want to take this idea and run with it.

It's cool idea (ha) but I don't think the chiller in a water cooler would have the cooling capacity for a larger volume system.

You could fill hot water bottles with very cold water, though. Anyone tried that?

It would work, like hydronic cooling, where you cool the water instead of heating it to cool the thermal mass you are using, which in this case is your body. You don't need much of a temperature differential if you are only cooling a bed, the body doesn't do well on cold surfaces, all you need is not quite as hot.

And, counterintuitively, good blankets would help. I stay cool in bed by using blankets. You insulate the heat away from you if you don't let in any hot air. Keeps you at the same temp that you sleep in in the winter, your body heat without adding cold air in winter, hot air in summer. If you let the hot air in, it doesn't feel good. But I lived in the desert most of my life, and that's a fairly normal trick for hot spaces. Once you get the temp to stabilize under the covers it's the same ,winter and summer, just keep out heat or cold as needed.

So I'd say cool the bed a bit, and put good blankets on and don't let the heat in, and it would be effective. Even better would be a bit of thermal mass that isn't the body, not sure what you'd want to use, would help make the cool water most effective.

And thinking on it, I'm honestly not sure you'd even need to cool the water, room temp might more effective than you'd think. I have a pillow made for neck damage, like a tiny waterbed, and it stays too cool for me to tolerate, feels like it pulls the heat out of me. That might be worth trying, get an air mattress with no leaks, put some water in it, not tight full, just an inch or so, and try sleeping on it. You might be surprised. I slept in a waterbed most of my life, and HAD to insulate the mattress top, the water when the heater wasn't being used, pulled my body heat out too much. It's weird to shake with cold when it's over 100 outside and no AC in the house.

Wow!  That's an unexpected bunch of info, I'll have to digest that.  I think our climate is pretty different from the desert.

The commercial product ad for the "sleepme" bed says you can set it as low as 55 degrees Fahrenheit, so I was thinking I'd want to set it really cold.  They say you won't wake up sweating in the middle of the night anymore, which is something I've noticed happeing sometimes, so I've started sleeping with a little less blanket cover so I'm slightly cold at the start, and then slow my breathing so I am having less heat exchange (losing less heat to the room).  It's also healhtier not to overbreathe, from my understanding, so I want to encourage that.

The commercial product ad for the "sleepme" bed says you can set it as low as 55 degrees Fahrenheit, so I was thinking I'd want to set it really cold.  

Personally, I'd LOVE to see data on what temps people actually end up with theirs set at. If more than a tiny few have it below 85 or so, I'd be VERY surprised. I might be wrong, but I would be very interested to see what the data shows

The temperature humans like their air at doesn't correlate well to the temperature the body does well with. Bodies are at 98. Taking it down to 95 is hypothermia. How hard would the body have to work to keep you out of hypothermia when laying on a 55 degree surface that is constantly pulling your heat off? That's VERY different than how much it takes to keep it up in 55 degree air. I think they market to people's ideas, but the actual number people end up comfortable at is not what they thought it would be.  

This is why hydronic heating works, keeping the mass at temperature makes it so air temperature is MUCH less relevant. For a house, you end up with your thermal mass only a few degrees higher than you want it to feel, for cooling a bed, I'd say only a few degrees lower that desired body temperature, and that needs to stay in the 98 range.  

:D

For what is worth, my dad (who was always roasty) & step mom (who was always cold) kept their waterbed at 95°F, year 'round - with heavy blankets & flannel sheets. Both swore they were comfortable, and (unless something else was going on) said they slept like babies.

I can see setting it to 55 degrees for temporary therapy, but not for actually sleeping.

A waterbed without a heater is uncomfortably cold for most people, but not all. Water is a huge thermal mass. The tube systems use colder temps because they have a gallon or two of liquid, not a hundred like an old school waterbed.

Hmmm. I wonder what a waterbed on top of a pebble bench would do???

OK, well this puts it all in perspective.  I do think it would be way more efficient than an air conditioner!  

So the hard part is getting the coolant tube to go through the mattress topper, and it sounds like you don't need to do it that way after all--instead you could just use room/well temperature water, run it through a kind of "drip irrigation"-like system where it's flowing through and dripping into a bucket.

Or just sleep on your rocket mass heater (I'd prefer to try that one).

Or a water bed...but that is made of plastic, right?

And wouldn't a water bed heat up to the temperature of the air around it over the course of the summer?  What is the average temperature over the course of the day in different climates around the world?

According to a quick search, the temperature in Boston varies between 67 and 82 Fahrenheit in the hottest month of the year (August).  

