I think my hand-wavy calculations led me to believe a new one would need to last a decade in order to pay for itself in energy savings, and I didn't have much faith in any modern company either building something that'd last that long or still being around in such a
*vast* time period :-)(Our Whirlpool fridge/freezer's comfortably over 30 years old now and still going strong - parts still seem to be readily available for when it does eventually have issues)
cheers
Jules
I thought they just pulled the power factor back into line. The motor being an inductive load messed up the power factor and leads to slight errors in the meter. Could be wrong but I'm sure someone will be along shortly to inform us about power factor and meters.
Dave Liquorice coughed up some electrons that declared:
Domestic meters are designed to read true power (kVAh meters do/did exists for industrial environments where the billing was sometimes done by the VA-h rather than a W-h).
A capacitor is all that's needed to fix the PF on an inductive load.
Cheers
Tim
Basic ffs are really very reliable, its only when you get into frost frees that things go wrong. 1970s... you're spending a lot of money you needn't. Even comparing an old one given for free with a brand new machine the new one's cheaper.
NT
Care to expand that for this bear of little brain when it comes to AC power measurement and power factors.
Aye, that bit I do know. Has any one opened up a savaplug to find out what is inside? I suspect not much more than a capacitor...
That is interesting So what makes the red light come on to say power is being saved?
Adam
a sizeable PCB incuding a triac. If I find it I could post a photo.
NT
Dave Liquorice coughed up some electrons that declared:
True power is taken by integrating (or taking the sum of) a series of instantaneous current and voltage measurements effectively multiplied. The old magnetic disc meters did this multiplication in an analogue fashion with a bit of clever physics to do with the way a voltage coil and a current coil interacted on an aluminium disc, turning it into a motor, which was balanced by a permanent magnet that tended to slow it down.
The speed of the disc gave the Watts and the integration was achieved by tying the disc to a counter.
A VA(h) meter basically just measures RMS voltage and RMS current and multiplies them (them being averages over a cycle or more) without regard for any phase angle between the current and the voltage.
I have no idea how a disc meter achieved this - never seen one , only heard of them.
In both cases, electronic meters are simpler conceptually - read current and voltage at sub cycle samples, then apply whatever maths is desired and keep a running total.
No idea. Probably chops the waveform in some way that I wouldn;t like to have going into my products :)
Ours doesn't seem to have any frosting issues - I think we have the manual somewhere, so I'll have to see if it says anything about frost-free operation. I did have to take a fan motor out of the freezer section last year as it was noisy - I was going to replace it, but gave the bearings a light oil and it's been OK since. I suspect its days are numbered)
Not so sure - I think most of our 'leccy bill goes on the baseboard heaters, tumble dryer, water heater, and cooker. I'm not sure a different fridge would make much of a dent in that - it might knock off 10% or so, but 10% still works out to about ten years for a typical fridge/freezer (electricity is pretty cheap this side of the Pond, whilst ff's are comparatively expensive*).
cheers
Jules
i am, i calculated it a few years ago. A new machine will ballpark a third the energy of an oldie. What your other appliances use is not relevant.
NT
It's relevant in that it gives me an estimation of what proportion of our monthly bill is down to the ff, rather than other devices.
1/3 power will cost $7/month to run rather than (an estimated) $20. That's a saving of $13/month, or $156/year.At a typical price of about $1200 for a ff of similar capacity with some kind of energy efficiency rating (the cheaper ones here are either a lot smaller, or still enourmously power-hungry), that's still 7 years before it pays for itself, assuming no major malfunction in that time.
If the modern product came with something like a free 15-year warranty, I'd listen - but all the new ones I've looked at around that price point don't exactly inspire confidence in them running for 7 years without some kind of problem.
Of course I don't know if the current one will last another 7 years, either - that might be asking a lot of it :-) But if it'll do another 2 or
3, I expect that there will be quite a few second-hand ones on the market that will be modern enough to run cheaply, not be as costly as a new one, yet hopefully have a little better build quality (plus I can assess the spares market a little too and avoid the unknowns and difficult-to-repair brands).It's hard to tell how this stacks up in the UK, though - electricity there always seemed far more expensive, and I honestly don't recall what typical ff prices were like (possibly cheaper than the US as they tend to be smaller* on average!)
cheers
Jules
I've never come across a kVAh meter. The usual industrial arrangement is a regular kWh meter plus a kVARh meter - reactive consumption being billed at x pence per kilovar-hour on top of the normal kWh charge. Kilovars (kVAR) - kilovolt-amps-reactive - is the 'reactive power' - i.e. the product of voltage and the quadrature component of the current (V*I*sin(phi), as opposed to V*I*cos(phi) for kW).
On a tariff where you're paying for kVARh there will normally also be a maximum demand charge, based on the monthly maximum demand in kVA (averaged over 30 minutes to exclude motor starting and similar inrush transient currents). In the past the maximum demand indicator would have been a third item of metering equipment. Nowadays all three functions are usually incorporated into one electronic meter.
this is uk.diy, not us.diy. FFs cost us 200-300.
NT
A decent one is nearer 700.
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