I put a geothermal heat pump in my house when I built it in 1995. Still going strong and has saved me thousands over its life cycle. The new ones today are are multiple times more efficient. It works as my air conditioner in the summer too. You did a great job explaining the physics involved.👍
Wet heat feels hotter because the water in air stops the water on your skin from evaporating. Not because the water in the air has more energy to transfer to you. So the primary means of your body to regulate your body temperature (sweating) becomes less effective.
@@s.m.7018 Depends on the temperature. If the air temperature is higher than body temperature you cannot cool down without evaporation. Remember, Dr was talking desert conditions.
Fun fact: on the ISS, the Electric Power System (EPS) includes a large number of Orbital Replaceable Units (ORUs) mounted on platforms outside the habitats, in vacuum, and these platforms are cooled by ammonia. But they didn't want the ORUs to become vacuum-welded to the platforms over time, so they use radiant heat transfer between the ORU and the platform. Basically, both the ORU and the platform have a large number of very thin fins, and they interleave with each other without touching. I think this was one of the very few smart things we did on the EPS design, and we own it to a guy named Dave Blackler.
I wonder how they keep the ammonia from freezing in the shadow of space being -250 f.. I would also like to see the insulation on ISS working with 250f in the light and -250f in the shade . That's pretty unbelievable stuff
Freon is a brand name of DuPont. Refrigerant is something that boils and turns from a liquid to a vapor at a lower pressure and temperature absorbing heat. Reject heat at a higher temperature and pressure turns a vapor to a liquid.
4:41 There are several mistakes at that point. First, specific heat is conflated with thermal conductivity. It's the latter that would matter for how hot air outside feels at a particular temperature (heat capacity doesn't matter because the air around a person gets replaced way too quickly). Humid air actually has lower thermal conductivity (search for 'Air Thermal Conductivity vs Humidity'). However, sweat evaporation is much more important than a small change in thermal conductivity. The reason why drier heat is more bearable is because it makes sweating more effective. In the extreme case where air is very hot and humid, "reverse sweating" can occur: the humidity of the air can condense on the skin, heating it up very quickly (though I'm not sure if such conditions naturally exist anywhere on earth).
As a Swede, I feel compelled to correct you on the use of heat pumps in colder tempereatures heat pumps start to lose efficiency at around 40 degrees F and become less efficient than furnaces at around 25 degrees F. In most of Sweden/Norway etc. (where most people live) there are only a few months that are that cold. Another way is to use a water to water heatpump and perform heat transfer with the ground water. No need to use coal or oil. Also, your Freon discussion did not feel up to date. Im pretty sure Freon is banned (even in the US), and something like Puron seems to have better thermal properties and not destroy the ozone layer.
It used to be a problem in the past but nowadays heat pumps are so advanced they are quite efficient even in low temperatures. For example heat exchangers couldn’t absorb any more heat because of ice buildup on the surface but now heat pumps defrost themselves with cycling heat back through the evaporator periodically to keep it free from ice.
@@kubismatik2 That's defrost cycle decrease effective runtime though, which is why even a low temp air source heat pump has a lower BTU rating at lower temps. Humidity in the cold makes a difference also, dry cold areas don't have as much an issue as wet and cold areas. The alternative is also a ground source heat pump, but the installation cost is much higher
Sandi Munro is fascinated by the engineering in Tesla's octovalve/Heat Pump. One of his observations is the collaborative effort that Tesla engineers went through when designing the system. Before they designed anything they collectively mapped out the entire thermodynamic needs of the vehicle (what needs heat, what needs cooling, what generates heat and what cools). They then designed the system to simultaneously meet those needs in the most efficient manner. The new thermal management system in the Model 2 Plaid is apparently the best yet.
@@colindavidson7071 Very few people have had the privilege of viewing the Model 2 Plaid. Including me. Obviously I meant Model S….where is spell checker when you need it.
Minor nit-- for your explanation of dry vs humid hot weather, you're completely right about what you say of the water molecules, except it's not the biggest reason why dry heat would feel less hot: it's mostly due to the fact that your sweat evaporates faster when the air is dry (there is less of a gradient in potential energy).
@@kedaruss - No, actually it's both. The question is what proportion is attributable to sweat + evaporation. It would be easy to design an experiment to verify that Dr. Know-it-all is right - just use a heat transfer surface that doesn't sweat.
@@jameshoffman552 If the air temperature is higher than body temperature you cannot cool down without evaporating liquid. That was the dessert situation that Dr was talking about.
Try going into a sauna, sitting for a while and then putting water on the coals. The room suddenly feels much warmer than before despite the temperature not changing.
In Australia, the generic term "air conditioner" in either cars or houses is still a heat pump, just optimised (in cars) for pumping heat from the interior to the exterior. In houses, the systems are able to pump heat either into or out of the house, depending on season.
@@blackf1ng3r62 it's a really old term from the original invention. The original was created for a book factory and the building needed cooling and the paper needed a specific humidity level. So that thing was a conditioner. We should call it an air chiller.
Not only the batteries produce heat. The motors and inverters produce a lot of heat also. Sometimes, the battery needs heating like before charging in the winter. All of these options of cabin heating or cooling, battery heating or cooling, power train cooling and absorbing or rejecting heat from the enviroment. Sorting out how they can support each other efficiently is the magic of the octovalve.
I cook with induction cooktop, and i notice how efficient it is, i wonder at the colder place i think they should combine induction to heat up the heat exchanger in the heat pump system.
