Live data from Hacker News

Smart thermostats inadvertently strain electric power grids

news.cornell.edu

211–220 of 226 posts

Re: Smart thermostats inadvertently strain electric power grids

#211

Earlier quoted context omitted.

Where do you live? I'm just curious because I can't imagine living at 78F anymore.

78 at my thermostat means some rooms in the upper floor might be 84+!

Same. I keep mine at 74 during the day and cool it to 71 closer to bedtime.

That, plus blocking the vent closest to the thermostat in summer, tends to get the upstairs to within 3-4 degrees of the thermostat setting.

Re: Smart thermostats inadvertently strain electric power grids

#212

Earlier quoted context omitted.

There's also the semi-mythical "Super Bowl Flush" https://news.arizona.edu/story/super-bowls-super-flush-just-...

Perhaps we should have a national “if it is yellow, let it mellow, if it is brown, flush it down” ad campaign.

A toilet flush costs me exactly 1 cent. I'm flushing until the financial incentives change significantly.

Re: Smart thermostats inadvertently strain electric power grids

#213
post #182

Earlier quoted context omitted.

I predict in certain areas, "free cooling" systems will become the standard. These are system which do just what you talk about automatically. When there is a need for cooling and exterior air is cool enough, supplement supply air with air from the outside. This way your AC system load is reduced, or if cool enough, the compressor doesn't need to run at all to remove heat from your home by replacing it with cooler ai…

I've been wondering why my Nest thermostat doesn't already have an option to do this. I can turn on the fan manually, but it's not smart enough to do that automatically when it's cooler outside than it is inside.

Your system only exchanges heat with the outside (via a refrigerant). The fan only circulates air; on its own, it doesn't draw air from the outside (by design; you don't want to be cooling outside air).

The system would need to have a second mode and a fresh air intake, as well as wiring and support from your thermostat. It can be done, but HVAC is a slow-moving industry.

Re: Smart thermostats inadvertently strain electric power grids

#214
post #146
post #138

Earlier quoted context omitted.

I wish I had a system like that and have thought about it a lot. I live in Calgary and today will be 28C and it will go down to 12C at night. I wish my system could just run a fan at 7am and draw in a ton of cool air to cool the house. Instead my AC runs for 30 minutes or whatever. Seems like a waste.

I'm working towards that with my Home Assistant installation, using inside and outside thermometers. You can trigger the fan based on the appropriate parameters, time of day, temps, etc.

Planning a similar system for the house we'll be completing on in the next few months.

Since we'll be renovating/refreshing the whole house I'll have the opportunity to do stuff I won't be able to do later without much more disruption.

Re: Smart thermostats inadvertently strain electric power grids

#215
post #178

Earlier quoted context omitted.

The dehumidifier does use power and produce heat which must be removed from my apartment by the air conditioner. Because it's less humid, I can maintain a higher indoor temperature and still be comfortable, meaning the air conditioner needs to run less. Do I use net less energy? In my case, yes, but your mileage may vary depending on your equipment, insulation, etc.

He's saying that you have two air conditioners: one that vents heat inside your house and one that vents heat outside your house. Your dehumidifier and your air conditioner are mechanically identical. The only difference between the two is where the waste heat goes. The exact same device is called a 'dehumidifier' if the waste heat is vented indoors and an 'air conditioner' if the waste heat is vented outside. There'…

I ended up buying a dehumidifier to complement my AC, which is ancient and can't seem to keep up with the humidity in the summer.

Before the dehumidifier I could get the room cool, but it still felt sticky. With both I'm able to keep the humidity at bay and cool the room as well.

Re: Smart thermostats inadvertently strain electric power grids

#216
post #146

Earlier quoted context omitted.

I'm working towards that with my Home Assistant installation, using inside and outside thermometers. You can trigger the fan based on the appropriate parameters, time of day, temps, etc.

Planning a similar system for the house we'll be completing on in the next few months. Since we'll be renovating/refreshing the whole house I'll have the opportunity to do stuff I won't be able to do later without much more disruption.

I did a bit of reading after posting my comment and it looks like many HVAC technicians recommend against doing this in a residential setting due to humidity issues. Sounds like most HVAC economizers are for commercial settings.

Re: Smart thermostats inadvertently strain electric power grids

#217
post #216

Earlier quoted context omitted.

Planning a similar system for the house we'll be completing on in the next few months. Since we'll be renovating/refreshing the whole house I'll have the opportunity to do stuff I won't be able to do later without much more disruption.

I did a bit of reading after posting my comment and it looks like many HVAC technicians recommend against doing this in a residential setting due to humidity issues. Sounds like most HVAC economizers are for commercial settings.

