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Bill Bianchi
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http://scialert.net/fulltext/?doi=jas.2010.406.412&org=11

That link is to a research paper exploring the feasibility of storing producer gas from a wood gasifier in pressurized cylinders. For those here who actually understand the techno-babble, feel free to sum up the info in layman's terms.

I can think of a few reasons to store it this way. It could be used to suppliment gasoline consumption while driving. It could also be used as stationary storage for home use, so you can make one long run at the beginning of the month and make enough to carry you through the rest of the month.

I assume the same could be done with methane gas.

For transportation, I'm referring to the hybrid systems that bring producer gas or methane into the engine along with regular gasoline. Works a bit like HHO electrolyzers, I guess. Seems like a pressurized tank would make running on producer gas or methane easier.

The extra energy required to compress the gas could be covered using a portion of the gas.

Just some reading material for anyone interested.
 
Marcos Buenijo
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Bill, I read through the paper. Most interesting is that fact that there is no mention of the energy required to drive the compressor as the energy consumed in compression is the primary reason why compressing producer gas is such a bad idea. However, there are other reasons including the danger of introducing impurities to a pressure vessel that might compromise the integrity of the vessel over time. I did some back of the envelope calculations that show compressing 2 units of producer gas to 100 psig with a conventional single stage air compressor driven directly by a conventional gas engine fueled by producer gas at 17% net thermal efficiency (including thermal losses from the gasifier) would consume 1 unit of producer gas by the engine. So, 1/3 of the gas is consumed just to take the gas to 100 psig. NOTE: This efficiency of 17% is typical of a gas engine fueled by a gasifier and operated at an optimal output.

The idea seems attractive, but the problem is simply that the energy density of producer gas is 1/8 that of natural gas. Compressing the gas to any significant degree is just not practical. The only way I've considered for an individual to store the gas that might have some merit is to store it daily in large latex weather balloons, but even this setting presents many dangers that are not worth the effort (toxic gas!). Besides, even a latex weather balloon 10 feet in diameter stores only about 70,000 btu of producer gas (equal to about 0.56 gallon of gasoline).

The short answer is that biomass might be considered as nature's solar energy battery. So, if someone wants to take advantage of biomass for fueling internal combustion engines, then wood is probably the best way to store this energy. Dual-fueling internal combustion engines is a possibility that I've considered also, and I personally think there is merit here. Although, most wood gas enthusiasts with experience tend to advise against it (they prefer a full wood gas conversion or an either/or configuration where one can switch from full gas or full wood). I'm convinced their position is largely subjective. The only solid argument I've heard against it is that a small gasifier used to dual fuel an automobile can be overdrawn to cause excessive temperatures and it's also possible to run out of wood fuel without realizing it which would consume the charcoal and cause excessive temperatures high enough to melt the gasifier. There is also the problem of ensuring sufficient air is drawn through a small gasifier at all times during operation (including idle). Of course, these problems would have to be engineered out, and I don't consider these to be difficult problems to solve in principle.

 
Bill Bianchi
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Marcos, thank you very much for going over this. The thought of propane tanks full of producer gas seems attractive, but it doesn't seem worth it after reading your summation. Thank you again for taking the time to read the report and typing your response in terms I understood.

That said, I'm working on a project I hope will be a game changer for producer gas production. I'm doing it using an external flame, almost exactly the same way folks who make charcoal do it. Instead of venting the producer gas into the air or routing it to a burner beneath the chamber the way charcoal makers do, I'm attempting to capture it and "clean" it up using the external flame to heat a reduction chamber. This should allow gasification of ANY gasifyable material using just one gasifier. I'll update my progress in a thread titled 'rocket stove Gasifier'.

My ultimate goal is to efficiently gasify landfill-destined waste. Reduce the amount of waste going into landfills by cleanly turning it into electricity by converting it to producer gas to fuel a generator.

Since compressing the gas is out, I'm going to store it in big innertubes. I'll weigh down the stack of innertubes in order to make pressure.

Please feel free to look over this experiment and comment.
 