You can boil water at lower temps if the pressure is high, water can be used aus a coolent, there are also heatpumps with water, but they have bad COPs
Just a comment on below her °C usage: Heat pumps are widely popular and useful in all of Sweden, and we are just east of Norway. There is no problem using heat pumps at below zero, but perhaps there is a problem if you use a heat pump that can go both ways. The "gain" (heating power / input electric power) do decrease, but even if you go from 4-5 to 3, it is a good deal. Here we most often use the heat pumps only to heat our houses, not cool them. I myself use "ground heat" (pipes in the ground with a special liquid) to draw heat from the ground, that makes it even more viable as a solution at below zero °C in the air. We use both air/air systems, and air/water systems (it is common to use water heated radiators or floor heating systems in Sweden).
Yeah some people are getting hung up on the loss of the heat gain from the conductive portion as a total loss of heating ability. The compressor contributes the same reliable portion of heat.
Using resistive heat is 100% efficient. Waste energy when using resistors to heat is also heat. Pumping heat can be up to five times more efficient than resistive heat since it does not run into the physics/thermodynamic laws that prohibit perpetual motion since it moves energy versus altering its form.
9:49 That's when the actual info you want starts... according to the tile. Still a bit more verbose than needed but is there. He never actually says HOW he just says that is possible, just that it is how it works... which is all we need. All the rest is him impressing us with his vast knowledge of how he knows simple physics.
A heat pump is nothing more than a window air conditioner. When you need heat, just take it out of the window and reinstall it in reverse. The outside heat fins are now on the inside. Cleaver valve design allows you to accomplish this without having to take it out of the window.
I wish Tesla's had some kind of a resistive heater that they could use for regenerative braking. Somewhere to put the electricity when the battery was cold or full. This is exactly how locomotives stop using dynamic braking. The top half of a locomotive is basically a giant toaster. In case someone doesn't know, all diesel locomotives are basically hybrids kind of.
Not sure Tesla uses Freon (R22). It has been illegal since Jan 2020. Precision would have one use a different term. ("refrigerant") or actual multi-syllable term.
Hi, just a quick note to say how much I enjoy your output, great stuff!. That being said, and sorry to nitpick, but I was rather surprised when you said that resistive heating is energetically inefficient. Perhaps I'm missing the point, but in thermodynamic terms this could not be further from the truth. In fact my understanding is that resistive heating should be 100% efficient, in that all the energy supplied to the element in terms of electrical current is turned into heat within a closed system. Now I'm wincing in expectation of being shot down in flames. Certainly no insult intended.
He means that it takes a lot of energy to heat air and batteries don’t have that much energy capacity especially compared to gasoline so using resistive heating when heat pumps exist isn’t an efficient use of the limited battery capacity.
@@trevorantram9242 Or another word, not to waste energy on heat generation, but to make use of unwanted waste heat from hot components like batteries or motor or inverter, and send them into the car cabin.
It's not efficient for its power consumption in the total potential work the battery could do. Yes on paper the device has its stat. Its in comparison the device as a unit can be considered less efficient compared to another device. Right?
I think you are only 100% correct. Resistive heating is "only" 100% efficient, while a heat pump is about 500% efficient (calculating output heat energy / input electricity energy), as long as it is NOT a closed system (since the heat pump takes heat out of the surroundings). So Dr. K-i-a is about 500% correct in this matter. Does that make any sense?
You mention norway. But the fact is we have fairly temperate climate across most of the country thanks to the gulf stream. So heatpumps are very popular here.
No - not an issue. On the channel Now You Know, they did experiments comparing a Model 3 to a gasser, showing that the Tesla heated up much faster (and that was a pre-heat-pump version). In my experience the thermal system is quite impressive in cabin cooling and heating.
A heat pump can have a small heater on the radiator i think it’s called , which makes it less efficient bellow 0 c , but still much better than gas or coal heaters . The reason their “bad” below 0 is that condensation builds up and freezes , stopping it work . But the external heater fixes that.
Looking forward to see what Tesla does for home systems. Seems to me if you had air heating, air conditioning, refrigeration and water heating all integrated you could save a lot of energy. We installed a heat pump water heater and it saves a ton.
Mmm, I didn't even know that combo was available. Interesting. And how about a "3 ton" heat pump for your house that's only the size of a mini fridge, plus it provides drinking or lawn watering water too? If anyone could do it, Tesla could!
@@DrKnowitallKnows Got ours from Rheem. We're in Florida, so it works great. Has a back-up coil, but I turned it off and have never missed it. In the summer it pulls about 0.6 kWh per day for two people. In January it pulls about 1.5 kWh. Costs about double that of a conventional coil heater, but should pay for itself in under 3 years.
@@DrKnowitallKnows There are already such integrated heating/cooling systems, for example in newer types of shopping centers and super markets. They are needing heat and cooling and they have it already.
Heat pumps are quite efficient even in could climates like Nordic countries. The best new heat pumps (of the type air - air) can operate at outdoor temperatures down to -35C. The COP is lower when it’s could outside, but may still be at around 2 (1 kWh of electricity gives 2 kWh of heat).
There's just one thing I don't understand, my 2020 model 3 that is parked in a garage maintained at 10°C in the winter uses the compressor to preheat the cabin. Is this whole "heatpump only in 2021 model 3s & Ys" just a marketing scheme because they just have more efficient compressors/gas and the octo-valve that I don't have?
