Sometimes you see things that make you go "Why the heck aren't they
doing something about this?  They'd make out like bandits!"
 
Case in point:
 
40-unit apartment building.  Laundry room is on the 2nd floor on the
north; the building goes east-west.  The laundry room has its own
water heater in a closet off the room proper.
 
There is a flue and some kind of unused pipe coming into the closet
area.  Running a gas heater would appear to be a piece of cake.
Despite this, the water heater runs on ELECTRICITY at probably four
times the cost.  So do the dryers.
 
Across the narrow dimension of the building is a blank wall.  It
would appear to be simple to mount flat-plate solar collectors
to this wall and heat (or pre-heat) the laundry-room water, for
free.  It would even have qualified - maybe still qualifies -
for tax credits.  But the sunlight that falls there just heats
up the bricks.
 
IIRC, sunlight in Michigan in the summer averages around 500 calories
per cm^2 per day.  A two-yard-by-five-yard collector (about 9 m^2)
running at 70% capture efficiency and 20% losses would be able to heat
about 160 gallons of water from 50 F to 122 F, every day.  Compared to
electricity, this would save up to about $2.30 a day, several hundred
dollars a year.  $4000 invested in solar collectors would appear to
have a near-guaranteed payoff much higher than the mortgage interest
rate; financially, a no-brainer.
 
And they're still using electricity.  Aside from being cheapskates on
the capital cost, can anyone tell me *why*?

26 responses total.

Agora33 #246 <-> Science #61

Another one is those little "wall wart" transformers we all have a
bunch of.  A dirty little secret is that they suck up power even
when they're not doing anything.  Supposedly, the parasitic draw of
the little black power transformers in the USA consumes the entire
output of a powerplant or two.

Just today, I unplugged the "wall wart" that recharges my hair
trimmer.  It wasn't plugged into the trimmer at the time, but it
was warm to the touch.  All that warmth was made from the parasitic
power that it was drawing for no useful purpose.

This one actually is a no-brainer... for the manufacturers.  Nobody
is going to pay extra to save a watt or two watts unless they're really
anal about it, but even two watts is a significant expense; that's 48
watt-hours a day, or about 1.4 kilowatt-hours a month.  At 8 cents a
KWH, it costs about a buck and a half a year.  Definitely a large
(and recurring) expense compared to a two-dollar transformer.

This is an example of people failing to mind the small expenses.  It
will probably take an EPA "Energy Star" program for small devices to get
this fixed.  In five years these things will probably be required to
have chips that turn them on every couple of seconds, detect if something
is connected to them, and shut down again if no power is required in the
space of 1/60 of a second or so.  It certainly wouldn't be that hard, and
it would save 99% or so of the power currently lost to parasite loads (no
pun intended).  The problem is getting everybody on board to make it happen.

I suspect the power draw of an unloaded "wall wart" is well under a watt. 
Actually, the entire output of one is usually only a few watts, unless it's
a really big one.  Your TV probably draws a similar amount of power all the
time, too -- otherwise you'd have to get up to turn it on instead of using
the remote.

Now, here's a good no-brainer.  Why do the lights that illuminate billboards
point up, instaed of down?  If they pointed down, it would reduce light
pollution *and* make more efficient use of the light.

Russ, I think you've probably answered your own question as to why the 
apt building you descirbed has electric water heaters. It's been my 
experience that most owners of large apt complexes are corporations 
that aren't the least bit ashamed of "being cheapskates on the capital 
cost" of their properties. Every dollar they shave off of their 
mortgage is another dollar that goes to the shareholders. Furthermore, 
the higher cost of operating an electric water heater is simply passed 
on to the renters. 

I just don't see how apt building owners have any econimic incentive to 
install energy-saving equipment, which is unfortunate.

Maybe it's a code thing.  It might be safer to not have gas
appliances in an apartment building.

Maybe it's an access thing.  Unless a gas utility pipeline goes across your
property in a right-of-way, you cannot get gas into a building.  Unless the
architect designs gas infrastructure into your building, you cannot attach
gas appliances to it.

I owned a home at one point that did not have gas, did not have accesses to
a gas pipeline, and would have cost me more than $100,000 to add gas
infrastructure to the house.  Needless to say, I learned to live with
electricity.  

