(Not so)Smart power meters

[scott2000]

The distribution wires have resistance so during peak current draw the voltage sags

Yeah, I was just wondering if this has an impact on the customer side of things as it relates to more or less usage because of any effects on equipment like AC motors or fridges etc....

///on phone with power company now....they said they don't intentionally throttle down power.
I'm waiting for a tech to tell them we're getting down to 115v and the transformer outside is humming pretty good during peak times.... and that my meter display is unreadable during parts of the day

 

[JohnRoberts]

Yeah, I was just wondering if this has an impact on the customer side of things as it relates to more or less usage because of any effects on equipment like AC motors or fridges etc....

///on phone with power company now....they said they don't intentionally throttle down power.
I'm waiting for a tech to tell them we're getting down to 115v and the transformer outside is humming pretty good during peak times.... and that my meter display is unreadable during parts of the day

I believe they get to bill for more power usage when they deliver higher mains voltage, so they are inclined to hit the high end of the range to increase billing revenue. Utilities running short of power is a relatively recent phenomenon, with CA being the poster boy for not enough juice.

JR

 

[scott2000]

I believe they get to bill for more power usage when they deliver higher mains voltage, so they are inclined to hit the high end of the range to increase billing revenue

Yeah they said they didn't get any alerts and did see a drop to 234 on my meter feed at the times I told them. Said the 115/116 I saw must have been from voltage drop on my end....
I'm at 117 as we speak.. and nobody's really around

I was asking the lineman? if he knew about how the lower voltage would affect my usage and he didn't really know but said it made sense it could increase it in some cases.

I think if a couple more neighbors get some Teslas, they'll be out here replacing this transformer outside which he said he's had to work on a few of because of that. Guess some fuse that's in the box goes first....

The transformers are specced to construction at the time so....

 

[Brian Roth]

Years ago when tankless water heaters became on the market, I read an article pointing out the possibility of overloading the local distribution grid if many houses switched to those units.

Bri

 

[scott2000]

Years ago when tankless water heaters became on the market, I read an article pointing out the possibility of overloading the local distribution grid if many houses switched to those units.

Bri

I heard they're not really a good investment unless they're gas because of the amount of energy they take to quick heat or something...

 

[JohnRoberts]

Years ago when tankless water heaters became on the market, I read an article pointing out the possibility of overloading the local distribution grid if many houses switched to those units.

Bri

I heard they're not really a good investment unless they're gas because of the amount of energy they take to quick heat or something...

I looked into tankless electric a couple years ago and you save the heat lost from a hot water tank sitting around 24x7.. it takes roughly the same amount of energy to heat the water just a lot of current all at once... Maybe don't fast charge your tesla and electric zero turn while taking a shower.

I recently looked at heat pump water coolers (yes they make those),,, $1800-$3000 for my size house and the features say they draw the same energy as a 100W light bulb...

I didn't buy one, but I am thinking of getting more insulation in my attic.

JR

 

[Tubetec]

Whats the cost of sending hot water to the other side of your dwelling in a copper pipe? and heating 30 liters in the immersion at a time
VS boiling a kettle or two to do the washing up ,
big savings , put the copper in the wiring ,not the pipework .

 

[JohnRoberts]

Whats the cost of sending hot water to the other side of your dwelling in a copper pipe? and heating 30 liters in the immersion at a time
VS boiling a kettle or two to do the washing up ,
big savings , put the copper in the wiring ,not the pipework .

I would think about that if I was building a new house (like my brother is)... But I am not.

About the only thing I am considering is maybe adding more insulation into my attic.

JR

 

[Tubetec]

I was able to achieve a three digit reduction in quarterly electricity bills by switching to using the kettle for the washing up over immersion every evening ,

I've found the pressure cooker a great energy saver , where typically in a pot , boiled beef or bacon takes a few hours at a moderate boil , in the cooker its done in under an hour on a low setting after the initial heat to build pressure is achieved , by my rough calculation it worked out at around 25% the energy compared to a pot for a similar result.

 

[scott2000]

I thought it was interesting to see how much usage a washing machine and a dryer use. Not too different from costs at a laundry mat..... although it's been a while since I've been to one so not sure of prices there and it's a rough guess looking at total usage. Would be neat to really look closer.

Another weird thing is that I didn't have any significant voltage sag all day yesterday and right now the voltage is 123/122. Yesterday it got to 119V at lowest. Weird coincidences I guess... It has been slightly cooler so maybe less usage by everyone in general.. Unless the power company had some way to bump voltage just in this section...

edit...oh well...back down to 117V hours later...Jinxed myself...

