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Author Topic: Save Electricity with Solar Kettles  (Read 29351 times)
Ivan
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« on: August 07, 2007, 09:37:16 PM »

Most people tend to drink several cups of tea a day. For several months of the year, all (or most) of this water could be produced by Navitron solar kettles. You can also pour the heated water into saucepans used for cooking in the evening, reducing the energy required to get the water from ambient temperature up to cooking temperature.

I don't drink any tea/coffee, but even so, we generally use 1.5litres to 3litres of solar-heated hot water each day.
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Example:

Let's say there are 3 people in the house, all of whom drink 6cups of tea each day. (say 6x 0.3litres=2litres). Let's also suggest that evening meal requires 2litres of hot water for cooking pasta/vegetables etc. Let's also say that the cook does not want to mess about with pioneering cooking techniques!

So the household can utilise 4litres of solar-heated water each day (3 tubes would heat 4.5litres....actually, if the weather is good, you can heat water up to 3times in each tube =13.5litres/day)

The energy required to heat 4litres of water from 15C to 100C is calculated thus:

Temp rise (C) x Volume of water (litres) x 4200 (heat capacity in JKg-1K-1)= 85 x 4 x 4200 = 1.428MJ =0.4kWh

Assuming the water would be heated electrically (it usually is if it a kettle, and if it is heated on a gas hob, it is so much less efficient that it might as well be heated electrically), then this is equivalent to 0.2kg CO2 (assuming the powerstation runs on gas - if it runs on coal, it would be twice as much)

Over half a year, this is equivalent to 73kWh or 37kg of CO2. Or put it another way, 8 worth of electricity.

If all of our 10million households did this, we'd save 730GWh of energy (365 000 tonnes of CO2) and 80million

« Last Edit: August 08, 2007, 07:24:59 PM by Ivan » Logged
NickW
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« Reply #1 on: August 08, 2007, 12:53:33 PM »

Ivan - I think your Maths is going a bit off course. I trust you employ an accountant to do your books at Navitron Wink

If 10 million households in one year save 146 kwh of electricity each then this equates to about 628,000 tonnes of Co2

The typical fuel mix for UK electricity gives a CO2 output of 0.43kg per kwh.

Anyway it would be interesting to see if navitron can come up with a practical solar kettle that can sit on my south facing kitchen window.

Regards

Nick
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Amaterasu
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« Reply #2 on: August 08, 2007, 03:12:31 PM »

as we have proved the solar kettle can work.

Would it be possible to make one that is ............... kettle shaped or at least jug shaped.

Yes I know there are all sorts and shapes of jugs but I'll leave that discussion to martin and his BGG photos.

A truly kettle shaped solar kettle would sell by the bucket load
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Geoff.........
Joules
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« Reply #3 on: August 08, 2007, 06:54:20 PM »

Or even a Solar MUG   Smiley


                 Joules
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Ivan
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« Reply #4 on: August 08, 2007, 08:08:54 PM »

Thanks Nick - I've revised the CO2 calculation - should be correct now. There were too many zeros on the end. Luckily, Navitron profits don't have so many zeros on the end


Ivan
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Jonzjob
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« Reply #5 on: August 11, 2007, 04:59:03 PM »

Not quite solar cooking, but I have a tube, water filled, leaning against a wall in the garden. It was put there yesterday to show some French friends how they work and how efecient they are. It took about 2 1/2 hours to heat the water to boiling in the 58mm tube. I had a copper insert tube stoob beside it and as it was windy it was quite cool. I picked it up and started to show our friends how it fitted in the tube. I got it about 12 inches into the tube and had to get it out quickly or let it go. It took about 5 seconds to get as hot as the water AT THE BULB which was still better part of 3 feet from the water! I was shocked at how quickly it got hot... The temp in the shade was about 29 dec C and the sun index was 7 going on 8, so nice and warm...

I have been thinking of how it could be used in that way, but my brain cell has gone on strike. The heat probably woke it up? Shocked
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Ivan
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« Reply #6 on: August 11, 2007, 07:03:50 PM »

It is quite amazing how fast heatpipes transfer heat - much much quicker than simple heat conduction alone
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CeeBee
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WWW
« Reply #7 on: September 14, 2007, 12:59:14 PM »

Would it be possible to make one that is ............... kettle shaped or at least jug shaped.
...
A truly kettle shaped solar kettle would sell by the bucket load

Has anyone tried mounting a kettle-like thing, with a suitable recess in the base, on the end of one of the heat-pipes? I haven't yet had hands-on an actual solar tube (perhaps I'll get some installed soon), but I imagine they're not the most convenient things to use as kettles, and prone to being broken. I guess one would have to insulate the 'kettle' for this to work, since unlike just having the water inside the tube itself, it would cool down at the rate which kettles normally do.

Unless I'm missing them, I don't see single tubes (with/without heat pipe) on the price list.
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rhys
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« Reply #8 on: September 14, 2007, 03:10:19 PM »

In the mean time we could all use eco kettles, only boil what you need. - I've got one and it works - a simple idea all kettles should be like this.
http://www.ethicalsuperstore.com/products/product-creation/eco-kettle/?gclid=CJ2Yx82Pw44CFQXnlAodmgaoCA
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Ivan
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« Reply #9 on: September 14, 2007, 04:55:18 PM »

How about this one, from Navitron? Boils EXACTLY what you need, on-demand and in 3 seconds

http://c-zero.co.uk/page.php?73
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paul
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« Reply #10 on: September 14, 2007, 05:01:09 PM »

How does it fare for de-scaling if used in hard water areas?

Paul
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Ivan
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« Reply #11 on: September 14, 2007, 05:15:43 PM »

Difficult to know. I don't think it has been on the market long enough to find out. I imagine that it might be clean-able, but can't say for sure.
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room101
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« Reply #12 on: September 16, 2007, 09:47:47 AM »

Do you know the output temp..... Huh
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rhys
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« Reply #13 on: September 17, 2007, 08:23:09 AM »

Sorry Ivan - didn't know you had a product!! Must keep checking the new website. I can't see that these types of kettles should be any different from an ordinary kettle in terms of descaling. Use descaling solution or good old citric acid once in a while.
« Last Edit: September 17, 2007, 09:12:05 AM by rhys » Logged
Ivan
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« Reply #14 on: September 18, 2007, 12:46:03 AM »

Output temperature is .......boiling!
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