|> | says...
|> |> |>
|> |> |> >I wish they would lower that requirement. Sure, it would annoy people
|> |> |> >that want to overheat their clothes. But over 3840 watts to dry
|> |> |> >These things are electricity hogs. Too bad there is too much politics
|> |> |> >going on between two different fundamentally corrupt political parties
|> |> |> >the USA for anyone to be able to get a requirement into the energy bill
|> |> |> >in Congress to lower the standard clothes dryer power needs. Try today
|> |> |> >to even find one that can run on a 20 amp circuit.
|> |> |>
|> |> |>
|> |> |> It is simply physics. You have to evaporate "X" amount of water. If
|> |> |> you dropped the power used per hour you would have to use it longer.
|> |> |
|> |> | ...wasting even more power (the motor will run longer).
|> |> There is an optimal rate. The motor can only run at a fixed speed to
|> |> allows the clothes to tumble properly. Too fast and they don't fall
|> |> in time to avoid just following the drum around in a circle. At this
|> |> rate of tumbling, there is only so much effective air flow that can be
|> |> used optimally. That dictates the heat rate. Yes, you can push it to
|> |> dry faster at a higher temperature. But it is less optimal when you do
|> |> that.
|> | the motor speed is irrelevant. Lower power implies longer drying,
|> | which means the motor will run longer. The heater will take the same
|> | energy but the motor more.
|> The motor speed is very relevant.
| Not to this discussion it's not.
Sure it is. If the motor speed could be varied to match the thermal
emission rate, then it would not be relevant. But since it cannot be
made to match, it therefore does affect the efficiency curve that is
a function of what thermal rate (temperature driven) is involved.
|> If you could make the clothes tumble
|> around in the air faster, then blowing the air through faster and running
|> more heat would make the clothes dry faster in the same proportion. But
|> you need to have all of these elements going at the advanced rate to make
|> things work equally well in that lesser period of time. The problem is
|> the motor speed for the drum CANNOT be increased because the clothes will
|> not tumble through the air at other than a small range of speed. Ever
|> wonder why dryers do NOT come with adjustable tumble speed (other than
|> the ones with a dual belt position to adjust for 50 Hz vs. 60 Hz power
|> to keep the tumbler at the same speed in all countries)?
| Irrelevant the the discussion at hand. If you'll remember, you were
| claiming that modern dryers used way too much power. You can reduce
| the power, but the time will increase. The motor will run longer,
| wasting power.
Or you can increase the heat, and while the whole running time will be
less, it will NOT be inversely proportional to the temperature difference
used. An increased temperature _will_
be a less efficient process.
There is a temperature which is the optimal rate, in terms of total energy
used to complete the drying, and it is NOT the highest temperature position.
|> |> Modern dryers are more efficient than dryers of decades ago when the 30
|> |> amp "standard" came about. Back then, the dryers lost heat in a number
|> |> of ways, and were not operating at maximum air flow efficiency. You
|> |> could feel the outside of the dryer being hot; that's wasted heat. They
|> |> run cooler on the outside today, so less power is needed for that optimal
|> |> temperate and evaporation rate.
|> | Ok, but that's irrelevant to your point. You whined that they should
|> | be using lower power now. Power isn't the issue, rather energy. They
|> | are.
|> The ability to turn the heat up beyond the optimal level for total energy
|> efficiency should be discouraged. I don't want to prohibit it, just make
|> it necessary for someone to go an extra step to get the higher heat if
|> they really want it.
| They already do. It's called "normal" mode (vs. "permanent press").
| You're barking up the wrong tree.
The "permanent press" mode is there to continue the drum tumbling after
the heat is gone to ensure the clothes are not in a constant position
during cooldown. This is used to reduce the wrinkles that would result
if cooldown were to take place with the tumbling stopped. It uses more
energy to have this effect, but it is necessary to get the correct effect.
|> |> And the motor is actually a small fraction of the power involved, especally
|> |> when on the high setting. By simply eliminating the high setting, you can
|> |> have a dryer that can still have 2 or 3 heat levels, or use the automatic
|> |> evaporation sensing mode, and never need more than 16 amps at 240 volts
|> |> the motor figured it wired to 240 volts instead of 120 volts).
|> | Good grief!
|> I think you will find that the greatest efficiency of a dryer is actually
|> the lowest or 2nd to lowest heat setting (depending on actual values of
|> those settings). What I want is for dryers to be made available on the
|> market that people can choose which are made for just this lower heat
|> level that is most efficient. Such a dryer would do with smaller elements
|> and smaller electrical wiring and switches. The plug would be smaller, too,
|> using NEMA 6-20P or NEMA 6-15P instead of NEMA 14-30P. The circuit wiring
|> for new work would also be less costly. People would save money on the
|> product. Some people would save money on the circuit wiring. People would
|> save money on their electrical bill. Everyone would be better off. But if
|> you really want to toast your clothes and your electric bill, then go ahead
|> and buy one that has a double heating element and uses a big NEMA 14-60P
|> plug, ceramic tumbler, and microwave thermal source!
| Good grief!
That kind of response is not very informative.
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
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