 

[JohnRoberts]

I was able to achieve a three digit reduction in quarterly electricity bills by switching to using the kettle for the washing up over immersion every evening ,

? not sure I understand.

I've found the pressure cooker a great energy saver , where typically in a pot , boiled beef or bacon takes a few hours at a moderate boil , in the cooker its done in under an hour on a low setting after the initial heat to build pressure is achieved , by my rough calculation it worked out at around 25% the energy compared to a pot for a similar result.

I recall my mother cooking with a pressure cooker. My understanding was that it's significant benefit was taking less time to cook (because of higher temperature water vapor).

My personal meal making approach is to use a Cuisinart slow cooker, where I cook a week's worth of meals at one session. I freeze the results in 1 cup pyrex dishes. This also helps with portion control. I won't turn this into a recipe veer, but on the topic of energy use, I made a thermal insulated igloo that surrounded the entire slow cooker. This likely reduced heat loss and energy consumption, but after over a year in use the humidity captured inside the thermal igloo corrupted the tact switches operating the slow cooker. I adjusted my strategy to now just thermally insulate the glass cover and this significantly reduces heat loss without capturing humidity released by cooking.

Years ago I experimented with trying to use Peltier heat transfer devices to serve as a slow cooking heat source, while simultaneously cooling my kitchen. While I had some success this was a little too rube goldberg for regular use.

JR

 

[cyrano]

Yes. If motors have to work longer or harder because of this, would it mean that their power consumption goes up? Would seem like a weird feedback but just curious.

Most AC motors in your home won't show any difference. RPM is usually frequency dependent and a +/- 10% voltage swing won't even be noticeable.

Also, at a higher voltage some appliances will draw more amps, and the electricity company will charge more, but you simply also get more watts, so there isn't anything different.

I've used electric cookers that produced a small but noticeable difference between peak and minimal voltage, but I doubt the average consumer would notice.

 

[scott2000]

Most AC motors in your home won't show any difference. RPM is usually frequency dependent and a +/- 10% voltage swing won't even be noticeable.

Also, at a higher voltage some appliances will draw more amps, and the electricity company will charge more, but you simply also get more watts, so there isn't anything different.

Thanks. What does the wiki info mean in this context? Do they mean extreme voltage differences to reach these duty cycles mentioned?

from wiki

"Current rise is detrimental to motors, since they run hotter. Also, to accomplish the same work the motors have to run longer, for example, if a refrigerator is running at 35% duty cycle at nominal voltage, at lower voltage its duty cycle may increase to 40%. Running hotter and running longer shortens the service longevity of motors."

 

[Tubetec]

Its quite simple , when you engage the 'sink' setting on the domestic hot water tank here your heating the upper section of the tank only , its around 30 liters of hot water , takes around 30 minutes ,requires around 1kw of power .

Of course it take liters of hot water flowing through the pipe before the copper heats and hot water arrives at the far side . So lets say I need 1 liter of boiling water in the basin to do the washing up for two people , its obvious , boiling 1 liter of water in the kettle saves me a vast amount of energy usage compared to heating 30 liters ,of which the first few liters are wasted heating the copper pipes and what eventually comes out at the other end is probably 50 degrees C ,

Theres also additional energies saved in the pressure cooker appart from just the shorter cooking times , because the pressure cooker is to a greater extent sealed , very little heat escapes as steam , thats good news , it means you have upto 5 times atmospheric pressure inside so the boiling point of water shifts upwards , fat and collagen breaks down at the higher temperature much quicker so even cheaper cuts of meat are still tender ,

So lets say the dials on the stove top are numbered 1-6 , to boil a large pot effectively I need to be at 4 on the scale , lets call it 2/3 full power ,
To boil the pressure cooker initially I need it on 4 also , but once its boils and the lid is on and pressure is up I can reduce it to 2 on the dial , instead of taking 3-4 hours at 2/3 full power in a pot , the pressure cooker takes 50minutes-1hr to do the same job at 50% of the power usage .

 

[scott2000]

instead of taking 3-4 hours at 2/3 full power in a pot

What the heck kind of pot and stove are we talking about? Is this just hypothetical to explain?

 

[cyrano]

Thanks. What does the wiki info mean in this context? Do they mean extreme voltage differences to reach these duty cycles mentioned?

The Wiki isn't wrong. Just that in practice, with motors, it takes a lot more voltage to make a difference. You can run most motors at double the nominal voltage. It won't harm them (unless you restrict motion) as the current goes down. Even a simple 12V relais can be run at 24V without damaging it immediately. It will shorten it's life expectancy, as a relay doesn't rotate and has more trouble getting rid of the heat.

