A while back,someone brought up the problem of switching stuff on
automatically only when the PV panel can meet the load. ie as weather
conditions allow.

Answer is here, someone is making one.
http://www.solarpowerportal.co.uk/ne...management9876

So you can set this up and go out to work. When the PV output meets the set
level it will switch on (and off).
Prevents inadvertent use of non PVpower.

On Apr 5, 10:02*am, "harryagain" wrote:
A while back,someone brought up the problem of switching stuff on
automatically only when the PV panel can meet the load. *ie as weather
conditions allow.

Answer is here, someone is making one.http://www.solarpowerportal.co.uk/ne..._embraces_ener...

So you can set this up and go out to work. When the PV output meets the set
level it will switch on (and off).
Prevents inadvertent use of non PVpower.

Its a strangely complex product for a very simple job.


NT

NT wrote:

On Apr 5, 10:02*am, "harryagain" wrote:
A while back,someone brought up the problem of switching stuff on
automatically only when the PV panel can meet the load. *ie as weather
conditions allow.

Answer is here, someone is making one.http://www.solarpowerportal.co.uk/ne..._embraces_ener...

So you can set this up and go out to work. When the PV output meets the set
level it will switch on (and off).
Prevents inadvertent use of non PVpower.

Its a strangely complex product for a very simple job.

Here is a much simpler solution, but look at the cost. You would
take quite a while to recover £190 plus Part P installation. The
calculation would also have to allow for the arrival of smart
meters.

http://chrisrudge.co.uk/immersion.htm

Both seem to have too simple an algorithm. They only look at
generation, not consumption.

The best arrangement should measure generation and consumption,
and only turn on specified equipment if there is sufficient
unused capacity.

Easily expressed, but not so easy to achieve in a manner that is
both compliant and cost-effective.

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

On Apr 5, 11:42*am, Chris J Dixon wrote:
NT wrote:
On Apr 5, 10:02*am, "harryagain" wrote:
A while back,someone brought up the problem of switching stuff on
automatically only when the PV panel can meet the load. *ie as weather
conditions allow.

Answer is here, someone is making one.http://www.solarpowerportal.co.uk/ne..._embraces_ener...

So you can set this up and go out to work. When the PV output meets the set
level it will switch on (and off).
Prevents inadvertent use of non PVpower.

Its a strangely complex product for a very simple job.

Here is a much simpler solution, but look at the cost. You would
take quite a while to recover £190 plus Part P installation. The
calculation would also have to allow for the arrival of smart
meters.

http://chrisrudge.co.uk/immersion.htm

Both seem to have too simple an algorithm. They only look at
generation, not consumption.

The best arrangement should measure generation and consumption,
and only turn on specified equipment if there is sufficient
unused capacity.

Easily expressed, but not so easy to achieve in a manner that is
both compliant and cost-effective.

Chris


In the case of offgrid solar pv, the solution is rather simple:
monitor battery bank V and turn on a relay when V is high enough. High
enough means power to spare from the panels.

With grid tied pv, as you say it means monitoring production and
consumption, but its not too demanding a bit of circuit design.

But more to the point, why would one do it with a grid tied system,
when you're better off exporting electricity then using it when the
sun's gone down.


NT

On Thursday, 5 April 2012 15:15:10 UTC+1, NT wrote:
In the case of offgrid solar pv, the solution is rather simple:
monitor battery bank V and turn on a relay when V is high enough. High
enough means power to spare from the panels.

With grid tied pv, as you say it means monitoring production and
consumption, but its not too demanding a bit of circuit design.

But more to the point, why would one do it with a grid tied system,
when you're better off exporting electricity then using it when the
sun's gone down.


NT

Huh? You get 21p for every unit generated (whether you use it or not). You get a further 3.2p for every unit exported back to the grid.

But in the evening, a typical tarrif will cost you about 10p per unit, so if you store rather than sell back, you have lost the opportunity of earning 3.2p in order to save yourself 10p.

I am, of course, assuming that you've got the battery / storage for free. If there is a cost per unit 6.8p (which I think there is) then you're right - you are always better off selling back to the grid than storing / using at a later time.

Of course, the most effective thing you can do is generate electricity and use it before it heads back to the grid.

Matt

NT wrote:

On Apr 5, 10:02 am, wrote:
A while back,someone brought up the problem of switching stuff on
automatically only when the PV panel can meet the load.

But more to the point, why would one do it with a grid tied system,
when you're better off exporting electricity then using it when the
sun's gone down.

Because the unFIT tariff means they're *not* better off doing that, they
get paid for generating it, and (unless they have a smart meter) paid
again on the assumption they export half of it, but the greedy sods want
to use it all for their solar powered bog seat warmers or whatever.

On Apr 5, 10:27*am, NT wrote:
On Apr 5, 10:02*am, "harryagain" wrote:

A while back,someone brought up the problem of switching stuff on
automatically only when the PV panel can meet the load. *ie as weather
conditions allow.

