Own consumption v export

pinnks

Eric

How strange. I have also experienced times when that happens, usually accompanied by varying combinations of red, amber and green lights on the link unit. Looking from the front the right hand light has shown red more frequently since their demise than ever before but as of now when typing this reply it is all working perfectly fine.

It might be worth checking the lights to see if it thinks its connected, rebooting the link unit and/or checking the link unit is pointed at the right IP address in advanced settings. It should be on automatic but may have been changed at some point and perhaps the IP addy associated with the domain name may have changed?

Indeed, I have just pinged live.myimmersun.com and it appears not to be the number it was when tech support was helping me resolve a problem many months ago and suggested changing the IP addy.

kladd21qa

I've just registered my master and slave unit on the website - and were accepted. Immersun has a good name (best?) for diverter switches for PV. I expect the company will continue with new owners - so continuing myimmersun probably makes sense for the receiver.
I have monitoring with Geo Solo 111 and Solaredge dashboard. I have the Immersun bridge but not installed.
It's a relatively new installation (Jan 2016) of 7.5 kW and I will have to wait a year to see whether I am approximately 'zero-energy' in a passive house with 4 adults and 2 children, including an electric e-UP! The slave unit was installed last week after I saw how often making more than 6kW and sending 3kW to the grid.
Its more important to me to get to near 'zero-energy' (making same annual kWh as I'm using) than to measure the return on investment cost on an Immersun. Wont know for sure until year-end, but its looking reasonable in any case - getting to near 'zero-energy', having lower utility bills, receiving FIT payments, and money back in 10 years (hopefully) from capital spend of £10k all-in.

ajbell

It's all about learning to use it efficiently.
I generate around 4000kwh per year and have got my consumption down to around 1000kwh (from the grid)
per year.

Martyn1981

Quick question for those that have diverters, and anyone who would be kind enough to check my maths.

A neighbour of mine is thinking of getting PV, so far they've had an £8k quote for 4kWp ..... but let's forget that.

So, I've suggested they copy my setup, and get 2kWp on their front roof (we have mini bay rooves that block some of the front), and 3kWp on the back roof, running through a 3.68kW inverter.

Here comes the fun, the low FiT and an E/W install makes the numbers tight, but they don't have gas (they've just disconnected from the mains). They use coal, and an immersion heater, so I can see (I think) large leccy savings from the water heating.

From April to September I generate 15kWh+ on average, so export, perhaps 10kWh. Am I right in thinking that a diversion of 7 to 8kWh per day is reasonable? There are four of them.

[If they use more leccy than me, and therefore have less excess, then it doesn't matter as they will see greater leccy (non water heating) savings, so it all balances out.]

So, what value does the water heating have, presumably it should be on E7 rate, which I think is 8p. Given that very low generation days are very rare in the best 6 months, is the following savings figure fair:-

8kWh x 30days x 6 months x 8p = £115. [The other 6 months will be relatively low.]

The water savings could be the difference between this being viable, or not.

Any thoughts? Thanks.

Mart.

pinnks

Interesting. There are just two of us and a normal (200l?) hot water tank. I have a top immersion but it is (I think) a longer one and seems to do what we need. We tend to use most hot water in the mornings. My system is not dissimilar in size to yours but faces in different directions and I generate about 4,500kWh per year.

On normal days we never run out of hot water (heated the day before) for morning showers and the water is generally hot by late morning - today there were three of us in the house, not bad morning generation and the water was hot by 12 noon. I was on my own from about 11 and the system grabbed a top-up between 2 and 3. Once the others return and we use water around meal time we might get a bit more top-up.

Today's numbers as of typing this:
Diverted 3.4kWh (normal days between 3 and 4.5 for us)
Exported 6.9
Generated 14.2
Imported 2.2
House 6.1 (total not including diverted)

On a better day the only real difference would be more generated and more exported. My expected August average is about 17kWh and the best I have ever achieved on any day is just under 32.

So, 8kWh into the diverter might be on the high side depending on use and size of tank but the system will certainly have capacity for that and there should be enough sun to get to that temp and maintain it into the evening, so that next day the water is still piping hot.

As to which rate to use, without gas I would assume the immersion would be put on E7, so 8p looks sensible.

If I were to use 8p my annual saving would be (see original post) about £60 based on never diverting more than about 4.5 units a day. Indeed the 735 mentioned below was based mostly on the immersion stat being at whatever the installer set it all those years ago. In March (I think) I wound it up to about 80 degrees to see what difference it made. Not a lot apart from an additional 1kWh or so extra diversion...

