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How about a version that can keep your coffee or tea warm using the power from the USB-C port?
by slabity 3y ago
How about a version that can keep your coffee or tea warm using the power from the USB-C port?
- askvictor 3y agoEven better would be to direct the laptop's cooling fan exhaust towards the cup, then mine some bitcoin.
- eru 3y agoIt would be interesting to run the numbers on power use here. I think you can draw a maximum of 100W via a USB-C port? (Though most laptops would really struggle with that, even when plugged in.) How much heat does a cup of tea lose per second at eg 20C room temperature and 60C water temperature? (Or whatever you want to keep your beverage at?)
- sp332 3y agohttps://physics.stackexchange.com/questions/5265/cooling-a-cup-of-coffee-with-help-of-a-spoon/5510#5510 https://physics.stackexchange.com/questions/5265/cooling-a-c... To counteract a 2-centigrade-degree drop per minute, you'd only need 35W to keep 250ml at a constant 85C. (Or 65C if that's where you start it.)
- tinix 3y agoso you could insulate the coffee so it doesn't drop in temperature, induction heating a vacuum flask maybe?
- MayeulC 3y agoI bet adding a lid substantially decreases the power requirements. Nit: please use Celsius (and "°C" if you can)
- sp332 3y agoI prefer centigrade over Celsius because it's not named after a person. Also I wanted to be clear that it's a two degree drop, not 2°C.
- eru 3y agoIf you want to be funky with your units, I suggest measuring 'coldness' instead of temperature and expressing it in bit per joule (or more conveniently Gibibyte per nanojoule). See https://en.wikipedia.org/wiki/Thermodynamic_beta https://en.wikipedia.org/wiki/Thermodynamic_beta > Though completely equivalent in conceptual content to temperature, β is generally considered a more fundamental quantity than temperature owing to the phenomenon of negative temperature, in which β is continuous as it crosses zero whereas T has a singularity.[6] > In addition, β has the advantage of being easier to understand causally: If a small amount of heat is added to a system, β is the increase in entropy divided by the increase in heat. Temperature is difficult to interpret in the same sense, as it is not possible to "Add entropy" to a system except indirectly, by modifying other quantities such as temperature, volume, or number of particles.
- klempner 3y agoThe relevant number here is 15W. In principle USB C goes up to 240W now, but that isn't relevant here. USB-C power is negotiated, with a full blown two way negotiation if you want more than 5 volts (or to draw more than 3 amps). Framework laptop ports don't support outputting more than 5V or 3A and so will max out at 15W. That is, this isn't a "struggle" -- because USB-C has negotiated power in general, just because it is possible to build USB-C ports that support 240W doesn't mean that a random port on a battery powered laptop has to support anything close to that.
- koromak 3y agoCan you explain what "negotiated power" means? Never heard of it, maybe the hardware on the receiving end needs to have built-in circuits which signal to the generating device that it can handle a certain voltage?
- zmgsabst 3y agoThat’s correct. The port powers up in the default low power mode, but the attached device can signal that it supports more if the device can provide it. You want to start off with low power — since starting off with high power could damage devices that don’t support it.
- deleted 3y ago[deleted]
- zamnos 3y agoYes exactly. You plug in the cables and then there's the following conversation: Laptop: *Om nom nom, 5 volts, yum!* Power supply: Hey, I can do 5 V, 9 V, 15 V and 20 V Laptop: I hear ya. Laptop: Can I get 20 Volts? Power supply: I hear ya. Power supply: Here's 20 volts! You get the idea. All the way up to whatever the device will accept. Past that, the device rejects the offer from the power supply. The original spec lists 5 V, 9 V, 15 V and 20 V, with support of for volts being kinda common because that's what cars use so the circuitry support already exists. According to spec, the charger is supposed to support all the voltages lower than it's max, but ofc not everything is spec compliant. 20 Volt @ 5 Amp is 100 watts which was the old maximum power usb-c PD could do. But it turns out that wasn't enough, so they renamed that to be Standard Power Range (SPR) and released when Extended Power Range (EPR). EPR adds adds 28 V, 36 V and 48 V @ 5 Amps, to the spec, for a new maximum of 240 Watts of power. (Longer desc of the conversation in table 5 in https://www.ti.com/lit/an/slva842/slva842.pdf https://www.ti.com/lit/an/slva842/slva842.pdf )
- deleted 3y ago[deleted]
- thinkmassive 3y agoUse a Peltier device and it should be just as easy to reverse it for cooling!
- flangola7 3y agoHow can you cool without hydraulics?
- yjftsjthsd-h 3y agoThermocouples are solid state electronics that move heat. https://en.wikipedia.org/wiki/Thermocouple https://en.wikipedia.org/wiki/Thermocouple
- tuukkah 3y agoThat article doesn't have anything on the moving of heat, but there's another one on thermoelectric cooling (the Peltier effect): https://en.wikipedia.org/wiki/Thermoelectric_cooling https://en.wikipedia.org/wiki/Thermoelectric_cooling
- moondev 3y agoA thunderbolt 10GbE nic is basically a hot plate in my experience
- seized 3y agoGet a Joeveo cup, then no need for heaters. It's the world's best travel mug. Its insulation cools the drink to drinking temperature then keeps it there for hours, perfect cup of coffee. Had mine for years, from the original Kickstarter. https://joeveo.com/ https://joeveo.com/ It's the Framework of coffee mugs.
- jokabrink 3y agoAh, shucks. They don't ship to Europe :( "Please note: because of recently-instituted tax collection requirements, we are no longer shipping to the EU or UK—sorry!"
- precommunicator 3y agoThere are services in US which will gladly give you an address in US and forward to almost all countries in the world. Search for "us package forwarding"
- jokabrink 3y agoOh neat, I didn't know that. Thank you.
- walthamstow 3y agoThere must be something available in Europe, I remember then-chancellor Rishi Sunak getting some stick for having a £200 heated mug with Bluetooth. Of course, now he's running the place.
- hombre_fatal 3y agoLooks like a run of the mill aluminum air insulated mug. What’s special about this brand?
- bobsmooth 3y agoWebsite says there's a layer of insulation between the vacuum walls.
- m463 3y agoI have one of these: https://amazon.com/dp/B07G9J4745 https://amazon.com/dp/B07G9J4745 and set it to 140, for nice warm coffee which it will maintain. It works well with 24w, so usb-c should have more than enough power.