Heat Transfer: Crash Course Engineering #14

Today we’re talking about heat transfer and the different mechanisms behind it. We’ll explore conduction, the thermal conductivity of materials, convection, boundary layers, and radiation.

***

RESOURCES:
Çengel, Yunus A., and Michael A. Boles. Thermodynamics: An Engineering Approach. 8th ed., McGraw-Hill Education.

***

Thanks to the following Patrons for their generous monthly contributions that help keep Crash Course free for everyone forever:

Mark Brouwer, Erika & Alexa Saur, Glenn Elliott, Justin Zingsheim, Jessica Wode, Eric Prestemon, Kathrin Benoit, Tom Trval, Jason Saslow, Nathan Taylor, Divonne Holmes à Court. Brian Thomas Gossett, Khaled El Shalakany, Indika Siriwardena, SR Foxley, Sam Ferguson, Yasenia Cruz, Eric Koslow, Caleb Weeks, Tim Curwick, D.A. Noe, Shawn Arnold, Ruth Perez, Malcolm Callis, Ken Penttinen, Advait Shinde, William McGraw, Andrei Krishkevich, Rachel Bright, Mayumi Maeda, Kathy & Tim Philip, Jirat, Eric Kitchen, Ian Dundore, Chris Peters
--

Want to find Crash Course elsewhere on the internet?

[jamespenny]

This subject adapted to the kitchen is so needed: there a lot of cooks who don't seem to understand the basics of heat transfer, for example a veggie pizza with all the veggies dumped in the center results in a puddle of water in the center, and all the toppings sliding off. The veggies need to be spread out to the edges. The same goes for the sauce, it does no good to just slap the sauce on carelessly and have the edges burning up and the center soggy.

[charlieangkor]

i actually live in cambodia and this is how i do it: two open windows with mosquito net and a fan blowing air between them. reverse according to which side of the house receives sun. im directly under flat roof which gets super hot from full sunlight so hot that just the radiant heat makes my desk hot while the air is not. and this is the only thing that keeps the room comfortable. the roof receives about 700 megajoules per day. when the heat is the worst i dump water buckets on the roof which evaporate quickly. one bucket reduces this by 40 megajoules. so 18 buckets eliminate the sunlight completely. a rack with wet clothes inside the room also helps obviously.

[helenday]

Thank you for the nice, interesting pictures. I find that learning hard things is SO much more pleasant and less stressful (and so I learn better) when it's in bright, lively colour.

[mijaz]

instead of reviewing my class notes i am gonna use this to pass my job interview.

[YYY-ydqn]

This is a great review for architecture students, especially with the examples used

[bobbyoneal]

The Metal Gear Solid reference made my day!

[EHBRod]

WHERE WERE YOU WHEN I TOOK HEAT & MASS TRANSFER?!?

[camiloiribarren]

Once again, back to physics and thank goodness I am refreshing this

[yondaime]

Heat conduction is a major hassle for thermoelectric coolers. The idea is pretty interesting, a cooler without moving parts, just pass an electric current through and it transfers heat from one face to the other (you can even reverse it by inverting the current). The problem is that you need a material with good electrical conductivity, otherwise it's going to generate a lot of heat due to the Joule effect. But good electrical conductivity generally implies good heat conductivity, so the material transfers heat back from the hot face to the cold face, like trying to fill a bucket with a sieve. That's why thermoelectric coolers are much less efficient than compressor-based coolers, although researchers keep finding better materials to improve performance little by little.

[rawanxy]

Thank you for this engineering series please expand I need more videos before I graduate haha

[engibear]

*I hear tell of quadruple-pane windows with special coatings that reflect the infrared and ultraviolet parts of the spectrum so that the only radiation that makes it inside your house is useful, visible light.*

*Use solar panels to catch everything that would otherwise be hitting your roof.*

[bruce-le-smith]

Nice rapid pace to this video, thank you!

[michaelquintana]

oh my God I died a little when I saw Solid Snake moving inside the box

[hedgehog]

Plate heat exchangers are almost unbelievably efficient. A small one maybe 20x10x5 cm can easily heat up water from 10 c to 30 c at incredibly high flow rates. It can essentially ensure that a house will never run out of hotwater because it can produce it so quickly that you can get hot water for every appliance and the shower in a home. Having lived my entire life with one I was stunned at the concept of running out of hot water when I heard about it.

[EvanMoon]

Thank you for breaking it down for us. We have an RV and we are trying to help the small air conditioner during the summer. We cannot put more insulation on the inside but we can put something to block the direct sunlight from contacting the top of the RV

[zacharyscott]

Ayy I see you throwin’ shade at h3h3 at 4:28

[danieldanieldadada]

4:12 transfer*
I'm so good at this

[Mero]

Can you guys at crash course do a geology course? Love your videos so much by the way they are so fun and educational

[sivaneshm]

Hi dear... Your videos are so much useful for me and Please keep uploading Thanks a Hats off to you a your team.... God bless you dear ✨✨✨✨

[shompakhan]

Please do a video on aeronautical engineering... I really love aeronautical engineering and I really want to become an aeronautical engineer in future.