Jump to content
Sign in to follow this  
missholly

Solar Powered Kiln?

Recommended Posts

Hi Everyone, new to the forum.

 

I live in Queensland, Australia and also have solar panels which typically generate around 2kw - 3kw per hour for about 6 hours per day. The kiln I'm interested in buying is listed as being 2.8kw and 10amps. Are there any electric buffs here who can demystify how much energy this means?  i.e. I don't understand the amps and how this effects the power consumed.

 

Thanks. Steve

Share this post


Link to post
Share on other sites

Watts is Amps times Volts.  A kilowatt is 1000 Watts of power.  Consuming 1 Kilowatt for one hour is one Kilowatt Hour.

 

You can expend 1 Kilowatt of power by having 12 volts of "electrical pressure" and about 83.3 Amps of electrical current flow.  You can get the same 1 Kilowatt consumption/dissipation by using about 4.5 Amps of flow with 220 Volts.

 

There are quite a few people these days that have solar arrays powering their electric kilns.... BUT... their installations are usually set up to generate power for a large energy consuming house.... not just for the kilns.  So the investment costs are recouped because of the HOUSE... not the kilns.

 

You'd have to do the payback analysis for a pure kiln installation.  The less often you fire that kiln.... the more the investment cost is a hinderance to getting a payback on that investment.

 

 

As Marcia mentioned... Studio Potter magazine did a lot of stuff on energy back during the last "energy crisis" period during the Carter Administration (when we put in out solar roof collectors and attached solar greenhouse).

 

best,

 

...............john

Share this post


Link to post
Share on other sites

Elon Musk-designer of the Tesla electric car and owner od Solar city Solar Panels, and also owner of Space X, is now selling a unit for $3,000-$3500 dollars U.S. that will store power from solar cells. You no longer need inverters and batteries. It's all in one unit as big as a furnace. Great for off grid living. I believe I saw it in this month's issue of Popular Mechanics.

I'll get back to you.

TJR.

GiselleNo5 likes this

Share this post


Link to post
Share on other sites

Elon Musk-designer of the Tesla electric car and owner od Solar city Solar Panels, and also owner of Space X, is now selling a unit for $3,000-$3500 dollars U.S. that will store power from solar cells. You no longer need inverters and batteries. It's all in one unit as big as a furnace. Great for off grid living. I believe I saw it in this month's issue of Popular Mechanics.

I'll get back to you.

TJR.

Thes units power some buildings in SF area-but I think its lighting and such. So you spend 15-30 k for soar panels then you add one of these cheap 3,500 units to store the power.I have always been a believer that electrictity is a poor heat source unless its near net zero cost.

The other exception is you have your own hydro on property.

Mark

Mark

Share this post


Link to post
Share on other sites

Elon Musk-designer of the Tesla electric car and owner od Solar city Solar Panels, and also owner of Space X, is now selling a unit for $3,000-$3500 dollars U.S. that will store power from solar cells. You no longer need inverters and batteries. It's all in one unit as big as a furnace. Great for off grid living. I believe I saw it in this month's issue of Popular Mechanics.

I'll get back to you.

TJR.

http://www.bloomberg.com/news/articles/2015-05-06/tesla-s-new-battery-doesn-t-work-that-well-with-solar

Share this post


Link to post
Share on other sites

I think sun and solar panels must work differently down her in the Southern Hemisphere (for sure the water spins differently!).

 

I have a 5 kilowatt solar system with a 5 kilowatt inverter that generates around 30 kilowatt hours per day in summer (sunshine for about 6 hours). My system generates about 20 amps at peak sun during the middle of the day.

 

Now, I am no electrician, but I tend to agree with J Baymore's point that if I did not inconveniently have a house hooked up to that solar system, I could certainly run my 15 amp single phase kiln with power to spare, but only for a few hours when the sun was shining brightly. If I installed another similar sized system alongside the first, I could probably run that kiln for 6 or 7 hours a day, but when the sun went down....game over. Industry may fire that fast, but I cannot....

 

However, i am lucky because like others here, for a monthly fee I have access to a giant battery called The Grid, to which I am connected. Essentially, I trade some of my spare power to the power plant down the street during the day (meaning they burn a little less coal), and in return they give me back a bit of power at night when i need it and my panels are twiddling their thumbs waiting for sunrise. Works out well for everyone involved.