Marcos Buenijo
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Bill Bianchi wrote:Marcos, thank you very much for going over this. The thought of propane tanks full of producer gas seems attractive, but it doesn't seem worth it after reading your summation. Thank you again for taking the time to read the report and typing your response in terms I understood.

That said, I'm working on a project I hope will be a game changer for producer gas production. I'm doing it using an external flame, almost exactly the same way folks who make charcoal do it. Instead of venting the producer gas into the air or routing it to a burner beneath the chamber the way charcoal makers do, I'm attempting to capture it and "clean" it up using the external flame to heat a reduction chamber. This should allow gasification of ANY gasifyable material using just one gasifier. I'll update my progress in a thread titled 'Rocket Stove Gasifier'.

My ultimate goal is to efficiently gasify landfill-destined waste. Reduce the amount of waste going into landfills by cleanly turning it into electricity by converting it to producer gas to fuel a generator.

Since compressing the gas is out, I'm going to store it in big innertubes. I'll weigh down the stack of innertubes in order to make pressure.

Please feel free to look over this experiment and comment.


I had a similar idea a couple years back. I considered sending the gas through a highly insulated chamber into which highly preheated air is introduced to provide high peak combustion temperatures in an attempt to crack tars (no external flame as this approach exposes the gas to higher temperatures... unfortunately, it would dilute the energy density of the gas by mixing it with combustion gases - oh well). So, the gasifier design is compact and highly insulated. The hot gas from the hearth moves directly to the insulated burn chamber where it mixes with highly preheated air. Since the gasifier is at a partial vacuum, then introducing preheated air to the chamber can be easily done by placing a small stainless steel tubing coil in counterflow fashion inside the chamber to admit air (along with turbulence for good mixing and higher temperatures). The air supply to the tubing coil is throttled with a small valve to achieve peak temperatures (as measure by a probe in the chamber). You might consider this as a first project since it's relatively easy to do.

A gasifier design from the 1980's did something similar where some tarry gas was taken off just above the hearth and burned, then the combustion gases were reintroduced to the hearth to raise peak temperatures and help crack whatever tars remained.

I believe there is a small company in Florida experimenting with plasma to crack tars from a gasifier.

 
Bill Bianchi
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Thanks for the info, Marcos. What I'm trying may not work. Or, it might. I figure I haven't failed unless I give up. If the heat from the rocket stove isn't enough, we're going to try to burn charcoal in the stove, since that's our byproduct anyway. If we melt our stove, we'll at least know we have the necessary heat to crack tar.

Turns out a member here posted about the answer to how you gasify not only wood, but any other organic feedstock as well. It was a post about charcoal gasifiers, started by---you, Marcos, if I remember correctly. I thought it was brilliant and saw the potential for gasification of just about any organic waste one might have locally available.

Marcos, do you know if I'm going to run into any trouble storing producer gas in a stack of innertubes? Does it go " bad" after a set amount of time? Will it degrade the rubber quickly, assuming our stored gas is clean? What is your preferred storage method?

If my partner and I fail to build a workable multi-fuel gasifier the way we're attempting now, we're going to move on the charcoal gasifier and making charcoal from municipal and agricultural waste briquettes.
 
Marcos Buenijo
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Bill Bianchi wrote:Thanks for the info, Marcos. What I'm trying may not work. Or, it might. I figure I haven't failed unless I give up. If the heat from the rocket stove isn't enough, we're going to try to burn charcoal in the stove, since that's our byproduct anyway. If we melt our stove, we'll at least know we have the necessary heat to crack tar.

Turns out a member here posted about the answer to how you gasify not only wood, but any other organic feedstock as well. It was a post about charcoal gasifiers, started by---you, Marcos, if I remember correctly. I thought it was brilliant and saw the potential for gasification of just about any organic waste one might have locally available.

Marcos, do you know if I'm going to run into any trouble storing producer gas in a stack of innertubes? Does it go " bad" after a set amount of time? Will it degrade the rubber quickly, assuming our stored gas is clean? What is your preferred storage method?

If my partner and I fail to build a workable multi-fuel gasifier the way we're attempting now, we're going to move on the charcoal gasifier and making charcoal from municipal and agricultural waste briquettes.


