Fridge/freezer on Economy 7 possible energy-cost-saving trick?

devondiver

Deleted_User said:

"Since refrigerators account for the major share of energy consumption in homes"?  Really?  Are these homes without space heating or hot water?

Ask the experts. They may be referring to electrical energy.

Deleted_User said:

I'd rather use the "phase change material" of molten salt in concentrating solar power stations with thermal storage than need everyone to change their refrigerator.

Everyone changes their refrigerator - sooner or later. Good idea - but not everyone has a SPS (take care with that molten salt).

Deleted_User said:

Large-scale renewables with energy storage means that there is much less of a peak vs off-peak anyway.

Questionable. Especially if many of us charge our cars during the day. And more of us can afford, and will need, air con.

QrizB

devondiver said:

Deleted_User said:

Large-scale renewables with energy storage means that there is much less of a peak vs off-peak anyway.

Questionable. Will we all charge our cars during the day?

I imagine we'll get to the stage where your car charge point will know when electricity is cheapest and you'll be able to tell it to charge then. (Intelligent Octopus already does something like this.)

It's a modern version of the old (mostly Scottish) heating tariffs where the energy supplier could control your storage heater charging times remotely, depending on the weather forecast.

[Deleted User]

devondiver said:

Deleted_User said:

"Since refrigerators account for the major share of energy consumption in homes"?  Really?  Are these homes without space heating or hot water?

Ask the experts. They may be referring to electrical energy.

Having worked on these things for more than a decade, I don't need a different expert to tell me that the quoted line is nonsense and likely selected to make the results of their study seem more important.

devondiver said:

Deleted_User said:

Large-scale renewables with energy storage means that there is much less of a peak vs off-peak anyway.

Questionable. Will we all charge our cars during the day?

Now, if you'd been thinking about shifting EV charging around, exactly as some ToU tariffs are trying to do and as future EV systems are planned to do - that would make a lot more sense.  EV batteries are a much larger energy storage source than the thermal mass of a refrigerator, the technology already exists, and requires only a simple software update to enable in many situations, and conceptually it's a much simpler thing to explain from the perspective of the end user who would be required to engage with the system (or at least give up control) in order for it to work.

And it's not questionable.  Areas of the distribution network with higher penetrations of EVs or other forms of energy storage tend to have flatter consumption curves, unless the owners are entirely failing to engage with the beneficial arrangements on offer to them.  This was proven in about 2014.

devondiver

Sorry QrizB - I edited that before I noticed your reply. It didn't say quite what I meant. But I take your point/s.

devondiver

[Deleted User] said:

devondiver said:

Deleted_User said:

"Since refrigerators account for the major share of energy consumption in homes"?  Really?  Are these homes without space heating or hot water?

Ask the experts. They may be referring to electrical energy.

Having worked on these things for more than a decade, I don't need a different expert to tell me that the quoted line is nonsense and likely selected to make the results of their study seem more important.

Yeah, whatever. . . 

It's easy to find numerous references which say that refrigeration accounts for c.10% of domestic consumption - and it's easy to just discount them as being selective. But what do I know - or care?

[Deleted User]

devondiver said:

[Deleted User] said:

devondiver said:

Deleted_User said:

"Since refrigerators account for the major share of energy consumption in homes"?  Really?  Are these homes without space heating or hot water?

Ask the experts. They may be referring to electrical energy.

Having worked on these things for more than a decade, I don't need a different expert to tell me that the quoted line is nonsense and likely selected to make the results of their study seem more important.

Yeah, whatever. . . 

It's easy to find numerous references which say that refrigeration accounts for c.10% of domestic consumption - and it's easy to just discount them as being selective. But what do I know - or care?

10% is now "the major share" - ok, I'm glad you don't care, because if you did then that logic would be worrying.

Please, go ahead and develop your game changing phase-change fridge/freezer, prove me wrong.  My opinion remains that there are much cheaper and already available technologies that have a much greater effect.

devondiver

Deleted_User said:

devondiver said:

[Deleted User] said:

devondiver said:

Deleted_User said:

"Since refrigerators account for the major share of energy consumption in homes"?  Really?  Are these homes without space heating or hot water?

Ask the experts. They may be referring to electrical energy.

Having worked on these things for more than a decade, I don't need a different expert to tell me that the quoted line is nonsense and likely selected to make the results of their study seem more important.