Both your Model 3 and the later Teslas of all types have one heat pump -- in yours normally called an air-conditioner because it's only ported to the hot and cold coils in one way, and can only provide cooling. Your 3 generates heat by running current through, and even operating, various devices, including the heat pump, while circulating fluid, but the heat is generated by electrical resistance and rather than the carnot cycle. That said, are you sure your 3 is pre-Octavalve? They changed over sometime in 2020.
@@jameshoffman552 I took possession of mine in mid March 2020, I know the concept of heatpump is just reversing the flow of the refrigerant, and it seems that my M3 uses it up until 0°C (sometimes waits till it's -5°C) before it kicks in the resistive heating. Oh I see what you mean, the pre-octovalve models were not able to warm the battery using the compressor, but can be cooled using it. Right?
Dr KIA - The legacy terms we’re saddled with, really get in the way of laypersons’ understanding of what’s taking place - - Why was ‘air cooling’ called ‘air conditioning’ when air heating & air cleaning/filtration are also a/c? - What we call an ‘air conditioner’ (air cooler) is just a (one-way) heat pump. At the start, when a heating function was added to a/c’s, the unit was called a ‘reverse cycle’ air conditioner (‘conditioner’ in this context was now an accurate use of the term; ‘reverse cycle’ conveyed to the layperson how it worked). - Originally, air filtration was done for the benefit of the equipment, not humans. But as we’ve learned about indoor air pollution, the emphasis has shifted to clean, properly-humidified air for human health & safety. Up to this video, I was uniformly impressed with the clarity & accuracy of your videos (my favorite being your projections of how fast FSD might become reality). This one is a tragic fail. You might consider pulling it now, and replacing it w/ ~3 videos ie, basic physics, current applications (incl. UV, humidity control & air exchange to suppress micro-organisms), and - - Possibly a 4th video on passiv-haus’ energy-free heating/cooling/lighting/hot water, via house design, attic ventilation, storage of saved heat/cold, aerogel skylights, induction heating for water & cooking, and evaporative cooling in low-humidity environments. Thank you for all your clear explanations on the many topics you cover.
Here I always believed that the amount of water in the air (humidity) affected the rate of evaporation of sweat on my skin. Does your claim mean that dry air can be neither hot nor cold?
Thank you for sharing. I never thought the heat pump was needed living in the North East with basically 2-3 months of cold weather (30 degrees or less). Would you say the heat pump extends the battery life as well?
Best explanation of convective heat transfer I ever heard. I always thought it was essentially air movement, but never thought of still air, and the impact of heat capacity of water molecules.
Someone wrote that the water molecules have a negligible effect due to them not adding mass to a given volume. Water just displaces air molecules. 100% humidity is the max moisture retention of air but definitely not very much water in reality.
Not sure about explanation of "feel" of dry heat and humid heat being just water molecules. Evaporative cooling from sweat is far more effective in our Fresno, CA, dry heat than your Atlanta humidity. Sweat matters.
Nice vid. On a different subject …. It always irritates me that people state that Tesla lead in number of miles driven gives them an unassailable lead in FSD. IMO the amount of data that Tesla uses to train its neural net is not directly related to the number of miles driven. Tesla requests data from the fleet when needed rather than recording every mile that the fleet drives. That means that the limiting factor is more to do with the number of cars currently on the road, how efficient they are in extracting quality data and the quality of their training. Tesla already have far more cars in their fleet than everyone else so the rollout of dojo is they key factor. Would be interested to hear your view
@@mikemccarthy1638 was that the one based on exponential growth? Didn’t like that one because I didn’t see any justification for the chosen scale on the time axis
I like the simple diagram of the inside/outside of a heating/cooling system using evaporation and condensation (expansion/compression, whatever words work best for understanding). I try to explain compression with the bicycle pump analog; when pumping up a tire, the pump gets hot. When I explain expansion, I use the paint can analogy (which you used, but for the other side, calling it 'opposite of a paint can' silly! ;-) ) or even better, a dust cleaner (compressed gas for cleaning computer parts etc). Those get extremely cold the longer you use them. I know, I'm pedantic! And nobody likes a know-it-all unless it's Dr. Know-it-all! :)
Re: humidity and heat. That was an explanation I have not heard before. I am sure that sweat evaporation also plays a major part in how hot it feels relative to humidity.
I generally like your videos but this has to be one of the most convoluted explanations of heat I’ve ever heard, and I’m not convinced that it isn’t flat out wrong. The fact that you had to add so many corrective subtitles during editing makes the explanation even more suspect.
Thanks. that is why my freezer can't bring the temperature down to -20C... ohh wait it actually does? So does a heat pump work at -20C? if not then please explain how your freezer works? is it magic?
@@DrKnowitallKnows Wrong all Freezers must be set by public health standards set to -20C (you should Google this) . It is the type of gas inside and pressures differences that is the difference between a fridge and freezer. Freezers are very efficient at -20C..
@@DrKnowitallKnows Here is the list of 100's of different types of Freons. Each has it's specific operating temperatures.. on some you can go down to -100C is the normal operating temperature and still be more efficient than using 410A at -1C en.wikipedia.org/wiki/List_of_refrigerants It all has to do with the boiling characteristics of the Freon being used. Most skating rinks will use the dangerous Amonia as the Freon.
Actually, to be precise, conduction is the transfer of energy through direct particle contact while convection is the transfer via particle translation/motion (the bumping at the end is conduction). Don't take my work or it, it's all over the internet, sometimes even from from doctor of physics that know it all.
