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Fastest Way to Drop Temperature

11/22/2017 2:39 PM

I am working on a home project. Basically, I'd like to design a six foot pod, where a person can walk into and then with a push of a button, the temperature in the pod drops rapidly in order to "shock" the person. The idea is to get the same effect as when jumping into a cold shower, but without getting wet. Any thoughts on a way to get this done?

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#1

Re: Fastest way to drop temperature

11/22/2017 2:43 PM

It's been done.

...And failed to be successful

Sports medicine

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#2

Re: Fastest way to drop temperature

11/22/2017 3:09 PM

What is the point?

Liquid substances that evaporate at room temperature, such as nitrogen, could make a big difference in temperature, but instead of cooling the body, it burns it because of the low conductivity of the human skin.

You would need to inject cold blood into the blood stream to cool down the body as fast as possible.

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#3

Re: Fastest way to drop temperature

11/22/2017 4:16 PM

How about chilling the pod ahead of time? That wouldn't necessarily take a high-capacity refrigeration system. Then the person simply steps into a cold space, maybe with a fan to give some wind-chill effect. Some calculations and safety features would be needed to keep from inducing frostbite.

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#4

Re: Fastest way to drop temperature

11/22/2017 4:35 PM

Hey no problem, you can rent or buy or build a small refrigerated trailer....

-10° to 40° F 6' x 8'

http://www.refrigerated-storage.com/special_events_

Probably the cheapest way to go would be a freezer if you don't mind laying down....$1500....I guess you could figure out a way to stand it up maybe with some reorientation of the freezer unit, maybe not worth the trouble though....

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#5

Re: Fastest way to drop temperature

11/22/2017 5:37 PM

You've got to think about thermal mass, or heat capacity. Humans are mostly water, and have high thermal mass. Air has very low thermal mass (0.0013 J/K-cm^3), so even if it's very cold, it only very slowly drops the temp of someone exposed to it.

By contrast, water's high thermal mass (4.2 J/K-cm^3) does a good job, about 3200 times better than air. That's why cold water, as in a cold shower, or even better, an ice-bucket, can rapidly lower skin temps and later body temps.

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#8
In reply to #5

Re: Fastest way to drop temperature

11/22/2017 7:10 PM

If you've ever walked into a walk-in freezer with the fans running, you would see how fast it cools....you can't take more than a few minutes in a tshirt....The air movement is important to maximize the wind chill factor....

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#6

Re: Fastest way to drop temperature

11/22/2017 5:56 PM

I can think of a number of ways, but don't want to be complicit in this endeavor.

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#7

Re: Fastest way to drop temperature

11/22/2017 7:05 PM

Don't be silly. What you propose is impossible!

A fools errand that is likely to end wasting time and money.

Put a pan of water in a 33°F freezer. Wait 4 hours. Then open the freezer, put one hand in the freezer and one hand in the pan of water, then shake your head and mutter, "What was I thinking?"

Also see #5.

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#9

Re: Fastest way to drop temperature

11/22/2017 7:18 PM

Well I’d say you have (2) pods, one is always cooled/cold (pod 1) and acts as a accumulator, this you keep cool/cold.

then you have pod 2, smaller then pod 1, this is one you walk into, you have a high cfm fan the will purge the cold air from pod 1 to pod 2. Depends on the size of pod and your CFM of your fan, the air exchange should be seconds.

or a walkin freezer.

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#10

Re: Fastest way to drop temperature

11/22/2017 7:59 PM

Just get a large refrigerator and take the shelves out. Cut a few holes for ventilation and keep plugs in them until ready for use. Done, and done.

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#11

Re: Fastest way to drop temperature

11/22/2017 8:03 PM

Buy a can of liquid nitrogen...you wouldn’t even need a room.

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#12

Re: Fastest way to drop temperature

11/22/2017 10:35 PM

Forget the button. Unless it activates fans in a freezer (basically giving you the equivalent of a wind chill factor of standing on a windy mountain top), or releases super-cooled gas your wasting your time.

Consider a very cold walk-in freezer design with fans or an ice bath (or similar). Anything else is going to either be too dangerous or too expensive to implement.

......

Ok, a dry ice (carbon dioxide) bath may do the trick without getting wet but you would have to be careful to prevent injury due to contact.

What exactly is the application?

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#13

Re: Fastest way to drop temperature

11/23/2017 6:30 AM

<...the temperature in the pod drops rapidly...>

  1. At what rate is the temperature to fall? Knowing this would enable a stab at the duty of the equipment that is to be developed. However, the constraint is the power limit available from the <...home...> utility supply, meaning some form of compromise may be necessary.
  2. From what starting temperature? What is the ambient temperature at the location of the installation? What is the ambient temperature of the <...person...>?
  3. To what end temperature? As others have indicated, a vat of something like liquid nitrogen would do the job as currently specified, however a <...person...> will not survive indefinite submersion, partly on the basis of the expected damage to biological structures during this experience, and partly due to the risk of suffocation (one assumes that the <...person...> is expected to survive this experience).
  4. Wouldn't it be better to have the [thing] at the end temperature and put the <...person...> into it? That is a "cold room", or similar. The rating of the equipment needed is determined largely by its size and the properties of the equipment's insulation.
  5. Size is important (or so it has been said for the purposes of making wallpaper stick to the walls...). How large is the equipment supposed to be - coffin-sized? Phone-box-sized? Tennis-court sized? What are the size constraints?

