Re: Suspension losses

On 1/19/2025 4:37 AM, Wolfgang Strobl wrote:

Am Wed, 15 Jan 2025 15:42:39 -0500 schrieb Zen Cycle
<funkmaster@hotmail.com>:
 

On 1/15/2025 1:42 PM, Frank Krygowski wrote:

On 1/15/2025 1:28 PM, Zen Cycle wrote:

On 1/15/2025 1:16 PM, Frank Krygowski wrote:

On 1/15/2025 1:05 PM, Zen Cycle wrote:

On 1/13/2025 11:03 AM, Frank Krygowski wrote:

>
It's certainly true that 100% of the electricity consumed by an
electric blanket becomes heat.

>
No, that isn't true either.

>
Please explain. What electrical energy goes elsewhere?

>
A very small amount of power is used for the indicator lighting and
electronic controls.
>

>

I write "either" because even _if_ it were true that electric
heaters are 100% efficient (which isn't true), saying 100% of the
electricity consumed by the device become heat is very different
than saying it's 100% efficient.

>
What's your definition of "efficiency?" As I said earlier, I think a
common one used for engineering matters is Desired Output divided by
Required Input, or something similar.
>
Do you have a different one?

>
Nope, it's the notion that every watt of power directly goes into
heating the targeted space that I'm stuck on.

>
You're moving goalposts. You objected to my statement "It's certainly
true that 100% of the electricity consumed by an electric blanket
becomes heat."

>
Nope, I addressed that point very specifically with "A very small amount
of power is used for the indicator lighting and electronic controls."
>
What you misinterpreted as 'moving the goalposts' was me taking issue
with Jeffs assertion that "electric heaters are all 100% efficient".
>
Note that "electric heaters are all 100% efficient" ? "It's certainly
true that 100% of the electricity consumed by an electric blanket
becomes heat."
>
The efficiency of the heater is determined by the energy that is used
specifically for generating heat. By that premise, it's logically
possible that that the heating element in a heating appliance may be
near 100%, but that some energy will be used for the control portion of
the system.

  Provided that the “control part” of the heater is not located in a
remote data center, this is completely irrelevant. If the control system
is part of the heater, the electrical energy used by the control is also
converted into heat.
 

>
If Jeff had written "Electric heaters are all _nearly_ 100% efficient" I
wouldn't have commented.

 You are barking under the wrong tree.
 Of course an electric blanket isn't 100% efficient. But this doesn't
have anything to do with how electricity is converted to heat.
 The relevant question is how much of the electrical energy supplied to
an isolated system serves the intended purpose, and where we draw the
line. If an electric blanket is intended to warm a person, but eighty
percent of the heat only slightly warms the cold air above the blanket
or warms the walls through radiation, then the efficiency of the
electric blanket is only twenty percent.  This does not change the fact
that the loss-free conversion of electricity into heat through an
resistor is just that: loss-free.
 Arguing that some heat might be stored inside the insulation of the
cable from the wall socket to the blanket for a few minutes is just
nit-picking.  There is no point to insert various "almost", "nearly",
"in the limit" into valid generalizations.
 I don't doubt that "electric heaters are all 100% efficient" is
misleading. But not because of those tiny losses you mention.
 There is a popular misconception that this physical triviality can be
applied to the entire system, from the original energy source to the
user of the heat generated.
 No energy source delivers even close to 100%. Even a solar panel has to
be produced and replaced every twenty or thirty years. There are energy
requirements for production, maintenance and recycling of power lines.
Renewables are much better than the alternatives, but still nowhere near
100%.
 

+1
The gap is between physics and epistemology of the specific example.
--
Andrew Muzi
am@yellowjersey.org
Open every day since 1 April, 1971