I'm assuming this applies to high humidity areas? Seems in drier climates this would reduce humidity/mold risks

Re: Smart thermostats inadvertently strain electric power grids

#218
This story has been posted here a few times, and it seems like every time the story has led to people knowing less about this topic than they did before the article.

That can't be a good thing. I'd assumed the dodgy source I read it through had twisted it, but it seems like Cornell is endorsing this contradictory take, which it basically repudiates at the end of the story. Why would they do that? Just for extra clicks?

First line

> may be falling into a dumb trap.

Why does he say 'may' here? Are they or aren't they? Isn't it his job to tell us?

> this so-called load synchronization will become a problem in the near future.”

Seems like they meant to say "might, in the near future, fall into a dumb trap".

I looked up their 40% figure and that seems wrong too:

> Parks Associates' smart thermostat research finds 29% of US internet households plan to buy one of these devices in the next six months. Smart Thermostat Market Assessment finds that adoption of smart thermostats has been flat for several years, at 13% of US internet households, despite owners reporting savings that meet or exceed their expectations.

So are they even talking about smart thermostats? It's not clear.

> Evidence showed that residents remain confused about how to operate their thermostats and are often unable to program it, the authors said.

That says 'thermostats' and basically described the problem that smart thermostats were designed to solve, since they don't need "programming".

Hmm, the related story at the bottom is another bullshit take by the same author. Does Cornell have a fake sustainability centre that just published FUD about renewables?

No, the academic involved seems to actually believe that networked heat pumps working in concert is actually a good thing, but must somehow feel that warning about the danger if we don't do is more newsworthy than saying, hey we can save money if we do .

https://www.engineering.cornell.edu/faculty-directory/k-max-...

> They explore the potential for aggregating a large number of controllable heat pumps for providing high-quality power-system services to manage peak load and integrate renewable energy, while maintaining thermal comfort.

I'm not sure I like Cornell spreading what amounts to misinformation. There's a dubious quote from the person who funds their sustainability school which suggests the main aim was to find things that were bad for the planet, but that weren't agriculture (since the funding came from rich farmers).

Re: Smart thermostats inadvertently strain electric power grids

#219

Earlier quoted context omitted.

Parties are supposed to be fun, so if someone offers to pay you to come to a party, that sends a signal that the party is not, in fact, going to be fun at all--otherwise, why would they pay you? On the other hand, paper straws are a shitty product that are unsuitable for use, but if I was offered a significant discount on beverages that were served with them...well, I wouldn't take it, but I could imagine someone who…

See, what you said is exactly the problem i have with mainstream climate solutions. The choice shouldn’t be paper straws vs plastic straws. The choice should be no straws vs straws. Similarly, the question shouldn’t be “can I run a/c slightly off peak” rather it should be “how can I run less a/c”. This applies all over the place. Electric cars have lifetime emissions that are lower, but in the same ballpark as ICE ca…

No, the question should be “how do we produce significant amounts more carbon-neutral energy instead of reducing the standard of living”.

Re: Smart thermostats inadvertently strain electric power grids

#220

Earlier quoted context omitted.

There is heat generated by the system, and heat generated by the power generation used to power the system. It’s definitely not a neutral system - that’d be thermodynamically impossible ( increasing entropy without external energy)

If you power the AC with 100% solar shouldn’t there be no extra heat generated? As in you’re merely absorbing some of the heat from the sun to then move existing heat around? Frankly, even without solar power it wouldn’t generate “extra” heat directly over a long timescale, it would only accelerate the release of existing “heat” currently trapped in oil/gas/nuclear/etc.

There’s a fixed amount of sunlight hitting the earth every day, but not a fixed amount absorbed. A solar panel captures more heat than a white surface that bounces most of the light back into space. So the act of solar-powered a/c would still result in a net increase in global heat, unless you put the solar panel on top of something that was absorbing more heat than a panel does. I have no idea of the actual practical math of this - like does a black roof absorbs more or less than a panel? But solar energy isn’t impact free, even if we set aside panel manufacturing.

Once the heat is captured by the solar panel, I think you’re right using it for a/c is neutral - just moving heat around.

As for burning stored energy, that has to play into the heat dynamics of the globe. Like if you release it all at once it stops processes that would remove it from the atmosphere (animals and plants die), and it creates runaway heating feedback loops. there is some level of burning stored carbon that the planet can buffer and absorb and results in no change in global temperature. So burning stored energy in excess of that is a big problem. Like how you can sit or walk without noticeably sweating, but running causes you to have to actively cool yourself by sweating.

Post reply on HN