OP
suntrap
Yes, it helps if no-one's there to mess up the consumption during the day! A diode will of course not do wonders for the current waveform but I agree is a very easy way to halve the heater's consumption.
Discuss Immersion Heater - PV electricity in the Central Heating Systems area at ElectriciansForums.net
Hi,
Looking back at earlier suggestions; a light dimmer board was thought to be a simple solution, having all needed interference protection etc, but was rejected through having a potentionmeter control.
It may help to note that you could use digipots, digitally controlled potentiometers, to replace the light dimmer potentiometer. You would have to use a microcontroller to control the digipot of course but to my way of thinking the microcontroller circuit has got to be the best way forward with its meter, display and perhaps wireless control capabilities.
I will research and post suitable devices and provide programming examples if converting a light dimmers make electrical sense!
I too am interested in getting an extra current transformer for my OWL, as I noticed the transmitter has three sockets on it (unless that's just for three phase supplies?). I haven't investigated it further yet, though.
You are correct of course, amended accordingly!Pedantic note: your "w"s (watts) should be capitals :stuart:.
I am very pleased to say that I have completed my system. I have heated the top part of my tank very quickly. ( only as deep as the length of the immersion heater ) I raised water temp 10 deg before the solar water system had got up to temperature and started to circulate. This was important as some people have said this system won’t work quickly enough and this proved it is much faster than the water type system. Also to confirm that I have had NO interference generated by the triac effecting either the radio or tv (10pcv2425 contains a snubber circuit ). This system, just to confirm doesn’t use an expensive plc and follows the spare power level in an analogue way NOT waiting until there is a spare 1,2 or 3 kw before switching on in steps and thus wasting potential energy. It runs as soon as there is a spare 100 watts and continues to feed all the way up to full power 3kw. All it contains is a small comparison circuit made from 2 opamps ( 741, 75p each ). I triac crydom 10pcv2425 ( just bought one on eBay for £12 ) . A power supply that provides -12 0 +12 vdc, 2 current coils from LEM model AT20B10 ( £ 54 inc vat for the two ). I have fitted and extra dist board with a Henley block to separate the measurements. I now need to find a nice box to put it all in and maybe add a couple of voltage meters form eBay just to make it very easy to see what power is being supplied. The future improvements would now be to add another heating element to the bottom of the tank and a relay circuit to switch between the elements once the top one is up to temp. I hope this will encourage some of you to develop your system. It just goes to show there are several routes to achieve free hot water. :- )
Fantastic. You must have spent ages doing that!
You could make the LED flash with every fraction of a kWh produced by the cells, like an electronic meter. Watching the LED flash beats TV any day of the week! When the relays are on, it could inverse flash (flash "off").
2) steady but lit 25% - indicates that 500w is being unused, and activates relay 1, with a diode in series to limit the load to 500w (yes it does work, I've done the sums on the leccy meter!)
3) steady and lit brightly - 1kw power is now available, so relay 1 is deactivated, and relay 2 activated switching the 1kw load.
I have only tested it with my meter which is a Ampy 5235 and it uses exactly half the full load.Have you established that all electricity meters can cope with this half wave rectification? For the positive half cycle you will be importing from grid and exporting for the negative half cycle, or vice versa. As long as the meter successfully averages out the power over a few cycles this is OK but if not it will register an export or import when none really exists (apart from the error between the 2 discrete steps and the real power available for export).
Great to hear there are 3 viable solutions.
Am having panels installed (tomorrow!!) and I'm not an electrician (although I dabble). I have a second CU that is already being used off one circuit to power an outside office/garage/studio
Am I correct in assuming that what I need to to 'future-proof' my system (for adding an immersion later) is to get the guys to do is
1. Install another CU (I won't do that)
2. Fit a Henley/Henly block
Is that all...if so I'll get down to Screwfix for the CU this afternoon! That's after I use the scaffolding (going up now) to mess around with the chimney stack and aerial...a bodgers work is never finished ;-)
1. Install another CU (I won't do that)
2. Fit a Henley/Henly block QUOTE]
No, my system requires no wiring changes. It is useful if the immersion is on its own MCB in any of the CUs, rather than having other devices hanging off that MCB. But not essential.
Hi All, as I posted a few days ago, I have been working on version 2 of my solar controller, and it is now complete and fitted, so I thought that I would post a few photos..
Andy, I have tried to separate the low voltage from the high voltage side, both electrically and physically, so yes you are correct, I have 2 opto-coupled relays housed separately to switch the high voltage (£4.20 delivered from Ebay).Brilliant stuff Paul - shows what can be done - I assume that this is the "display head" and you have the "guts" else where for the CT inputs and contactor outputs.
Are you prepared to release your designs free or for a fee?
