Help, dog water bowl heater ran by solar thermal energy...

[Sunking]

unless you actually buy bare nichrome wire, you are usually "getting" a composite element, often called CALROD.

http://en.wikipedia.org/wiki/Heating_element
Tubular (sealed element, often known by the trademark "Calrod"): a fine coil of Nickel chrome wire in a ceramic insulating binder (MgO, alumina powder), sealed inside a tube made of stainless steel or brass. These can be a straight rod (as in toaster ovens) or curved to span an area to be heated (such as in electric stoves, ovens, and coffee makers).

Any heater "wire", uninsulated, in water, is a hazard.

+1 Warm Fuzzy Mike. That is the point I have been trying to make.

[Mike90250]

unless you actually buy bare nichrome wire, you are usually "getting" a composite element, often called CALROD.

http://en.wikipedia.org/wiki/Heating_element
Tubular (sealed element, often known by the trademark "Calrod"): a fine coil of Nickel chrome wire in a ceramic insulating binder (MgO, alumina powder), sealed inside a tube made of stainless steel or brass. These can be a straight rod (as in toaster ovens) or curved to span an area to be heated (such as in electric stoves, ovens, and coffee makers).

Any heater "wire", uninsulated, in water, is a hazard.

[john p]

Just about all the heating of the water was done by the element NOT BY CONDUCTION OF ELECTRICITY BETWEEN THE 2 BRASS RODS.

[rick1]

run parallel water lines from your engine cooling system to an old vehicle water heater and place under water pans. You will have plenty of heat.

[Sunking]

I sure do not plan to do that experiment!

Well folks who think water is not conductive might. They will change their mind real quick if they survive.

Also, some vaporizers use bare electrodes with no resistance wire between them to heat the water. But you have to add a measured amount of salt to make it work. It has the advantage of stopping the heat once the water has evaporated. But they are carefully designed so that you can't touch the water!

Or baking soda to lower the resistance enough for the voltage it operates at.

Do you remember the electric hot dog cookers that just stuck an electrode into each end of the hot dog? That only works because of the salt in the dog.

Did it many times when I worked for a utility during demostations at public elementary schools. We did not use the manufactured cookers, we used very high voltage to demonstrate what would happen to fingers if they touched a high voltage line. The hot dogs explode. It is not nessecarly from the salt content but the water content with all the impurities and dissolved metals like magnesium, zinc, iron and copper found in all meat and most water.

In the field during the winter working outside we used 2 nails connecters to a pigtail plug into 120 VAC. Submerged the nails into a pot of water and bring it to a boil in just a minute or two so we could make coffee and hot chocolate.

You are correct you can submerge nichrome wire in water and pass current through the wire. At the same time the water will form a parallel path and also conduct more current. Current through a resistance develops heat aka power in watts However even at 12 vdc the dog would jump back when he feels the current flowing in his tongue just like you do tasting a 9 volt transistor battery. Farmers are very much aware of the problem with stray voltages at cattle water tanks induced by currents flowing through a MGM utility line. The potential difference between the cows feet and water tank is very small measured in the milli-volts, but is enough to cause the cattle not to drink from the tank.

[inetdog]

OK John drop your blow dryer in the bathtub while taking a bath and let us know how it works out for you.

I sure do not plan to do that experiment!
Also, some vaporizers use bare electrodes with no resistance wire between them to heat the water. But you have to add a measured amount of salt to make it work. It has the advantage of stopping the heat once the water has evaporated. But they are carefully designed so that you can't touch the water!
Do you remember the electric hot dog cookers that just stuck an electrode into each end of the hot dog? That only works because of the salt in the dog.
But as a practical matter, the difference between 120 volts AC and 12 volts DC is pretty substantial. You would still potentially be electrolyzing the water, but not as fast.
And the dog might feel a tingle in his tongue, but would not be harmed. (How many of you have "tasted" a 9 volt battery on your tongue?)

I think that the major objection would be that the resistance would not be controlled and so the heating rate would be unpredictable.

[Sunking]

Pure water is actually a pretty poor conductor - might even call it an insulator.

That is true but there is no such thing as pure water available. It is the minerals and inpurities dissolved in water that make it a conductor.

[Sunking]

its not true and I and everyone elso doesnt know it either. Open wire jug elements were made for about 60 years and were made in the millions. The jugs were porcelain and had replaceable elements...FACT believe it or not.
If your statement was true how would cold water get hot using an open wire element in the COLD water? IF there really was a short circuit it would not be heating the water.
And at 12v dc the amount of loss between 2 electrodes(wire) in water would be miniscule compared to the current flowing in the heater(nichrome wire) element.

