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Slow Electricity: The Return of DC Power? (2016)

lowtechmagazine.com

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Re: Slow Electricity: The Return of DC Power? (2016)

#91

Post by elcritch »

xxs wrote: post #73
pkulak wrote: post #70

Earlier quoted context omitted.

Exactly. The problem here is that everyone will just switch to gas for everything. Dryer, stove, water heater, car, etc. That’s terrible! The 380-volt DC sounded nice, so long as DC to DC is more efficient than AC to DC, but I have no idea if that’s true.

DC-DC actually converts DC to high freq. AC 1st, then uses a transformer and then rectifiers, smoothing, feedback, etc. If no isolation, i.e. common ground is fine, a choke instead of a transformer is fine too.

One possible benefit of a DC-DC circuit is that the converter can choose its switching frequency. That can give some room for optimizations for power or size.

Re: Slow Electricity: The Return of DC Power? (2016)

#92

Post by Reason077 »

pkulak wrote: post #70
IlliOnato wrote: post #37

I read the whole article with sympathetic interest, until the conclusion: > One way to solve the problem of high power devices is simply not to use them -- this is the approach that's followed in sailboats, motorhomes and caravans > Obviously, this strategy implies a change in our way of life. It would mean that electricity is used only for lighting, electronics and refrigeration, while non-electric alternatives are…

Exactly. The problem here is that everyone will just switch to gas for everything. Dryer, stove, water heater, car, etc. That’s terrible! The 380-volt DC sounded nice, so long as DC to DC is more efficient than AC to DC, but I have no idea if that’s true.

The article overstates the conversion losses anyway. Modern solar inverters are something like 95%+ efficient.

Consumer devices vary, but it’s a safe bet that modern cool-to-the-touch GaN power adapters are far more efficient than those old black bricks from the 1990s.

Saving a few % just isn’t worth all the incompatibility and inconvenience of rewiring your entire house for.

380-volt DC sounds dangerous!

Re: Slow Electricity: The Return of DC Power? (2016)

#93

Post by nielsbot »

tootie wrote: post #66
function_seven wrote: post #44

Earlier quoted context omitted.

I get unreasonably angry when Victorian cosplayers think they've found the solution to our wasteful modern life. Simply eschew modern conveniences and spend hours each week beating your clothes against a rock! Simple , instead of grocery shopping twice a month, ditch that wasteful freezer and walk to the farmers' market down the block before dinner each night. Was it cloudy yesterday? Simple! , take a whore-bath¹ at…

It's frequently much more energy intensive too. Cars are a lot more efficient than horses and dishwashers are more efficient than hand washing.

Can you explain how dish washers are more efficient than hand washing? Is it about water use? What if you don’t run the water while you soap your dishes and only rinse them in a rinse tub?

Re: Slow Electricity: The Return of DC Power? (2016)

#94

Post by cassepipe »

OtomotO wrote: post #84
tetromino_ wrote: post #82

Earlier quoted context omitted.

Re clothes dryers - many Americans don't have much choice. Most apartment buildings in the US prohibit drying clothes on the balcony (to avoid giving the impression that poor people might live there). And some towns and neighborhood HOAs prohibit outside clothes lines even for residents of single family houses.

TIL... Land of the free my ass

TIL means "Today I learned. Well today I learnt.

Edit : Don't downvote. I am just the messenger. I just wanted to spare the googling to someone

Re: Slow Electricity: The Return of DC Power? (2016)

#95

Post by pomian »

IlliOnato wrote: post #37

I read the whole article with sympathetic interest, until the conclusion: > One way to solve the problem of high power devices is simply not to use them -- this is the approach that's followed in sailboats, motorhomes and caravans > Obviously, this strategy implies a change in our way of life. It would mean that electricity is used only for lighting, electronics and refrigeration, while non-electric alternatives are…

Some things you can't recreate. But vacuum cleaners, refrigeration, freezers, coffee machines, kettles, dishwashers, and even driers, are all possible and available. Not sure about a microwave, but normal heating elements are there.

Re: Slow Electricity: The Return of DC Power? (2016)

#96

Post by jusssi »

Karrot_Kream wrote: post #86
tetromino_ wrote: post #82

Earlier quoted context omitted.

Re clothes dryers - many Americans don't have much choice. Most apartment buildings in the US prohibit drying clothes on the balcony (to avoid giving the impression that poor people might live there). And some towns and neighborhood HOAs prohibit outside clothes lines even for residents of single family houses.

I've usually hung my laundry indoors or on the stairs if I lived in a place with stairs. I realize this requires some space, but usually keeping the clothes in front of the window is enough to have them dry. I've had one of [1] these for years and it hasn't let me down yet. [1]: https://www.ikea.com/us/en/p/frost-drying-rack-indoor-outdoo...

