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more needed for GVCS
  • I looked through the Global Village Construction Set and I noticed two glaring omissions: refrigeration and air conditioning. Most of the world's poorest people live in hot climates, and without these elements modern civilization is much more difficult. Refrigeration means the preservation of food and medicine; air conditioning gives comfortable conditions in extreme heat (and with solar power, your greatest electrical production is during the greatest demand for AC).
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  • I agree with Robotguy; There's a need for refrigerated storage of medical items and for air-conditioning of medical facilities in certain circumstances, if not for personal comfort, as well as for food storage and preservation.

    Somewhere I have a document on creating a solar-powered batch freezer, which uses ammonia as a refrigerant in a solar collector, then after sufficient energy is collected, the pressurized ammonia is dumped via an expansion orifice inside an insulated box, creating a batch of ice by expansion of the ammonia. This is just like a regular air-conditioner, except running in intermittent cycles instead of continuously.
    The ice is then moved to an icebox to refrigerate vaccines or seeds or whatever.
    This system requires attention daily to operate, but could be a valuable system for remote areas, and once installed doesn't have many moving parts or upkeep.
    I'll see if I can dig up the document when I get home.

    I've thought that a sufficiently sized system could produce ice for a superinsulated ice-house, with a daily batch of ice being made and dumped down a chute (for example) into the ice-house to keep foods in cold storage.
    Other refrigerants could be used, such as propane.
    There are lots of options.

    For food preservation, instead of refrigeration, I'd like to see small-scale electron-beam food irradiators become available. As opposed to gamma-ray irradiators, which use radioactive materials to bombard foods with sterilizing gamma rays, electron-beam systems use a high-energy beam of electrons (similar to what's inside a CRT tv or monitor) to sterilize food and medical materials with much safer electron radiation. There's also X-ray irradiation, which has greater penetration.

    A system the size of a home oven could protect food for an entire village, when combined with airtight containers like glass jars with sealing lids. Such a system could make meats and dairy products almost shelf-stable for consumers who don't have access to electrically operated (and polluting with CFCs) normal refrigerators.
    I'd heard about electron beam sterilizers coming onto the market, but I think they were talking about large-scale systems for food processing facilities. Has anyone heard of smaller-scale "appliance" irradiators? If not, maybe we could design such a beast.
    Blah blah safety blah blah. Yeah, yeah, I hear you already.... "radiation" can be dangerous. So is standing in the sun. Done right it would be a great boon to mankind. Let's do it right.
  • Fridges have been discussed here:

    The "Einstein fridge" in that article sounds like what Wolfrick is talking about.

    (Edited by the admin to remove the extra dot at the end of the URL - Thanks, @Flipnash and @bburnaman!)
  • the link brings up an empty page.
  • Living in Texas, where we have summer all but three months a year, I am fixated on making sure that some sort of air conditioning is included in any solution that I seriously consider. My wife and I are interested in building a green home in the country, using as much of a sustainable approach as possible, but I can't even begin to imagine doing that without some method of cooling the environment. I'm spoiled by my A/C, and I'm not giving it up. (I'm able to soothe my conscience by knowing that we use an electric provider who uses 100% wind energy).

    I've looked into some options, but I think that it will ultimately require a number of them combined. I like the idea of using a solar chimney in the building plan. Does anyone have any practical experience using one of in the real world, particularly in a very hot (90-100 F/32-38 C) and very humid (80-90%) climate?

    BTW, the link somehow appended that trailing period of the sentence. This one takes you to the page that Conor references:
  • As a northerner, I have difficulty agreeing with the assertion above this reply. This is partially because of an understanding of passive cooling techniques used for thousands of years, but more because I have difficulty accepting the basic premise.

    If am omission is glaring, then its non-existence, once established, should be apparent to everyone, from Africa to the Arctic. In a modern and wealthy society we can afford to demand comfort. However, millions of people die daily and have little interest in anything they cannot eat.

    It is my opinion that as this community develops there will be information outside the core GVCS that deals with air conditioning and refrigeration, but I do not believe this information belongs on the core list. One of the essentials for being on the list is: "Essential contribution to an infrastructure for living and working." Granted, comfort is important, but both air conditioning and refrigeration are, in my opinion, non-essential modern conveniences. Moreover, it is important to consider the energy demands of such devices. Are they consistent with our ideals?