Appreciate the effort, but all of the corrections in subtitles was distracting tbh I stopped listening in the last 5 minutes an just kept staring at the screen for the next update/correction. I normally listen to the audio rather watch the video, so glad I noticed the corrections on this video or I'd be waay misinformed. Again, I appreciate the effort but being more of an educational video vs. informative I think 1-2 errors would have be fine but there seemed to be much more than this that could have be addressed before releasing the video. Sorry.
You described convection heat as if it were conductive. You describe the poor heat transfer through air in microgravity. The correct description is that as gases get hotter they expand in volume while retaining the same mass, therefore becoming less dense, and tending to go UP by buoyancy. Therefore a hot object that conductively transfers heat to surrounding air tends to establish a gas flow that takes heat away from the object in an upward direction; and this only works where there is net gravity; otherwise there is no UP direction. I should have written Encyclopedia Britannica! EDIT: Your explanations keep getting worse... Energy doesn't go from cool liquid to hot air; it is the other way around. Well, Quantum Physically heat moves both ways; but per the simpler model you got it exactly backwards. This is getting really bad Doctor. Sorry to say, but this video needs a *recall.*
I was born in 1945 and remember when people used to get a technician to change the compressor in your refrigerator and recharge the freon. In the 80s I remember them still doing this but now the freon gas is so expensive they sell you a new fridge and throw the old one in the dump. I think this has come about because of the EPA and because freon is not necessarily freon it is more a generic name because the old freon was dangerous to the ozone layer. Google says the price went from $26 to $300 according to what I just read. Are we getting boon-doggled?
My question is: why doesn’t Tesla use carbon dioxide as the refrigerant in its heat pump? Unlike hydrocarbon refrigerants, which are toxic and flammable, CO2 is devoid of toxicity, and it suppresses fire and explosions. It has excellent refrigerant properties. In fact, CO2 refrigeration was patented in Britain as early as 1850, and by 1870 an American businessman installed CO2 refrigeration in a cargo ship to transport beef from Texas to New York City. Mercedes has developed CO2 air conditioning systems for its big sedans to meet strict new European Union standards that discourage refrigerant toxicity. Why doesn’t Tesla do likewise????
I put a geothermal heat pump in my house when I built it in 1995. Still going strong and has saved me thousands over its life cycle. The new ones today are are multiple times more efficient. It works as my air conditioner in the summer too. You did a great job explaining the physics involved.👍
Wet heat feels hotter because the water in air stops the water on your skin from evaporating. Not because the water in the air has more energy to transfer to you. So the primary means of your body to regulate your body temperature (sweating) becomes less effective.
His explanation was so wrong that hurts
that's why dew point is so important
Yep, the whole part about water molecules should be deleted :(
The two explanations are not mutually exclusive.
@@s.m.7018 Depends on the temperature. If the air temperature is higher than body temperature you cannot cool down without evaporation. Remember, Dr was talking desert conditions.
Fun fact: on the ISS, the Electric Power System (EPS) includes a large number of Orbital Replaceable Units (ORUs) mounted on platforms outside the habitats, in vacuum, and these platforms are cooled by ammonia. But they didn't want the ORUs to become vacuum-welded to the platforms over time, so they use radiant heat transfer between the ORU and the platform. Basically, both the ORU and the platform have a large number of very thin fins, and they interleave with each other without touching. I think this was one of the very few smart things we did on the EPS design, and we own it to a guy named Dave Blackler.
Woah! That's pretty amazing. Double radiative cooling--now that's rocket science at its best! Thanks for sharing this very cool (hahah) tidbit!
Couldn't find a satisfactory explanation of vacuum welding, so now it's your responsibility to learn me something 😉
Gonna need a response or head explodes
I wonder how they keep the ammonia from freezing in the shadow of space being -250 f.. I would also like to see the insulation on ISS working with 250f in the light and -250f in the shade . That's pretty unbelievable stuff
Freon is a brand name of DuPont. Refrigerant is something that boils and turns from a liquid to a vapor at a lower pressure and temperature absorbing heat. Reject heat at a higher temperature and pressure turns a vapor to a liquid.
4:41 There are several mistakes at that point.
First, specific heat is conflated with thermal conductivity. It's the latter that would matter for how hot air outside feels at a particular temperature (heat capacity doesn't matter because the air around a person gets replaced way too quickly). Humid air actually has lower thermal conductivity (search for 'Air Thermal Conductivity vs Humidity').
However, sweat evaporation is much more important than a small change in thermal conductivity. The reason why drier heat is more bearable is because it makes sweating more effective. In the extreme case where air is very hot and humid, "reverse sweating" can occur: the humidity of the air can condense on the skin, heating it up very quickly (though I'm not sure if such conditions naturally exist anywhere on earth).
As a Swede, I feel compelled to correct you on the use of heat pumps in colder tempereatures heat pumps start to lose efficiency at around 40 degrees F and become less efficient than furnaces at around 25 degrees F. In most of Sweden/Norway etc. (where most people live) there are only a few months that are that cold. Another way is to use a water to water heatpump and perform heat transfer with the ground water. No need to use coal or oil. Also, your Freon discussion did not feel up to date. Im pretty sure Freon is banned (even in the US), and something like Puron seems to have better thermal properties and not destroy the ozone layer.
It used to be a problem in the past but nowadays heat pumps are so advanced they are quite efficient even in low temperatures. For example heat exchangers couldn’t absorb any more heat because of ice buildup on the surface but now heat pumps defrost themselves with cycling heat back through the evaporator periodically to keep it free from ice.
