Rocket powered refrigerator

   Rocket stove/refrigerator. The propane powered refrigerators which are common in recreational vehicles have no moving parts other than the hot and cold gases flowing through their expansion tanks, condensers, and heat exchangers. Without getting into huge detail on the workings of these machines just know that the fridge works when the boiler section is heated with a flame.

     I am new to computers so I'm hoping someone familiar with this type of fridge can glean some graphics off the net and drop it under my post.

    So on the simplest units there's a section of pipe called the boiler which needs to be heated. Rather than purchasing expensive propane this could be accomplished simply by attaching the boiler to the side of a rocket stove heat riser or placing this same boiler inside the riser provided it can withstand that sort of extreme heat. It wouldn't take much of a rocket stove to produce a much larger fire than my propane fridge has.

    This unit would use a light metal rocket stove with no thermal mass similar to what is used for cooking in the tropics. Trying to run this off your RMH would cause overheating in the summer when the refrigerator needs to be fired more often.

    One large scale boiler tube should therefore be able to handle a household size refrigerator and freezer. For my purposes I envision a walk in freezer like you find in stores and restaurants with a small refrigerator section accessible via regular refrigerator doors set in the side of the unit.

    I can imagine building this on the south side of a house so that concentrated sunlight could power the fridge in the summer. Alternatively, the rocket could power it all year as long as it can be separated from the house so as to not cause overheating. The stove effluent could be piped to a Coppola  where it would initiate convective currents and actually aid in cooling the house.

    So, in winter we get free power for the refrigerator since all of the heat used by the refrigerator remains within the house and in summer the rocket stove powers the refrigerator and the waste heat powers a Coppola exhaust system.   A large refrigeration unit with plenty of thermal mass in the form of food or ice  could be fired when ever Coppola venting or hot water are required.

    In environments like mine where summer temperatures aren't that extreme and all this venting may be overkill the waste heat from the flue pipe could simply be used to heat water.

    If any of you have heard of such a unit please let me know about it. Otherwise I'll bide my time until the next time I am asked to demolish a restaurant and start monkeying. I sold all of the components including insulated walls from an old cooler three years ago for $500 since storage was an issue . Now I need one,

Between this post and the thread you started on using a rocket stove to produce light, you have some very interesting ideas!  But, if you are in a cold climate, you can use the winter temperatures to produce refrigeration.  So you really only need a summer refrigerator.  I plan to use wood for everything including cooking at my next place (will use solar as much as I can, but wood for everything else), so I can see using the waste heat from the rocket stove powering refrigeration while I cook on top of the stove.  I can also see the waste heat used in a food dehydrator -- how could you make it serve both purposes at the same time? 

Kathleen

      So far I've come up with nine different uses for the rocket stove. All of them are adaptations of existing technology which I'm planning to incorporate into the ultimate hybrid system turning the rocket stove into the center of all energy consumption and distribution within the home providing heating, cooling, ventilation, dehumidification, and possibly some electricity.

      If I were making a dehydrator to incorporate it would be a curved slab of sheet metal with dozens of long, thin stainless steel nails protruding toward the inside of the curve. Food could be impaled on these nails and this contraption could be hoisted skyward on a rope and pulley system. The food could face the exhaust pipe at varying distances according to the intensity of the fire and the items being dried. One side of each chunk of food would be warmed from the stovepipe and the other side would still get some heat since the sheet metal would be warm. You'd want to avoid using the dryer when stinky foods are brewing below. This is literally the first thing that popped into my head and not something I've worked on in any detail. I suppose it could work as a solar dryer as well.

You might be interested in this ..it has been a joint project headed by a university in Britain and developed over the past 4 or 5 years. It would appear  now to be in production... 
 http://alfin2300.blogspot.com/2010/07/score-stove-for-cooking-refrigeration.html

Pam wrote:
You might be interested in this ..it has been a joint project headed by a university in Britain and developed over the past 4 or 5 years. It would appear  now to be in production... 
 http://alfin2300.blogspot.com/2010/07/score-stove-for-cooking-refrigeration.html

I didn't find anything in the blog article listed above to indicate it was beyond the research stage.

the home page has a bunch of stuff on it but the blog had a better  image so that's the one I linked to..there's more info on this page  http://www.score.uk.com/research/default.aspx   I believe the research is ongoing but it has been proven to work and is undergoing  development in Malaysia.  It was never intended to be released in first world countries  afaik.

