How to Make an Adjustable Split Heat Pump Freezing Air Conditioner -40°C to +50°C. Save Your Money.

[@R.U.H.]

Register & Enjoy $19 coupons at JLCMC: jlcmc.com/?from=RUH1 #JLCMC #diyairconditioner #how !!! Turn on subtitles !!!

[@nayayelin-nk4hc]

Can you make a water dispenser with hot and cold water using your heat pump?

[@ТимаКама]

WATER FROM THE AIR Hello. Try to make a device for collecting water-condensate (water from the air), i.e. the cooled part of the refrigerator (or expand the area for snow-condensate with metal plates) the cold part with frost (snow) on the metal (metal plates) cools down, builds up snow after some time the valve with warm air or water switches and is supplied to the snow and washes away the condensate (snow) - thus it will receive water from the air (very cheap and can be used in the desert). As options for heating snow - heating from a turbine - induction heating - heating in a box through glass in the sun - magnifying (reducing) lens and heat with a beam, a direct beam or heating a stone in water ВОДА ИЗ ВОЗДУХА Привет. Попробуй сделать установку по сбору воды-конденсата (вода из воздуха), т.е. охлажденная часть холодильника (или расширить металлическими плитами площадь под снег-конденсат) холодная часть с инеем (снег) на металле (металлическими плитами) охлаждается, наращивает снег по истечению какого времени переключается клапан с теплым воздухом или водой и подается на снег и смывает конденсат (снег) - таким образом будет получать воду из воздуха (очень дешево и можно использовать в пустыне). Как варианты нагрева снега - нагрев от турбины - индукционный нагрев - нагрев в коробке через стекло на солнце - увеличительная (уменьшительная) линза и лучом разогревать , прямым лучом или нагрев камня в воде

[@brutusmaximus5380]

Can you list the components that you ordered?

[@heronimuswicak.s5820]

u want us to ask u, but no one in the comments get answer from u..

[@sirlayorn7355]

You can buy an old refrigerator case from the 1950s and redesign its cooling system. It is made of steel with a thickness of 2 mm and painted by completely dipping into a bath of paint (3 times). This is a very, very stylish design and it will never rust, unlike modern products. While verbally supporting the care of nature, the producers force us to change the equipment every few years - and such an old refrigerator has been working for 50+ years and longer!

[@sirlayorn7355]

This was a google-translated comment, be lenient ))

[@Сто-у9м]

Вы абсолютно правы. Так и с машинами и всем остальным. Под видом защиты экологии нам предлагают больше покупать😂

[@bayram6561]

@@Сто-у9м MILLETI KARBON AYAK İZİ ADI ALTINDA SIKE****KLER

[@이윤수-k7w]

This is an interesting video. I'm not sure what refrigerant is being used in this refrigeration cycle, but I don't see a typical condenser. Generally, a refrigeration cycle without a condenser cannot maintain thermal equilibrium, and if it continues to operate, the cooling effect will disappear. Therefore in this video, it seems that a very small amount of refrigerant is being adjusted to flow through the piping between the compressor and the capillary tube, allowing it to function like a condenser

[@davegeorge7094]

It's insults your intelligence, yes?

[@lpqlbdllbdlpql]

It's essentially cooling and heating the same air so yeah

[@biglew1161]

based on limited knowledge of the refrigeration cycle, and not knowing flow direction of the compressor, it looks like the refrigerant is getting compressed (condensed) into the coils on the fan, and evaporating into the expansion tube device. so to me it looks like this is operating backwards. but it does look like it works. put the compressor between the coils on the fan and some more coils before the expansion tube, I think it would be almost a complete ac

[@briansmyla8696]

The refrigerant is most likely butane.

[@onemischiefmaker7032]

@@briansmyla8696 YES and it did not shown getting a vacuum pulled either.. The basic bomb!!!

[@shiaolan]

Look mom! I built a refrigerator out of refrigerator parts!