@@kubismatik2 That's defrost cycle decrease effective runtime though, which is why even a low temp air source heat pump has a lower BTU rating at lower temps. Humidity in the cold makes a difference also, dry cold areas don't have as much an issue as wet and cold areas.
The alternative is also a ground source heat pump, but the installation cost is much higher
R22 is phasing out. R410A is going to be obsolete soon. R32 coming down the pipe
Yes he shouldn't have used a named banned refrigerant, but just said refrigerant.
Sandi Munro is fascinated by the engineering in Tesla's octovalve/Heat Pump. One of his observations is the collaborative effort that Tesla engineers went through when designing the system. Before they designed anything they collectively mapped out the entire thermodynamic needs of the vehicle (what needs heat, what needs cooling, what generates heat and what cools). They then designed the system to simultaneously meet those needs in the most efficient manner. The new thermal management system in the Model 2 Plaid is apparently the best yet.
Legacy auto manufacturers are doomed.
I haven't looked into the S yet, but given how fast they iterate I'm sure it's incredible
I think the new Plaid has a larger radiator as well to help with heat removal from the battery pack.
You've seen a model 2 plaid? Wow! Most of us are still waiting for the model 2 to be announced!
@@colindavidson7071 Very few people have had the privilege of viewing the Model 2 Plaid. Including me. Obviously I meant Model S….where is spell checker when you need it.
Minor nit-- for your explanation of dry vs humid hot weather, you're completely right about what you say of the water molecules, except it's not the biggest reason why dry heat would feel less hot: it's mostly due to the fact that your sweat evaporates faster when the air is dry (there is less of a gradient in potential energy).
The reason why humid heat feels hotter is because it slows the evaporation of sweat which is a cooling mechanism in humans.
Yes, that too. This stuff is all quite complex when it interacts with biology. Thanks!
@@DrKnowitallKnows No, not "that too" but "exactly that"
@@kedaruss - No, actually it's both. The question is what proportion is attributable to sweat + evaporation. It would be easy to design an experiment to verify that Dr. Know-it-all is right - just use a heat transfer surface that doesn't sweat.
@@jameshoffman552 If the air temperature is higher than body temperature you cannot cool down without evaporating liquid. That was the dessert situation that Dr was talking about.
Try going into a sauna, sitting for a while and then putting water on the coals. The room suddenly feels much warmer than before despite the temperature not changing.
In Australia, the generic term "air conditioner" in either cars or houses is still a heat pump, just optimised (in cars) for pumping heat from the interior to the exterior. In houses, the systems are able to pump heat either into or out of the house, depending on season.
I must be a nerd, Matt - I * really * get the irrits when people call an air conditioner a heat pump . Happens a lot in Tasmania .
@@blackf1ng3r62 can you explain the difference please?
Look up Sealioning .
@@blackf1ng3r62 it's a really old term from the original invention. The original was created for a book factory and the building needed cooling and the paper needed a specific humidity level. So that thing was a conditioner. We should call it an air chiller.
@@matttownsend7119 the difference so far is cars just used the system to cool because heating was supplied from engine
18:30 or a ground source heat pump. Still about 300% efficiency, you just need to bore a deep hole.
Not only the batteries produce heat. The motors and inverters produce a lot of heat also. Sometimes, the battery needs heating like before charging in the winter. All of these options of cabin heating or cooling, battery heating or cooling, power train cooling and absorbing or rejecting heat from the enviroment. Sorting out how they can support each other efficiently is the magic of the octovalve.
I cook with induction cooktop, and i notice how efficient it is, i wonder at the colder place i think they should combine induction to heat up the heat exchanger in the heat pump system.
You can boil water at lower temps if the pressure is high, water can be used aus a coolent, there are also heatpumps with water, but they have bad COPs
Just a comment on below her °C usage: Heat pumps are widely popular and useful in all of Sweden, and we are just east of Norway. There is no problem using heat pumps at below zero, but perhaps there is a problem if you use a heat pump that can go both ways. The "gain" (heating power / input electric power) do decrease, but even if you go from 4-5 to 3, it is a good deal. Here we most often use the heat pumps only to heat our houses, not cool them. I myself use "ground heat" (pipes in the ground with a special liquid) to draw heat from the ground, that makes it even more viable as a solution at below zero °C in the air. We use both air/air systems, and air/water systems (it is common to use water heated radiators or floor heating systems in Sweden).
Yeah some people are getting hung up on the loss of the heat gain from the conductive portion as a total loss of heating ability. The compressor contributes the same reliable portion of heat.
Is radiant heat at all popular in new builds?
One thing an equilibrium of energy must be to withstand the shock of temperture desintegration of machines.
Heat pump = Fridge with reversed radiators.
Warm radiator is inside, cold radiator is outside.
Could water heat and cool as well or a natural substance for fast or slow moving particles to cool or heat.
Please, do octovalve.
The water liquid in the air is the energy. Please look more into T/P and saturation
Using resistive heat is 100% efficient. Waste energy when using resistors to heat is also heat. Pumping heat can be up to five times more efficient than resistive heat since it does not run into the physics/thermodynamic laws that prohibit perpetual motion since it moves energy versus altering its form.
9:49
That's when the actual info you want starts... according to the tile. Still a bit more verbose than needed but is there. He never actually says HOW he just says that is possible, just that it is how it works... which is all we need.
All the rest is him impressing us with his vast knowledge of how he knows simple physics.
A heat pump is nothing more than a window air conditioner. When you need heat, just take it out of the window and reinstall it in reverse. The outside heat fins are now on the inside.
