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

zeupater

silverwhistle wrote: »

It's a new A+ freezer and, as I mentioned, kept full, if necessary with bottles of water. If I go away on holiday I'll unplug the timeswitch.

As I initially noted, the freezer came on this morning and didn't appear to be working any harder than a normal switching cycle, although one would presume it stayed on a little longer than normal ....

Hi

Unless the freezer is a new inverter type (very rare), the duty will be fixed - it's just the length of the cooling cycle which varies, so you shouldn't hear/notice any difference other than it being on for longer.

If you reach around the back of the unit and touch the condenser when the freezer is operating normally it will be 'warm' towards the end of the cooling cycle ... if you repeat this when using one of your 'extended' daytime cycles you will find that the condenser is hot. Depending on the quality of the components used in manufacture, operating the compressor at high temperatures for a greater proportion of it's life than it was designed for will naturally lead to premature unit failure ....

There's a 'rule of thumb' which can be applied to electrical and mechanical items which suggests that for each ~10C rise in operating temperature above nominal design temperature there's a good chance of halving the lifespan ... I'd guess that switching the freezer off overnight in order to utilise pv generation during the day will result in the condenser temperatures averaging somewhere around 20C-40C (pure guess - but over 30years ago I was involved in the design/specification of condensers for the domestic market) higher than normal operation ..... although the unit will be designed to cope with this in order to 'rapid freeze' the contents when filling, the effect of doing this on an everyday basis is likely to be a reduction in unit lifespan of 75% to 95% ... it's just a case of offsetting the cost of the additional replacement freezers against that of the energy saved ...

HTH
Z

silverwhistle

Thanks, I'll keep an eye on the temperatures. It's all a learning curve, and if it does have disastrous consequences I'll share the knowledge! These days where appliances are designed for multiple and varying markets I would imagine heat/climate tolerances would be greater than in the past, and touch wood/tocca ferro, appliances seem pretty reliable these days.

nigelpm

Good post Zeu. That was my point as well.

You might think you are saving £7.50 a year but ultimately if you have found a cost saving the manufacturer would most likely have implemented by now so its likely you are just offsetting the saved energy against component wear and tear.

shavy65

As a relatively new PV-er, I was thinking....
I`ve found it is very hard to use even half of what I`m generating, which is why I find my immersion heater link-up so beneficial. Although I try to use as much of my generated elec as possible I feel I`m still getting max water temp meaning I`m `wasting` electricity by exporting......is it a feasible idea to run a storage heater during day light hours? My concern is the heater running when there`s not enough generation to cover the running cost hence importing the surplus. I was thinking possibley using a sort of light sensor socket device which would only turn heater on during daylight.
I`m sure this has proabbly been discussed and there is a major flaw in my idea somewhere though, glad if someone could point it out for me! Cheers.

jimmyboy420

You'd need something like a Wattson I'd guess

EricMears

shavy65 wrote: »

I was thinking possibley using a sort of light sensor socket device which would only turn heater on during daylight.
I`m sure this has proabbly been discussed and there is a major flaw in my idea somewhere though, glad if someone could point it out for me! Cheers.

Not quite that simple - if it switches on with daylight you'd get it starting at 6am but might not start generating enough till (say) 10am so you'd be paying to run it for those 4 hours (AND another 4 at end of day).


You could refine the idea slightly by buying a small solar panel (the sort of thing used to trickle charge a caravan battery) and arrange to switch heater on via a relay when the small panel was generating a particular current.


But buying a Wattson & an Optiplug is probably easier.

Kernel_Sanders

nigelpm wrote: »

if you have found a cost saving the manufacturer would most likely have implemented by now so its likely you are just offsetting the saved energy against component wear and tear.

Silverwhistle wasn't suggesting any saving in electricity, therefore you must have thought that manufacturers are now designing appliances with solar PV in mind. They are not. So oblivious are they to this usage that they continue to boast on the box of how powerful the higher setting is without even stating the wattage of the lower one in the instructions!
This is the reason I haven't bought a tumble dryer.

silverwhistle

Where I used to live in another country the supermarket flyers used to advertise white goods, including freezers with an autonomy of 24 or even 36 hour, presumably to meet a rural market where O/H lines and climate meant more frequent and longer outages. There doesn't appear to be any real technical problem with having the compressor on/off for longer periods if common sense is utilised. This weekend I've been entertaining and freezing down lots of ice-packs for a sporting injury so have left the freezer on full time.

Further down the line the increasing amount of renewables such as PV and wind and the need for better demand management will change manufacturer's attitudes, but perhaps reading forums like this will help their awareness of how we are approaching the issue as individuals.

orrery

silverwhistle wrote: »

Further down the line the increasing amount of renewables such as PV and wind and the need for better demand management will change manufacturer's attitudes, but perhaps reading forums like this will help their awareness of how we are approaching the issue as individuals.

No, I think that this is the sort of area where there needs to be co-ordination. We need domestic appliances that can talk to some central co-ordination, such as a smart meter, which can manage their response. Washing machines and dishwashers that can be triggered in sequence depending on the power available, and the freezers and fridges topped-up in between.

tunnel

orrery wrote: »

No, I think that this is the sort of area where there needs to be co-ordination. We need domestic appliances that can talk to some central co-ordination, such as a smart meter, which can manage their response. Washing machines and dishwashers that can be triggered in sequence depending on the power available, and the freezers and fridges topped-up in between.

Solar storage will eventually do away with the need to turn off appliances during the night, they're just too expensive and cumbersome at the mo to make it a viable solution. Give a couple more years with the advances in technology and I believe we'll all be posting on here about the best storage solution to compliment your PV