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Silicone sponge strip for solar distiller

June 20, 2019 — BarryK

For the solar water distiller prototype #2, I used EPDM sponge rubber strip, 3x10mm, as the gasket between the glass and wood frame. EPDM rubber is one of the better rubbers, but still not classified as "food safe".

Gradually working toward building #3, and for that have located a supplier of silicone sponge strips:

https://www.ebay.com.au/itm/Silicone-Sponge-Square-Strip-White-Foamed-Rubber-Seal-Gasket-C-S-3x3mm-25x30mm/223556026020

I ordered 5x15mm, 5m length, total cost including postage and GST to Australia was AU$30.47

For the record, here is another supplier:

https://www.ebay.com.au/itm/4x4-20x30mm-Width-x-Thick-Silicone-Rubber-Solid-Strip-Sealing-High-Temperature/123720667402

Prototype #3 will probably not be built for a considerable time, as need to do more testing of #2, plus solve some issues, such as getting lower water drip rates. As mentioned in a post yesterday, I need to get the drippers down to about 0.4 - 0.7 litres/hour. Standard drippers from a hardware store only go down to 2 litres/hour. Carocell achieves this low rate by a custom designed dripper, and a water head of about 48cm.  Cuurently, have three 1mm diameter holes in aluminium pipe, but this does not give much control of dripping rate. 

Tags: nomad

Testing F-Cubed Carocell 1000 solar distiller

June 19, 2019 — BarryK

I posted about the F-Cubed Carocell 1000 solar water distiller, that was given to me about 5 years ago:

http://bkhome.org/news/201904/fcubed-solar-water-distiller.html

It has been in the shed all that time, and only recently I got it out and  put it together. Today is the first test. Yesterday, I tested my home-made prototype #2 solar water distiller:

http://bkhome.org/news/201906/2nd-test-solar-water-distiller-prototype-2.html

I was expecting it to be overcast today, however, the rain has been delayed, and it is bright sunshine all day, just a few wispy clouds that came and went. So, an opportunity for more testing. Would like to test the two panels alongside each other, however, want to do some modifications to my prototype first. So, tested the Carocell on its own.

I set it up at 9.15am, Wednesday 19th June 2019, and allowed the water to disperse through the cloth until 9.25am when I connected the outlet bottle. As you can see strong sunshine:

img1

At 9.25am, ambient was 11degC, front of the panel (about two inches above, measured with IR thermometer) was 34degC, back was 21degC. Blue sky, a few wispy clouds here and there.

At 10.30am ambient was 15degC, front 53degC, back 40degC. More wispy cloud in the sky, not in front of the sun though.

At 12.10pm, ambient 17degC, front 56degC, back 43degC. No cloud to be seen anywhere. measured irradiance: 870W/m2.

At 2.50pm, stopped the test, as shade from the patio had reached the panel.

Total collected distilled water: 3.10 litres.

The surface area of the cloth is 1.02m2. My prototype #2 is 0.466m2, so less than half. So, will need to take that into account when comparing. Much sunnier today than yesterday, but even so, my prototype has got some catching-up to do.

One thing that I want to improve is the water-dripping from the top pipe. The Carocell has a very nice design:

img2

...it seems, that purple/pink pipe has holes in it, with some kind of black plastic thing sitting on top of each hole. There is a water-head of about 48cm, and water bubbled out from under that black thing. I wonder how that is designed? Is it a standard part from somewhere?  -- don't think so, as it has "FCUBED" stamped on it. 

Tags: nomad

2nd test solar water distiller prototype-2

June 18, 2019 — BarryK

Just a short report. There is some sunshine today, Tuesday, 18th June 2019, the rest of the week overcast with showers, then next week rain, rain and more rain. So, have taken the opportunity to test the solar water distiller today.

This is prototype #2, that I reported on construction of, with DIY plans, a couple of days ago:

http://bkhome.org/news/201906/diy-solar-water-distiller.html

I looked outside at 9.00am this morning, and it was cool, with mostly sunny sky, just some wispy cloud here and there. So, at 9.05am had the panel setup and ready to go.

At 10.00am, ambient temperature was 13degC, the front of the panel, holding the IR thermometer at 90 degrees from the plane of the glass, about 2 inches away, got 28degC, and on the back 23degC.

I noticed about midday that the sky had become more cloudy.

I came back at 2.15pm, the sky had become more blue, less clouds, ambient now 17degC, front 43degC, back 37degC.

I had to stop the test at 3.10pm, as shade from the patio had reached the edge of the panel. Measured collected distilled water: 560 millilitres.

From today's test, have identified two issues. Firstly, the water flow from the three 1mm holes is a bit more than I want, and cannot adjust down. I think, need to try with two 1mm holes, or drill even smaller holes -- presuming that I can find a smaller drill-bit.

Secondly, the temperature on the back of the panel, 37 degrees C, will be reducing the efficiency of the panel. I am going to experiment with some extra insulation stuck onto the back.

Next test, will probably setup the Carocell solar distiller alongside, for comparison. That is the "gold standard" to measure against, as it is very high efficiency. 

Tags: nomad

DIY solar water distiller

June 16, 2019 — BarryK

Prototype #2 has been built, and setup for the first time. Every day is overcast, so I am waitng for a sunny day to continue testing.