Cleaver valve design allows you to accomplish this without having to take it out of the window.
You just need to put a swivel top and bottom. Bam I control my comfort in this room!
I wish Tesla's had some kind of a resistive heater that they could use for regenerative braking. Somewhere to put the electricity when the battery was cold or full. This is exactly how locomotives stop using dynamic braking. The top half of a locomotive is basically a giant toaster. In case someone doesn't know, all diesel locomotives are basically hybrids kind of.
Not sure Tesla uses Freon (R22). It has been illegal since Jan 2020. Precision would have one use a different term. ("refrigerant") or actual multi-syllable term.
Probably R 32
@@hectorarcelus6602 Probably R32. I'm just old so all refrigerants are freon--just like all tissues are Kleenex. That's on me :)
@@DrKnowitallKnows Or R-1234yf
@@juhak27this guy knows
Thought you were going to discuss octo part, not basic hvac of any old heat pump. Missed opportunity.
Way to make those clicks... Came to learn about Tesla heatpump integration, got general explanation of how heatpump works...
Is the Tesla heatpump dedicated episode out yet? Can I have a link ?
Hi, just a quick note to say how much I enjoy your output, great stuff!. That being said, and sorry to nitpick, but I was rather surprised when you said that resistive heating is energetically inefficient. Perhaps I'm missing the point, but in thermodynamic terms this could not be further from the truth. In fact my understanding is that resistive heating should be 100% efficient, in that all the energy supplied to the element in terms of electrical current is turned into heat within a closed system. Now I'm wincing in expectation of being shot down in flames. Certainly no insult intended.
He means that it takes a lot of energy to heat air and batteries don’t have that much energy capacity especially compared to gasoline so using resistive heating when heat pumps exist isn’t an efficient use of the limited battery capacity.
@@trevorantram9242 Or another word, not to waste energy on heat generation, but to make use of unwanted waste heat from hot components like batteries or motor or inverter, and send them into the car cabin.
It's not efficient for its power consumption in the total potential work the battery could do. Yes on paper the device has its stat. Its in comparison the device as a unit can be considered less efficient compared to another device. Right?
I think you are only 100% correct. Resistive heating is "only" 100% efficient, while a heat pump is about 500% efficient (calculating output heat energy / input electricity energy), as long as it is NOT a closed system (since the heat pump takes heat out of the surroundings). So Dr. K-i-a is about 500% correct in this matter. Does that make any sense?
I use an air cooler with water and ice packs its nice.
Understood the basics BUT didn’t know about the molecular level. Great education session.
You mention norway. But the fact is we have fairly temperate climate across most of the country thanks to the gulf stream. So heatpumps are very popular here.
Thanks for the information i always wanted to know how the tesla heat pump worked
Strictly speaking the indoor part of the A/C unit doesn’t radiate cold, but it’s a much simpler way of looking at it than what’s really going on 🤣
Cold can not be radiated. Cold is not to radiae. Cold is the same as darkness.
Right we should always talk in relation to heat only. Like adds heat or removes heat.
You are a fantastic teacher
Knowledge =pass
Wisdom= pass
Understanding =fail
Looking forward to more on the Tesla heat pump.
This makes me want to check the laws in my state. 😮
Compressors are evidently more efficient than shorting a charge through an alloy to produce temperature changes inside a vehicle.
Really well done. Learned a lot and loved that you provided a basic physics foundation, then examples including the Tesla apparatus. Nice job.
One of my favorite topics, Thanks
How long does it take the cabin in a Tesla to heat up for those that live in colder climates? If it’s 32F outside is there an issue with heating?
No - not an issue. On the channel Now You Know, they did experiments comparing a Model 3 to a gasser, showing that the Tesla heated up much faster (and that was a pre-heat-pump version). In my experience the thermal system is quite impressive in cabin cooling and heating.
@@jameshoffman552 thanks for the detailed reply.
A heat pump can have a small heater on the radiator i think it’s called , which makes it less efficient bellow 0 c , but still much better than gas or coal heaters .
The reason their “bad” below 0 is that condensation builds up and freezes , stopping it work . But the external heater fixes that.
Most just reverse the heating/cooling cycle for a bit to defrost the coils. Much more efficient than using a resistance heater.
Please explain the octavalve
Looking forward to see what Tesla does for home systems. Seems to me if you had air heating, air conditioning, refrigeration and water heating all integrated you could save a lot of energy. We installed a heat pump water heater and it saves a ton.
Mmm, I didn't even know that combo was available. Interesting. And how about a "3 ton" heat pump for your house that's only the size of a mini fridge, plus it provides drinking or lawn watering water too? If anyone could do it, Tesla could!
@@DrKnowitallKnows Got ours from Rheem. We're in Florida, so it works great. Has a back-up coil, but I turned it off and have never missed it. In the summer it pulls about 0.6 kWh per day for two people. In January it pulls about 1.5 kWh. Costs about double that of a conventional coil heater, but should pay for itself in under 3 years.
@@DrKnowitallKnows
There are already such integrated heating/cooling systems, for example in newer types of shopping centers and super markets. They are needing heat and cooling and they have it already.
@@MBighk the carrier split systems are fair priced
Yes, "information is entropy" topic please. I don't really understand either, so I'd like to hear your take.
Thanks for the explanation of the process.
Please do a video on entropy!!
Wow! Great explanation, thank you 🙏!!
Heat pumps are quite efficient even in could climates like Nordic countries. The best new heat pumps (of the type air - air) can operate at outdoor temperatures down to -35C. The COP is lower when it’s could outside, but may still be at around 2 (1 kWh of electricity gives 2 kWh of heat).