Effectiveness of indoor hang drying depends on air humidity and circulation. In our previous place, at end of August indoor RH would be around 70% (edit: outdoor would be around the same so opening a window wouldn't make a difference). In practice that meant that some of the clothes hadn't completely dried the next day, and were starting to smell.

Re: Slow Electricity: The Return of DC Power? (2016)

#97

Post by pleb_nz »

tootie wrote: post #66
function_seven wrote: post #44

Earlier quoted context omitted.

I get unreasonably angry when Victorian cosplayers think they've found the solution to our wasteful modern life. Simply eschew modern conveniences and spend hours each week beating your clothes against a rock! Simple , instead of grocery shopping twice a month, ditch that wasteful freezer and walk to the farmers' market down the block before dinner each night. Was it cloudy yesterday? Simple! , take a whore-bath¹ at…

It's frequently much more energy intensive too. Cars are a lot more efficient than horses and dishwashers are more efficient than hand washing.

I read somewhere modern people spend the same amount of time doing chores as someone before electricity. It wouldn't surprise me if it were that far off the truth. We own so much more and are told we need things when in reality maybe we don't?

Re: Slow Electricity: The Return of DC Power? (2016)

#98

Post by spijdar »

nielsbot wrote: post #93
tootie wrote: post #66

Earlier quoted context omitted.

It's frequently much more energy intensive too. Cars are a lot more efficient than horses and dishwashers are more efficient than hand washing.

Can you explain how dish washers are more efficient than hand washing? Is it about water use? What if you don’t run the water while you soap your dishes and only rinse them in a rinse tub?

I haven't watched this video in a while so apologies if it's not specifically elaborated on, but I believe it's covered here: https://youtu.be/_rBO8neWw04

From memory yes, it's partially about water usage, but dishwashers are in general just pretty good overall about efficiently using energy to maximize "food grime removed" per unit of resources fed in. Even if you're careful with water usage while hand washing, I think a decent dishwasher will beat you.

Another advantage is the dishwasher heats its own water, whereas with hand washing either you need to use a house-wide water heater or preheat water in a kettle or something, which will have its own energy wastes. This of course depends also on how your house's water is heated.

One page I found googling elaborates on these ideas, concluding that you could potentially be more efficient hand washing, but only with a lot of effort: https://www.treehugger.com/built-in-dishwashers-vs-hand-wash...

Re: Slow Electricity: The Return of DC Power? (2016)

#99

Post by rini17 »

lovemenot wrote: post #74
Robotbeat wrote: post #28

So, I used to be "team DC" as well, but after learning up a bit, I realized there are still a lot of advantages to AC in the 21st Century. One reason DC power is more viable nowadays is (as others here have mentioned) the use of DC-DC converters. They internally actually use AC to do the conversion (usually at much higher frequency to save weight and cost on inductive elements). But they're not super cheap (not cheap…

>> With DC, nothing is really at the same voltage, so you need DC-DC converters all over anyway, This may be the case now, but it's just through historical lack of standardisation, resulting from AC having been the one true standard. It's not inherent to DC. USB PD is attempting to address this issue. It is standardising voltages for DC-powered devices.

There are inherent factors, though.

1. Any time you mix motors and electronics, motors produce brownouts and spikes which can cause directly connected electronics to malfunction. DC-DC converter mitigates that. LEDs are particularly prone to overload with just minute increase in voltage and dim/flicker with decrease.

Not inherent to DC but same thing happens with poorly designed appliances that emit RF which then interferes with everything connected to the circuit.

2. Voltages. You can't standardize electronics power supply to 12V because semiconductors are most efficient at lower voltage, which depends on particular technology.

Re: Slow Electricity: The Return of DC Power? (2016)

#100

Post by yoz-y »

dheera wrote: post #25
yoz-y wrote: post #22

Earlier quoted context omitted.

> I break about a USB-C cable a week I don’t know… that seems excessive, even people I’ve known to handle all of their stuff like it’s free have managed to go mostly through 1-2 cables a year.

I mean, the people who design this stuff don't do any user research, they sit in offices and think everyone else sits in offices. Reality is if you go out at all you've probably figured out that phones only come with 1/2 day of real battery life (because they do the damn factory tests with full bars of reception, not real world 1-bar reception), and you needed to charge a phone stuffed in one pocket with a battery in…

To me it seems that those use cases would require a massive and rugged connector like the computer mains plug. Realistically I suppose the solution is to have some sort of a bag. For me when hiking or biking I always charge my phone in the backpack/saddlebag/front bike pouch. For the laptop on knees it might be preferable to have a plug on the back (usb-c charging has the advantage that it can have multiple options, at least right/left side. Another option is angled cables mostly immune to slamming from the side and somewhat resilient to angular momentum due to small size.

For chewed cables I agree. But again to actually make a resilient cable it would need to be thicker than most modern phones, the connector is not the weak point here.

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