I decided to document the build, so anyone can reproduce it:

http://bkhome.org/nomad/diy-solar-water-distiller.html

Photo when first setup:

img1

Showing condensation after only a short time running, on cold overcast day:

img2

The materials cost is higher than I would have liked, but hey, I am hooked, and already planning #3. May have to pull #2 apart and re-use some components. Next time, aiming for lower-cost and lighter weight, and durability when exposed to inclement weather.

Got to say, this is fun! 

Tags: nomad

Scrubba clean clothes while camping

June 16, 2019 — BarryK

I am always on the lookout for something useful when camping. Clothes can be cleaned at a campsite, if water is available, just by agitating them in a bucket, with detergent, then rinse, then hang up.

So, is this a gimmick, or really useful?...

https://thescrubba.com.au/

img1

Here is a youtube video:

https://www.youtube.com/watch?v=834LBMRqhuc

...you be the judge! 

Tags: nomad

DreamPot thermal cooker

May 31, 2019 — BarryK

I am always on the lookout for new ideas for camping. came across this, recommended in a Facebook caravan & camping group: the DreamPot.

img1

This webpage explains it:

https://www.dreampot.com.au/how-it-works/

And here is a short video:

https://www.youtube.com/watch?v=cxRw8U1UUSI

Would need a heat source. On previous camping trips, I have used a burner screwed on top of a gas cylinder, so that would do the job. Saving 88% of the gas on each use, makes it an attractive proposition.

The 3litre size would suit me. Well, maybe, might consider buying it one day, not now. 

EDIT 2019-06-01:
Received an email from Derek, that this is a very old principle, that is very easy to do yourself. Just get a cardboard box, and insert a saucepan, with clothes or anything packed around it.

Yes, there is no need to spend $199! Some types cost a lot more.

There is another one named BillyBoil, much cheaper, AU$80. I also read that Aldi sometimes has a thermal cooker, as a special buy. Apparently, the Aldi one had a 36W 12V heater, to keep up the temperature, and it sold for AU$99.

While reading reports on thermal cookers, I came across mention of the temperature "danger zone", which is 5degC to 63degC. If using a thermal cooker, the temperature must not drop to 63degC or below, to avoid food poisoning. The Wikipedia has info on this:

https://en.wikipedia.org/wiki/Danger_zone_(food_safety)  

EDIT 2019-06-03:
Received an email from Jon, which included this:

We use to use an ordinary pressure-cooker and a straw filled box back in the '70's. The pressure cooker had the pressure-cap off while on the stove until boiling, cap was on then until time to open up, hot still after about 4hrs.

The idea of using a pressure cooker is very interesting. 

Tags: nomad

Silicone on silicone and silicone on pine

May 30, 2019 — BarryK

My education continues! One comment: a lot of information on the Internet is incorrect or misleading. I read yesterday, that silicone sealant will not stick to cured silicone sealant. Wrong.

I tested Selleys 401 silicone sealant, on top of the same sealant that has cured for several days. It bonds extremely well, and I was unable to pull it off. That information on the Internet may be for neutral-curing silicone, or just one type that the author tried, then made a sweeping statement.

Wood is the same story. Some web pages state that silicone sealant will not stick to wood, others say it will. My experience with selleys 401 is that it doesn't, or does so very poorly.

So, I tried Parfix "Roof, Gutter and Concrete" silicone sealant, which is neutral cure, on unpainted dressed pine, also on pine sandpapered with 60-grit sandpaper. In both cases, it suck extremely well, and again, I was unable to pull it off.

I haven't tried, but won't be at all surprised if the Parfix sealant bonds well to aluminium also (which Selleys 401 doesn't). Hmmm, should find out for sure, will do a little test today. Will also test Parfix on cured Parfix! 

Academic papers on tilted wick-type distillers

I have found some practical academic papers, with very useful experimental results:

"Solar Stills for Desalination of Water in Rural Households"
https://www.tsijournals.com/articles/performance-analysis-of-wick-type-solar-stills--a-review.pdf
  OR: https://www.sciencetarget.com/Journal/index.php/IJES/article/download/326/79

"Experimental study of an inclined flat plate-type solar water distillation system"
https://link.springer.com/article/10.1186/s40807-016-0026-4

"An experimental study on an inclined solar water distillation system"
https://www.academia.edu/15414535/An_experimental_study_on_an_inclined_solar_water_distillation_system
-- free download, but have to join academia.edu

There is some very interesting information. For example, one researcher was reading just 60 - 65degC inside the still at high-noon, at external ambient of 25degC. This is still hot enough for evaporation to take place from the wicking cloth.

One researcher used a black bath towel. I had thought that would be too thick, but hey, if they can do that, so can I...

Bath towel wicking cloth

I bought a black cotton bath towel from Kmoart, for just AU$6. BigW also has them, same price, but they have embossing, whereas the Kmart one is just a plain surface.

Tested it this morning, very positive result. Capillary action was observed to be better than the felt, though I haven't quantified that. Just an observation, that the water tended to get absorbed more readily.

The three 1mm holes are working OK. The water is spreading out, and only a few dry spots after 15 minutes, and very little water has made it out the bottom drainage pipe. Excellent, dry spots are one of the problems with this type of still, and it is a matter of correct angle and water flow rate. 

Tags: nomad