Solar Panel immersion heater automatic switch.

[hophead]

Hello, I have recently installed a SolarImmersion mark III and very pleased with its operation. It works with my existing 3kW heater and simply uses all power that would otherwise been exported. Have not done the sums, no real data on how much hot water costs me, to figure out how long/short the payback period is but hate wasting free energy. Regards Bob

 

[Glynn Fletcher]

Hi, thanks very much trader9, I've read all about your "invention" and am very impressed. The thing is, although I am quite OK with wiring a 13 amp plug the equipment you describe may as well come out of the TARDIS. I am possibly older than your Grandad and all the valve theory I did at college seems a bit old fashioned now. The next post from Hophead really filled me with a good feeling that I should buy the SolarImmersion. If you could build one for just less than half of the cost, brilliant! If you can't build one then buying is the only option and at least this will be guaranteed for a year. Thank you both for your imputs.
Glynn.

 

[Warlord2001c]

Immersun installed by Worcester as part of our 4kw system on 08/03... Hot tank of water pretty much every day so far (excluding the one March day we were covered in snow!)... 37kWh in my tank instead of the grid and GCH water cycle running once a day now instead of twice and sometimes not even that depending on our hot water usage.

 

[Glynn Fletcher]

Now the only problem I have is do I buy a SolarImmersion or a Immersun. If the two who have had them installed are both happy I am definately going to take the plunge. £250 or £350. does it really matter what's a hundred quid when the savings are so good.
Thanks to all,
Glynn.

 

[danesol]

Now the only problem I have is do I buy a SolarImmersion or a Immersun. If the two who have had them installed are both happy I am definately going to take the plunge. £250 or £350. does it really matter what's a hundred quid when the savings are so good.
Thanks to all,
Glynn.

Just to get up to speed on this thread, before you get comfortable thinking its a decision based on just two units - there is another to consider :smiley2:

Intelligent Immersion.

again at around the 200 ish mark......

 

[Glynn Fletcher]

Thanks very much to Danesol. I've read about it and sent for details. I'm glad I found this forum. Now I can hear the inverter fan going full belt, I'm generating just over 3Kw and using hardly any. I hate paying for electricity but I hate giving it away more. Looking forward to when I can sit back in a hot bath with a can of Newcastle Brown.
Glynn.

 

[Earthstore]

put the kettle on....

 

[Glynn Fletcher]

Just heard back from inrelligent immersion. Very nice letter and lots of information. I think I will go for this one . They are passing on my enquiry to their wholesaller and then he will contact me with prices etc. I will of course put them on here when I get them.
Glynn

 

[Glynn Fletcher]

After reading all about the above 3 types I have gone for the one Danesol suggested, the Intelligent Immersion. This seem the best one on offer and I bought it last night for £250.00. The fitting is, I am assured, incredibly simple and then just forget about it. I'll give an update later when I receive it and it's been working for a bit. Thanks to everyone for their input.
Glynn

 

[hophead]

Hello Glynn, Good luck with the Intelligent Immersion and look forward to further reports. Hopefully my Solar Immersion will be just as reliable, certainly made the most of yesterdays sun. Bob

 

[thushar]

SolarImmersion (http://solarimmersion.co.uk) is having a special offer now - Price is only £199 (was £249) !! may be the best time to buy it http://solarimmersion.co.uk

 

[Glynn Fletcher]

I have had the Intelligent immersion fitted for a few months now and can only say BRILLIANT.
Not only do you use all the power generated but the electricity supply company pay you for the half of your generated power which they assume you are sending back to the grid even though you are not sending any back.
I have the output from the Intelligent Immersion going to the immersion heater now the central heating is switched off and in the colder months when the central heating is on the output from the I/I will be switched to a storage heater which I bought off ebay for a tenner. I tried this out a few weeks ago and the storage heater was incredibly hot just when you needed it ie in the evening. Normally storage heaters are getting cooler by evening but of course mine is being heated up all day not at night.
If anyone has any doubts about getting one of these for their solar panels I say "go for it".
Glynn.

