On Jan 25, 5:06*pm, mike wrote:
On 1/25/2013 6:18 AM, wrote:





On Jan 24, 11:19 pm, *wrote:
On 1/24/2013 4:55 PM, Dimitrios Paskoudniakis wrote:

"Wes *wrote in message
...
Electric company wants me to install a device that lets them remotely
alter the duty cycle of my AC compressor.

Is this truly harmless?

Can it make the thing less efficient, or wear out / burn out sooner?

--
Wes Groleau

I live in Maryland near DC. I have A/C on the first floor and basement
and a heat pump for the upper level. I get $50/month discount for the
four months of May - August by allowing the utility to be able to shut
off the A/C.

Two years ago during a heat wave, they shut it off from 11:30 AM - 7:00
PM. By that time, my upstairs thermostat read 91 F. That's not a typo..
It got back to a sleepable temp by about 1:00 AM.

You just need to decide what's more important, saving a few bucks or
having ensured comfort.

Yep, that's the issue. *To do any good, they have to turn it off when
you most need it.- Hide quoted text -

- Show quoted text -

But they are not supposed to turn it off for eight hours straight.
The idea is to turn them off in groups for maybe 20 mins
at a time, if necessary. *Either something exceptional was happening
or something screwed up. * As I said before, I had one on mine
here in NJ for over 10 years and never noticed any difference.
It's going to depend a lot on the shape of the electric system
in the area. * But still, turning it off for 8 hours doesn't seem
right. *Wonder if he complained to the utility and what they
said? * You would think if they did that to people, most of them
would say come take this thing off, end of story....

Do the math. *If the power isn't off longer than the thermal time-constant
of your house, it does zero good.

That's not true. There are a lot of AC's that during peak
demand days, ie when it's 100F out, could be running almost
constantly for hours. Take folks that have setback thermostats
for example. They have it set to come on at say 3 or 4PM so
that the house will be cooled down by the time they come home.
If the utility cycles say 1/3 or half of them to be off at a time,
they
have reduced their load. It clearly doesn't require turning off
the AC for 8 hours straight to be effective.



There's a very strong
correlation between how much you suffer and the goodness
of decreasing peak load for the utility. *And that happens
at the peak load time when you most want the air conditioning.

The point is that I think it's very unusual for a utility to
shut off your AC for 8 hours straight.



If you turned mine off for 20minutes, I'd never notice, because it
doesn't run that often. *And the utility would have gained nothing
because mine wouldn't have run anyway.

That's true if it doesn't run that often. But I'd say there
are enough AC's running a lot so that cutting them back
so they can only run say 20 mins or half the time will indeed
make a difference. There's a big difference between that
and cutting you off for 8 hours, which is nuts.




Take the energy saved while it's off. *Subtract the energy used
when it comes back on to bring the temperature back to where you
want it.
Unless the number is positive, or the recovery time is outside
the peak load window, the utility gained nothing.

The way to solve the problem is to store heat (cold) locally.
Cool a tank of water during off peak and use it to reduce
the peak load. *That trades efficiency loss for load leveling.

How practical is that?

So, did you call them up to find out if they actually intended to
cut your AC off for 8 hours? Or if something went wrong?
I had the same kind of system for over 10 years and never
had any experience like that. Never had a single occasion
where I could tell it was even activated. And if I did, and
they told me that's how it's supposed to work, I'd call them
up and tell them to remove it. Did you?