On Aug 19, 3:10Â pm, Eeyore
hotmail.com>
wrote:> z wrote:
>> Eeyore wrote:
>>> "Daniel T." wrote:
>>>> John Larkin wrote:
>
>>>>> Sure, but where does the electricity come from?
>
>>>> Power plants that run at much higher efficiency
>
>>> Not that great actually.
>
>>>> (and much cleaner per kilowatt of energy produced) than any automobile
>>>> engine
>
>>> How do you reckon they're cleaner ?
>
>>>> could ever hope to do.
>
>>> Overall thermal efficiency from typical power plant to power socket is in
>>> the 30-40%% region.
>
>>> A very large marine diesel can and does EXCEED 50%% thermal efficiency. Only
>>> now are combined cycle gas turbine generators coming on line that can beat
>>> that but you still have transmission losses.
>
>>> Graham
>
>> Little known fact; efficiency of electrical generation is currently
>> half of what it was in Edison's day. Well, it's a trick question,
>> though; Edison was businessman enough to sell off the heat as a
>> byproduct (isn't that what they call cogeneration?) but today
>> utilities, as monopolies, are too lazy too chase that efficiency/cash.
>> too bad for all of us.
>
> Good point.
>
> Certain Scandinavian countries in particular make use of this 'waste heat' for
> district heating.
>
> I can see a potential move to local district co-gen (as opposed to GW central
> plants) being very attractive.
>
> Graham
There's always a tendency to think about heating and forget about
cooling. The US population has shifted towards the South, and there is
that pesky warming trend we hear about...
The point is, without AC it would be difficult to live in lots of
places, so waste heat would have to be converted to cooling to get the
same effect. Can be done, but requires big changes. For places like
Texas, solar panels that generate the most when the sun is beating
down on your roof seem like a better be
---plus they would shade the
roof.
-tg
