Solar Immersion Question

[Puff]

I plan on installing 8Kw of PV at my property (plenty of S facing space) and don't want to export to grid. Until I get batteries, want to use excess energy to heat my hot water tank & not use the ASHP. Once the tank gets to the desired temp, the immersion will cut off. Are you able to heat more than one immersion? Within the property, there will be 2 holiday lets and my home, so kind of makes sense to spread the love in some way if possible.

If so, then will the PV have to be wired to where the mains comes into the property or can I get away with anywhere "downstream" of that point? Just affects the the length/complexity of the cable runs from the PV.

 

[Murdoch]

Why don't you want to export to the grid?

 

[Puff]

Why don't you want to export to the grid?

DIY install, so no MCS registration, which I need for export. Eventually will have batteries but with 3 properties, probably best for me to heat the HW if I can with the excess energy. 

 

[ProDave]

What kit have you bought?

If you install more than 3.8kW of pv that is capable of exporting to the grid, then you need prior approval of the DNO using a G99 application.  If you install no more than 3.8kW you can install it without prior notification on a G98 application.

Or are you talking TOTALY off grid, where the PV generation feeds an inverter and the loads from that inverter are on completely separate circuits to anything connected to the grid?  To achieve that you NEED battery storage.

 

[Murdoch]

DIY install, so no MCS registration, which I need for export. Eventually will have batteries but with 3 properties, probably best for me to heat the HW if I can with the excess energy. 

I think you need more knowledge ... and especially as it sounds your entire installation will be diy

 

[Puff]

I think you need more knowledge ... and especially as it sounds your entire installation will be diy

Hence why I'm here  

Kit will be MCS accredited but I do not wish to attach to main network. I understood, perhaps wrongly, that you can set up your system such that any "excess" is not sent back up the line to the grid. Which is why I wish to push excess into HW immersion(s) and the original question. Happy to obtain whatever approval I need to but not MCS as I'm sure that I will use all/most of my excess anyway.

DIY in as much as I'll set up PV/Inverters etc until I need to connect it to something, at which point I'll get an expert.

 

[ProDave]

The normal setup for that is the PV charges a battery bank and then an off grid inverter generates as much as the loads connected needs.

What you are asking for is a normal "on grid" inverter that outputs as much as the panels are generating, to power whatever is connected with excess to go to the immersion heater.

I have never heard of such a system as a normal on grid pv inverter needs the grid to synchronise to which you won;t have.

Are you actually having a grid connection or are you totally off grid?

You might get more help and quirky ideas from the Navitron renewables forum,.

 

[binky]

OK, so you need a grid tied 16A limited export  inverter to get DNO approval. 

PV needs to be connected on its own cct back  to your Consumer Unit. Likewise an Amp clamp will need to go on your meter tails to achieve the 16A limitation, along with setting the inverter to do that. So you will need inverter reasonable close to main board. DO NOT share an RCD with the solar and any other cct.

Immmersion controllers are great, but I can't think of any that 'daisy chain' to multiple units. You woudl need wireless controllers as they also need an Amp Clamp at the incoming meter tails, so perhaps just use standard immersion timers and set them up for different times of day on your holiday lets, with an immersion controller on your house. 

 

[Murdoch]

Hence why I'm here  

Kit will be MCS accredited but I do not wish to attach to main network. I understood, perhaps wrongly, that you can set up your system such that any "excess" is not sent back up the line to the grid. Which is why I wish to push excess into HW immersion(s) and the original question. Happy to obtain whatever approval I need to but not MCS as I'm sure that I will use all/most of my excess anyway.

DIY in as much as I'll set up PV/Inverters etc until I need to connect it to something, at which point I'll get an expert.

Then what would you do when the immersion is up to temperature?

 

[binky]

Then what would you do when the immersion is up to temperature?

it turns off, but will have stored X kWh of energy in the water. There's no export tariffs to be had these days, so batteries and water heating are good options, especially water heating as it saves buying gas / leccy and is a lot cheaper than a set of batteries. 

 

[Murdoch]

it turns off, but will have stored X kWh of energy in the water. There's no export tariffs to be had these days, so batteries and water heating are good options, especially water heating as it saves buying gas / leccy and is a lot cheaper than a set of batteries. 

I think your idea of a wind turbine sounds better