I am not buying the idea that 82 feels cool to me just because my internal temperature is 98...it feels more like the bare floor gets hot pretty quick and then is stifling and sweaty.  Partly because it is insulative so it traps my body heat.

A stone (thermally dense) surface that hasn't reached more than an average temperature of whatever's the mean of 82-67 (= 75) degree Fahrenheit would always feel cool...but I am not so willing to sleep on bare stone.  Some insulation between me and the hardness, please!  So, straw mattress...now I'm back to being insulated.

If I put the rocks on top of me that might be less of an ouchy.

I don't think this will sell as a luxury product, but I like the direction this is going.  I am going to try napping with a rock this summer before I try it for overnight and report back.  Anyone else try these experiments?

I still think of poor Nathaniel in the hottest part of the world, where the ambient temperature day-long would be higher than human temperature!  There I doubt a rock would help, plus they don't make them anywhere else like the do in New England.  But maybe you could dig up some sand and put that in a pouch to sleep with, or a weighted blanket that has pouches in it.

https://www.amazon.com/Natural-Cooling-Sleeping-Treatment-Massager/dp/B08K8ZG9LS

Not endorsing this, but there's jade sleep masks for cool therapy.  They advise putting it in the fridge beforehand.  

Pearl, your point about how cooler than a few degrees below body temperature is uncomfortable is really important, thanks for pointing that out!  That's a game-changer in how we think about this, I think.

I am still puzzled by the part where you'd put on a thick blanket in summer to keep hot air out...presumably it isn't over 98.6 F at night, right?  can you say more about that part?

Joshua Myrvaagnes wrote:And wouldn't a water bed heat up to the temperature of the air around it over the course of the summer?

This is a big advantage to those heavy blankets - if you go a size up from what's actually needed for the bed (so a full size would get queen, a queen size would get king,etc), they insulate it will enough that, at least on my folks' waterbed, just putting a hand on, or even sitting or laying on top of the blankets, it was the same temperature as the rest of our beds. But, pull those blankets back, and oh, soooo nice!!

Joshua Myrvaagnes wrote:Pearl, your point about how cooler than a few degrees below body temperature is uncomfortable is really important, thanks for pointing that out!  That's a game-changer in how we think about this, I think.

I am still puzzled by the part where you'd put on a thick blanket in summer to keep hot air out...presumably it isn't over 98.6 F at night, right?  can you say more about that part?

I think one could do an experiment in the shower with a thermometer and a pail. Take a few showers, hot, comfortably warm, cool, and cold. Once adjusted, let the water collect in the pail and record the temperatures. (It would also be super-easy if you had an on-demand water heater that you could just set the output temperature, then experience that in the shower.) My mom had hers set to 106*F and she'd just open the hot tap for her showers. No need for scalding hot water at 140*F. Whenever I take a cool shower, I'm amazed at how close to "hot" that I set the valve, nowhere near "cold" only!

Carla Burke wrote:This is a big advantage to those heavy blankets - if you go a size up from what's actually needed for the bed (so a full size would get queen, a queen size would get king,etc)

After sharing a bed with my brothers at different times in the past, I determined that the nominal quilt sizes are only good for a single person in any given size of bed. Yes, you can walk up to a queen size bed in a hotel and observe that the quilt overhangs the bed on both sides. Put two people in that bed and you will observe that there is maybe an inch of overlap on both sides. But as soon as one of them turns over, there is going to be a gap that allows air in on the other side. Or one of them will be uncovered. Alternatively, observe that same bed after a single person has slept in it all night and you will see that one side of the bed is almost completely uncovered. There simply isn't enough quilt to go around.

I thought that this was another instance of shrinkflation. But it happened in my grandparent's old beds as well. So I have concluded that you must buy the next higher size of quilt if you intend to sleep two people in a bed. And it has worked fairly well for me. I use queen sized sheets on a queen sized bed with a king size quilt. With me, my wife and a nursing infant we stay sealed in quite well.

Joshua Myrvaagnes wrote:Pearl, your point about how cooler than a few degrees below body temperature is uncomfortable is really important, thanks for pointing that out!  That's a game-changer in how we think about this, I think.

Yes, I think so too.

I am still puzzled by the part where you'd put on a thick blanket in summer to keep hot air out...presumably it isn't over 98.6 F at night, right?  can you say more about that part?

Why do you use a thick blanket in the winter? To keep yourself comfortable regardless of exterior temperature. Same with using them in the summer. The temperature your body calls comfortable hasn't changed with the exterior air. What HAS changed though, is if you let cold get in, your body can warm the space back up, whereas if you let heat get in, your body can't cool it back down.