There's just one thing I don't understand, my 2020 model 3 that is parked in a garage maintained at 10°C in the winter uses the compressor to preheat the cabin. Is this whole "heatpump only in 2021 model 3s & Ys" just a marketing scheme because they just have more efficient compressors/gas and the octo-valve that I don't have?
Both your Model 3 and the later Teslas of all types have one heat pump -- in yours normally called an air-conditioner because it's only ported to the hot and cold coils in one way, and can only provide cooling. Your 3 generates heat by running current through, and even operating, various devices, including the heat pump, while circulating fluid, but the heat is generated by electrical resistance and rather than the carnot cycle.
That said, are you sure your 3 is pre-Octavalve? They changed over sometime in 2020.
@@jameshoffman552 I took possession of mine in mid March 2020, I know the concept of heatpump is just reversing the flow of the refrigerant, and it seems that my M3 uses it up until 0°C (sometimes waits till it's -5°C) before it kicks in the resistive heating. Oh I see what you mean, the pre-octovalve models were not able to warm the battery using the compressor, but can be cooled using it. Right?
A little verbose but great video! Thumbs up and subscribed! Nice starship Enterprise!
Dr KIA - The legacy terms we’re saddled with, really get in the way of laypersons’ understanding of what’s taking place -
- Why was ‘air cooling’ called ‘air conditioning’ when air heating & air cleaning/filtration are also a/c?
- What we call an ‘air conditioner’ (air cooler) is just a (one-way) heat pump. At the start, when a heating function was added to a/c’s, the unit was called a ‘reverse cycle’ air conditioner (‘conditioner’ in this context was now an accurate use of the term; ‘reverse cycle’ conveyed to the layperson how it worked).
- Originally, air filtration was done for the benefit of the equipment, not humans. But as we’ve learned about indoor air pollution, the emphasis has shifted to clean, properly-humidified air for human health & safety.
Up to this video, I was uniformly impressed with the clarity & accuracy of your videos (my favorite being your projections of how fast FSD might become reality). This one is a tragic fail. You might consider pulling it now, and replacing it w/ ~3 videos ie, basic physics, current applications (incl. UV, humidity control & air exchange to suppress micro-organisms), and -
- Possibly a 4th video on passiv-haus’ energy-free heating/cooling/lighting/hot water, via house design, attic ventilation, storage of saved heat/cold, aerogel skylights, induction heating for water & cooking, and evaporative cooling in low-humidity environments.
Thank you for all your clear explanations on the many topics you cover.
Here I always believed that the amount of water in the air (humidity) affected the rate of evaporation of sweat on my skin. Does your claim mean that dry air can be neither hot nor cold?
Nicely explained, thanks
Jump to 20:00 for the start of explanation.
Your welcome
Thank you for sharing. I never thought the heat pump was needed living in the North East with basically 2-3 months of cold weather (30 degrees or less). Would you say the heat pump extends the battery life as well?
You never thought the heat pump was need? What do you mean? And yes the power consumption is lower for a electric compressor than the element heater.
You need to familiarize yourself on air conditioning heatpumps and latent heat in change of state.
Really fine description.
Is it safe for the car to continue driving if heat pump is dead?
11:38 This!!!
Heat pump = AC reversible unit. Nothing new under the sun.
Thank you.
Wonderful explanation thank you
Best explanation of convective heat transfer I ever heard. I always thought it was essentially air movement, but never thought of still air, and the impact of heat capacity of water molecules.
Someone wrote that the water molecules have a negligible effect due to them not adding mass to a given volume. Water just displaces air molecules. 100% humidity is the max moisture retention of air but definitely not very much water in reality.
Beautiful explanation. Thank you!
Ah i get it now. Great explanation 👍👍
I can’t wait for Tesla home HVAC
All air conditioning systems are unidirectional air to air heat pumps.
And it works because of the magic of the phase change of the refrigerant.
Not sure about explanation of "feel" of dry heat and humid heat being just water molecules. Evaporative cooling from sweat is far more effective in our Fresno, CA, dry heat than your Atlanta humidity. Sweat matters.
Agreed
Very interesting.
In Germany they change the refrigerant to R 280 or propane.
Thank You
Nice vid. On a different subject …. It always irritates me that people state that Tesla lead in number of miles driven gives them an unassailable lead in FSD. IMO the amount of data that Tesla uses to train its neural net is not directly related to the number of miles driven. Tesla requests data from the fleet when needed rather than recording every mile that the fleet drives. That means that the limiting factor is more to do with the number of cars currently on the road, how efficient they are in extracting quality data and the quality of their training. Tesla already have far more cars in their fleet than everyone else so the rollout of dojo is they key factor. Would be interested to hear your view
The points to make would make teslas lead even more unassailable
Dr KIA did an excellent statistical video on why he concludes that FSD will become reality quicker than most folks think.
@@mikemccarthy1638 was that the one based on exponential growth? Didn’t like that one because I didn’t see any justification for the chosen scale on the time axis
Freon does attack ozone, but it is a terrible greenhouse gas too!
Freon is a brand of refrigerant. They are soo prevalent that now we call all refrigerants Freon. Commercial HVAC/r tech here if you have any questions
I like the simple diagram of the inside/outside of a heating/cooling system using evaporation and condensation (expansion/compression, whatever words work best for understanding). I try to explain compression with the bicycle pump analog; when pumping up a tire, the pump gets hot. When I explain expansion, I use the paint can analogy (which you used, but for the other side, calling it 'opposite of a paint can' silly! ;-) ) or even better, a dust cleaner (compressed gas for cleaning computer parts etc). Those get extremely cold the longer you use them.