Consider drying and charring particulate biomass in situ using the approach I described in the other thread. I'll go over it again here: It might be possible to replenish charcoal to a charcoal gasifier in situ by using engine exhaust heat to char particulate biomass, then finally directing the remaining engine exhaust gases (and heated air from the cylinder cooling) for drying the biomass fuel. What I'm thinking here is particulate biomass might be dried while contained in a hopper, then the biomass forced through a long auger tube that can be aggressively heated with engine exhaust. The biomass might be charred and dropped into the charcoal gasifier to replenish charcoal. The tricky part is finding a way to pull the pyrolysis gases generated inside the tube into the air supply tube where they can be combusted to incinerate most of the tars and add heat to the reactor to raise peak temperatures in the reactor and crack whatever tars remain in the fuel (and those that can't be pulled into the air supply tube). I speculate, but it might be a matter of simply connecting lines from the air intake to the proper points along the auger tube, and possibly connecting the engine exhaust to the auger tube at the proper point along the tube.

I think you could store gas inside innertubes indefinitely (won't go bad). However, I advise against storing the gas at all due to it's low energy density and toxic nature. I prefer storing it in the form of biomass.

I think some hybrid charcoal configuration like I suggest above is promising. In particular, I think the best system would perform all processing in situ (such as, while the system is operating raw biomass would be fed into a chipper/shredder, to a drying hopper, then fall by gravity into an auger tube to be forced through the system as described before). NOTE: What I describe there is really just another configuration for a biomass gasifier, meaning, that it does the exact same thing as an Imbert gasifier. The possible advantage is that thermal losses from the gasifier is lessened, and a lot of heat can be added. Charcoal happens to be an excellent thermal insulator, and the Kalle design can confine the reactor to within a mass of charcoal. Also, the vessel itself can be highly insulated to lessen thermal losses further. Note that the Kalle purposefully adds engine exhaust gases to the reactor to protect against excessive temperatures, so clearly there is energy available for processing tars. The goal is to send enough tar to the reactor for processing (which will lower temperatures due to the endothermic nature of the reaction) while simultaneously sending tar in with the intake air for combustion (to increase temperatures due to the exothermic nature of the reaction). The problem is reduced to figuring out how to split the flow of pyrolysis gases properly from the auger tube to the intake air tube and hopper to achieve optimal reactor temperatures.

 
Marcos Buenijo
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Bill, there is another paradigm that you might consider. Assuming you are considering a system suitable for a residential scale, then it can be more efficient to combust biomass fuel directly for heating applications. I don't mean heat merely for space heating and water heating, but also for space cooling and even water processing. I discuss these elsewhere, but I'll make a discussion here as well. First of all, I take the position that we tend to consider "alternative energy" as various means to generate electricity primarily because we have grown dependent upon this source of energy for a long time now. Well, generating electricity at the micro scale is not nearly so efficient as can be achieved in massive power plants. For example, a good wood gas engine system operates at a net efficiency of roughly 15% in generating ac electricity, and this assumes the system is operated at an optimal output. Once the system operates outside this optimal range, then efficiency can drop a great deal. At a low part load where generators tend to operate, the efficiency is roughly 1/2 the optimal output. Expect a net efficiency well under 10% for a wood gas engine system operating in a real world application. If a large system were operated at an optimal output at all times (say, for feeding electricity to the grid), then efficiency can remain near optimal levels. However, there is a catch 22 here... what about the waste heat? Can this energy be put to full use in such a setting?

I am absolutely certain that a relatively simple chilled water system can be constructed at a residential scale to provide cooling at an overall coefficient of performance of about 2/3 (and this is conservative). That is, the cooling capacity can be fully 2/3 of the heat rate of the furnace that powers the system. Furthermore, the condenser for the system can provide heat at about 150F, and at nearly the same rate as the cooling capacity. So, during summer one could burn biomass directly to power a chilled water system that also provides all water heating, and can also dry the biomass fuel. The same system can also provide all space heating and water heating during winter months. Water pasteurization is also possible by tapping the furnace heat, and very little energy is required here. NOTE: Water processing is often neglected in off grid systems, and sadly the most reliable means for processing water (pasteurization) is rarely considered... again, I chalk this up to our long dependence on centrally controlled resources.

