Richard Forster

Thanks a lot for the feedback, R Scott, I appreciate it and your suggestions seem very sensible and practical. I've had a brief look at the whizz bang websites, and may well throw down for them now that they've come recommended here

For sure, microhydro is nice... if you have a source of running water to borrow from.

Thanks, R Scott. So, it is all theoretical at the moment, but I'd say our aim would be to process a fairly large number of birds (say 150-250) at least once per week. From what you're saying I'm thinking that we might be best to use both - an icemaker on the day of the processing supplemented by some large blocks made (with salt) in a chest freezer, say one per day in between processing days, or whenever the sun is shining. I'm thinking that on on processing days we would probably need to resort to running a generator anyway, especially if we are running an electric plucker and an electric scalder (I like the idea of using a more efficient heat source for this, but then the convenience of a thermostatically controlled unit when in the midst of chicken slaughtering and eviscerating is appealing). So, perhaps it would work to start the ice maker running on processing days as soon as the sun is shining on the solar panels, and then once we are ready to start processing to run it along with the plucker and scalder directly from the generator, presuming it could handle the load. Does this sound feasible?

Bill Bradbury wrote:

Wind and solar outputs must be run through separate inverters, so the cost is significantly higher than for one or the other..

Bill, do you mean that they need separate charge controllers? I know very little about all this, but I would have thought that since the inverter comes between the batteries and the end use, the inverter wouldn't care how the batteries were being charged, so long as whatever is charging them is being controlled properly?

Here's a Chinese company that sells hybrid solar-wind systems. They appear to have a charge controller that handles both solar and wind...

And here are some more schematics that seem suggest it can be done... though all these links may well be fantasy for all I know...

Aloha Permies,

Not sure if this is in the most appropriate place so please feel free to relocate my post if there is a better sub-forum.

I am looking into the feasibility of doing a pastured poultry broiler operation on an off-grid property here in the beautiful subtropics of Hawaii. The property we're looking at currently has a small solar system which I'm guessing would need to be upgraded substantially in order to produce enough ice to cool down the meat after processing, and to keep it cool while transporting it to market. I'm thinking that we would probably need to use several coolers quite full of ice to progressively cool the carcasses off and then several coolers, say, half-full of ice, to transport them in. While I've been looking into the ISAAC (Intermittent Solar Ammonia-water Absorption Cycle) ice-makers, I'm afraid the $7000 price tag is prohibitive and alas I don't yet have the chemistry knowledge or the engineering skills to do it myself...

So, my question is: what would be the most energy efficient means of producing the necessary ice - a chest freezer or a purpose built ice maker? (or can you think of a climate-appropriate, outside-the-(ice)box solution to my conundrum?

I've noticed that most ice makers are rated according to how much ice they can produce in a 24-hour period. Obviously, if our electricity is produced by photovoltaics we would probably want to produce most of our ice while the sun is shining in order to avoid drawing down our batteries excessively. So, I'm guessing this would mean that an entry-level commercial ice maker that produces 100 lbs of ice in a 24 hour period would really only yield somewhat less than 1/2 of that figure the way we would want to use it. Then too, I'm not sure how to compare the energy consumption of an ice-maker with that of a chest freezer, since presumably the chest freezer works harder to make things frozen and then not so hard to keep them frozen, so that their energy consumption specs probably don't reflect the type of use we would subject it to on days when we needed a lot of ice all at once to process 100+ birds at a time.

I also came across a tip for making ice-packs for coolers that recommended using reusable bottles and dissolving a few spoonfuls of salt per bottle of water to be frozen, as this apparently reduces the time needed to freeze the water and also makes the ice last longer before it melts. Obviously it wouldn't be possible to utilize this energy-saving strategy when using an ice cube maker, but I'm also wondering if the ice makers aren't more energy efficient in the first place such that these gains would be irrelevant.

Does anyone have any experience or the knowledge necessary to teach me how to make an educated choice?

Many thanks!

Tina Paxton wrote:
How did you treat the bamboo with flame?

I have used an electric heat gun and a hand-held propane torch, but you could use pretty much any heat source, I think. Here's a photograph from a website called bamboogarden.com of someone using some kind of propane stove - which actually looks like it would be easier to use and probably more efficient than the hand-held torch, although perhaps not as good as a rocket stove?



Basically you just need to apply heat to the skin of the bamboo until the natural oils rise to the surface giving it a kind of burnished appearance. Quite often you'll see moisture dripping out of the cut ends and at the branch nodes, so clearly the process helps to remove unwanted water, and I guess the idea is that the sugars that attract the bugs and borers are converted into something less palatable. Sorry that I can't give a more scientific account of what actually happens at the cellular or chemical level

On curing - the main thing, I would say, to dry the bamboo slowly in the shade. Ideally you should stand it up vertically, but if you have to stack it horizontally, it is good to rotate it fairly often so that it dries evenly. Drying it horizontally in the sun without rotating it is a surefire way to end up with cracked poles. You can always use those for split bamboo, though!

Julia Winter wrote:I asked about using the timber bamboo at Columbia Ecovillage in Portland (OR) and was told that things they've made of bamboo have only lasted 3 years or so. I don't think they put the bamboo up away from the ground, though, that might make a big difference in longevity.

There are various factors that can influence the longevity of bamboo. The time of harvest is reputed to be very critical - that is, for greatest durability the culms should be harvested during the dormant period of the plant's growth cycle - when sugars and starches have been drawn out of the culm and down into the rhizomes, as it is these sugars and starches that attract the boring insects that are the most common cause of rapid deterioration of bamboo poles. The bamboo culm itself also needs to be harvested at the right age - for most species the culm should be at least 3 years old, ideally in its 4th year... Then too, some species are better suited for some uses than others.

There are also various forms of post-harvest treatment that can extend the useful life of the bamboo. Chemical treatments (such as copper sulphate or borax/boric acid) are probably the most straight-forward and effective, although traditional methods such as soaking in salt/brackish water and/or running fresh water, and heat treatment can apparently also be helpful. Robyn Francis of Djanbung Gardens in northern NSW has an interesting article on using trans-evaporation to get chemicals into the cellular structure of the bamboo. Be sure to check out the discussion in the comments as another Permie in North Queensland also reports on their experiments which are now into their second decade, if I remember correctly...

Proper curing - drying for six months or so in a shaded location after harvest and before use is also pretty important to avoid shrinkage and cracking...


I recently used some bamboo that I planted about ten years ago, harvested a couple of months back and treated using the flame from a propane torch (I know, not very cool, maybe for my next project I'll use a rocket stove!) to make a frame for a "flow-through worm bag." I'll try to get my act together and post a pic soon

There are a few that are mostly solid at the base of the culm. This chart has a nice description of the typical sizes and characteristics of many species. Notice that the largest diameter species with solid culms described here is the clumping Bambusa stenostachya, which can reach a base diameter of 6 inches and a height of 70 feet. Bambusa burmanica is somewhat more modest, at 4 inches and 50 feet. Another candidate would be Dendrocalamus strictus, which can apparently get to be about 5 inches. The Guaduas from South America are also pretty solid at the base and get to about 4 inches diameter... These are all pretty tropical species, so depending on where you are located they may or may not be easy to find. From memory they all tend to be on the thorny side too If you are in a more temperate or cold climate you might be able to find a running bamboo with solid culms but I'm not aware of any that reach a pretty large diameter.