Pam wrote:
It was never intended to be released in first world countries  afaik.

Why do they do that?!?  I've seen quite a few interesting little gadgets that were only going to be sold in or released to 'developing countries.'  I realize that at the moment the market would be small in developed countries, but it's certainly not a non-existent market, and some of these items would be just as handy to some of us as they are to people in the 'developing countries!'  It makes me feel like a second-class citizen at times!

Kathleen

Didn't you know?  Everyone in first world countries is living the life of luxury and has no need of such things 

Actually I bet it has more to do with getting funding which is a lot easier if it looks as though you are not going to nibble at the toes of big business in first world countries. Universities are often careful about not irritating companies who might possibly fund research.  I wouldn't be at all surprised if some if not many, large companies fund research with the proviso that a) they have access to any sort of technology they find useful and b) nothing that comes out of it will be used in "their" markets unless by them.  That way the companies get brownie points and tax writeoffs and have no risk to "their" market.  e.g The peasants in India and so forth are not going to be buying electric stoves and fridges from Westinghouse anytime soon so why not?

Of course; I have no proof of this but it's a very strong suspicion. These SCORE stoves will likely now undergo all sorts of dolling up and end up being sold to the RV crowd for megabucks.

Pam wrote:
Didn't you know?  Everyone in first world countries is living the life of luxury and has no need of such things 

Actually I bet it has more to do with getting funding which is a lot easier if it looks as though you are not going to nibble at the toes of big business in first world countries. Universities are often careful about not irritating companies who might possibly fund research.  I wouldn't be at all surprised if some if not many, large companies fund research with the proviso that a) they have access to any sort of technology they find useful and b) nothing that comes out of it will be used in "their" markets unless by them.  That way the companies get brownie points and tax writeoffs and have no risk to "their" market.  e.g The peasants in India and so forth are not going to be buying electric stoves and fridges from Westinghouse anytime soon so why not?

Of course; I have no proof of this but it's a very strong suspicion. These SCORE stoves will likely now undergo all sorts of dolling up and end up being sold to the RV crowd for megabucks.

I guess that makes a twisted sort of sense.  Still aggravating, though!  I've lived quite a few years in situations that weren't much if any better than what some people have in third-world countries, and expect to finish out my life without grid power.  Some of these contraptions could make my life easier right here in the good old US of A, and I'm sure that applies to a lot of other people, as well.

Kathleen

I like this idea. also thinking of having the option to switch over to biogas.... i have been watching youtube from india and it looks so easy to make no?

Pam wrote:
the home page has a bunch of stuff on it but the blog had a better  image so that's the one I linked to..there's more info on this page  http://www.score.uk.com/research/default.aspx   I believe the research is ongoing but it has been proven to work and is undergoing  development in Malaysia.  It was never intended to be released in first world countries  afaik.

The best image I could find, is on the pdf pointed to on the left side of this page called "Overview". The address to the pdf is too long for me to grab easy.... but if you look at the picture of prototype 01, it is possible to see both scale and components. There is burner - tube - car radiator - tube - woofer speaker. These are all things easy to find. The fun part is getting the first tube dimensions just right to resonate at 60Hz. The rest would be easy... but it is only enough to charge a cell phone... 5w or so. The acoustic alternator they are developing is designed or maximum efficiency, rather than fidelity. Many speakers are in the range of 1% for the less expensive ones.... even the costly ones are only about 10% in that configuration though good cabinet design can raise this to 25%.... with a loss of frequency range (folded horns for example). A speaker designed for 60Hz operation with a tuned resonator could be much higher.

However, the alternator could be removed and the design still used for chilling. The question would be, is it any better than a rocket connected to a propane fridge salvaged from an RV? The thing to remember in the case of cooling is that the fire needs to burn all the time or intermittently 24/7 unless you run one to make ice for a separate cooler.

I wonder if Marcus has an opinion on this.

- the average European shops for food every day, and his/her fridge is 30% to 60% of the size of an average american refrigerator, and generally more efficient!

If you had a high % of The volume of the Fridge filled with ice or just cold water, you could easily carry your fridge 12 hrs or a little longer, But this would still be a
daily chore to manage, probably every one should have a large Cooler With an over wrap of additional Insulation to transfer the contents of your fridge when you
need to be away or ''off-grid'' for a while ! Just my 2 cents ! Big AL !

Dale, this is very interesting. If you (or anyone) could get this working safely and reliably, that would be an amazing step for homesteader types.

