On Tue, 15 Sep 2009 16:47:46 +0000 (UTC), David Taylor
wrote:

On 2009-09-15, Zero Tolerance wrote:
On Tue, 15 Sep 2009 09:39:13 +0100, "Norman Wells"
wrote:

However, he ignores the fact that he's also losing 45 watts of heat. To
keep his house at exactly the same temperature, an extra 45 watts of heat
need to be pumped out by whatever heating system he has, for as much of the
year as he needs any heating at all. Admittedly, that may be a bit cheaper
if it's gas-fired, but it's still the same amount of energy, so it's
unlikely to have a huge impact on climate change.

This is an old (and thoroughly discredited) logical error. Saving 45
watts of energy is not the same as saving 45 watts of heat. For a
start, most of that energy is expended in doing the 'work' - e.g.
lighting lights, spinning discs, and so on. Any excess heat generated
after that (unnecessary) work is done is minimal.

By your logic, if I leave a Sky+ box on standby, then the 20 watts it
spends on spinning the hard disc is converted into 20 watts of heat.

It is, through vibrations and friction in the bearings.

If that were true, it would turn Sky+ into a free energy machine -

It would not.

which is impossible - breaking every scientific law there is.

No, it would not.

Quite. Scientific laws would be broken if energy went into a box of
electronics (from the mains connection or a battery) and did not come
out in some form: heat, light, sound, whatever.

--
Peter Duncanson
(in uk.tech.digital-tv)