by emergency i mean something to be used in time of crisis.
On top of all I put before I forgot to add your food freezer needs to maintain a temperature of below -16 deg C
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do you think this design can be simplified :http://www.egr.msu.edu/mueller/NMReferences/MuellerN_2002_ASME_PIDNewsL_WaterAsRefrigerant.pdf?
There is a long way from chilling to freezing. AFAIK the only way to get freezing air from normal air is by using a Ranque-Hilsch vortex tubhttp://en.wikipedia.org/wiki/Vortex_tube It doesn't get much simpler- no moving parts just compressed air. The simple version of your link is to blow a stream of air over a wet screen - this will cool by about 10 deg C see Swamp AC. I can't see an easy way to freeze without using some power source.
using a power source is fine. i am fixing an old air compressor and putting a prototype together soon.
The temp drop in commercial tubes can be 45 deg C so well below freezing from a room temp start.The idea is simple a spinning column of air has a restriction in the way such that the lighter hot air which tends to be in the center goes through leaving the heavier cooler air to exit the other way.The restriction can be as simple as a washer with a suitable sized hole.
thanks , i modified my search based on your input and found what i was looking for here :http://www.vortexair.biz/Cooling/SPOTCOOLPROD/Vortex_Technical/vortex_technical.htmlInlet pressure ,temperature VS cold output temperature .this is very interesting because it implies that you can continuously cool an air stream and potentially liquify air.
Yep but it's not an energy efficient way to do it.
i looked into vortex cooling and like to do some experiments.if outlet of cold stream of vortex (a) be used as inlet of compressor or inlet of a second vortex(b) then temperature drop could be substantial.has anyone tried building a vortex? there are some youtube videos but hard to follow.this is what i like to do 1- build several vortex tubes using PVC tubes 2- assemble them in series 3- measure pressure , temprature , flow rate at each inlet/outletthe data from above can be analyzed on decide on what to do next.thanksMichael
How much do you want to freeze or What do you want to keep frozen Have you seen freeze can sprays. A
anything that can be saved by 'cooling' or freezing. tell me about freeze sprays because i looked at techniques used in Skil resorts for snow making , it can be a promissing method with cheap raw material.
Ski resorts have to collect and maintain large below ground water storage which are the primary element super spray guns send into the air above a ski path when conditions are optimum for night freezing. A
same technique can be use without large water storage. instead of an open system , imagine a closed system with water-solutions instead of just water. water is great because of its thermal properties but it freezes at 32 ( see water enthalpy of vaporization ). i think freeze spray should be definitley considered.
The snow machines operate outside at or below zero: freeze spray should be definitely not be considered for a freezer. L
+1Also, are you in a particularly hot climate? cold climate? somewhere prone to flooding? tornado's? hurricane's?Having more info about your location, and what you might perceive as a potential emergency situation would help in offering you good suggestions.
hi i am in california , but lets say 'anywhere usa' lets say there is an act of nature or a man made disaster and large number of people need services.
Hi there, we seemed to have posted our comments at the same time, so I saw your reply to iceng, after my comment was added.I wrote you an answer (separate from this thread, as it was a little long), but in addition to my suggestions, I would advise having a "bug out" plan, because regardless of the disaster, I would not want to stay in a heavily populated area. I live in a large city, and in the event of a disaster (earthquake or otherwise), my ultimate plan is to leave the coast for a less populated area.
good ideas , but i am freeze-nut case , like to freeze everything.
The RV-Fridge reconditioned under $650 Runs off a 12VDC easily for a couple days or AC line is the easy best answer for you. . . . A
but it is not a red-neck solution , please read the requirements :-) just kidding .
to MH76dk , rick , iceng : during hurricane katrina having an emergency refrigiration wasn't a luxury it could have saved many lives. i think having an emergency plan for yourself or community is not paranoid there are other things to be worried about , but i am only interested in heating/cooling and computers :). lets write requirements : 1- a device that can quickly provide cooling/freezing for x number of hours 2- cost is not important within reason 3- it has to be simple with a red-neck quality
For what? Not food I hope. L
low temperature can save lives! remember hurricane katrina ?
How, or to ask again, what for? L
I personally don't think having an emergency plan is paranoid. There are many scenarios where you could be left to your own devices for many days if not weeks. I live in an earthquake prone area, and although we haven't had a "big one" in my lifetime, it makes a great deal of sense to plan for the worst and to hope for the best.I think you should look into getting a portable generator, and to keep additional fuel supplies. It's something that you can take with you, if you need to flee from your community, and can power lights and other things as well. Having a secondary power supply from batteries, could allow you to transport a reasonable sized food storage cooler, and keep the contents cold while in transit (using the battery supply). The other huge benefit is having food sources that are dry storage, canned, or freeze dried. It may not taste the best, but it'll keep you and your family alive in an emergency and doesn't require any special storage.Obviously, the other important factors to consider are water, alternate shelter, additional clothing, a well stocked first aid kit, cash money (as most banks and ATM's can become inaccessible), as well as things to meet the needs of specific family members (medications, etc).