Here's a link to some explanation and diagrams.

http://home.howstuffworks.com/refrigerator.htm

http://www.robertsewell.ca/propane/




EDIT::: I love posting to zombie threads .

Dale Hodgins wrote:   Rocket stove/refrigerator. The propane powered refrigerators which are common in recreational vehicles have no moving parts other than the hot and cold gases flowing through their expansion tanks, condensers, and heat exchangers. Without getting into huge detail on the workings of these machines just know that the fridge works when the boiler section is heated with a flame.

     I am new to computers so I'm hoping someone familiar with this type of fridge can glean some graphics off the net and drop it under my post.

    So on the simplest units there's a section of pipe called the boiler which needs to be heated. Rather than purchasing expensive propane this could be accomplished simply by attaching the boiler to the side of a rocket stove heat riser or placing this same boiler inside the riser provided it can withstand that sort of extreme heat. It wouldn't take much of a rocket stove to produce a much larger fire than my propane fridge has.

    This unit would use a light metal rocket stove with no thermal mass similar to what is used for cooking in the tropics. Trying to run this off your RMH would cause overheating in the summer when the refrigerator needs to be fired more often.

    One large scale boiler tube should therefore be able to handle a household size refrigerator and freezer. For my purposes I envision a walk in freezer like you find in stores and restaurants with a small refrigerator section accessible via regular refrigerator doors set in the side of the unit.

    I can imagine building this on the south side of a house so that concentrated sunlight could power the fridge in the summer. Alternatively, the rocket could power it all year as long as it can be separated from the house so as to not cause overheating. The stove effluent could be piped to a Coppola  where it would initiate convective currents and actually aid in cooling the house.

    So, in winter we get free power for the refrigerator since all of the heat used by the refrigerator remains within the house and in summer the rocket stove powers the refrigerator and the waste heat powers a Coppola exhaust system.   A large refrigeration unit with plenty of thermal mass in the form of food or ice  could be fired when ever Coppola venting or hot water are required.

    In environments like mine where summer temperatures aren't that extreme and all this venting may be overkill the waste heat from the flue pipe could simply be used to heat water.

    If any of you have heard of such a unit please let me know about it. Otherwise I'll bide my time until the next time I am asked to demolish a restaurant and start monkeying. I sold all of the components including insulated walls from an old cooler three years ago for $500 since storage was an issue . Now I need one,

No problems, put a small diversion pipe in your stove pipe. This is to restrict heat flow, even better with a car thermostat fitted in reverse, too much heat and your fridge is a freezer

PS Dale,

Complete with solar collector, and a wet back. Follow Coles and use CO2 as the refrigerant and one only need heating above -30*C.

Kathleen Sanderson wrote:

Pam wrote:
It was never intended to be released in first world countries  afaik.

Why do they do that?!?  I've seen quite a few interesting little gadgets that were only going to be sold in or released to 'developing countries.'  I realize that at the moment the market would be small in developed countries, but it's certainly not a non-existent market, and some of these items would be just as handy to some of us as they are to people in the 'developing countries!'  It makes me feel like a second-class citizen at times!

Kathleen

There's also the deterrent factor (for a non-university project) that the developed world:
1) tends to require extensive, independent testing and 'permitting' processes; this may be for safety or to protect the existing makers' markets, but it costs $$$ to do things this way.
2) tends to reward enterprising but less-than-thoroughly-tested novelties with lawsuits, which are judged according to public expectation and not any particular principles of physics
3) tends to be full of people accustomed to plenty, including reliable mass-produced equipment tailored to on-grid and affluent lifestyles. It's hard to do a one-off heater system using purchased parts for less than you'd spend on an existing, mass-produced item. And many customers in the US are not satisfied with the aesthetics or function of scrounged systems.

In other words, the bar is higher for success, and the price of failure greater, in the developed world.

In the developing world, something which is very efficient, very affordable, or completely independent of reliable utilities may just find an audience that is actually grateful for your efforts. If it does work well, the rewards are enormous - your effort is truly a charitable contribution saving lives and restoring human dignity. Even if it doesn't work exactly as planned, chances of being sued are small. And when you factor in the international sympathy factor / noncompete support from industry, it just gets very attractive.

I think sometimes college professors also like to use the "developing world" scenario to get their students out of the suburban box, into a realm where basic principles still apply.
from a suburban box, inventing a new video game mod sounds a lot more time-effective and risk-free than inventing something that actually heats, cools, cooks, or otherwise manipulates the physical universe.