 

Cost of all this? In Australia a system like mine can be had installed for about $8000 AUD ( call it $6000 to $7000 USD).

 

Bottom line for me is that it is possible to run a kiln off of solar panels, but only for a short time each day, unless you are connected to the grid and arrange "power sharing agreements" with the local power plant.

JBaymore likes this

Share this post


Link to post
Share on other sites

Tyler, I agree that you can't run a kiln from solar power. They don't work in a closed system. John, I also agree with you. Solar can create enough power to run a kiln, but it must be tied into the grid in order to use it.

 Neil, could you elaborate briefly on what you mean by "closed system"? 

 

I don't think there is any technical reason that would prevent someone running a kiln only off of solar panels.  If you had enough panels to run the kiln (see my earlier comment on this above), and could fire in four or five hours, on a sunny day you could get the job done. 

 

And there are even a few tricks you could play to cheat those constraints.  If your kiln (and the pots in it) had sufficient thermal mass to retain some of its heat overnight, you could effectively "preheat" the kiln the day before to get a headstart for the actual firing day.  How well this trick would work would depend on all the variables already mentioned including solar system size, kiln electricity requirements, kiln insulation thickness and type, kiln firing cycle, etc.

 

Another workaround for many kilns would be to simply reduce the power going to the elements.  Many electric kilns have a dial on them somewhere which (while most of us never mess with it) allows us to regulate the amount of power going to the kiln elements.   It is almost always set on "high" to get maximum power because we are all connected to the grid and getting all the power we want anytime is not a problem.  However, this dial can also be turned down to put less power through the elements.  So for instance if I didn't want my 20 amp rated kiln to draw 20 amps when switching on and off to heat the elements, I could turn that dial down to say, 10 amps.  The downside is that the elements will need to be on a lot longer at any given point in the firing to hit the right temperatures, and at the top of the firing even when they are on 100% of the time you may still not get enough power to the elements to hit the necessary temperatures for your firing cycle.  Again, this will depend on other variables in your system like kiln size, load density, insulation, etc..  Also not sure this is ideal for your element life, but a kiln technician may have a view on this?

 

Finally, in the near future (five year?), the kinds of household batteries which Tesla, Enphase, SMA and other are bringing to the mass market will make it completely feasible to run a kiln off grid.  You will be able to turn on your kiln in the evening and run it off batteries for the first part of your firing.  By the time you enter the high-energy part of the firing cycle the next morning, your house batteries are spent, but the sun is rising and your kiln starts to lean on the power generated by the solar panels themselves to get to temperature and finish off the firing (note to self: do not run washing machine or space heater at this time :rolleyes:

 

The $64K question is: how much will it cost?  If household batteries follow the same trajectory as solar panels, their prices will drop rapidly from here (thanks Elon!).   Tesla's new house battery is $3500 for 7 kilowatt hours (kwh) of daily use and guaranteed for 10 years (oh, and you will also need an inverter unless you get a new solar system where one inverter serves both batteries and panels).  Seven kwh of available electricity overnight is probably not quite enough at the moment for the aspiring off-grid electric kiln user, but it is not that far short.  Back of the envelope says that a 20 amp, single phase kiln that is on for one hour would use 240v x 20 amps = 4800 watts (or 4.8 kw) per hour.  That means your 7 kwh battery is dead in about an hour and a half (realistically probably even sooner than that).   However, since your elements are only powered up for brief intervals in the early part of most firings, you would probably stretch the battery charge out much longer than this.  Cut to the chase, based on what we know now (early days in the battery story) I would probably want a 20kwh battery if I was running a kiln plus some other light household stuff (frig overnight, etc.). 

 

Finally, let me just say this whole topic is not academic, at least not to me.  I have a potter friend who I am helping to get a household solar system now.  For various reasons my friend will likely go off grid sometime in the next five years and we have needed to make sure that her single phase 20 amp klln would still work even off grid.  Through lengthy discussions with the electricians we know that it will definitely work from a technical perspective right now today.  However, like the CEO of Solar Cities said about the Tesla batteries, it does not - at the moment - make sense economically.  

JBaymore likes this

Share this post


Link to post
Share on other sites

 

 

 

  It has been because of this poor attitude that my presence on this forum has been minimal.

