Davey's Water Heater

[sprocket]

As someone who has tried & failed to make a Davey's heater in the past, I'm quite excited by this. However, I can't understand their payment-system. For instance, this Microsoft-translated link points to the all-important 'bell' part. There is a 'crossed-out' 10,000 rubles as a result of a 1,000 rubles reduction, yet in dollars it's listed as 9,000 - currently 100 rubles equals 2.86 dollars! These are quoted as being able to bring 100 litres of water to boiling-point in 2-3 minutes using just 300 watts - kinda unbelievable.

Yet their cheapest boiler, the UPS 15 only costs 14,000 rubles, which is about $400. Quite a price-discrepancy I would have thought - 10,000 rubles for just the bells, versus 14,000 rubles for a working unit.

[sprocket]

It is difficult to obtain the numbers from the video.
Please:
quantity of water
increase in temperature
time
voltage
amperes

thank you.

------------------------------------------------------------------
Трудно получить цифры с видео.
Пожалуйста:
Количество воды
повышение температуры
время
напряжение
ампер

спасибо.

I don't understand that video. I presume he is boiling the same amount of water in the kettle for comparison. The Davey heater is pulling 10-11 amps from what is presumably 220V mains supply for about 5min to boil the water - that's over 2KW. How is that more efficient than your average kettle? That is more or less what I was seeing as well when I tried this.

[RAMSET]

телефон сломан

Phone number does not work from this post

http://www.energeticforum.com/renewa...tml#post255349

thx
Chet

[wrtner]

I don't understand that video. I presume he is boiling the same amount of water in the kettle for comparison. The Davey heater is pulling 10-11 amps from what is presumably 220V mains supply for about 5min to boil the water - that's over 2KW. How is that more efficient than your average kettle? That is more or less what I was seeing as well when I tried this.

I would forget the videos and go by what he says:

7A
220V
1800 seconds
50 litres
85 degrees centigrade

If he has stirred the water fully, and is not measuring the heat right above the heater, then, using the spreadsheet in post 90 (or the regular formula), this does compute to a COP of 6.4

[wrtner]

Sprocket's link in post 91,
ledd.satom.ru/p/2084527-sfera-dlya-kotlov-otopleniya/ - Translator

mentions the heating of 100 litres in 2-3 minutes with 300 watt.

This is long way from the recently reported test where 50 litres are heated in 1800 secs, i.e. 30 mins.

[sprocket]

Sprocket's link in post 91,
ledd.satom.ru/p/2084527-sfera-dlya-kotlov-otopleniya/ - Translator

mentions the heating of 100 litres in 2-3 minutes with 300 watt.

This is long way from the recently reported test where 50 litres are heated in 1800 secs, i.e. 30 mins.

I distill all my drinking water, and it takes me a minimum of 5 hours @ 700Watts to distill just 5 litres. It must take 30min (1800secs) to bring that 5 litres to the boil. So I'd look at being able to boil 50 litres of water in the same time, at about twice the watts, as being quite a 'step-up' - therefore, either of the figure-sets you list would be great if true!

[wrtner]

It depends if they have their experimental technique right. What the website suggests is a COP of well over 700.

Have you tried solar distillation? The RAF used to have a pyramid shaped arrangement for their air/sea rescue dingies which sat on the sea and condensed out seawater. The idea works.

[sprocket]

It depends if they have their experimental technique right. What the website suggests is a COP of well over 700.

That's the reason I thought it was "kinda unbelievable". I'd settle for the 6 COP of course!

Have you tried solar distillation? The RAF used to have a pyramid shaped arrangement for their air/sea rescue dingies which sat on the sea and condensed out seawater. The idea works.

No, I haven't. I've searched for some designs in the past half-heartedly though - stuff like pollution by dust, bugs, rainwater etc. as well as lack of a compact design have been the main reasons I haven't given it a go.