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Author Topic: Looking for manufacturer of dc immersion heaters  (Read 29200 times)
biff
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« on: April 03, 2012, 02:52:00 PM »

Hi folks,
        I have been searching back through the old threads,looking for a link to a firm who make immersion heaters in dc to the customers voltage requirements.I did copy the link but cannot find it.maybe someone out there can help. help
                                                                        Biff
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supremetwo
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« Reply #1 on: April 03, 2012, 03:23:01 PM »

http://www.reuk.co.uk/Immersion-Heater-Elements-for-Wind-Turbines.htm

http://www.howden-electroheating.com/
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biff
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« Reply #2 on: April 03, 2012, 03:54:54 PM »

Thanks you Supremetwo.
                    Just what i was looking for.
                                               Biff
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biff
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« Reply #3 on: April 23, 2012, 09:05:44 PM »

Well folks,
           I seem to be taking my time aquiring these new water heaters,I did contact some of the people who manufacture these immersion heaters.They all have one thing in common,They are very hard to speak to and very expensive to pay.Despite having emails the required specs clearly so as to save time.The first link i contacted ,i was told that the guy with the tech expertise was not at work that day,no problem,i emailed the required specs and waited for a few days.Quotation duly arrived,,£130.00 each plus carriage of £75,,and so i says woops!! well thats a bit rough but i may as well go ahead,so i rang up to have a blether(its always good to talk) but again the tech guy was off work,,then i got a call back to ask if i had a vat number,to which i said NO and the kindly lady says well there will be vat on that which will bring the total for 2 immersions to £404.00,or 500euros +..So i sat down slowly  Cry :'(and said i would have to consult the lady of the house.Then i learned of an irish manufacturer which was bound to warm the cockles of my heart only to find out i would get screwed even harder not counting carriage.
  So i trawled the net,even went to america with their 120mains in ac,,incredibly these folks were working with 6" immersions and something like 450watt for approx £100.00,,They had 6","7" 8" immersion heaters,,With the "BIG UN " at 750watt..Wot Appened to the america where everything used to be 10 times bigger than the rest of the world put together,,? There is nothing worse than paying through the nose for something you could have bought much cheaper but lacked the information to source it.It makes me feel quite ill,i guess it is against my religious beliefs which tells me i would be much better off with the dosh in my own pocket.
 So i am still looking for a source to supply me with2kw x 120dc immersions in 2" and 2"n a quarter bst.Maybe someone on here might know.
                                                                        Biff
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ecogeorge
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« Reply #4 on: April 23, 2012, 09:51:32 PM »

Have access to 2.25" BSP elements  in 3kw, 3.8kw, 6kw (1 or 3 phase)  9kw (3 phase) 12 kw (3 phase).
Using ohms law ,,,,,,,

V = I ◊ R    or    
I =    V/R
 or    
R =    V/I
Taking 6kw single phase   6000w/230v = 26.08A
R= 230/26.08    =8.819 ohms

Therefore @ 120 v     I=120v/8.819 ohms    or 13.6A

13.6 A x 120v = 1632w
Is that enough??

Suggest  6kw element between £35-£60  but will have to check tomorrow.

Same equation for 3kw gives 818w. I expect a 9kw 3phase could be split down to 3 x 3kw giving 3x818 =2454w.
Have some manufacturer branded elements (2kw + 3kw 230v ) in 2" BSP I think -will check stock and prices (to you  Wink  tomorrow)
Rgds George.

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supremetwo
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« Reply #5 on: April 23, 2012, 10:08:17 PM »

Another for you to try:-

http://www.tpfay.co.uk/OurServices/bespoke_design.aspx
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« Reply #6 on: April 23, 2012, 10:18:22 PM »

Just a general question     about AC  and DC  heat elements    is a PWM  signal ( rapidly on and of switching  of the DC chargecontroller) ok for a AC heat element  ( i  know AC is  meaning  as well switching or alternating) ?

Thanks Billi
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« Reply #7 on: April 23, 2012, 10:22:48 PM »

Heating elements are basically just resistors, they don't generally care about AC vs DC. 

You can use PWM DC if you like.  Obviously the effective power output will reduce pro rata with the duty cycle but presumably this is what you want to happen.
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biff
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« Reply #8 on: April 23, 2012, 11:59:26 PM »

Great news George,
                  The 6kw in one tank plus the 2kw+3kw in the other should be good,Totaling 2992watts in 120dc.should be plenty.
  Thanks for the link Supremetwo,,
                             Biff
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« Reply #9 on: April 24, 2012, 03:36:59 PM »

What are you after the immersions for?  If it's not for a wind turbine and if you can convert your dc to 230Vac, EricW has a circuit that can dump it to a standard 3kw immersion, over a range of say 200W to 3kw.
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biff
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« Reply #10 on: April 24, 2012, 05:05:34 PM »

Hi Artful_bodger,
                   I have two hot water tanks,One downstairs with central situation and one upstairs,One is a water heater and the other is just the ordinary hot water cylinder,with double indirect quick recovery coils,The idea is to dump the excess energy from the wind turbine and the solar arrays into these hot water tanks so that during the night the heat releases slowly to provide good background heat.If there is too much,like say during a storm,then the excess hot water can be pumped around the c/h system when it reaches a certain temp and the stat triggers the pump.Our controller is 120volt and dumps at 138/139 volts.
  I have all the cables installed,the water heater insitu and just waiting for the right immersions for the job.
                                                Biff
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« Reply #11 on: April 24, 2012, 05:19:48 PM »

I hopes you have good decent sizes cables and not running too far.  The cables might act as heaters themselves, and not in a good way like russ_fae_fyvie experienced  Undecided

Also, what are you using for the switchgear?  If you have ~25A of DC current rattling along a circuit and you connect/disconnect in a hurry that gonna make a bit of a spark! 
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biff
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« Reply #12 on: April 24, 2012, 10:21:20 PM »

Hi Clive,
       The cables are are extra heavy even though the amps are low(still under 18amp), the voltage is high.There will be no thermostat in the head of the immersions and  they are wired direct to the controller with no switchs inbetween.The final connection to the immersions is done with a 50amp anderson connection which will be properly secured against accidental opening.
 The controllers in question have no problem switching on and off the large 2kw resistors that have already been acting as dump loads in each controller,So the switching gear has already stood the test of time, The fans will still operate to cool the boards just in case.All i have to do(methinks) is disconnect the resistors and plum in my cables.There are 3 sets of cables ,2 sets which well exceed the specs and one set of jump lead spec.It might sound like a very expensive bit of cabling but i dont want to have to dig it all up again.
 When the immersions reaches the required temp,an ordinary pipe stat on the expansion pipe triggers the pump  for the water heater and send it round the c/h,this setup is already installed on the hot water cylinder.
                                                         Biff
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« Reply #13 on: April 24, 2012, 11:58:02 PM »

No problem biff, I trust ya!!

Just my grandfather had a 120v DC generating set and he used to say that stopping high voltage DC in a long wire is like stopping a speeding train.  It builds up a momentum of sorts and can jump switches (ever seen it happen for real !) but it sounds spectacular !!  Big blue arcs jumping across the switch like lightening!
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« Reply #14 on: April 25, 2012, 12:47:46 AM »

It can also let a crack like a pistol shot Grin
                                        Biff
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