In short, if your goal is micro scale power generation at the residential level, and you desire to make the most of limited biomass resources, then stepping outside the electricity generation box should interest you.
 
Bill Bianchi
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The water chiller interests me very much. Electricity, transportation fuel, home heating, and hot water heating are fairly simple to handle with passive and active systems; gasification, fuel alcohol still, solar panels, wind gadgets, TEG technology.

AC has thrown me for a loop, though. I've looked into absorpsion cycle chillers/refrigerators/freezers/ice makers. While possible, there aren't many products for sale that use this for air conditioning, at least so far as my searches have gone. I've been wracking my brain for a while on this. Even tried to figure out a small, personal AC system designed to cool off one or two people, rather than the whole house. Still think it would use less energy overall to cool the people down rather than a whole house, or even one room, but I'm not sure how to do it yet, or even if it's possible or viable.

You gave me a name to look up in another thread. I'll be looking him up today.
 
Marcos Buenijo
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Bill Bianchi wrote:The water chiller interests me very much. Electricity, transportation fuel, home heating, and hot water heating are fairly simple to handle with passive and active systems; gasification, fuel alcohol still, solar panels, wind gadgets, TEG technology.

AC has thrown me for a loop, though. I've looked into absorpsion cycle chillers/refrigerators/freezers/ice makers. While possible, there aren't many products for sale that use this for air conditioning, at least so far as my searches have gone. I've been wracking my brain for a while on this. Even tried to figure out a small, personal AC system designed to cool off one or two people, rather than the whole house. Still think it would use less energy overall to cool the people down rather than a whole house, or even one room, but I'm not sure how to do it yet, or even if it's possible or viable.

You gave me a name to look up in another thread. I'll be looking him up today.


I think I referenced Ken Boak earlier. Mr. Boak owns a small home on a 1/10 acre suburban lot in the UK. He's been running his home off grid for a few years now using a single cylinder Lister Diesel engine. He used waste vegetable at first, but now fuels the system with a wood gasifier using wood chips. The most interesting part about his system in my opinion is the extensive heat recovery he's able to accomplish. He's also seeing good thermal efficiency by keeping the engine loaded down at all times and avoiding a lot of battery losses. He does this by powering an ac generator head with the engine. While the system is operating he is powering the home with the generator while also charging a battery system. The electric loads powered by the generator include electric heating elements, and this particularly helps to keep the engine loaded. All the while the system heats and stores a large volume of water. So, when the engine is shut down during most of the day there can be electricity provided by the charged battery, and heat provided by the store of hot water. Air conditioning might be provided with such a system by driving an automotive a/c compressor with the engine to freeze mass of water that can be used in a chilled water system. I don't suggest trying to cool an entire home as this seems impractical, but a chilled water system can be used for cooling single rooms or even personal spot cooling. A similar approach might be had with photovoltaics. A dc motor powered by a PV array could be used to drive an automotive compressor. Also, a large chest freezer might be powered by a PV array to freeze water bottles to be used for personal spot cooling. An advantage here is that a modest battery system is needed as the freezer can be powered as a diversion load off the battery... unfortunately, this would not provide much cooling capacity.