-Erica

Dale Hodgins wrote:   Rocket stove/refrigerator. The propane powered refrigerators which are common in recreational vehicles have no moving parts other than the hot and cold gases flowing through their expansion tanks, condensers, and heat exchangers. Without getting into huge detail on the workings of these machines just know that the fridge works when the boiler section is heated with a flame.

 
    I can imagine building this on the south side of a house so that concentrated sunlight could power the fridge in the summer. Alternatively, the rocket could power it all year as long as it can be separated from the house so as to not cause overheating. The stove effluent could be piped to a Coppola  where it would initiate convective currents and actually aid in cooling the house.

    So, in winter we get free power for the refrigerator since all of the heat used by the refrigerator remains within the house and in summer the rocket stove powers the refrigerator and the waste heat powers a Coppola exhaust system.   A large refrigeration unit with plenty of thermal mass in the form of food or ice  could be fired when ever Coppola venting or hot water are required.

    In environments like mine where summer temperatures aren't that extreme and all this venting may be overkill the waste heat from the flue pipe could simply be used to heat water.

    If any of you have heard of such a unit please let me know about it. Otherwise I'll bide my time until the next time I am asked to demolish a restaurant and start monkeying. I sold all of the components including insulated walls from an old cooler three years ago for $500 since storage was an issue . Now I need one,

I like the cuppola exhaust system (see also "solar chimney"), but I like the direct-solar idea even more.

Sunlight is plentiful in our region during the same season when there's too much heat, and we'd need to run the fridge more often.
(Our early spring weather April and May have more cloud cover, compared to the solar-symmetrical months like July and August when you have more heat and also more direct sun.)
So I'd love to see a fridge that was powered by a solar primary heater, and maybe some way for it to thermostatically tap into a second (combustion) heat source when solar was insufficient.

In our (inland sub-alpine) climate, alternatively, you could probably just direct-vent it to outdoors when the solar heat is not enough; it's below freezing for several months at a time.
We're thinking about a cold-closet and a built-in fridge in our next home improvement scheme, but I hadn't really thought about combining them.

All you really need to run a thermostatically controlled system is a reliable direction to run things when the temperatures are off. One side always has to supply the cool, or the heat. Yes?
I wonder if you could do a thermostat on the outside to determine if the outdoor temperature meets your fridge needs (say 5 degrees below the desired temperature), which would switch the 'activation' signal between two systems (like solar and RMH, or cold-closet vents and heat-powered refrigeration).
Then a second thermostat on the inside of the system like normal, to "activate" when more cold is needed. It doesn't care whether the cold comes from an active refrigerator, or a passive vent.

The big challenge would be making sure there's sufficient heat or condensed coolant stored in the system to cover the 'activate' command when the fridge needs more cold at night, or when the fire is not lit. That's where propane and other refined fuels really shine - power on demand. But with the right refrigerant, I think you could build a heat-storage mass like a soapstone chamber into a rocket mass heater, that would still be warm enough to push vapors through a full night's cycle.

Does the heat source have to stop when the fridge is not drawing? 'Cause that sounds like a bigger issue to me than the rest of it. You could open and shut a shutter on the solar version, or divert the power if it's solar-electric. Maybe on the rocket heater you do a radiant 'lense,' a parabolic reflector of warm mass that points toward the heating unit, but is easily blocked with an insulation shutter when heat is not wanted.

That might be where Allan Lumley's suggestion of a cool-storage mass inside the refrigerator (a block of ice that's made during long cycles, and then a long period when it can run as a simple icebox) will help alleviate these issues. If you can get it down to a daily cycle, management and energy use becomes a lot easier.

Bear in mind that this is all theory for me.
I have accomplished 2 (count them, two) pieces of plumbing work in my life, and the second one was today.
(Oh, I lied, today makes 3 if you count taping and tightening the leaky toilet valve. But a chicken can still count them on the toes of one foot.)

Does it sound good, at least?

