From this website
fridge/freezer, so naturally. They decided to find an energy-efficient and ozone-friendly model. It was also fitted with a SavaPlug which saves a further 20% on what is the most energy-intensive device in the house after hot water and central heating
I have no idea what it is, but you can be sure that it doesn't work. The fridge manufacturers go to a lot of trouble to get good energy efficiency so that they can put 'A' stickers on the things in the showrooms. If there really was a 50p device to save 20% of the energy for free, it would already be incorporated into the design.
Christian.
Erm...This is IMM you're talking to. You know, IMM, as in magnetic water softners??
and that was my argument in the shop. They seem to sell for about 20 quid IIRC.
Darren
These days, it usually is.
Savaplugs did work on old fridges, especially those where the door was regularly opened. Comparing fridge energy costs and their replacement costs, then there's a lot to be said for modern higher-efficiency fridges anyway.
-- Die Gotterspammerung - Junkmail of the Gods
Don't use logic with IMM. He believes every advert he reads.
Just ran a search on 'Google' and found they cost between £18 and £24. If they do work it would be some time before you got your money back. Also they look quite bulky.
What were they? Some sort of anti-cycling logic?
Christian.
It is not from a makers web site, and it woiuld be nice to know if others have the same results.
A quick google search will probably throw up a number of suppliers. Think they cost about £20 - £25. As for the energy savings, I guess it depends on the quality of the appliance you fit it to. I would imagine that the Savaplug works by allow full power to be drawn to achieve the necessary start-up torque when the pump is stalled, but then limits it once the pump is running. Depending on the quality of the appliance, it may already be fitted with similar energy saving circuitry. Probably worthwhile if you have an ancient old fridge or fridge freezer, but with a modern, energy-efficient A-class then I reckon the savings would be minimal and the payback period make it uneconomic.
Cheers Clive
energy-efficient
The web site said they have an energy efficient fridge and a Savaplug.
energy-efficient
Also from the same website
Energy-efficient and ozone-friendly fridge/freezer by Bosch. It is A-rated (the most efficient rating) for both fridge and freezer cycles and uses a hydrocarbon instead of the more prevalent HCFCs as the coolant fluid. This model was a mechanically perfect slight second (note light scratch on front) so was reduced to £600 from £1000 from Roy Waring (Engineering) Ltd (tel
01777 870487). The combi-oven was £600 from the same place. The SavaPlug is a British invention which will save about £12 a year per unit and costs £25 from the highstreet.
If you wrap a magnetic water conditioner around the mains flex, you'll even get an additional 20% reduction in energy usage, giving a total reduction of
40%.Christian.
Not even IMM could get this saving.
80% of 80% is 64% hence the saving would be 36%.Maybe we should not confuse with him mathematics and science in one go!Bob
That does seem to be the general idea looking at several sites (generally a word for word repeat of the manufacturer's blurb). I don't know much about pumps, but surely the pump only draws the power needed to keep it running? There is an Estates Review page that favourably covers their use by Redbridge Borough Council on
Better still, we could install 6 conditioners on the flex. Then we would save 120%. The fridge would, in effect, be producing electricity that we could use round the house, like running a few fan heaters.
Christian.
Must admit I was sceptical - not so sure now....
If you have a look at the makers web site:-
The argument they state, is that the motors used (especially on smaller devices) are oversized so as to accommodate the high torque requirements at switch on from the stall position. Once the motor is spinning and at a steady state, you can use the PWM power control to reduce the power input into the motor. This should not impact the motors ability to run the compressor since it is oversized. This will give savings as a result of less power dissipation in the motor, and they also suggest that you get better efficiency from a more highly loaded motor than a lightly loaded one - the reduced power input resulting in an increase in the loading on the motor.
I don't know enough about AC induction motors to comment on the motor efficiency issues, although I can see advantages to having a power factor corrector on the inductive motor load.
As others have suggested - it may well be that some fridge manufactures already include such facilities in their compressor design these days.
As an aside: does anyone know if a domestic electricity meter measures real or apparent power?
No, that is basically the problem.
Look at a workshop compressor. Any modern one will have an "unloader valve" (You can hear this hiss whenever the compressor motor cuts out). The function of the unloader is to empty the compressor cylinder of compressed air, so that next time it starts up it's pumping into a low pressure, rather than trying to start against an already full cylinder. As it is, workshop compressors pull a huge current at startup and running one without an unloader would pop the fuse on a domestic supply.
Fridges (of any sort) don't have such valves. There's a natural reluctance to add any such potential leaky valve to a sealed regrigerant system. So when a fridge compressor starts, it's pumping into a high load. Such a compressor motor must thus be rated for its starting power, which is over-rating it for the running power.
The Savaplug reduces motor power electrically, after a small delay from first starting. It's a good idea, although the original plugs were far from cheap. It's also an idea that's easy to build inside a new fridge, and my understanding is that many of them now do so.
-- Die Gotterspammerung - Junkmail of the Gods
We have had this thread a few times in the (several years ago) past. The general speculation/conclusion was that _very_ old fridges and freezers might save some juice this way - the plug is mainly just a diode IIRC!).
It is also possible that under normal conditions of service there is a small amount to be gained but that under arduous conditions (like the hot week in early August) the plug might actually interfere with the correct operation of the motor.
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