 

Best wishes to all,

 

Tyler

 

Maybe an issue that needs to be discussed is why people get disgruntled and leave these forums. The thread the other week about what people get out of these forums was a nice warm and fuzzy one but if we as a group are to grow then perhaps we need a bit of constructive criticism. I4,300 members and how many last more than a few months? 

 

Tyler, I for one have noticed your presence here has been dwindling and have missed your thought provoking discussions. 

 

Peace,

Madeleine

Share this post


Link to post
Share on other sites

Tyler,

 

We have never met but let me say this.

 

Thanks for being willing to comment and put yourself out there. I may or may not agree with you in this context, but I have enjoyed your insightful posts in many parts of these forums, and hope to be able to continue to benefit from your thoughts here in the future. I acknowledge and respect your concerns, and feel that you would not express them if they were not sincere.  I appreciate your providing a different view supported by your considerable experience and solid arguments. 

 

I have enough experience to know that as smart as I think I am, I am still wrong about a great many things, and that is why I am here. In life I have found that my understanding only grows when tested by others.  There is no finality, only give and take, and the inevitable progression. 

Share this post


Link to post
Share on other sites

I hate to see anyone, who contributes, to these forums, leave.

 

We have a lot of great, knowledgeable posters here, and it is expected, that sometimes there will be disagreements. I hope this is something we can all move past, because losing even one of those good posters hurts the forums.

 

Min, to address your question, I think a lot of users leave, because they are here for a "quick fix". They think they want to get into ceramics, but don't understand everything it takes. Some, upon learning more here, take a step back, and proceed a bit more cautiously, some just get turned off, by the time and effort it takes ("Are you saying my viewing of the movie 'Ghost', doesn't mean, that I can instantly start make huge, useable wares, and 'bake' them in my oven?!!! This is stupid!"), and are never heard from again.

 

And there are even those, who some here more than others, are familiar with, that come in just to ask questions, for no apparent reason, other than to ask questions,

 

Heck, there are even those who try and get free R&D out of the posters and forums!

 

In any case, those users don't last long, because once they see, that they aren't going to get exactly what they want, they leave.

 

I do think those types of posters make up the bulk, who don't return. As I initially said, it is much more concerning, when we lost a contributing poster, who has been here for some time. I hope we can move on from disagreements, and continue to make this a great place to interact/ learn.

Share this post


Link to post
Share on other sites

I still mourn the loss of Norm :( . 

 

You have taught me a lot @Tyler Miller, thank you for that. I hope you can find it in you to stick around. Always love reading your posts.

 

I agree that lots of people come for an easy fix to find their question comes back with even more questions and very few definite answers.

Share this post


Link to post
Share on other sites

Norm definitely had a lot to contribute, but he made a discussion personal, and questioned the credibility and integrity of some other posters.

 

That happened with another poster too, though the latter departure was less... "Volatile", I guess one could say.

 

I think the problem is, we as people, take any questioning/ contradicting of our knowledge, as an attack on us personally. We shouldn't. Things change, especially information. Look at History or Science/ Medicine, the "Facts" change all the time based in new discoveries. If a doctor is not up to date, that doesn't mean they are an idiot. It's our job as humans, to stay up on the changing information, so that we can continue to contribute to one another. And that's why it's sad to see such apathy, in regards to correct information by today's youth... But that's a whole other topic all together...

bciskepottery likes this

Share this post


Link to post
Share on other sites

Solar is possible today with some of the advances in solar panels.  

 

Dependent on the kiln size and power requirements some small electric ones run at under 20 Amps and 120 volts which amounts to only 2,400  Watts.  But on the other end of the spectrum the max you probably do would be a kiln running at about 30 Amps and 240 Volts or 7,200 Watts.  Now looking at the expense though Solar panels range from about $1.50 to $5.00 per Watt that they produce.  With that in mind your looking at a minimum of $3,600 for a small kiln and $11,000 for the larger kilns.  

Yes it is possible but I seriously doubt that it is economically feasible.  .  Also if you use longer firing times than 8 hours you may have issues during the night.when there is very little solar energy.  

Share this post


Link to post
Share on other sites

A potter here on the Central Coast runs his huge kiln off of solar power. It's probably at least 3'x3'x5'. Not sure how many panels or what kind of power storage he has, but I could ask him if you'd like. I'm interested in doing that myself. 