[@SSM20985]

Butane liquefies at 30°C under a pressure of 3.8 bar. If the return gas from the evaporator is below 30°C, this pressure can also decrease. Therefore, the pump must be specifically designed for gas, and its minimum compression pressure should be 4 bar for it to be feasible. Additionally, if possible, please use a pressure gauge in your videos to make it more credible

[@HABENHAND]

For those who don’t understand how an air conditioner works, this video is a real eye-opener! I built it myself and can confirm: it’s not a fake, it actually works. Before accusing, it’s better to understand the basics. Thanks for the helpful video and the chance to make everything with my own hands!🥶💯💪

[@akashdeeplakra3583]

Wow ur PC setup looks cool .Well it heats up ur feet too

[@beginnereasy]

Water boils at a lower temperature in a vacuum. It's possible to make a body heat steam generator (runoff goes to a condenser)

[@longanghoai9881]

Heat always diffuses from the center outward, so copper pipes should be wound in concentric vortex coils, you will increase efficiency !

[@d1.004]

Fantastic how big of a room would that unit cool or would it just be for a fridge/freezer application ???

[@cooperationsoundx]

This is just incredible! I tried making this DIY air conditioner and was pleasantly surprised - everything worked! It really works, no fake! Thank you so much for the detailed guide and for recommending the store where I could order everything I needed for assembly. Huge thanks for such helpful content and for assisting in finding the materials!

[@martintatak8851]

The video was uploaded 6 days ago and you commented 5 days ago. That means only after a day this video was uploaded you have built it? You had all the parts laying around?

[@mdnnjony4000]

@@martintatak8851 the logic. maybe he used only principle

[@tomvocas5858]

@@martintatak8851 He had, as he may has some share from affiliate link provided...

[@MrSudoma]

You tried it but don't know what parts you need. I smell al lyer.

[@zend1999]

His mother works at FedEx, please do not persecute him.. 😁

[@manman-sg1zt]

I think that that compressor has a piston about 10 times smaller than the motor. But it doesn't matter what it takes if it works. I had doubts that it would work but apparentaly it does. Have a like for the effort.

[@rowanarmitage79]

This guys knowledge of thermodynamics is obviously brilliant, insomuch as he has disproved so many well established laws of thermodynamics.

[@BurkenProductions]

Ok? So how does it work? Would be nice with some explenations!

[@TheStigma]

Same principle as any AC, refrigerator or heat exchanger: A refridgerant gas is compressed (compressor) into a liquid state and passed through capillary tubes (extremely thin, to retain pressure). When this liquid gas enters the evaporation chamber (cold side, like a radiator for example) it sudden has room to expand and the pressure drops drastically causing the liquid to become gas again. This sudden gas expansion absorbs heat from the surroundings - this happens to all gases in general, which is why something simple like sweating can cool you down. The hot gas is passed back to the compressor which forcefully squeezes the gas back into liquid with high pressure. This forces the gas to release all the heat it had absorbed (hot side). The result is that you can use some energy to move heat from one place to another - for example from inside a fridge to the outside (usually back). Or an AC can use fans on either side to move heat inside to outside, or vise versa. ACs are often designed so they can run in reverse also, to provide both heating and cooling capacity. A heat-pump (basically much like an AC) can achieve 350-400% heating efficiency compared to an electric oven which can never be more efficient than 100% - because it is not making the heat itself, but stealing it from the outside. I hope that helps :)

[@valentinloginoff]

​@@TheStigmaso, let's look to the system from video. Parts on wrong place. Compressor made pressure, after must be condesor coil with fan, next thin tube who divide system to high pressure side, and low pressure side. Next part vapor coil/heat exchanger. I have no idea, how system from video can work.

[@TheStigma]

@@valentinloginoff I think several parts that you find in a normal system has been skipped here to make the minimum configuration that works to show the principle. Like the expansion valve is also effectively the condenser here. I suspect the machine is intended as more of a proof of concept/principle than effective functionality - because it would definitely not be practical to cool air. In any case it is a very non-standard setup. I'm not a HVAC engineer, so I can't verify this works 100% - it just looks plausible based on what I do know.

[@valentinloginoff]

​@@TheStigmain frige we have simple AC system based on thin tube. But order of components always is same.

[@TheStigma]

@@valentinloginoff I think technically all you strictly need for a loop to function is the compressor, a space for the gas to expand, and somewhere to dump the excess heat. Everything else is kind of optional. But like I said, this is not my best area of expertise, so it is better to argue this with someone who builds these systems if you want certain answers. It is well over a decade since last I did some DIY with these types of systems.

