The Insatiable Power Hunger of Home Electronics 340
An anonymous reader writes "A Wall Street Journal columnist recently got his hand on a power meter and decided to write about his findings, the resulting article being discussed here on Slashdot. That author concluded that gadgets are getting a bad rap, and are relatively insignificant power consumers in the grand scheme of things. A rebuttal has appeared, arguing that not only are modern electronics significant power consumers already, while everything else is becoming more efficient, home electronics seem to be getting worse. This echoes the Department of Energy's assertion that 'Electricity consumption for home electronics, particularly for color TVs and computer equipment, is also forecast to grow significantly over the next two decades.' Are gadgets unfairly maligned, or getting an unearned pardon?"
Things are getting more efficient... (Score:5, Informative)
Re:My results (Score:3, Informative)
Yeah was about to say your missing a 2x multiplier if your in the UK. None of the equipment complains about running on 50hz instead?
A lot of equipment is completely oblivious to this shift in frequency. Most affected are appliances with AC motors and clocks. If the first thing an appliance does is convert AC to DC (as with almost all electronic appliances) then no difference will be noticed. If there is a transformer before the first rectifier, then there may be a slight loss of power.
Re:My results (Score:4, Informative)
Two comments:
First, these are Volt-Amps, not necessarily Watts. National Grid is going to charge you for Watts. The "Watts=VoltsxAmps" formula only works for 100% resistive loads or DC. On AC, you have to adjust for reactive power.
Second, what is going into your power converter that you are using to run your Canadian appliances in the UK? In other words, how much have you increased the insanity?
On a side note, don't you just love those British 3-prong plugs? Just be careful not to step on one in the middle of the night barefoot! :-)
the same verdict is being reached all over (Score:4, Informative)
Re:two simple things would totally fix it (Score:5, Informative)
Glad you asked. The main reason is safety regulations. Devices that plug in to your household power need 3rd party certification (e.g. UL approval in US). Power supply design is a specialty, and although any EE could do it, not all can do it well, quickly and cheaply. If you (as designer) spec an external transformer, then you don't have to worry about the approval. You just buy an approved transformer and design your device to work on low voltage. This saves you thousands of dollars and many man-hours of time per design by not having to hire an independent lab to verify your safety compliance.
As an additional benefit, you can sell you product to work with different AC voltages just by supplying the appropriate transformer for each market. Plus, when you buy an external transformer, you get economies of scale because it can power not only your devices but many others built by thousands of other firms.
Re:Things are getting more efficient... (Score:3, Informative)
Re:My results (Score:2, Informative)
Say's Law (Score:1, Informative)
From a modern macroeconomic viewpoint Say's Law is subject to dispute. John Maynard Keynes and many other critics of Say's Law have paraphrased it as saying that "supply creates its own demand". Under this definition, once a producer has created a supply of a product, consumers will inevitably start to demand it. This interpretation allowed for Keynes to introduce his alternative perspective that "demand creates its own supply" (up to, but not beyond, full employment). Some call this "Keynes' law".
However, these detractors, at the very least, have an argument.
Re:My results (Score:3, Informative)
There are actually several different kinds of British plugs. The giant square prong plug is only the most recent incarnation. There are the "lighting" plugs that have round prongs and are more akin to a US plug in size. They were actually the standard until the 70s or so. There are also shaver sockets with two prongs spaced similarly to US sockets. Some even have a voltage switch to select 115V or 230V.
UK plugs are ridiculously overengineered, but I can't say the same about the rest of their house wiring. Having an entire floor of a house on a single 30A circuit is still shockingly common. As are "ring mains" where all the outlets are connected in a giant loop with hot and neutral returning to the fusebox in two directions (this is still a parallel circuit). The problem is if one branch of the circuit is broken, the other side may be asked to carry twice rated current.
-b.
Re:two simple things would totally fix it (Score:3, Informative)
This is true to an extent, but the amount of power drawn in "zero load" conditions is quite small. The more load placed on the secondary, the more load seen on the primary. Some energy is wasted as heat. IIRC, a typical iron-core transformer is around 85% efficient at 50/60 Hz line current.
Switch mode power supplies can be much more efficient (such as a laptop "brick" or a PC supply) but they are often designed cheaply, resulting in less efficiency...
In general, cheap "wall wart" plug-in transformers do waste some power even when the device is off or even disconnected. They do produce some heat just being plugged in; however it is generally less than 1 watt with no load...