-Erica

Here's another point, toward the question of why these things are invented for the 'developing' world, and not as popular in the 'developed' world:

"Cost is one reason—absorption chiller systems typically cost $7,000 to $10,000 per ton of cooling; one-ton window air conditioners from big box retailers start around $250—but companies can save on electric bill as well as enjoy a more benign environmental image." http://www.scientificamerican.com/article/solar-refrigeration/

I have seen local farmers using a cheap add-on to a standard window air-conditioner to make a room-sized cool room for produce; the cost is far less than trying to rig up an absorbtion refrigeration system... at least, less than purchasing one custom-made.
The cost differences from any typical 'developed' location compared to 'undeveloped' (which includes off-grid in the industrial nations):
- cost comparisons between custom and pre-fab units always favor pre-fab: there needs to be a big enough market for a standard appliance in order to reduce the per-unit costs, in the developed world there are reliable standard power and big markets full of people who can afford convenience.
- in off grid locations it is far more typical to build for yourself, from scratch, if units or parts are not available in your area. The cost of custom labor is not usually factored into the equation; instead, local or obtainable skills are the primary factor.
- the absence of grid power / the cost to install and maintain miles of new power lines in order to enjoy the 'cheap convenience' of a pre-fab solution.

These cost factors may equalize somewhat as power gets more expensive, but there will always be some energy advantages to living in certain locations, or among a large enough population to support certain kinds of business.

-Erica

Love this idea!
I tried to come up with all sorts of refrigeration ideas at one time - even trying to figure out if I could power one by riding a bike for an hour a day.
This would be a huge thing.
I want someone to do this and then tell me how to make one. LOL

i think but could be wrong, wouldn't be the first time, that you would have a problem with regulating the heat input. get it too hot and you may have a high pressure gas release of ammonia which wouldn't be nice. from what i know about the cycle on these fridges there is a point where the gases are separated i suspect the the temperature of the heater is fairly critical . mine has a 120 watt element and a gas consumption of 13 grams per hour. should be fairly easy to see what that is watts. i bet it is not far off 120 watts or so. ther is ayahoo tech forum called refrigeration alternatives. might be worth having a look there and reporting back.

Give us updates please Dale!  did your flying suit ever fly?  This thread is twelve years ahead of me, I really hope you've found some great solutions meantime.

I recently learned that the fridge doesn't actually refrigerate, it is simply stealing cold air from the freezer (at least in older, freezer-on-top models), through a little vent that can be adjusted.  This leads me to think that you can make a fridge section of your thing and a freezer section and not worry about the freezer getting too cold--you can always close the vent  between the two as needed.

I too like the passive solar powering of this better than the rocket powering, but in winter it could certainly be rocketed.  I am trying to understand just how much heat is needed.  Seems like 1.5 square meters of solar collection would power a normal fridge, assuming an average of 5 hours of sun per day, and if the sunlight can be focused with some parabolic lenses you have your heat need, more or less where you want it to be.  

I second Big Al's point about smaller fridges and fresher food.  A fridge's contents expand to the limits of the size of the fridge by Murphy's second law of expansion.  Buy a second fridge and now you have more rotting food in the back of it.  

Joshua Myrvaagnes wrote:Give us updates please Dale!  did your flying suit ever fly?  This thread is twelve years ahead of me, I really hope you've found some great solutions meantime.

I recently learned that the fridge doesn't actually refrigerate, it is simply stealing cold air from the freezer (at least in older, freezer-on-top models), through a little vent that can be adjusted.  This leads me to think that you can make a fridge section of your thing and a freezer section and not worry about the freezer getting too cold--you can always close the vent  between the two as needed.

I too like the passive solar powering of this better than the rocket powering, but in winter it could certainly be rocketed.  I am trying to understand just how much heat is needed.  Seems like 1.5 square meters of solar collection would power a normal fridge, assuming an average of 5 hours of sun per day, and if the sunlight can be focused with some parabolic lenses you have your heat need, more or less where you want it to be.  

I second Big Al's point about smaller fridges and fresher food.  A fridge's contents expand to the limits of the size of the fridge by Murphy's second law of expansion.  Buy a second fridge and now you have more rotting food in the back of it.  

I take that back about rocket in winter--maybe it's better to have an outdoor-ish freezer in winter and then adjust upward with a little added solar heating , rather than trying to do thermostatic cooling.  But on the other hand if you have the high technology only in your cooling device and no high tech heating device then it makes sense to use the cooling device.

An easy thermostatic heating device might be a heat pad...but if your greens freeze on top and stay mushy on the bottom then that is a failing.  Probably better just to stick your greens in water at room temperature and eat them sooner, and grow more on your windowsill.

I realized I don’t know if a propane fridge is indeed thermostatic other than cycling the propane off and on…maybe a simpler soliton is hiring Maxwells demon to sort it out.  

https://permies.com/t/40/132501/Refrigerator-doesn-power-build

Adding link to other similar topic thread.