Re #5:  I've been in several apartments where the hot water was
heated by gas.  Probably not coincidentally, the heat in these
places was also gas-fired and so were the dryers.  Stoves are
almost universally electric, however.
 
Re #3:  Nameplate values on my trimmer's wall wart are 120 V 60 Hz
1.2 W input, 1.2 V 150 mA output.  The rated output is only 0.18 watts
max, so it's wasting 85% of its power input according to the nameplate.
If the idle current draw is mostly magnetizing current for the
transformer, it would be about the same loss at no load.  I am not
likely to do any calorimetry on the wall-wart to actually measure it,
but the warmth of the case appears consistent with 1 watt wastage.
 
Televisions are an excellent example.  If I recall correctly, most of
them have a single power supply for everything, and nothing is switched
except the high-voltage sections.  This means that almost the entire
electronics board is powered all the time, and the "instant on" feature
even runs the picture tube filament at reduced power.  If only the
remote control and button-scan section was powered when "off", and that
was run by a power supply which turned on only long enough to charge a
capacitor every few seconds and then went off-line, you'd see the idle
power draw fall from watts to milliwatts.  Again, 99% or more of the
idle power draw could be eliminated.
 
Bllboards probably have up-lights because they're easier to change
and don't put as much wind-load torque on the mounting.  I'm of the
opinion that billboards shouldn't be allowed to shine light into
space, or have any direct light fall outside their own leased plot.
People who live near billboards have a right to see the stars too.
 
Re #4:  I do see such an incentive.  Most apartment owners deal with
third parties, such as AAL, for laundry machines.  They must get some
kind of cut, a part of the "take" and maybe a rental fee for the space,
from the laundry company.
 
Out of this revenue, the apartment owner has to pay the expenses.  If
that expense includes providing hot water, the apartment owner has
an incentive to do it as cheaply as possible.  If the owner can slash
expenses by $70/month/building, that's real money.  If the apartments
are also supplied with hot water by the building, the potential savings
are much larger.  There's also a possible revenue boost from the "green"
image.  If you can cut expenses by about half a unit's rent per
building, that is a serious addition to the bottom line.

Actually, most TVs now are equipped with switching power supplies, which
draw *very* little idle current.  While keeping the filaments hot, if TVs
still do that, is probably significant, keeping the power supply energized
probably isn't.

While you're at it, want to comment on all the power wasted magnetizing
doorbell transformers? :)

And what about those refrigerators? 
They're especially bad for the environment!

this item reminds me of why I like m-net better than grex.

it makes me wonder if grexers go campin

and if so, what the hell do they get out of it but additional pathologies and
neuroses?
shit!

pah

You guys remind me why I got bored of M-Net.  Too many there couldn't see past
the last coat of paint, thought a screwdriver is a drink and hammer is what
they did to the last response.  Many are here because M-Net is / was down and
most couldn't lift a finger to help getting it back up if they even wanted
to.              (Bang, bang time over.)

I think a lot also has to do with codes, UL and liability.  Perhaps the
flue pipe you saw in the closet had problems that would have been
expensive or impossible to fix.  One begins to appreciate these things
after one has dealt with building departments, building inspectors and
tried to design products the pass UL, etc.  There is a lot you can get
away with in a private home but it's pretty difficult, and costly if you
get caught, to do so in an apartment complex.  I'm sure that solar
collectors would be a difficult and expensive thing just to push through
our local building department.

...mmmmm rhubarb pah.

i'ud laika slice pappy!

Uh oh, klaus...yew better watch out. Once you start responding to 
them, they never stop. People on grex crack me up. They all act like 
what happened to Mnet couldnt happen here. And there always seems to be 
some kind of strange blaming tone...sheesh. 


Anyhow, getting back to the discussion at hand. What possible reason 
would anyone have for trying to save a few pennies on electricity? OH 
sure, I suppose there are some people who care about things like global 
warming but why would those people who dont care about such things want 
to change the status quo?

I believe "instant on" was outlawed because of the number of TVs spontaniously
combusting.  1974-75 rings a bell.  