Answer is here, someone is making one.http://www.solarpowerportal.co.uk/ne..._embraces_ener...

So you can set this up and go out to work. When the PV output meets the set
level it will switch on (and off).
Prevents inadvertent use of non PVpower.

Its a strangely complex product for a very simple job.

NT

Not at all simple.

On Apr 5, 3:15*pm, NT wrote:
On Apr 5, 11:42*am, Chris J Dixon wrote:





NT wrote:
On Apr 5, 10:02*am, "harryagain" wrote:
A while back,someone brought up the problem of switching stuff on
automatically only when the PV panel can meet the load. *ie as weather
conditions allow.

Answer is here, someone is making one.http://www.solarpowerportal.co..uk/n..._embraces_ener...

So you can set this up and go out to work. When the PV output meets the set
level it will switch on (and off).
Prevents inadvertent use of non PVpower.

Its a strangely complex product for a very simple job.

Here is a much simpler solution, but look at the cost. You would
take quite a while to recover £190 plus Part P installation. The
calculation would also have to allow for the arrival of smart
meters.

http://chrisrudge.co.uk/immersion.htm

Both seem to have too simple an algorithm. They only look at
generation, not consumption.

The best arrangement should measure generation and consumption,
and only turn on specified equipment if there is sufficient
unused capacity.

Easily expressed, but not so easy to achieve in a manner that is
both compliant and cost-effective.

Chris

In the case of offgrid solar pv, the solution is rather simple:
monitor battery bank V and turn on a relay when V is high enough. High
enough means power to spare from the panels.

With grid tied pv, as you say it means monitoring production and
consumption, but its not too demanding a bit of circuit design.

But more to the point, why would one do it with a grid tied system,
when you're better off exporting electricity then using it when the
sun's gone down.

NT- Hide quoted text -

- Show quoted text -

You get paid whether you export it or not.
So it makes sense to use as much as you can.

On Apr 5, 4:43*pm, larkim wrote:
On Thursday, 5 April 2012 15:15:10 UTC+1, NT *wrote:
In the case of offgrid solar pv, the solution is rather simple:
monitor battery bank V and turn on a relay when V is high enough. High
enough means power to spare from the panels.

With grid tied pv, as you say it means monitoring production and
consumption, but its not too demanding a bit of circuit design.

But more to the point, why would one do it with a grid tied system,
when you're better off exporting electricity then using it when the
sun's gone down.

NT

Huh? *You get 21p for every unit generated (whether you use it or not). *You get a further 3.2p for every unit exported back to the grid.

But in the evening, a typical tarrif will cost you about 10p per unit, so if you store rather than sell back, you have lost the opportunity of earning 3.2p in order to save yourself 10p.

I am, of course, assuming that you've got the battery / storage for free. *If there is a cost per unit 6.8p (which I think there is) then you're right - you are always better off selling back to the grid than storing / using at a later time.

Of course, the most effective thing you can do is generate electricity and use it before it heads back to the grid.

Matt

Grid tie has no battery.

On Apr 5, 4:53*pm, Andy Burns wrote:
NT wrote:
On Apr 5, 10:02 am, *wrote:
A while back,someone brought up the problem of switching stuff on
automatically only when the PV panel can meet the load.

But more to the point, why would one do it with a grid tied system,
when you're better off exporting electricity then using it when the
sun's gone down.

Because the unFIT tariff means they're *not* better off doing that, they
get paid for generating it, and (unless they have a smart meter) paid
again on the assumption they export half of it, but the greedy sods want
to use it all for their solar powered bog seat warmers or whatever.

I export more than 3/4 of what I generate.
The scheme is about reducing emissions anyway.

On Apr 5, 5:38*pm, harry wrote:
On Apr 5, 4:43*pm, larkim wrote:



On Thursday, 5 April 2012 15:15:10 UTC+1, NT *wrote:
In the case of offgrid solar pv, the solution is rather simple:
monitor battery bank V and turn on a relay when V is high enough. High
enough means power to spare from the panels.

With grid tied pv, as you say it means monitoring production and
consumption, but its not too demanding a bit of circuit design.

But more to the point, why would one do it with a grid tied system,
when you're better off exporting electricity then using it when the
sun's gone down.

NT

Huh? *You get 21p for every unit generated (whether you use it or not). *You get a further 3.2p for every unit exported back to the grid.

But in the evening, a typical tarrif will cost you about 10p per unit, so if you store rather than sell back, you have lost the opportunity of earning 3.2p in order to save yourself 10p.

use before export: per unit: 21p generated
use, export, use later: 21p +3.2p in, 10p out
so on that basis youre right


I am, of course, assuming that you've got the battery / storage for free. *If there is a cost per unit 6.8p (which I think there is) then you're right - you are always better off selling back to the grid than storing / using at a later time.

Of course, the most effective thing you can do is generate electricity and use it before it heads back to the grid.

Matt

Grid tie has no battery.

indeed


NT