While I do not know of any small absorption chillers available for purchase that might be suitable in an off grid setting, I do believe that building such a unit can be done using inexpensive components. Of course, developing such a unit properly would be costly. The main problem is devising a system to maintain the high vacuum required (I'm considering those systems that use water as the refrigerant). I suggest using a liquid desiccant such as aqueous calcium chloride for its ready availability and low cost, the ability to isolate the desiccant in a part of the system for regeneration (i.e. heating to remove the water), and the ability to efficiently heat the desiccant with a simple means (as compared to using a solid desiccant). I mentioned elsewhere a big advantage of this kind of system in that it provides a source of heat at a rate roughly equal to the cooling capacity, and at a fairly high temperature on the order of 150F. Furthermore, since such a system can in principle be devised to operate at a low output for long periods, then there is more opportunity to use the available energy efficiently while also avoiding the use of large thermal masses. The ideal off grid power system in my mind would use a biomass fueled chiller that provides space cooling, water pasteurization, water heating, biomass drying (and other heating applications like food drying and clothes drying if desired - the heat here is essentially free) while also being configured for space heating during the winter months. Excellent insulation and passive solar strategies can be used to minimize fuel consumption for temperature control in the home. A photovoltaic system makes sense for electricity while also greatly minimizing electricity usage. A small genset can be available for battery charging only when necessary.

* On water pasteurization: it seems 150F is not sufficient here, but the condenser of such a system can heat a water source to 150F, then it can be pumped slowly to a secondary heat exchanger in the furnace to take it to pasteurization. Most of the heat gained in the furnace can then be returned to the 150F water before it enters the furnace using a compact counterflow heat exchanger. A second counterflow heat exchanger can then be used to preheat the water before it it heated by the condenser. This would regenerate most of the heat back into the system. The condenser can then be used to keep a thermal mass at 150F that can be used for on demand water heating purposes. The cool pasteurized water is passed through a filtration system before it's potable, delivered to a non-pressurized storage tank, and an on demand pressure pump is use to deliver the water to the home.

NOTE: I wasn't going to discuss this, but maybe I should because people are not generally familiar with absorption chillers that use water as a refrigerant. The basic idea is that liquid water will evaporate rapidly at a high vacuum. This will quickly lower the temperature of the water to ambient. If there is a means provided to continually remove water vapor from the system, then the water will continue to evaporate such that the temperature is very low (even approaching freezing, and adding a salt to lower the freezing point can take the temperature lower). A desiccant will absorb water vapor from the system to drive this evaporation process. However, there has to be a means provided to "regenerate" this desiccant. This is done by heating the desiccant to remove the water vapor. The water is released in the heater at a higher pressure (still at a vacuum), and the water vapor is condensed (the source of the 150F temperature mentioned before). The higher pressure in this part of the system can then force the water up through a small line back to the water vessel that is elevated. Chilled water is provided by insulating the water vessel, then placing a heat exchanger in the cold water. Pumping water through the heat exchanger provides a continual source of chilled water for air cooling. The regenerated desiccant solution has to be pumped to a system that encourages its absorption of water vapor. It might be sprayed through atomizing nozzles in a chamber, or allowed to flow over packing material that provides a high surface area for exposure to the water vapor in the system. Note that the desiccant does not absorb well as its temperature rises, and the process of water absorption raises the temperature of the desiccant. Therefore, keep this part of the system uninsulated and flow the desiccant at a fairly high rate to prevent excessive heat build up there. So you see, it is very simple. The problem is building it so it's reliable and cost effective, and just plain practical.
 
Bill Bianchi
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You are miles ahead of me on this. The best I've come up with so far is a possible portable, single person cooler made from a small fan, styrofoam beer cooler, and a pipe.
Fill cooler with water. Put pipe in the water, both ends of the pipe coming out two holes cut into the lid. No water gets inside the pipe as both ends remain above the waterline at all times. Stick it in the freezer until you have a block of ice with a pipe through the middle. Take it out, press the lid down, put the fan on one end of the pipe, and aim the other end at yourself.
For constant cooling, make two of them, so one can be freezing into ice while the one in use melts.

LOL, that's my redneck approach for single person cooling. Goofy, but the extra load put on the freezer might be less than running an AC unit to cool a room---maybe. The only thing I can think to do to make this not cost money is to run an absorpsion freezer on homemade methane or producer gas.

Your idea sounds better than mine. Wish I knew enough to try it. If any DIY plans exist, I would be interested in getting ahold of them.
 