Share this post


Link to post
Share on other sites

I have always thought we all gain by diversity of thought.

I am sad when anyone leaves  the board by taking different opinions personal.

I try and not take things personal even as over the years I know a few where tossed my way.I can always feel ok that we all agree to disagree now and then.

I have noticed your absence Tyler and have missed your take on subjects recently.I always wonder about folks who vanish or never post back on subjects.

i thought folks like Norm added a lot to the forum but since its all up to each of us on how and when we use or not use the foruem there is not much we users can do if someone chooses to leave.

I think a thick skin is needed for long life here and I guess I have that even though as an old geezer my skin is thiner as one gets older (I'm taking literally here)

As an unpaid consultant I may not have the best take on this subject.

I do know as Benzine said many come for quick fixes that just cannot happen and hence they drop out.

Mark

Share this post


Link to post
Share on other sites

I think it is important to remember that - for almost all of us - the question is not really "can I run my kiln off of solar panels?"  The only potters that will be asking that are probably large production houses where in fact all the power the panels could produce and then some is consumed solely in the business itself on a daily basis.

 

For the rest of us, once you have made the investment in a solar power system, and are harvesting sunlight and turning it into electricity, you use that electricity everywhere you can and don't waste any of it if at all possible.  Selling it to the grid is the least desirable course of action because the power company usually charges you a lot more for electricity you import then for the exact same electricity when you sell it to them.  When you are not using the solar system to power a kiln (the other 350 days a year) you it will  running your house, sheds, washing machines, pumps, etc. etc.  Indeed, that is the basis on which the decision for most of us will ultimately be made - can I run my house on solar power, and if so, using it occasionally for the kiln is just gravy.

 

Again, when reasonably costed batteries in adequate sizes become available to the mass market, we will need to examine the whole proposition again, because stand-along (ie, completely independent of the grid) power systems will become an unavoidable proposition.  I think that will happen in the next five years.... 

GiselleNo5 likes this

Share this post


Link to post
Share on other sites

Simply from a practically no experience with kilns stand point, and only college course experience with ceramics, as an electrical engineer here's how I would go about developing a solar powered kiln:

 

I would start from scratch and build my own kiln using the most insulating material possible [the material used to fashion Space Shuttle tiles?].  Then I would string NiChrome wire as multiple 12V circuits to distribute the current load.  In other words I wouldn't even use an inverter, but just go directly from solar panel to heater wire.  And, because of the low voltages, the current would be extremely high, so to minimize resistance loss in the transmission wires [i.e. the wires that bring power to the kiln], I would, have, say, ten or twenty separate solar banks and each bank would run a separate heater element in the kiln.  Also, it would be a lot easier to switch a fraction of the current involved [ala Solid State Relay and temperature feedback system]. So, say I want a total of 3000 Watts, and say I used 20 solar banks, that would be 3000/20 = 150 watts per bank for a total of 150W/12V = 12.5 Amps per bank.  Far smaller wire gauge could be used for the transmission lines and switching only 12.5 Amps is a lot easier than switching 250 Amps!!

 

If a firing can be done in 6 to 7 hours, then sun power all the way.  If not, then perhaps car battery chargers could be used to apply 12 volts to the heating elements when the sun goes down, thus solar would be a supplement to mains power. But, if the kiln is well insulated, then it could be brought to firing temperature and that temperature maintained with minimal power after that.  Thus the solar panels would carry the brunt of the most power intensive portion of the firing cycle -- ramping up the temperature -- and then when the sun goes down, only a minimal amount of mains power would be required to keep the temperature constant.

Share this post


Link to post
Share on other sites

 

The original thrust of my post was to disambiguate the phrase "solar powered electric kiln."  The phrasing, as it stands is misleading, since solar power alone cannot heat anything  (they may be able to provide theoretical power, but this does not work in practice), and on-grid systems are dependent on the grid to provide the power quality necessary to complete a firing.  

 

 

Not sure what you mean -- power is power and power from a solar power system can heat just as well as mains power, as long as the system can handle the current involved.  As for power quality it seems to me, as long as there is enough "power overhead", a temperature control feedback system can maintain the temperature as precisely as needed no matter what the source of the power [especially if I custom designed it -- as I have a tenancy to do being an engineer and all ;) ].

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×