    While I do slightly question the presence of a Bakery Oven and Dairy Milker, I am familiar with both milking and baking and know the amazing impact these devices have upon time and production volume.

    I think it is important to maintain a clear vision of our mission.
  • @ARGHaynes - your "millions of people die daily " statement is unsubstantiated. Two million a day x 365 days is 10% of the population of the Earth per year. The actual number of deaths from all causes, according to the US Census Bureau ( ) is 56 million per year, or 154,000 per day. Some fraction of that is due to malnutrition.

    As far as air conditioning and refrigeration, there are ways to do that which do not require a lot of electricity. They may not be part of the core system, but I see no harm in including information about them.
  • @Daniel - Thank you for your input, I will have to make a point to be more careful with my usage of English; though, unless my math is wrong, 730,000,000 does not exceed the current world population.

    According to Wikipedia, the number of starvation related deaths is difficult to come by, but malnutrition affects a mere 14% of the world.

    Also, thank you for clarifying the point I was attempting to make. While I feel they should not be part of the core system, developing information on them is not bad.
  • My math was wrong, I corrected my previous post.

    Let me make a stab at clarifying things in engineering terms. "Food Storage" and "Living Space Climate Control" are necessary functions in most locations and circumstances. What design you use to perform those functions can vary from simple and passive, to complex and active. What quality in performing the function you demand can vary according to circumstances. A dry pit to store root vegetables is simple and cheap, and has worked for thousands of years, and has some spoilage rate associated with it. If you demand less spoilage, you may need a more complex design. Similarly, if you accept 15-35C as the allowed temperature range for your living space, you can get by with a simple design (and lots of warm clothes in winter). If you demand tighter control of temperature, you may need automatic thermostats and heat pumps.

    So in designing the GVCS, I don't think there will be a single solution suitable for every location and circumstance. I think a bread oven is listed as one of the core machines, but that is not much use where you cannot grow wheat. I think we need to think in terms of basic functions that need performing, then provide different options as needed.
  • I think I may not have clearly expressed that my response was not calculated to say that the modern methods of food storage and living space climate control that has become normative in modern America is not important. Rather, I was arguing that a complex, active model of each is not important enough to make the core list.

    I do think that the Bakery Oven would be useful for more than just wheat bread.
  • "Cooking" is the necessary function, since it destroys micro-organisms and some food toxins, and makes food more digestible. A Bakery Oven is one possible device to perform the function.

    I have actually built a 2 meter cubed medieval village oven for a historical group, and I agree they can be used for any kind of cooking. They are pretty simple devices at that level, mostly bricks and earth. Actually running one makes it very clear that without a thermostat controlling an electric heater, it is way less work controlling one big firebox than a lot of little ones. Also a large oven is more efficient because it has a smaller surface to volume ratio (less heat loss), and can cook successive items with the residual heat after the fire is out. In fact the next day it still was sufficiently warm to let the bread rise.

    Even with modern equipment there are still gains to be had from a big oven, such as combining the cooking of a number of different items. But perhaps "Community Oven" is a better name for it than "Bakery Oven". The latter is too specific a name indicating a limited function.
  • To a person with a high fever caused by Malaria or Dengue, air conditioning is beautiful. In the most poverty-stricken areas of the world, if they have an electricity supply then it is because they have a medical clinic (and nothing like what we would call a medical clinic in the developed world) with a refrigerator for preserving medicines.

    Producing your own food supply is wonderful but food needs to be preserved - in many cases refrigerated or frozen. If you really want to create a global village construction set, something to help people lift themselves out of grinding poverty and bring them into modern civilization, then we have to look at these things that are simply taken for granted in the West.
  • Let me chime in here by saying I really feel our core values are already too broad in scope. Where do we draw the line? We can't build everything all at once. Our combined resources will only get so much done in the next few years. Somehow, we need to find a way to narrow our choices. Otherwise, we run the risk of thinning out production and getting nothing finished.

    I would choose to concentrate on the most basic of needs first. Growing food and building homes would be high on the list. Refrigeration and metal smelting would not even be on the list frankly.

    I would look at each of the proposed projects and ask myself, what is to be gained. What are the alternatives to self replicating. Refrigeration is a good example of a mass produced product that costs very little in the grand scheme of things. There's not enough benefit AT THE MOMENT to bother spending our precious resources on this.

