So now I have a solar PV system how do I make the most of it???

Zenoka wrote: »

Does anyone know if there is a device that can sense when you are exporting and send that electricity to a hot water heater? We would really like to use the surplus to help towards heating our water, DH is good at diy and is already talking about fitting a 500w imersion, but we want a system that will automatically control it for us.

Does such a thing exist? I've searched but not been able to find anything.

Yeah, such a device would be the only way to ensure a high proportion of the generated power was used in your own home, but I haven't seen an affordable home version of such a device yet. I expect as well as the cost of the device, there would be a degree of rewiring involved too. Also, 500w wouldn't do the job all the time - you'd probably need a 3kw heater is you want to ensure all the generated power is used on the best days.

But the savings you would make for the power used to heat the water is then not likely to be 10p/kwh. It would be the rate you would otherwise heat the water by - and for most, that means displacing gas at tier two rates, which is around 3p/kwh, probably saving an extra £30 pa typically. While saving £30 is better than not saving £30, you don't want to spend too much in order to save £30 (i'd say £100 for about a 3/4 year payback, but others don't seem to mind a 15 year payback where solar energy is concerned, equating to about £450, but that makes no sense to me).

While the whole idea of changing bhaviour to use the output is seductive (and no doubt I would too), the savings benefit over what you'd save should you change no behaviour i'd think would be quite small - say £30pa, from say typically £60 to typically £90 - this mainly due to tier two savings (i.e.the expensive tier one covering the standing charge will still be there). Including the fits, for those who get them, the return rises from something like, as an example, £1260 from £1290 for those behavioural changes. Ie, not really worth busting a gut over imv. (especially when you alter behaviour for tiny uses, such as charging your phone up, which, if it save anything, is just pence pa).

Although some people advertise electricity bills being halved by solar panels, I think that is misleading for almost everyone, and it's useful I feel to get figures for the likely savings, in order to see if any particular course of action is worthwhile or not.

The device I've seen for this purpose (automatically diverting unused Solar Power generation to a specific circuit in the house, typically a water heater) was called the EMMA. Google it and you'll get the info you want.

But as others have said, it's not economical for a domestic setting. I recall it was near the £1k mark plus the installation cost, which for a £30 saving seems absurd.

....or have solar panels that belong to someone else and are just getting the free leccy of course. I which case you are very interested in how you can use as much as you can of what you are generating.....

penrhyn wrote: »

As your unused solar power is fed into the grid, for which you are handsomely rewarded there is no point what so ever in doing this.
Unless of course you have severed your grid connection.

Penrhyn. You are not handsomely rewarded for feeding unused solar power into the grid. If it's your own system you are likely to have to pay over 3 times as much to buy back what you export, so it is very much in your interest to use your 'own' power if possible. The handsome reward is for generating electricity, independent of who uses it.
As an aside, if a grid connected system is severed from the grid it will not work.

rhiwfield wrote: »

One or two thoughts .....

.... Not sure about slow cookers ....

Hi

My slow cooker, capacity 5.5l(?)/digital seems to draw a constant 181W on 'high' setting, I did measure the 'low' and 'keep warm' settings once but didn't bother noting their timings. Be wary, some slow cookers can consume two to three times this, they are either thermally inefficient (bad insulation) or rely on thermostatic control to cycle their power more often (not good in balancing a pv environment), so check the specs if they're published.

What needs to be remembered is to always boil the water before adding ...... and unless you have 20 minutes a time to pfaff about in the preparatation stage browning and caramalising in a frying pan, all the time wasting the energy you thought you were saving anyway, either forgo the flavour benefits, or get a larger capacity pot and cook in batches .....

Mmmmmmm .....

HTH
Z