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Solar heating WVO
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To reduce electricity costs I am in the process of setting up a solar heating system for heating up WVO before the biodiesel reaction. I am using a couple of 2nd hand solar hot water panels to do it. Has anyone experimented with this?
I hoping the sun will generate enough thermo-suction to suck the oil through the panels like it normally do to water.
I am looking at heating 500 litres or so of oil for my reaction. I may have an issue with keeping the oil hot as I don't have a storage tank, just the panels. i am thinking I will run it straight from the panels into my reaction tank.
If all goes to plan I won't have to heat the oil at all with electricity.
 
Registered: August 07, 2003Reply With QuoteReport This Post
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and use a header tank to accumulate the hot water.
The hot water can then be pumped via flexible hoses through a heating "spear" which can be immersed in the drums. Another alternative is to stand the drums in a shallow water bath connected directly to the absorbers. The water transfers the heat directly to the drum and heats the oil.


If you use the oil as the heat transfer medium, it will cause problems.
eg, What if the oil solidifies in the piping. The oil in the panels will get very hot, any water in the oil will boil and the pressures will rise excessively, possibly causing damage.

40 000 KM in a '90 Mazda 2 litre diesel on SVO with biodiesel start/purge.
 
Location: Perth W.Australia | Registered: August 10, 2001Reply With QuoteReport This Post
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The panels I have are solahart panels that are designed to pump a 'glycol' solution through them(which apparently is vegetable based) the guy I got them off said. The glycol heats up and is pumped into a sleeve in the water storage tank and heats up the water by transference, just like you have described Tony.

The solar heating elements in the panels are steel and the guy said water would rust them out.

I have never had oil vegetable oil solidify here in warm northern NSW so I hope that isn't a problem here.

I will experiment with the oil and if I have problems I will let y'all know.
 
Registered: August 07, 2003Reply With QuoteReport This Post
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This is motor coolant.
The panels are filled with this solution, the same as you use in your car coolant system, it is water with ethylene glycol added.
I would still use this solution in the absorbers and have a heat exchanger, which gets the heat from the coolant and transfers it to the water.

40 000 KM in a '90 Mazda 2 litre diesel on SVO with biodiesel start/purge.
 
Location: Perth W.Australia | Registered: August 10, 2001Reply With QuoteReport This Post
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What you're saying makes the most sense Tony.
The system is designed to use the stuff so why hassle around trying to get it to suck oil!?
Let the Glycol heat up and trnsfer the heat to the oil.
Thanks for the advice.
 
Registered: August 07, 2003Reply With QuoteReport This Post
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Glycol is not vegetable based. Its purpose in a heat exchanger is only to lower the freezing point. It wont stop corrosion of itself. Water won't cause corrosion either in a totally sealed system. If you need a freezing point depressant how about using the glycerine you get from making BD after removing the soap.
 
Location: Australia | Registered: July 17, 2001Reply With QuoteReport This Post



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Neutral
How would one remove the soap from the byproduct we produce and end up with fairly pure glycerine? Confused
 
Registered: April 03, 2001Reply With QuoteReport This Post
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but engine coolant also includes corrosion inhibitors.
quote:
Originally posted by neutral:
Glycol is not vegetable based. Its purpose in a heat exchanger is only to lower the freezing point. It wont stop corrosion of itself. Water won't cause corrosion either in a totally sealed system. If you need a freezing point depressant how about using the glycerine you get from making BD after removing the soap.


40 000 KM in a '90 Mazda 2 litre diesel on SVO with biodiesel start/purge.
 
Location: Perth W.Australia | Registered: August 10, 2001Reply With QuoteReport This Post
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To get the soap out of the bottom layer just acidify. The FFA will float to the top very slowly. The glycerine will now contain salt from the acid and the caustic. Some may crystallize out depending on how concentrated it is.

There is no need to worry about corrosion in a closed system provided the material is not acid. So after acidifying to release the FAA you would need to add a little NaOH to get back to neutral or a little alkaline.

It is different in a car radiator and much trickier to avoid corrosion because air is always present so corrosion inhibitors are required. In a closed system corrosion would cease when the oxygen was used up.
 
Location: Australia | Registered: July 17, 2001Reply With QuoteReport This Post
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What type of acid would you use and what percent concentration, and in what proportion to the glycerol?
Would this technique apply to glycerol produced by KOH?
How should one mix and for what period of time?
How long to settle? Any special temp for mixing or settling?
Thanks in advance
Diff
 
Registered: January 21, 2003Reply With QuoteReport This Post
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"What type of acid would you use and what percent concentration, and in what proportion to the glycerol?"

Any cheap acid. Sulphuric works but is dangerous and hard to handle if bought concentrated. Hydrochloric is available from pool shops and is cheap and easy to use. Phosphoric is expensive but works well.

One frequently hears that it is good to use phosphoric because it produces a sludge which can be used as fertilizer. I think if you do the sums you will find that if you use hydrochloric the money you save will buy more fertilizer.

If you use pool hydrochloric you may find that salt crystallizes out. If this is annoying dilute the acid a bit. How much to use? Ask your high school child to work this out. Basically you need to put in an amount equivalent to the amount of caustic used and a bit more. You can use an indicator to tell when you have achieved acidification. Methyl orange is about right, changing colour from pH 3.1 to 4.4. When you think it is right keep stirring for a while and check the pH again as it seems to take longer than you would expect.

"Would this technique apply to glycerol produced by KOH?"