I've run motors at double voltage and more. As long as the motor has enough cooling and can run at it's nominal RPM or a bit more, it won't burn. Of course, the bearings will wear out sooner and even the commutator might show wear sooner, but it won't burst into flames. You need to notice the duty cycle as specified by the manufacturer. Some motors (on small compressors, fi) are designed for a 50% duty cycle.

If you want to damage a motor, you'll need to restrict motion. Just applying overvoltage isn't enough.

Resistive loads, like water heating, will draw double the current if you double the voltage. That means four times the power and it might burn within minutes. The same goes for incandescent bulbs.

Boiling 1 liter of water takes about 100 Wh. A bit more in winter, a bit less in summer. The loss on a classical water heater is mainly determined by the quality of it's isolation. I've got a mini water heater under the sink. It delivers boiling water, but not in great quantity. It's a 5 kW heating element. The content is just a few liters, but it has superior isolation to keep the loss down. It's called a Quooker. See:

https://www.quooker.be/nlbe/
It's fantastic for the chef as it speeds up things a lot. Need to peel a tomato or boil an egg? Just get boiling water from the tap, put on the fire and start timing.

Obviously, I don't use it to do the dishes. It could do it, but with just a few liters, it isn't enough to fill a large sink, even when you need to add cold water.

The only disadvantage is that it can cause serious burns. Fortunately my friends know my kitchen is dangerous.

It's also best to hook it up to a water softener, otherwise it will need to be descaled after maybe six months, depending on use.

 

[scott2000]

ust that in practice, with motors, it takes a lot more voltage to make a difference. You can run most motors at double the nominal voltage. It won't harm them (unless you restrict motion) as the current goes down

Right. I'm more curious about the effects of power consumption when the voltage supply goes down. Does it, in theory make consumption increase? More current, longer running to achieve same result.
And what kind of voltage drop would we be talking about... Hopefully this makes sense.

 

[JohnRoberts]

The Wiki isn't wrong. Just that in practice, with motors, it takes a lot more voltage to make a difference. You can run most motors at double the nominal voltage. It won't harm them (unless you restrict motion) as the current goes down. Even a simple 12V relais can be run at 24V without damaging it immediately. It will shorten it's life expectancy, as a relay doesn't rotate and has more trouble getting rid of the heat.

I've run motors at double voltage and more. As long as the motor has enough cooling and can run at it's nominal RPM or a bit more, it won't burn. Of course, the bearings will wear out sooner and even the commutator might show wear sooner, but it won't burst into flames. You need to notice the duty cycle as specified by the manufacturer. Some motors (on small compressors, fi) are designed for a 50% duty cycle.

If you want to damage a motor, you'll need to restrict motion. Just applying overvoltage isn't enough.

Resistive loads, like water heating, will draw double the current if you double the voltage. That means four times the power and it might burn within minutes. The same goes for incandescent bulbs.

Boiling 1 liter of water takes about 100 Wh. A bit more in winter, a bit less in summer. The loss on a classical water heater is mainly determined by the quality of it's isolation. I've got a mini water heater under the sink. It delivers boiling water, but not in great quantity. It's a 5 kW heating element. The content is just a few liters, but it has superior isolation to keep the loss down. It's called a Quooker. See:

https://www.quooker.be/nlbe/
It's fantastic for the chef as it speeds up things a lot. Need to peel a tomato or boil an egg? Just get boiling water from the tap, put on the fire and start timing.

Obviously, I don't use it to do the dishes. It could do it, but with just a few liters, it isn't enough to fill a large sink, even when you need to add cold water.

The only disadvantage is that it can cause serious burns. Fortunately my friends know my kitchen is dangerous.

It's also best to hook it up to a water softener, otherwise it will need to be descaled after maybe six months, depending on use.

Isolation? do you mean thermal insulation? I have added extra insulation wrapped around my hot water heater on top of the stock thermal wrap.

JR

 

[cyrano]

Of course, John, insulation. Dutch only has one word for both, so I often mistake one for the other.

 

[Tubetec]

The presure cooker has been around a longtime , with the current high cost of energy its use makes more sense than ever . There is of course a standalone version now also . Ordinary stove top works just fine .

The Instant pot is the modern self contained microcontroled version of the pressure cooker

Heres the electrical comparrison between items cooked in either the oven or an instant pot ,
Does an Instant Pot use a lot of electricity?, it amounts to a massive saving in energy .