OK John drop your blow dryer in the bathtub while taking a bath and let us know how it works out for you.

[Kurtk]

Pure water is actually a pretty poor conductor - might even call it an insulator. However, if you have impurities in the water it quickly becomes a conductor. When I first got my panels, I connected wire leads with several inches of bare copper to one panel and stuck them in a bowl of water. Very little current... I poured in salt and the amps increased greatly! (ps... this is also a cool way to make small quantities of hydrogen and oxygen gas as you're literally breaking apart the water molecules) If you catch the bubbles in a cup (fill it w/ water upside down and let the bubbles displace the water 'til you have a full plastic cup of gas stick a smoldering match in there and it'll ignite w/ a sudden "pop". (Watch the hairs on your hand.)

This is one of many fun experiments to do w/ kids.

[john p]

its not true and I and everyone elso doesnt know it either. Open wire jug elements were made for about 60 years and were made in the millions. The jugs were porcelain and had replaceable elements...FACT believe it or not.
If your statement was true how would cold water get hot using an open wire element in the COLD water? IF there really was a short circuit it would not be heating the water.
And at 12v dc the amount of loss between 2 electrodes(wire) in water would be miniscule compared to the current flowing in the heater(nichrome wire) element.

[Sunking]

You cannot just go submerging nichrome wire or resistors in water. The water will short out the circuit. It ihas to be insulated like any direct electric heating element. TOTALLY NOT TRUE.

It is true and you know it. Water is conductive period, and you know it. If it worked it is because the current flowing through the water was heated. Some current would flow through the wire but it is in parallel with a lower resistance of the water.

[john p]

You cannot just go submerging nichrome wire or resistors in water. The water will short out the circuit. It ihas to be insulated like any direct electric heating element. TOTALLY NOT TRUE. I was using nichrome wire wound around a ceramic former in a bucket of water for power testing 200 and 300w amplifiers for over 20 years . I also made an electric jug to run of the 12v battery in my 4wd for camping . it was used for years.IT WORKED PERFECTLY EVEN IF A BIT SLOW
Obviously it was a theory of his ,not ever tested in real.

[Sunking]

I see what you're saying and yes i definitely had the sun hours and daylight hours mixed. So that creates an issue. So question, if i get 1.3 sun hours a day in December, and a panel gets 10w, I'm only going to generate 13 or so watts in a day ?

Close but no cigar. A 10 watt panel with 1.3 Sun Hours will generate 13 watt hours at the panel terminals, not 13 watts as you stated. However due to system losses of about 50% efficiency around 6.5 watt hours is useable at the battery.

And if I use the nichrome wire I can bring temp up on two linear feet at a thin guage

You cannot just go submerging nichrome wire or resistors in water. The water will short out the circuit. It ihas to be insulated like any direct electric heating element. Very doubtful you stand a chance at making one. At least not as cheap as $6 to $10 just buying one.

As you can begin to see using solar PV and batteries to heat water is pointless and way to expensive.

[Naptown]

I see what you're saying and yes i definitely had the sun hours and daylight hours mixed. So that creates an issue. So question, if i get 1.3 sun hours a day in december, and a panel gets 10w, I'm only going to generate 13 or so watts in a day ? Correct

And if I use the nichrome wire I can bring temp up on two linear feet at a thin guage for between 3-5 watts per hour. But with that I would only get three hours or so of run time ag full strain. Hmm.. but thats in worst weather. If i had a thermometer attached it wouldn't need to run unless the temp dropped to where it kicked on , and could store on average enough to run for for a few hours each day ?
You will still need a larger panel

Thanks again guys

Comments in red.

[Nmeeker]

I see what you're saying and yes i definitely had the sun hours and daylight hours mixed. So that creates an issue. So question, if i get 1.3 sun hours a day in december, and a panel gets 10w, I'm only going to generate 13 or so watts in a day ?

And if I use the nichrome wire I can bring temp up on two linear feet at a thin guage for between 3-5 watts per hour. But with that I would only get three hours or so of run time ag full strain. Hmm.. but thats in worst weather. If i had a thermometer attached it wouldn't need to run unless the temp dropped to where it kicked on , and could store on average enough to run for for a few hours each day ?

Thanks again guys