Marcos Buenijo
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Bill Bianchi wrote:You are miles ahead of me on this. The best I've come up with so far is a possible portable, single person cooler made from a small fan, styrofoam beer cooler, and a pipe.
Fill cooler with water. Put pipe in the water, both ends of the pipe coming out two holes cut into the lid. No water gets inside the pipe as both ends remain above the waterline at all times. Stick it in the freezer until you have a block of ice with a pipe through the middle. Take it out, press the lid down, put the fan on one end of the pipe, and aim the other end at yourself.
For constant cooling, make two of them, so one can be freezing into ice while the one in use melts.

LOL, that's my redneck approach for single person cooling. Goofy, but the extra load put on the freezer might be less than running an AC unit to cool a room---maybe. The only thing I can think to do to make this not cost money is to run an absorpsion freezer on homemade methane or producer gas.

Your idea sounds better than mine. Wish I knew enough to try it. If any DIY plans exist, I would be interested in getting ahold of them.


Your idea is fundamentally the same as the one I mentioned where a chest freezer is dedicated to freezing water bottles for use in spot cooling. While it's true that a freezer does not operate as efficiently as a room a/c unit (mainly because the evaporator of a freezer has to get to very low temperatures for safely storing frozen food for long periods), not having to cool an entire room should reduce electricity consumption dramatically. One could literally install some ducting (and a condensate drain) on a chest freezer to direct air through for spot cooling purposes. Such a system might be practical (especially for sleeping in a hot climate).

BTW, the absorption chiller I discussed is similar in many ways to a silica gel/water aDsorption chiller. In this case the desiccant used is silica gel (a solid). See a description here: http://www.solarnext.eu/pdf/eng/products/Info_Adsorption_e.pdf . It's really amazing that these units work as well as they do since it uses only silica gel, water, heated water (or steam), cooling water, and pumps. Silica gel will last indefinitely under these conditions. I prefer a smaller system powered by a higher temperature heat source for better performance (and high temperatures at the condenser which allows using the heat again in heating applications), and using a liquid desiccant solves a lot of problems. Yeah, calcium chloride is corrosive and this would probably lead to some problems over time, but replacing a few components periodically is no problem. I've decided that trying to build a system with silica gel is a lot more trouble at the micro (i.e. individual) scale than it's worth.

 
Bill Bianchi
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Marcos, is that absorpsion chiller you linked for sale right now? Or, is it something the company hopes to roll out at a later date? Can that chiller be converted for air conditioning the way you described, assuming it is for sale right now? Not looking to cool a whole house, just a room.
What is the fuel source it uses? Would it be practical to fuel it with methane from a home scale digester, or would it require more than the average digester can provide?
Barring methane, would wood gas make a suitable substitute? For this, I would definitely store the gas in innertubes to keep the chiller working during hot spells and so I can run it without running a gasifier at the same time. I know producer gas is dangerous to breathe and it's flammable, but so is propane and NG. I think it can be done safely the same way methane is stored, if common sense is applied.

There are a few questions for you.
 
Marcos Buenijo
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Bill, I understand there is a company in Europe (Germany I believe) that is currently selling these units. See www.sortech.de . The units are fairly high capacity and capable of cooling an entire home. Unfortunately, good results from that particular system requires a supply of cooling water that is difficult to come by in hot weather. Increasing the temperature of the heat source will compensate, so steam should work well. I was very enthusiastic about using silica gel for an adsorption chiller, but I am now a lot more optimistic about using liquid desiccants.

Their unit is devised to use solar heated water. There is also a natural gas furnace as a back up. In principle, it could be heated by a methane digester. However, I note that providing enough methane with a digester would not be practical for the average person. A good rule of thumb here is that the cooling capacity of the unit is about 2/3 of the heating capacity of the furnace. Wood gas would be great, but again, I advise strongly against storing wood gas. Just use a biomass furnace to make steam for the system. A rocket furnace could work well. NOTE: Wood gas is A LOT more toxic than methane or propane! It contains about 20% CO, and only 2-3% will kill. One lung full of wood gas will kill you. Besides, the energy density of wood gas is too low to make this practical. I encourage you to do the math here to convince yourself. Wood gas has about 135 btu per cubic foot.