What I do in the heat is before bed I wipe my body down with a cool wet rag, towel off only any drippy excess, give it about 3 minutes then go to bed. This lets a bit of excess body heat be dissipated before bed. Cold shower is even better. I keep the heavy covers pulled up on the bed all day, to keep the heat out as much as possible. Laying still enough to not let more heat in through gaps in the bedding is trickier but can be learned. It's the same trick you use on freezing cold nights.

I stumbled on this when I was a teenager, in the "I want to sleep till noon" stage. We would go camping in New Mexico, and I learned that if you stayed well covered up, as long as you let no heat in, you could sleep through even high temperatures as the day warmed up. The minute you let the hot air in, it was game over! Letting the sun hit the bedding ended it too, as it changed the heat in the air spaces of the blanket past what could be dealt with. I learned later that I had rediscovered what others had learned before me.

These days I'm in Missouri, muggy heat that holds all night. And it still works.

The stuff you said about using stones as cool thermal mass, yes. I have a heating pad that has stones in it, and when it's off, if it's at air temperature, putting it under the covers just before you get into the bed with the blankets takes some of the excess heat as your body stabilizes the temperature under the covers. Toss it off when you think about it, or let it stay in the bed, doesn't matter, don't let hot air in when you do it though!

:D

There are some great practical explanations here. There is a growing "clan" or number of fans out there who will advocate for matress toppers or whatever technology can keep you cooler at night. There is a body process every night where we go into a mini hyberntion so our mitochondria can do their nuclear energy production. For that process our body temperatures go below normal. I'm sorry to say I dont have a number for you. The source for this information is related to Dr. JACK Kruse's work. There are a multitude of podcasts with interviews with Jack. He also is a cold plunge advocate. Having a shockingly "cold" shower should help, But ice baths are better. The temperatures that daily cold plungers use go down to 39°F. My top podcast suggestion is "Undoctrinate Yourself" with Alexis Cowen, she has an incredible series that covers the decentralized medicine perspective.  

As for maintaining a cold bed, absolutely, bigger blanket. Maintaining the seal on the insulation is the same for cold or hot. I've been using my duvet this summer.l, though I dont have any data to report as the consistency of my blanket cover is terrible. My three year old regularly kicks of the sheets etc. I was like that too as a kid. I wonder if the ambient air temperature is a necessary input for our bodies at night?

I keep a pillow filled with ground walnut shells in my freezer. On hot nights I put it under my sheet . Cools down the entire bed long enough to fall asleep then the cool air from outside comes in and does the rest of the night. Low tech and nothing to repair down the road. Plus no noise from a pump - something to consider before building anything to cool your space.

Joshua Myrvaagnes wrote:According to a quick search, the temperature in Boston varies between 67 and 82 Fahrenheit in the hottest month of the year (August).  

I am not buying the idea that 82 feels cool to me just because my internal temperature is 98...it feels more like the bare floor gets hot pretty quick and then is stifling and sweaty.  Partly because it is insulative so it traps my body heat.

A small refinement on this:  98.6*F is your **core** temperature.  Your body works hard to maintain this, and yes you are hypothermic if **your core** drops to 95*F.  But your extremities are usually lower, the surface in general is lower.  Your thermal regulation depends on this because your body produces heat during metabolism.

I feel temperature in two fundamentally different ways.  When touching a surface, what I feel is heat transfer -- a surface feels cold because heat is leaving my body or hot because heat is entering my body.  This is different from "I feel too warm", which is my body encouraging me to alter my environment to allow it to cool better.  As a desert person who now lives in a humid climate, I struggle at 80*, but 90--100 "back home" feels cozy.

There are some other complicating factors.  As others have noted, a blanket is not a heater, it's only an insulator.  If you are uncomfortably warm with a blanket over you, it's because your body is trying to release heat and the blanket is inhibiting that.  This is why a blanket can be very comfortable in a hot summer after you reach equilibrium.

Returning to what we know about hypothermia, there are three contributing factors: cold, wet, wind.  You probably don't want to climb into bed wet, but some surface moisture and a breeze will lower your temperature quickly (the same "phase-state-change" cooling as sweating).    In the summer, you can wipe a damp cloth over your skin and walk around a little before you climb into bed.  A fan works if you have that option, but keep in mind that electric fans produce heat, so they can make your body feel cooler due to the breeze, but they also (slowly) increase the temperature of the room.  Incidentally, getting some breeze can be helpful in the winter, especially if you're using a sleeping bag, because you want your skin dry.  A damp sleeping bag is very hard to heat in the cold.