 

[ex 2 Base]

I have a home constructed controller for our PV system. Its basic but does work. I'm using three 400 volt, 55 micro farad capacitor with each controlled by a 24 volt dc, 25 amp relay. By selecting one in series with the immersion heater element we get approx. 400watts two 800 and three 1200 watt going to our immersion heater. Originally we had a 110 volt site transformer, I thought how much heat energy is being loss in the TX cores and windings and caps have no heat loss if they are not faulty. Three low voltage switch manually operated as and when required. I have clip on ammeter around the meter tails as an indicator. I have a question and would like to satisfy my mind, should a contactor disconnect the mains from the PV system when my/our system is connected to the immersion heater element. I'm never sure that we are taking energy from the mains. Your comments would be much appreciated. John

 

[echase]

I have a home constructed controller for our PV system. Its basic but does work. I'm using three 400 volt, 55 micro farad capacitor with each controlled by a 24 volt dc, 25 amp relay. By selecting one in series with the immersion heater element we get approx. 400watts two 800 and three 1200 watt going to our immersion heater. Originally we had a 110 volt site transformer, I thought how much heat energy is being loss in the TX cores and windings and caps have no heat loss if they are not faulty. Three low voltage switch manually operated as and when required. I have clip on ammeter around the meter tails as an indicator. I have a question and would like to satisfy my mind, should a contactor disconnect the mains from the PV system when my/our system is connected to the immersion heater element. I'm never sure that we are taking energy from the mains. Your comments would be much appreciated. John

If the mains is disconnected from the inverter it will drop out as the inverter can't deliver current without a mains connection, as otherwise it does not know how to synch with the mains frequency.

How exactly are you deciding when to switch in the next capacitor? When you measure the grid with an ammeter like this you have 2 problems:

1) It can't tell you which way the current is flowing so how do you know you are not importing current to feed your immersion?

2) Because of your large capacitors it is shifting the power factor of your house away from unity. Thus the ammeter is not reading real power consumed. In the extreme if you strapped such a capacitor across the mains with no other house load the ammeter would read lots of current but the utility meter would clock up almost no cost because the two currents are nearly 90 degrees out of phase. Your situation is somewhere in between where the current registered could be more than what the immersion is actually consuming.

You really need a measurement of real power to operate such a set up well.

 

[Glynn Fletcher]

Hi Ex 2 base,
Considering the output from the solar panels change every 12 seconds you must be sitting on top of your switch pile all day. Go for the Intelligent-Immersion .I has come down in price since I fitted mine from £250 to almost £200 and it's hands free.

 

[Trader9]

Hi echase,

I did post here some years ago about a system I built from plans on the internet at openenergymonitor.org.

Look for Robins Mk2 solar diverter, you won't be disappointed. It cost me less than £50.00 for the parts and is now available in kit form.

Since I installed this system about three years ago I have diverted more than 4.2 MWh of surplus solar into my immersion or a night storage heater I have in the winter.

This system is simply brilliant and completely automatic once installed.

Regards Trader9.

 

[ex 2 Base]

Thank you trader9, not being the most competent on the computer I'll find it. Back to echase item 1, I switched off every thing connected up my watt meter to the heater element and using my clip on ammeter proved that the solar energy was going the heater. The capacitors are connected in SERIES with the element forming and RC circuit not in parallel as in power factor correction. I notice others have used a site transformer to drop the voltage , these transformers are not continuously rated and there are heat looses as well, so discounted that idea. By using the Xc component its act as a loss dropper without the heat loss. But I'd rather have a fully automatic system and will give trader9 idea a go. thank you all for your comments and interest. Ted

 

[sharpener]

By using the Xc component its act as a loss dropper without the heat loss.

True. I have often used the principle to power small items from 240V without using a transformer (but only where the circuit does not need to be isolated from the mains!).

But your RC circuit will still have a leading power factor, and to be any use Xc needs to be large-ish compared with R, so this effect will be quite significant and echase's comments are valid. (I recently had to fix a blown capacitor in a 125W fluorescent fitting, this was a series capacitor too and the vector diagram was quite bizarre, the value of Xc was about twice that of XL and in direct opposition to it.)

My own immersion heater controller uses an analogue multiplier to calculate the power from continuous readings of current and voltage, this gives a true power measurement - with sign - and has been working well for the last 3 years.

 

[Dan]

Don't mind me while I bump some threads in the solar PV forum. If they're not current or applicable topics, just ignore the threads; they'll drop off the page. If they are, feel free to chip in and chat solar stuff in the solar panels forum.