I know, I'm pedantic! And nobody likes a know-it-all unless it's Dr. Know-it-all! :)
will be nice to know how tesla heatpump works at -30C, when parked, i.e. no energy from motors/battery is utilized through octovalve
Well it would be slow but the compressors heat contribution would be just about 99% heat available.
Please do the OctoValve video. Bill
More in depth stuff like this please!
Freon depletes ozone. Ive never heard it called a greenhouse gas. Water is by far the biggest greenhouse gas.
Re: humidity and heat. That was an explanation I have not heard before. I am sure that sweat evaporation also plays a major part in how hot it feels relative to humidity.
I don’t have a heat pump in my model x. 😢
I guess it pumps in high energy heat and depressures it out of the house. According to needed.
I generally like your videos but this has to be one of the most convoluted explanations of heat I’ve ever heard, and I’m not convinced that it isn’t flat out wrong. The fact that you had to add so many corrective subtitles during editing makes the explanation even more suspect.
It's like he was just creating content and hadn't created a quality product. Lame
People in Norway can still use a heat pump all they have to do is just burry the outside coil under ground where it is 50 degrees F year round
Thanks. that is why my freezer can't bring the temperature down to -20C... ohh wait it actually does? So does a heat pump work at -20C? if not then please explain how your freezer works? is it magic?
They work at wider differentials they’re just not very efficient. And -4C is plenty cold for a normal freezer.
@@DrKnowitallKnows Wrong all Freezers must be set by public health standards set to -20C (you should Google this) . It is the type of gas inside and pressures differences that is the difference between a fridge and freezer. Freezers are very efficient at -20C..
@@DrKnowitallKnows Here is the list of 100's of different types of Freons. Each has it's specific operating temperatures.. on some you can go down to -100C is the normal operating temperature and still be more efficient than using 410A at -1C en.wikipedia.org/wiki/List_of_refrigerants It all has to do with the boiling characteristics of the Freon being used. Most skating rinks will use the dangerous Amonia as the Freon.
Actually, to be precise, conduction is the transfer of energy through direct particle contact while convection is the transfer via particle translation/motion (the bumping at the end is conduction). Don't take my work or it, it's all over the internet, sometimes even from from doctor of physics that know it all.
The phenomenon involves both convection and conduction.
My 2015 KIA SOUL EV had a heat pump. Copied by TESLA. So what is the big deal Mr. know it all?
You should call it a review of how home HVAC work and little to no review on tesla auto heat pump.. uff
Appreciate the effort, but all of the corrections in subtitles was distracting tbh I stopped listening in the last 5 minutes an just kept staring at the screen for the next update/correction. I normally listen to the audio rather watch the video, so glad I noticed the corrections on this video or I'd be waay misinformed.
Again, I appreciate the effort but being more of an educational video vs. informative I think 1-2 errors would have be fine but there seemed to be much more than this that could have be addressed before releasing the video. Sorry.
Uh a heat pump is an air conditioner. It just makes sense to put a switching valve in so you can switch from heat and cooling with the same system
Yeah death valley vs Fort Sill Oklahoma
You described convection heat as if it were conductive. You describe the poor heat transfer through air in microgravity.
The correct description is that as gases get hotter they expand in volume while retaining the same mass, therefore becoming less dense, and tending to go UP by buoyancy. Therefore a hot object that conductively transfers heat to surrounding air tends to establish a gas flow that takes heat away from the object in an upward direction; and this only works where there is net gravity; otherwise there is no UP direction.
I should have written Encyclopedia Britannica!
EDIT:
Your explanations keep getting worse... Energy doesn't go from cool liquid to hot air; it is the other way around. Well, Quantum Physically heat moves both ways; but per the simpler model you got it exactly backwards.
This is getting really bad Doctor. Sorry to say, but this video needs a *recall.*
Agree. multiple missteps in this one, sadly.
Definitely
I was born in 1945 and remember when people used to get a technician to change the compressor in your refrigerator and recharge the freon. In the 80s I remember them still doing this but now the freon gas is so expensive they sell you a new fridge and throw the old one in the dump. I think this has come about because of the EPA and because freon is not necessarily freon it is more a generic name because the old freon was dangerous to the ozone layer. Google says the price went from $26 to $300 according to what I just read. Are we getting boon-doggled?
Got a little worried for a second when you said you were going to pass hot gas.
Excellent stuff, than you
I thought that they would use a Stirling engine to move heat back and forth. No freon is needed.
My question is: why doesn’t Tesla use carbon dioxide as the refrigerant in its heat pump? Unlike hydrocarbon refrigerants, which are toxic and flammable, CO2 is devoid of toxicity, and it suppresses fire and explosions. It has excellent refrigerant properties. In fact, CO2 refrigeration was patented in Britain as early as 1850, and by 1870 an American businessman installed CO2 refrigeration in a cargo ship to transport beef from Texas to New York City. Mercedes has developed CO2 air conditioning systems for its big sedans to meet strict new European Union standards that discourage refrigerant toxicity. Why doesn’t Tesla do likewise????
I guess we didn’t want to talk about changing state from gas to liquid and liquid to gas and how that absorbs and releases heat.
Different video?
Is this Technology connections now or what?
For heat why no use propane instead. Not environmental friendly as battery but better than gasoline.