ASavvyBuyer

We have a 100 litre hot water tank with a 1.2kw immersion heater mounted in the bottom of the tank. Using a REUK diverter, we have all the hot water we need from March till September. Don't expect to have to turn on the gas boiler for heating water until October.
We don't have a way of measuring the amount of electricity that gets diverted to the immersion heater, but estimate on average 4kw a day.
If we had to use gas at 2p/kw would equate to 2p x 4kw x 210 days = £16.80. REUK diverter cost £30. Therefore, REUK diverter payback less than two years.

Martyn1981

pinnks wrote: »

So, 8kWh into the diverter might be on the high side depending on use and size of tank but the system will certainly have capacity for that and there should be enough sun to get to that temp and maintain it into the evening, so that next day the water is still piping hot.

ASavvyBuyer wrote: »

We don't have a way of measuring the amount of electricity that gets diverted to the immersion heater, but estimate on average 4kw a day.

Thanks, so it might be a bit less, and that fits with what I've read people saying (now I think about it .... doh!) with mentions of perhaps 1,000kWh pa.

So that will dial it down a tad. I'm thinking income and savings of around £500 pa, but a cost of perhaps £6k (across 2 rooves). Tight, perhaps too tight for them, me, I'd say 8% gross is ok, but I need to warn them that winter gen is low given the orientations and slightly shallow rooves (30d).

Thinking about it, the current FiT level is quite clever. The government get to claim they are supporting domestic/demand side generation, whilst not actually doing anything of the sort.

Mart.

Heedtheadvice

I too have an immersion plus bridge.
It is a real shame this company is/has failed as their basic unit is excellently, the comms aspect and server presentation a bit less so but nonetheless useful.

I have had comms issues and only in June had to update the bridge firmware - so suggest that you all do that if still possible as it contains some fixes. It seemed to be particularly bad according to tech help with BT homehubs. It was much better once updated. (Left led going orange I.e. comms from server to bridge).

It has been happening again but resets on after disconnect from router, power cycle router and when back up cycle and reconnect bridge.

I hope someone buys the company and keeps it working for the sake of the technology development, deliver of more units if there are customers, the staff and of course customers who need suport and server data analysis.

Failing that it would be great if the comms code to get data out of the immersion could be released - far from ideal but something. If the company does not get bought it would be good to buy any immersions that were then surplus to requirements in case ours fail!

EricMears

pinnks wrote: »

Eric

How strange. I have also experienced times when that happens, usually accompanied by varying combinations of red, amber and green lights on the link unit. Looking from the front the right hand light has shown red more frequently since their demise than ever before but as of now when typing this reply it is all working perfectly fine.

It might be worth checking the lights to see if it thinks its connected, rebooting the link unit and/or checking the link unit is pointed at the right IP address in advanced settings. It should be on automatic but may have been changed at some point and perhaps the IP addy associated with the domain name may have changed?

Indeed, I have just pinged live.myimmersun.com and it appears not to be the number it was when tech support was helping me resolve a problem many months ago and suggested changing the IP addy.

I can log into the Myimmersun webpage OK but initial screen has no numbers on it. Pressing the little 'house' icon gets me today's figures but every one reads zero. If I select a date on or before 31st July I do see a set of figures that look fairly normal (but haven't actually checked to see that they match my records). Selecting 1st August or later gets me a set of figures that are all zero.

The IP address shown in advanced settings looks a reasonable sort of figure and my router settings show that a device is indeed connected to that IPA. Lights 1 & 2 on the TP-link box are green, 3,4 & 5 are blank, power light is green.

I've reset the myimmersun function from the Immersun unit. Checked the firmware version and it's saying that there is no later version available.

Immersun unit itself seems to be working OK - I can look at the unit and see if it's importing or diverting.

I've just switched Immersun unit (I wouldn't expect to divert anything before 9am so am not losing anything by doing that)


Whoops ! I've got a lot of little boxes on that shelf and was looking at wrong one last night ! The MyImmersun box was indeed showing an orange & red light so have just switched it off for an hour or so

Heedtheadvice

Re immersion and bridge
FYI:
Latest info given to me 24 June 2016
Bridge firmware version latest 2.82
IP address 192.168.1.98 (edit: that of my bridge! )

Eric your symptoms of a graphical display but with no data corresponded to when I had a comms problem but that was usually associated with the orange light on the server to bridge side.