And they're cursed for a region, you don't define a distance as volume! As I'm typing that, I realise this also defines a distance as a bodypart, ah well
this post was submitted on 15 Jan 2025
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Going from Watts to BTU's while researching for a solid state multi-power-state TEC cooling solution. I feel this.
But what temperature is that at? And what is the ambient temperature? And what if the power is not at exactly 120V? And what about if I put a fresh dead hooker in it every day?
Ahh, daylight saving saves on Kwh!
For something that doesn't run continuously, like eg. a refrigerator, then an average daily usage is more useful, no? "This product draws 1.5 kW with a duty cycle of 0.08" doesn't really help when comparing efficiencies of potential purchases, you'd need to convert it to electricity consumed in a set period anyway.
No, it's because watts are joules per second, so kWh are (energy / time) * time. Cancelling the units would be expressing the energy directly in joules.
But the XKCD mentions kWh/day specifically, in theory the times can cancel out, leaving you with kW
But instantaneous and average kW are very different, and it would take more time to describe that distinction than to use kWh/day.
Ok that's fair, I kinda glossed over that part. Both are valid interpretations, I think.
My freezer was labeled in max watts, kwh/day, and kwh/year. Because the cumulative watts over time is what I pay for my power bill. That way it's a simple multiplication that tells me how much having that freezer would cost.
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If we just used watts life would be so much easier.
The beauty of SI units is you just add or remove zeroes.
Unless you're converting seconds to minutes, hours, days, years, etc.
Then you get things like watt hours. Or light years.
Which is why neither are SI-units
The Hives were right, we need to convert to the metric system for time.
Fun trivia. It's called a second because it's the second division of an hour after minutes. You can keep going with thirds and fourths for sub second time.
There's nothing wrong with kilowatts, it's an SI unit. The problem is hour, which is 3600 seconds, and we have ancient Egyptians to blame for this, who divided the day into 24 hours despite having already developed base-10 numerical system.
Kilowatt per kilosecond, which is 1 megajoule, would work better.
I really don't get the issue with kWh. Things are rated in W and we mostly care about the hours they're powered on. If I wanna figure out how many kWh a PC that needs 300W used in 4 hours, I multiply 300*4. If I wanna know how many joules it used, I have to do 300*4*3600. Only one of those can be done in your head in 3 seconds.
You gotta use an escape character, specifically a backslash ( \ ), when dealing with *s on lemmy.
Otherwise you end up with "stufflike this!"
When it could have been "stuff*like this*!"
ETA: Damn, you're good. Fixed it before I even finished this post!
One pet peeve of mine is the usage of watts and kilowatts though. Chargers are often labelled like 1 second lasting batteries :/
Damn, I was convinced it was the Babylonians with their base-60 system.
That actually works great.
60 is cleanly divisible by 1, 2, 3, 4, 5, and 6, 10, 12, 15, 20, and 30.
10 is cleanly divisible by 1, 2, and 5.
Yeah Babylon was very clever but also looking at their math and writing makes it clear why they had to have a class of people to do their math and writing
I have no problem remembering what 1 is divisible by.
It would've been better if we had a 6 or 12 based number system
The big reason for 60 over 12 or 6 is the divisibility by 5. That makes it divisible by all numbers through the first 3 primes.
To get it divisible by all the numbers up to the next prime (7), you'd have to go to 420, and the one after that (11) you'd need to go to 27,720, and 13 would require a whopping 360,360.
The problem with base 60 is needing to know and remember instinctively the names, symbols, and relative positioning for 60 digits. Like, I love Babylon, they're underrated for certain, but imagine teaching this to a 5 year old. Imagine doing calculus with this shit. Now remember that their writing impliment was a triangular reed and their written marks were entirely triangles and straight lines.
I knew a 26-letter alphabet by the time I was 2.
Yes, but set to music i assume and not nearly to the level one was expected to understand the ordering of digits.
In base 34: 1…9,a…z,10 it's slightly more than half the digits the babylonians had, and as someone whose career involves a lot of math I don't want to be dealing with at a glance trying to figure out the approximate difference between jl5x and ik8r
As an adult with a college degree in stem I know my digits and their ordering perfectly and without question unless literally trying to trip me up. The alphabet, I know in that specific order and would have to think to start in the middle. I don't want to do series or sequences on that shit and if you do then good for you
kWh is already an uncanceled unit, drives me nuts even without adding per day
(Energy / time) * time? fuck you
It's because the times aren't the same. Maybe same unit but different context so they can't be canceled.
It's like saying you work 8 Hours/day (Eight hours per day). Both are units of time, but their context is different and their combination forms a new meaning beyond the units.
1 KWh is using 1KW for one hour. Because of demand pricing the time you use that KW is important. Like in terms of energy grid using a whole ton of power for one minute vs same total over a long time is different and important dispite being the same amount of energy.
Edit: some phrasing
Time cancels out.
I work 8.
Gotta convert time to the same units before canceling: you work 1/3
Rough day today, I pulled 10 radians.
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That's 203.7cm for anyone wondering
Damn, would've been an added joke to make the ceiling 150 gallons / ft2
My car needs 0.07 square millimeters of fuel on the highway.
square? Damn it uses no volume of fuel at all!
Isn't that crazy efficient? I seem to remember about 0.3mm²?
Way back of you asked Google "38 mpg in mm^-2" it would tell you.
I love that it's the size of the thread of fuel you would consume as you drive down the road.
Edit: oh no, that's about right. It's a diameter of about 0.25 mm. I think that's what I was thinking of.
Not sure. I asked my cat Jeepity.
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