Andy
Mine does that and also has an override to turn the immersion on if you want a top up on a sunless day. Some LEDs or an LCD are useful or else you don't know if the unit is working properly.
Looks like we have at least 3 viable solutions here. My one achieves the same aim as the others but I use cheaper components that are just as effective. The Crydom 10pcv2425 is pretty expensive (around £100) unless you find a cheap one somehow, as inie meanie did. So I went for a different approach that does not use such an expensive relay but provides the same function. My whole component cost including the box, current transformer, fuses, relay, processor board, etc. is less than just the 10pcv2425. On the other hand I am charging a modest cost for the design and for assembling it, as I don’t have the kit version available at the moment. My making them up saves you the potentially hazardous work of dealing with the mains side (but some of you are electricians so you don’t mind that).
I don't currently supply an LCD but am providing the connections for one as I do connect one to test and calibrate the units. I’ll make them available later for retrofitting when I get around to writing the full LCD software. LEDs provide much of the info that an LCD could supply.
Yes I agree, but shouldn't there be a dividing line between a commercial product and a Open Source product?Hi Paul
I too have spent many many hours developing and testing, and I am at the stage of deciding whether to develop into a fully commercial product. I am currently investigating patents in this area. If I am not able to proceed I will produce a drawing and try to explain the calibration process. It's all moving a bit fast at the moment, But have been told not to show the circuit. I hope you understand.
The unit's performance is not in question!I am shipping some units to customers next week and am hoping they will be able to give an unbiased view here of the unit’s performance. That will I hope partially make up for my reluctance to publish the design here. Full marks though to Paul for his excellent and clear posting of his design. I think the only item I share with his is the same CT.
If anyone wants a more accurate clamp style CT I recommend the Magnelab units available from Rapid Online. But >twice the price. I have 2 on a commercial system that sends my PV statistics to a web portal so the installer and I can remotely monitor my system. High accuracy is not needed for an immersion controller but is for accurate energy metering.
it appears that personal gain has got in the way.
Good luck Guys...
I don't think we need to worry about lawyers right now.Hi
Tell me what you think. I personally dont want to get into any thing on the legal battle side as I cant aford to go head to head via laywers. :-(
I don't think we need to worry about lawyers right now.
Noone is going to take a home hobbyist on. I brought up the EMMA patent to settle the confidential design/commerical debate.
I would be keen to see the patent disappear though.
I am pretty sure that power control similar to the EMMA has been discussed before the EMMA patent. I may be wrong.
If anyone finds an article published before the EMMA patent then post. Thats pretty much all we have to do.
If we find the evidence then we will open up competition to those who know how, competition giving rise to improvements, hopefully cost savings, more improvements etc, etc. Once the systems are reasonably priced we can all just buy one rather than risk a home fire (Mr EMMA thats a market gap hint).
I am especially miffed about the EMMA patent as I had the same idea round the same time but through a number of reasons (thought it had been discussed before, was told that meters ran backwards etc) and a medical condition (bone idle) left it alone. Secondly the EMMA cost is really high.
I think that SB home system overlaps the EMMA patent which if so is interesting. SB seem switched on and seem to have a green home game plan. They have had digital interfaces in their inverters (bluetooth now) for a while. I think that may reveal a plan which may predate EMMA. Hoping anyway.
The EMMA people did a mailer via LinkedIn contatcs a few months back. I first contacted them last year so they must have picked it up from that. When I spoke to them this time, they said Mk II version is due out soon - I thinkk they said this summer but don't quote me on that - and it addressed the high cost issue.
...... at a reasonable cost. i.e. hundreds, not thousands.
Not only because it wouldn't be worth it but because there would be no legal grounds to do so. However, if anyone is using intellectual property covered by the patent to make money, they may well do, and I presume that is one reason why people here selling kits or complete units are being cagey about what their systems consist of.Noone is going to take a home hobbyist on.
I think that the EMMA patent covers use of phase controllers.Not only because it wouldn't be worth it but because there would be no legal grounds to do so.
I think that the EMMA patent covers use of phase controllers.
inie meanie has downloaded the PDFs and I have posted links.
I would be interested in your and other's views as I am new to the language of patents i.e. do these patents cover a specific design or do the patents cover all designs, used in this PV context, which embody a phase controller?
Again I find it hard to understand how a patent may restrict designs which use well understood components, its would be like saying that a resistor were part of the patent claim and that therefore all solutions which use resistors are covered by the patent. Daft.
Anyway would be interested in views as the systems on offer are very expensive and competition (open or commercial) would be best.
Agreed.The difference between patent theory and practice is that even if a patent is ultimately invalid, if the company holding it decides to prosecute you because you are selling a product that infringes it, you could spend a large amount of money defending yourself in court.
Reply to Immersion Heater - PV electricity in the Central Heating Systems area at ElectriciansForums.net
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