I don't know how much this unit costs, but I suspect it's quite expensive. Also, getting unit imported here would be that much more pricey. For your purposes, I really think you should consider actually building something. I know it's intimidating, but I am convinced it can be done.... and that it can work well using existing mass produced components IF the capacity is kept low (no higher than one ton cooling). I think you can build a functional low capacity unit with a lot less money that what it would take to purchase the sortech unit IF you do sufficient research to prevent wasting too much time and resources. I have a lot of ideas here.

NOTE: Minimizing electricity consumption from an absorption or adsorption unit requires high temperature from the heat source. Therefore, I personally advocate for using a furnace to generate steam under pressure and using copper heat exchangers to transfer the heat to a liquid desiccant. For example, this silica gel/water unit using solar heated water at modest temperatures during hot weather requires a water spray to cool the cooling water. Also, the pumping rate of the cooling water gets high and this consumes more electricity.
 
Marcos Buenijo
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http://www.sortech.de/en/about-sortech/press/

Press release that briefly describes the advancements being made by Sortech in developing compact adsorption cooling systems. Some proposed applications include automotive a/c systems and much more compact stationary units and with lower capacity. Me thinks this technology is very promising. Briefly, it seems the folks at Sortech have figures out how to crystallize zeolite desiccant onto surfaces without using any kind of adhesive. This is allows them to achieve very high surface areas for rapid water vapor adsorption under a high vacuum (for high cooling rates) while also allows for rapid water desorption rates since the heat source is transferred to the zeolite more efficiently (due to the greater surface area and better heat transfer due to lack of adhesive).
 
Marcos Buenijo
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I'm mentioning this only for interest as I don't necessarily believe it would be practical to do the following for a small unit (and I'm really only interested in fairly small units suitable for cooling a small off grid home). It is possible to devise a heat powered chiller system to achieve a cooling rate significantly higher than the rate at which heat is applied. This is done by staging (often called "multiple effect chillers"). Basically, a high temperature heat source is applied to the first stage and the heat dumped from the regenerator of the first stage at such a higher temperature that it serves as the heat source for a second stage. This can be done over multiple stages. The power requirements of the desiccant pump tends to go up, and there are added complexities like more heat exchangers and lots of check valves and what not, so there are serious down sides. However, it is interesting.
 
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Bill Bianchi : The Gas absorption chillers are old technology I don't know any that don't use Ammonia as the Chilling gas !, These units were mainstream many years
ago ! All meat lockers and cold storage were all ammonia Units up until the '50s, Today - well if you Googled Servile gas refrigerators you will be shocked at what some
rich people are willing to pay to 'be off of the Grid' ! It's not even pie in the sky by and by it is to laugh ! The 'Icy Ball' were just the earliest models! Big Al !
 
Austin Clarke
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Producer gas has very low energy density. For transportation, hybrid systems that bring producer gas or methane into the engine along with regular gasoline could be used.
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compressed natural gas cylinders
 
Marcos Buenijo
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Austin Clarke wrote:Producer gas has very low energy density. For transportation, hybrid systems that bring producer gas or methane into the engine along with regular gasoline could be used.


True. However, the low energy density of producer gas means more energy is required in compression. If producer gas is used at all, then it seems best to generate and use the gas real time (i.e. with a gasifier). You mentioned using producer gas (or methane) to supplement gasoline. This seems a good idea to me. Methane (i.e. natural gas) is a candidate for compression for its low cost and higher energy density (as compared to producer gas). Biogas might be used as well (has roughly half the energy density of natural gas). However, a small gasifier might be used to supplement gasoline to an engine. I've made a few posts on this, and I still think it's a viable configuration. I think more vehicles can be candidates for such a dual-fuel conversion as opposed to a 100% conversion to biomass. For example, a vehicle fueled with 100% wood requires a large engine to compensate for the power loss. A dual-fuel system might see good results with a smaller engine. Also, the size of the cooling and filtration system can be smaller in a dual-fuel set up vs. 100% wood. Now, it's not necessarily practical, but if one desires to fuel an automobile with biomass, then I prefer this "dual-fuel" configuration over a full conversion where the vehicle is powered with 100% biomass.
 
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