Yes. And if you use KOH the fertilizer will be even better. But KOH is dearer than NaOH and the advantage in using it for easier handling is small - if you keep the glycerine warm while working on it it won't solidify.

"How should one mix"

You must already have a method of mixing to make the BD. That will do. Settle till the glycerine is clear. The FFA will be very dark as it appears to collect most of the material which darkens the used oil. That is why BD is so pale.
 
Location: Australia | Registered: July 17, 2001Reply With QuoteReport This Post
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It would be cheap to say that I am eternally gratefull to you, because there is nothing eternal but change.
However, I count among my great blessings, that you are a member of this forum.
If my gratitude cannot be eternal, perhaps it is infinite.
Diff
Thank you for not suggesting nitric.
 
Registered: January 21, 2003Reply With QuoteReport This Post



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I know its a little off topic, but if I recall correctly, you did some tests of the effects of waste veg oils on copper, and then the resultant "green coloured oil's effects on steel

Can you recall where on this now huge forum I might find the article??

H.C. Searching everywhere Div. SWC
 
Location: Swansea, U.K. | Registered: March 09, 2002Reply With QuoteReport This Post
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No I have never tested veg oil on copper. I have seen biodiesel kept for a long time in contact with copper go green and I do not think this had anything to do with sulphur. Copper exposed to moist air in an alkaline environment goes green. Sorry, no help.
 
Location: Australia | Registered: July 17, 2001Reply With QuoteReport This Post
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Just an update on the solar heating of the veggie oil, it has been a long time coming but it is working.
The method: I am pumping straight oil (used and strained veggie oil) around two second hand solar panels using a 55 watt pool pump (found thrown out). I am using a 300 litre hot water storage tank to store the hot oil. The oil circulates around the system and gets hotter and hotter. It works a charm. The only cost for heating the oil is to run the 55w motor!
It is all very basic- just used old garden hose and a few plastic fittings to plumb it up.
On a cloudy day it took 3-4 hrs to heat up 250 litres of oil to about 50-55 degrees C.

C'mon folks go solar.
 
Registered: August 07, 2003Reply With QuoteReport This Post
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scube, Nice work,sounds ex....yep I'm up for a go at that...Cheers
 
Location: Australia (vic) | Registered: May 14, 2003Reply With QuoteReport This Post
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Good work; I am thinking of using panels of building paper to focus heat on a particular area to melt tallow but your idea is much more advanced.
 
Location: west of the black stump (sometimes) | Registered: September 04, 2004Reply With QuoteReport This Post
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Scube,
How about a picture ?
regards
dva
 
Location: Yorks,England | Registered: June 30, 2001Reply With QuoteReport This Post



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As you can see the original post for the Solar panels was made some time ago.I am pleased to say the system is still working fine.
I have been having fun with those solar panels!!
Those panels are really efficient at heating! i haven't found any problems with pumping oil around the system. I recommend it as a cheap way to heat veggie oil! I will try and get some pix up, have to wait a few weeks till I get hold of a digital camera.
If you're thinking of playing around with them try and find panels that don't have leaks. You can sometimes see leak marks on the panel through the glass. Even so, if there are leaks you can solder them up pretty easily. One of my panels had a leak but I took the glass off and crudely soldered it up. I am using two panels. If you want to do the same make try and make sure the tank and panels come from the same system. This will mean you won't have to muck around trying to fit odd bits of plumbing and buying expensive fittings.
I also recommend hose clamping all bits of hose. The oil can get quite hot and you don't want a bit of hose slipping off.
I use a gear pump to pump the Waste Veggie Oil out of my settling tank and into the solar storage tank for heating. Gear pumps are great and in my experience the best pumps for transferring oil (they can be sourced secondhand at auctions and junkyards).
One of the beauties of the solar hot water tanks is that they have a number of mounts already on the tank so they are easy to plumb. I found out early on in the piece however, that you need to use one of the mounts as a breather (one at the top of the tank). There is always going to be a bit of air in the system- in the tank or panels and when that air is heated it will expand. If you don't have a breather to release that pressure you could find the whole system blowing a hose and pissing oil everywhere! Not a good scene! So that breather is essential.

By chance I found out that the system will also act as a crude distiller! ie for distilling excess methanol out of glycerine byproduct. I pumped some glycerine into the tank and pumped it around the panels. After a few hours I could hear the system boiling away (methanol boils at around 60 degrees C). I had steam coming out the breather mount. I attached a pipe to it and the steam condensed into a liquid in the pipe. To confirm my hunch that it was methanol I collected it into a cup and (away from the solar tank) lit it up. Sure enough it burnt!Methanol!! I don't think you get much for the effort- more experimentation needs to be done, however, it could be used to purify the glycerine of methanol for all the soap makers out there.

On another tangent- the trusty used solar panel makes a damn fine solar food dryer!!! No electricity needed here.
I had a spare panel lying around so I drilled 4 holes into the aluminium side (for hot air and moisure to escape). I drilled out the pop rivets that hold down the glass, peeled it off and whacked some galvanised mesh down on top of the panel for the fruit to sit on. I then layed bananas over the top half of the panel and put the glass back on top. Sure enough at the end of a sunny day the bananas are nicely dried!!
Crude but effective!

Viva La Solar Panel!!!
 
Registered: August 07, 2003Reply With QuoteReport This Post
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In a few post up above mention is made that there is no corrosion problem in a closed system - WRONG - all liquids contain dissolved air and therefore oxygen and therefore corrosion takes place especially in a warm environment such a a heating system.
 
Registered: November 12, 2004Reply With QuoteReport This Post
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