Yeah, whatever. . . 

It's easy to find numerous references which say that refrigeration accounts for c.10% of domestic consumption - and it's easy to just discount them as being selective. But what do I know - or care?

10% is now "the major share" - ok, I'm glad you don't care, because if you did then that logic would be worrying.

Please, go ahead and develop your game changing phase-change fridge/freezer, prove me wrong.  My opinion remains that there are much cheaper and already available technologies that have a much greater effect.

You can play with semantics all you like. Many would agree that 10% is significant. Wherever did you get the idea that I was developing anything? I have no drum to beat here. You suggested earlier that the authors of a study to which I randomly referred had "been selective in order to make them seem important". Sounds familiar.

mmmmikey

A bit of a tangent, but here's another thought and some numbers....

My fridge used 8.9kWh in September. 8.9/30*365=108 i.e. 108kWh per year.

I pay 6.9p/kWh night and 47.31p/kWh day on E7

Total annual cost of running fridge on E7 = (7/24 * 108 * 0.069) + (17/24 * 108 * 0.4731) = £48.65

So this is what it would cost me to run my fridge on E7 "out of the box".

But what I actually do is run the fridge off energy stored in a battery that charges overnight at E7 rates, so the numbers become:

I pay 6.9p/kWh for off peak electricity for 7 hours per day.

For the other 17 hours I use off peak electricity stored in a battery but there's an efficiency loss and it costs me 10.6p/kWh

Total annual cost of running the frdige = (7/24 * 108 * 0.069) + (17/24 *108 * 0.106) = £10.28

(Actually it's a bit less than this because the fridge uses solar power for some of the time which costs me 0.0599p/kWh (that's what I would otherwise receive if I exported it))

Keep in mind this is not purely hypothetical - this is what I am actually doing now and this is all based on actual measurement and October E7 costs.

So without inventing anything it is already possible to run a fridge for less than £1 per month using a mid-range whole house battery system.

devondiver

mmmmikey said:

A bit of a tangent, but here's another thought and some numbers....

My fridge used 8.9kWh in September. 8.9/30*365=108 i.e. 108kWh per year.

I pay 6.9p/kWh night and 47.31p/kWh day on E7

Total annual cost of running fridge on E7 = (7/24 * 108 * 0.069) + (17/24 * 108 * 0.4731) = £48.65

So this is what it would cost me to run my fridge on E7 "out of the box".

But what I actually do is run the fridge off energy stored in a battery that charges overnight at E7 rates, so the numbers become:

I pay 6.9p/kWh for off peak electricity for 7 hours per day.

For the other 17 hours I use off peak electricity stored in a battery but there's an efficiency loss and it costs me 10.6p/kWh

Total annual cost of running the frdige = (7/24 * 108 * 0.069) + (17/24 *108 * 0.106) = £10.28

(Actually it's a bit less than this because the fridge uses solar power for some of the time which costs me 0.0599p/kWh (that's what I would otherwise receive if I exported it))

Keep in mind this is not purely hypothetical - this is what I am actually doing now and this is all based on actual measurement and October E7 costs.

So without inventing anything it is already possible to run a fridge for less than £1 per month using a mid-range whole house battery system.

Sounds brilliant! All you need is a battery system and controls - which in the near future will be commonplace in many homes

BTW - I started this thread on a 'just a thought' basis. There was no intention to propose inventing anything, or bettering any of the myriad energy-saving technologies which may be in the pipeline or in existence. I just wondered whether or not the simple exercise of transferring something from a freezer shelf to a fridge shelf and back again once per day may possibly have some benefit. Nothing could be simpler; and none of the speculation so far provided has really answered my musings. So maybe I need to get some 'smart plugs' and try it.

victor2

mmmmikey said:

.....

So without inventing anything it is already possible to run a fridge for less than £1 per month using a mid-range whole house battery system.

That is a great achievement and nicely illustrates how running costs can be reduced, but even if you put aside the initial cost of the solar system, what will its ongoing costs be? The batteries won't last forever, so what is their monthly cost?
We have friends who are totally off grid and rely on solar/battery to run a large fridge/freezer and LED lighting, plus little things like phone and laptop chargers only as capacity is available. They still have to switch off the fridge at night in the winter to prevent the (expensive) battery system shutting down completely.