Where there is a high risk of natural disaster there is generally a local emergency plan then goes into action. Public shelters, emergency food supplies, water supplies, communications etc. To stock up an even reasonable amount to be significant for an individual is neigh on impossible.Water is the most important and your going to need for drinking only around 3.8 ltr or 130 US oz per day assuming moderate activity. For 3 or 4 people for several days that's a lot of water to store and it needs to be recycled regularly, protected fro contamination and be available throughout the disaster.Food wise your going to need 2000 Kc + per day per person assuming your in a high stress situation. If your body mass is high you may get by on slightly less but WILL loose weight. This food needs to be kept fresh one way or another, possibly without power and may need to be eatable raw as cooking may not be an easy option.Your going to need the means to build or access a safe shelter that will keep out wind rain and cold.Your going to need a means of creating heat/fire. This needs to be reliable and easy for everyone to use.Your going to need clothing that will allow you to stay out all night in low temperatures - because you don't know when the disaster will happen.Your going to need to communicate somehow possibly over long distances without a ready supply of electricity.You will need a fairly extensive tool kit of hand tools.Your going to need to be able to cope with emergency medical events, Injury, shock, hypothermia, Sickness, Diarrhea, broken bones, Dislocations and penetrative wounds. Medication doesn't last forever so needs recycling over time.You will need reliable transport that at best will use a fuel that is readily available and at worst needs no fuel at all. This transport may need to travel over disturbed and rough terrain as good roads can't be assumed.If the disaster is more global you will need a means of defense, this should use some kind of ammunition that is readily available and or can be manufactured using crude tools.All in all for the majority of us this isn't a practical or viable way to cope, we live in organized society so we can help each other, if that society breaks down then we may as well give up because the survivors will be living in remote areas and already well practiced in living off the land.For the supermarket shoppers we would have little chance.
You are correct, but the reality is that even in a society with contingency plans there is a responsibility on the part of the individual to prepare and be self-sufficient for at least 72 hours. This is also advised for people in disaster prone areas because implementing those plans can take an enormous amount of time when resources are stretched in dealing with the critical and emergent situations that can come from something like an earthquake. In order to work with Emergency Services, it was a requirement to take a Disaster Preparedness Course (among others), and we analyzed a number of actual scenarios. In each case, it was clear that for the first 48 to 72 hours the majority of people were essentially on their own. As a result, we were required to create and maintain emergency kits for home, the car and for work, (as we would obviously not be able to leave if a disaster occurred while we were on shift). Those plans had to extend to all family members, and take into account where we might be, and what our needs were depending on the time of year etc. Again, for something like an earthquake, the immediate focus is on dealing with the subsequent fires, and possible floods and treating those who are injured or rescuing those who are trapped. Due to ruptured gas lines, down power lines, broken water mains, compromised sewer systems, etc, the services that we've become dependent on must be shut down. For those reasons, (among others), even the "supermarket shoppers" should have backup resources and plans in place in the event of a disaster, because the likelihood that shelters and other services become available any sooner is very low.
:-) i can understand that we have exactly the same traffic problems! people get stuck for days on the M25 round London! :-)I feel fortunate not to live in a high risk area of the world. I agree on the ices house we have a stately home close by and they have an old 16th century ice house - about 20 feet deep and it was lined with straw and then filled with ice from the lake in winter. This would last all through the summer giving them somewhere to store food and get ice to make Ice cream. An inscription from 1700 BC in northwest Iran records the construction of an icehouse, "which never before had any king built." In China, archaeologists have found remains of ice pits from the seventh century BC, and references suggest they were in use before 1100 BC. Alexander the Great around 300 BC stored snow in pits dug for that purpose. In Rome in the third century AD, snow was imported from the mountains, stored in straw-covered pits, and sold from snow shops. The ice formed in the bottom of the pits sold at a higher price than the snow on top
using water as a refrigerant is still in use in many part of the world.the only change i like to make is to make it a closed system.pressurized air + water + anti-freez -> spray -> pump -> circulate
If you want a real "redneck method" and have a backyard, consider building an icehouse like they used in the days before freezers and refrigerators. They would dig a large hole into the ground, and would line and layer it with blocks of ice and straw or sawdust. Normally, they'd get their ice over the winter, and put it into their icehouse, and when their food storage was added, and the trap door shut, the food could stay cold or frozen, over the Spring, Summer and through to the Fall. It's a cheap method, and would work (provided you don't live in an area prone to flooding, or an extreme desert). For added benefit, use rigid foam to line the walls.
refrigerated trucks would work great on a community scale. The trailers have cooling units built into them and they operate for days, even weeks, with no other connections. I have seen the units stacked on freight trains moved across country. The units a fueled up when put on the train and they maintain the trailers contents at below freezing for the transport period. You don't need the truck to run them, only to move them.
great idea , but as i mentioned before " it is not a red-neck solution , please read the requirements :-)
A couple of days crisis or a couple of years crisis?I mean, if you only worry about losing power a few days, get some kind of generator, and hook your most important electrical appliances up to that for backup.If you worry about not having food a few years from now, i think your paranoia is misplaced, ending up in that situation its likely you would need a lot of more important stuff than access to frozen food a year from now (like shelter, protection from the looters, and perhaps protection from whatever the crisis is)
frozen food doesn't last forever (actually it more or less does) so you need to have a cycling system in place.How much food can you store, how long will it last, is it worth the bother/cost.Depending on your reasons/definition of crisis you may be better off training in foraging for natural food.