Pepperman wrote:That's exactly how it works. No individual has control over your fridge, it's just a very simple (and very cheap) chip that the manufacturers pop into cold appliances which senses grid frequency and then delays the refrigeration cycle by a few minutes as long as the temperature of the cold appliance doesn't fall outside of a set range. This technology is such an easy win and such a non-issue but sadly it's going to be portrayed in certain sections of the media as THE STATE REACHING INTO YOUR HOME AND SWITCHING OFF YOUR APPLIANCES.
I sincerely hope that it becomes part of product standards as soon as possible. It should have been implemented years ago because the churn rate of white goods is slow so it'll take a long time for it to have an effect.
Well said. I can understand the likes of the Daily Mail intentionally getting the wrong end of the stick. I'm disappointed some on PowerSwitch are too though.
Ok. give me the right end of the stick.
Taking the specific example of a fridge, how does DD differ specifically from existing internal thermostatic control systems in fridges? What does it specifically do that they don't and how exactly does it do it?
Tarrel wrote:I still don't understand why the refrigeration cycle would kick in anyway, if the temperature was within the acceptable range. Maybe I just don't "get" fridges.
Let's say the refrigeration cycle is supposed to kick in when the internal temperature gets up to 5 degrees, at that point the chip that monitors grid frequency decides whether the grid is being stressed or not and tells the fridge to either go ahead and start its cycle (if it's not stressed) or wait another few minutes before starting (if it is stressed).
During that time the temperature in a modern fridge won't have increased more than a small fraction of a degree but the stress on the grid might well have subsided a bit either through fluctuations in demand or supply ramping up.
If after a certain period the grid is still stressed then the fridge kicks into its refrigeration cycle anyway because it needs to keep temperatures down.
All it's doing is taking a dumb appliance and making it a little bit more intelligent by making it monitor two parameters rather than one. There's probably a few GW of dumb cold appliance load cycling on and off in the UK randomly at the moment so making it intelligent so that a big chunk of it doesn't kick in at the same, possibly inappropriate, moment is a good thing.
As applied to a fridge, DD would work in two ways depending on whether or not the compressor was running when the grid frequency falls.
If the compressor was running then it would stop a few minutes earlier than if under the control of a simple thermostat.
If the compressor was not running, then when called for, the start would be delayed by about 60 seconds.
The total effect of large numbers of fridges and other appliances being so equiped would be to reduce the load on the grid for a few minutes at times of sudden shortage so as to permit of gas turbine plant starting up and relieving matters.
"Installers and owners of emergency diesels must assume that they will have to run for a week or more"
Tarrel wrote:I still don't understand why the refrigeration cycle would kick in anyway, if the temperature was within the acceptable range. Maybe I just don't "get" fridges.
Let's say the refrigeration cycle is supposed to kick in when the internal temperature gets up to 5 degrees, at that point the chip that monitors grid frequency decides whether the grid is being stressed or not and tells the fridge to either go ahead and start its cycle (if it's not stressed) or wait another few minutes before starting (if it is stressed).
During that time the temperature in a modern fridge won't have increased more than a small fraction of a degree but the stress on the grid might well have subsided a bit either through fluctuations in demand or supply ramping up.
If after a certain period the grid is still stressed then the fridge kicks into its refrigeration cycle anyway because it needs to keep temperatures down.
All it's doing is taking a dumb appliance and making it a little bit more intelligent by making it monitor two parameters rather than one. There's probably a few GW of dumb cold appliance load cycling on and off in the UK randomly at the moment so making it intelligent so that a big chunk of it doesn't kick in at the same, possibly inappropriate, moment is a good thing.
So, in short, DD forces an appliance to work less in favour of maintaining it's own internal equilibrium and, instead, work in favour of maintaining the equilibrium of an external system (in this case, the grid) where deemed necessary.
Yes - which it can do perfectly well thanks to its thermal inertia. DD doesn't work for lighting, but does work for fridges, freezers, storage heaters water heaters etc.
Tarrel wrote:I still don't understand why the refrigeration cycle would kick in anyway, if the temperature was within the acceptable range. Maybe I just don't "get" fridges.
Let's say the refrigeration cycle is supposed to kick in when the internal temperature gets up to 5 degrees, at that point the chip that monitors grid frequency decides whether the grid is being stressed or not and tells the fridge to either go ahead and start its cycle (if it's not stressed) or wait another few minutes before starting (if it is stressed).
During that time the temperature in a modern fridge won't have increased more than a small fraction of a degree but the stress on the grid might well have subsided a bit either through fluctuations in demand or supply ramping up.
If after a certain period the grid is still stressed then the fridge kicks into its refrigeration cycle anyway because it needs to keep temperatures down.
All it's doing is taking a dumb appliance and making it a little bit more intelligent by making it monitor two parameters rather than one. There's probably a few GW of dumb cold appliance load cycling on and off in the UK randomly at the moment so making it intelligent so that a big chunk of it doesn't kick in at the same, possibly inappropriate, moment is a good thing.
So, for years, fridges have been wasting energy by keeping themselves unnecessarily cold?
What this is basically saying is; "Fridges need to be kept below 5 degrees. Well...maybe not quite 5 degrees. 5.5 degrees is Ok if it avoids stressing the grid."
If that's the case, why not just turn the thermostat on the fridge up (down?) a little, run it at 5.5 degrees and save the energy all the time, not just when the grid is stressed. Let's face it, people put an awful lot more stuff in their fridge than they need to (ketchup for instance), so I doubt whether half a degree is going to make much difference.
Gees, the end-user won't notice anything different with the fridge.
What this is basically saying is; "Fridges need to be kept below 5 degrees. Well...maybe not quite 5 degrees SOMETIMES. 5.5 degrees is Ok if it avoids stressing the grid AND ONLY LASTS FOR A FEW MINUTES."
because of what civ101 said above: "thermal inertia"
The fridge will keep half-an-eye on the grid and mostly do it's thing. When it needs to, it will fully open one eye and pay more attention to the outside. And change it's behaviour slightly.
It's making electrical-appliances more socially responsible. I've just repeated what others have said.
Teqs is the solution but hardly anyone likes that either. We can't have everything.
The idea is not energy saving as such, the total energy used by a standard fridge and a DD equiped one will be virtually the same.
The idea is to achieve a very short term demand reduction at times of grid stress, thereby permitting a reduction in the amount of energy wasting part loaded "regulating reserve" generating plant.
There are many ways in which total electricity used may be reduced and this is is desireable for financial and enviromental reasons, but is NOT the same as DD control.
"Installers and owners of emergency diesels must assume that they will have to run for a week or more"