The concept of instant on is still around.  It may not exactly be instant but
it's faster than when coming up from a cold start.  Standby power consumption
is also down significantly on many TVs.   I took a watt meter to my 13 year
old TV a few years ago, after hearing from one person that they measured
theirs at 23 watts, and found that it was only drawing 1 or 2 watts while off.
I also considered doing something about all the wall warts all over the house
but that became a daunting task!  I could crack open their cases and put
switches in them, but one would have to crawl around on the floor to turn
things on and off.  One could install a central low voltage transformer and
run the power from that to all the wall wart devices.  Wires running all over
and wide variety of voltages used would make that troublesome.  Wall warts
allow manufactures to cheaply isolate high voltage from low voltage, thereby
reducing risk of shock to the operator while minimizing expense.  It's a
pretty good solution to the problem from a safety / engineering / UL /
marketing standpoint.  Now if only something could be done about their losses.

The active adverb is "cheaply". It's an example of the technological
"tragedy of the commons". Each wart is so cheap and draws so little power
that there is no obvious reason to regulate them - until there are
millions in service. 

There are a half dozen or so just around this computer - but they are
all on power strips and get turned off when the computer is shut down.
But others are always on - the answering machine, cordless phone bases,
laptop chargers...and some that don't come right to mind. For these,
it is their inefficiency that is the culprit.

Some of the larger wall warts -- like ones for laptops -- are now being
constructed as switching supplies instead of linear ones.  I'd expect that'd
result in lower idle power consumption, as well as less power lost to heat
in actual operation.

Some of this will fail for the same reason the Honda Insight won't be a big
seller.  The payoff takes too long.  You'd have to drive for around 200,000
miles to pay for the extra cost of an Insight with its fuel savings.  Not
many modern cars even last that long.

The instant-on TVs that tended to spontaneously combust were, IIRC,
non-solid-state ones that kept *all* the filaments burning.  Very wasteful
of power.

If a single wall wart's power consumption is such a small percentage of a
household's energy use (and it is), then millions of them in service ought
to also be that small a percentage of the nation's use.

There is that tragedy of the commons again. *Each light bulb* is also
a small percentage of a household's energy use, so why turn out a
light when you leave the room? (Many don't, of course.)

I suspect there are much more serious wastes than wall warts.  Excessive
outdoor lighting, for example, which also contributes to light pollution. 
Standard water heaters are another example.  On-demand units are much more
efficient, because you don't have 40 gallons of water being kept hot all the
time.

Outdoor lighting helps reduce crime though from what I understand. 

Much outdoor lighting is very poorly designed - the light is supposed to 
fall on the surrounding pavement, etc. - not head directly up to the
sky.  

Here we go again...  Want to know more about light pollution?  Use your
favorite web browser and do a search on "dark skies".  You will find a
lot of very good information (And some not so good).  Power lines lose
power too.  They just doubled the voltage on the high tension lines that
run along the front of our house.  It's like 32 KV now.  (Watch where you
fly those kites, kids!)  Doing so reduces the I^2 R losses.

Re #22:  On-demand units do a very poor job of one thing, and that is
demand-side management.  Heating everyone's shower water between 7:15 AM 
and 7:25 AM takes much more generating capacity than heating the replacement
water between 7:20 and 8:30, and a lot more than predicting the demand curve
and pre-heating the water between 11:00 PM and 6:00 AM.  If you have some
idea of the hot-water needs from historical data and can get by with the water
in the tank until the sun hits the collectors, you don't need any generating
capacity.  (This works better if the water heater, washing machine and
dishwasher are networked and go by priorities when there isn't enough hot
water to run them both at once.  Expect to see it in Europe very soon.)

Cost of generators is a large part of the cost of electricity.  If buying
an electric water heater required a deposit of $500/KW of draw to pay for
the capital cost of the generators required to feed it, you wouldn't see
many of them.  Electric water heaters have huge external costs.

Which isn't to minimize the contribution of wall warts.  In proportion
to their useful output, wall warts are probably one of the top 3 most
wasteful users of electricity in the average person's home.  They may
be cheap, but they are not inexpensive when all the costs are added.

Re #24:  Outdoor lighting which creates glare can actually make it
harder to see the items supposedly being made visible by illumination.

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