The question as posed so far will result in a range of WAG [Wild-a$$ed guesses]. The only way to get a reasonable answer is to restart by writing an User Requirement Statement for the equipment:

  • "Provide a facility that does the following, and satisfies the following performance criteria and operational constraints:
  1. etc., etc."

otherwise the forum doesn't have much to go with and will respond with more and more WAGs, which is not really what is wanted, is it?

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#14

Re: Fastest Way to Drop Temperature

11/23/2017 10:18 AM

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#17
In reply to #14

Re: Fastest Way to Drop Temperature

11/23/2017 7:45 PM

That's what post #1 was about..

what took so long?

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#15

Re: Fastest Way to Drop Temperature

11/23/2017 11:49 AM

I have heard that when people go into a supposed haunted house and apparition appears, a cold chill runs up the back of the spine. So maybe a psychological shock of this type could be created.

Whereas the person, " feels " cold, although no change in the surrounding air temp has actually taken place.

The limiting factor would be a persons sensitivity or reduction in induced suggestion.

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#16
In reply to #15

Re: Fastest Way to Drop Temperature

11/23/2017 1:32 PM

The problem with this is it varies from person to person and repeatability is an issue.

It really depends on what the original poster is trying to accomplish.

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#18
In reply to #16

Re: Fastest Way to Drop Temperature

11/23/2017 7:54 PM

Gone are the days of questionable caffeine.. Just step into the "scare the $#it out of yourself pod".

...With literally thousands of sinister augmented realities to shock you to the brink of death! You'll be alert and on edge for 6 what? 6 yes 6 Fuuuull Hours guaranteed.

....hmmm.. don't know about that one.

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#19

Re: Fastest Way to Drop Temperature

11/24/2017 2:55 AM

Well what's your budget for this project....?

...cause you could build something really cool if you have enough money....big refrigeration for a small space....

https://www.diytrade.com/china/pd/12130194/meat_cabinet_quick_freezer.html

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#20

Re: Fastest Way to Drop Temperature

11/26/2017 1:37 PM

Was any of this helpful?

Can you please provide some more information and feedback regarding your particular application.

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#21

Re: Fastest Way to Drop Temperature

11/27/2017 10:17 AM

How about instead of a cold room, have something like a chilled waterbed mattress for the person to lay upon. They stay dry* and if they pass out they don't fall.

*may need to have the mattress in a low humidity room to prevent condensation from forming on the mattress.

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#22

Re: Fastest Way to Drop Temperature

11/29/2017 4:00 AM

I don't like the idea of doing this just to shock someone. There are legitimate reasons to need to cool a person quickly.

It wouldn't be too complicated to cool a person rapidly with a combination of approaches.

Flush their mouth with chilled mildly saline solution. A mouthpiece could be constructed that minimizes risk of problems with asperation.

Supply cold air to breath.

Conductive chill pads can be places where major arteries and veins are near the surface. Inside the thighs, inside the upper arm and places around the neck.

Cold air can be blown against the top and back of the head.

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#23

Re: Fastest Way to Drop Temperature

11/29/2017 7:14 AM

The Original Poster seems to have evaporated. Perhaps the thermal shock of the above replies to the original post was sufficient to fulfil the perceived need...

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#24
In reply to #23

Re: Fastest Way to Drop Temperature

11/29/2017 9:30 AM

Thank you all for all the replies. Apologies, I've been away for the holidays. The idea behind the experiment was to use a device that would WAKE YOU UP in the morning without getting you wet. The most feasible idea I think is to build a freezer with a fan on top and then expose yourself to the wind chill. But not sure if even this would effectively achieve the desired effect. That being something similar to what you feel when you jump in a cold swimming pool. You guys made me realize (I'm a not an engineer) that cold air blast wouldn't really produce the "shock" effect that I am after.

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#25
In reply to #24

Re: Fastest Way to Drop Temperature

11/29/2017 2:05 PM

What seems to be the issue? Is this some sort of medical problem waking up?

Link

I had a fellow Engineer that had a similar problem and a audible alarm wasn't enough so he built a sprinkler system into his bed.

Adding that the person has to be in a bed complicates things........How about a mild (MILD, not dangerous) electric shock from say an electric fence controller? This is relatively inexpensive, easy to set up, control and regulate the amount of shock the person receives.

Perhaps worth a try.

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#26
In reply to #24

Re: Fastest Way to Drop Temperature

11/29/2017 4:09 PM

Waking from sleep is typically a process involving increasing the temperature of the body.

Cold may be startling and cause muscle contraction, but it is really the opposite direction if the desire is lasting alert wakefulness.

Of course being too warm can also cause one to be sleepy.

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