    A farm tractor on the other hand is well worth the effort. These are expensive machines. There is much to be gained in designing and replicating such a thing. Not to mention it can be used for many different tasks.

    Do we need refrigeration, yes I think so. We also need clothing but we really don't need to build a mechanized loom because i can go to the store and buy what I need for cheap.

    The Dawg
  • How about incorporating a modular reversible heat pump in the GVCS? It could be used to heat and cool houses and greenhouses, to refrigerate food and medicine, for geothermal energy and many other applications. SHPEGS have pretty much designed an open-source one already - see
  • Please check the GVCS Selection Criteria:
  • in my opinion the personal fabrication machines, Liberator, lifetrac+attachments should take priority over all other machines in GVCS. Some of the machines could probably even be omitted.
  • @Dawg, again, I totally agree. No sense reinventing the wheel... especially for things like a mechanical loom or whatever right now. Walmart exists... it's not a violation to purchase cheap-ass t-shirts there based on principle. The industrial fab machines are where OSE can have the most impact, allowing people to mold their immediate environment to a more sustainable and productive one.
  • @eBell, I will chime in with agreement too. I think it is easy to get caught up with the "we could do anything" idea and forget that we are trying to build a foundation for a new way of doing things-- not trying to make a space colony.
  • I do think that refrigeration is a an important priority in tropical developing coutries. I live in Brazil, and, in the case of the majority of the poor in this country, a refrigerator is one of the top "first purchases" after some money is saved. In my own experience I know how refrigeration is so important: live in a small farm, and with refrigeration my eggs and vegetables last more, I can preserve medicines and save time and fuel cooking each other day.

    But I discovered that traditional refrigerators are big power hungers! I can live confortable with the small pv system we have for back up eletricity, but we still need the grid for the refrigerator (I would need to double my pv system just for the refrigerator). To design and build a extra-low energy consumption refrigeration is one of the top projects in my "to do list".
  • >> To design and build a extra-low energy consumption refrigeration is one of the top projects in my "to do list".
    You may be interested in this -

    It's a very simple conversion that turns a chest freezer (about $200) into a fridge that uses only 150 Watt-hours a day, compared to 1000 Watt-hours a day for a normal fridge. You need to buy a thermostat to do the conversion, which is $150 at most.

    Also, put the fridge in the coldest possible place, so it'll use less energy. Maybe bury it.
  • @Conor - besides the conversion you pointed to, you can add lots of insulation around the outside of the chest freezer to reduce heat leaks. I used to do that for group camping events. Take a large cardboard box, line it with sleeping bags and some foam pieces during the day, and nest the usual plastic cooler inside it. It made quite a bit of difference in daytime ice use. For an electric freezer make sure not to cover up whatever part is used to eject heat from the compressor (coils or metal plate on the back)
  • I will definitively try to hack a freezer termostat someday, but I need first to find a realy cheap chest freezer to experiment with. A new chest freezer here starts at about US$ 400,00.

    But, In fact, I'm following another track. I'm experimenting with and trying to improve the Zeer pot:

    I get a 10 degree(celsius) drop in temperature with the original design. I'm trying to figure out how to combine the evaporative cooling with forced convection, geothermal cooling and better insulation to get a bigger drop.
  • Free piston stirling or thermoacoustic engines can be used in reverse quite effectively for refrigeration. The Stirling cycle being completely reversible, although there are some minor changes apparently if you want absolutely optimum efficiency.

    The Coleman Stirling power cooler used a stirling cooler device developed by sunpower. Sunpower also has developed stirling cycle based bigger consumer fridges apparently.

    So this thing Colin said is totally doable, and it's true refrigeration is a must really. If an 1kW FPSE was developed for the dish thermal solar system it would be too big to be ideal for a fridge, but maybe it would work for a larger walk in fridge or freezer okay. In any case the development experience would port very well to a smaller one.

  • Check out "indirect" or multi-stage evaporative cooling: You are limited to the wet bulb temperature, though. So you can cool a cabinet that a refrigerator sits in, but will likely need a supplementary cooler for some foods to not spoil.

    I have updated this wiki page with information I previously collected about design and implementation of a solar powered ammonia absorption icemaker.  I'm convinced this design can be augmented with multiple stages, insulation, and thermal mass to create as large a walk-in freezer that we care to have - in addition to a source of cool to store food in.  I shall have to doodle some design drawings up for it, if people think this is a pattern that just might be worth putting some design time into.


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