[@hqdefault]

What if instead of that cylinder you use a CPU liquid cooling block?

[@bryanwarmuth6434]

so this system is simply using the presure change of a can of butane to cool its not a heat pump at all yhe small tube creates the preasure change but when the tank is empty its done

[@martinsaunders7925]

When an artistic plumber builds refrigeration.

[@Copimi]

0:00 - farm 2:12 - internet cafe 3:12 - back on the farm

[@davegeorge7094]

Leaks down in short time? Modified diaphragm water pump?

[@terischannel]

I think you would appreciate the AC I'm building for my garage.

Brother, you sand the inside also of pipes and flux the inside of the join to drawl the soldier into the join.

[@en2oh]

It’s typically called sweat soldering

[@gregorykusiak5424]

You caught my attention with that inlet valve from the refrigerant can…

[@EngDrewman]

Looks like a butane can for a camping stove, i.e. fuel grade R-600. That's fine for an experiment like this but not good for compressor longevity.

[@artemmm2]

What's the purpose of the bypass on the cone cylinder?

[@beng9310]

Is the weird U tube supposed to increase the low side volume? Why is it only set up to operate intermittently, where it could operate continuously if the capillary was relocated to the blue valve? Can that tiny compressor really handle that suction line resistance? You bent and soldered all those tubes and joints, but you gave up a the suction and discharge lines?

[@sgtbrown4273]

It's not necessary

[@motivationdoyouknow]

The video is awesome! Huge thanks for the links to the products - they were really helpful! I'm waiting for my paycheck to order the high-pressure tubes. They are five times more expensive in our local store, and I feel the quality is worse than what you showed.

[@MegaSPeter]

What pump are you using for this project?

[@tttuberc]

Any info on that tiny compressor?

[@tttuberc]

@@SteffenF thanks

[@eduardopal650]

É da hora,mas pra que serve?

[@Rafael-i1d1q]

This is amazing!! Please make more projects like this! By the way, can JLC send me a package to Switzerland? What gas did you use to fill it?

[@kajakfahrerr]

should be propane, but idk

[@codures]

Mind that working and safe operating are 2 different things. In Europe insurances are kinda picky when operating flammable gas, especially for indoor appliances. The cheapest AC sold compliant to our regulations was ~180€... If your house worth less than 130€, you may safely disregard this comment.

[@rochaaraujo9320]

Why that copper U pipe on evaporator?

[@richardchambers256]

Good question! Anybody?

[@yannkitson116]

Where do you get the compressor and what are the specifications?

[@kyriakoslykoudis9133]

prolly from a cheap car air compressor, they can pull alot of PSI.

[@longtoothevecruentusinvict6956]

I wonder if something like this could be adapted to PC water cooling. The motor would have to be quieted down somehow though...

[@Jasonliggett69]

I’m thinking ASIC cooling perhaps?

[@Matt-ht8mc]

similar concepts are used for servers and high end PC

[@АлексейГрачёв-й6р]

Принцип как у холодильника Камерлинг Оннеса, со столь же низким кпд. Только нафига там П-образный аппендикс?

[@breannestahlman5953]

Where to get the copper "bulb" that we first saw on the video?, does it have a special technical name?

[@davegeorge7094]

It's liquid filter found everywhere, look behind a minifridge.

[@JD_Mortal]

Not sure why the return is restricted and extended... You want that cold excess to return to the pump, to cool it down. If anything have it fork to the hot supply, before the valve, so it gets super cooled. If the valve was temperature controlled, you can stop it from freezing, reducing pump stress and get super efficiency output that matches demand. Freezing over actually means there is not enough coolant in the unit. That is why home units die. The temps get cold enough to create insulating frost and also freeze up the freon, clogging the lines and killing the compressor that can't compress liquids or frozen solids.

[@ZERE0N]

make a figure 8 ware coper rods are through plastic crosses and runs around through it

[@RubyHome-20]

very unique idea

[@MotivationStandUpAndGo]

good!!!!!!!!!

[@Mitrasto22]

link to buy product¿

[@ИгорьДенисов-ц8к]

Просто холодильник...по заставке подумал демонстрация эффекта Ранке.

[@davegeorge7094]

And the condenser does not come after the evaporator, what are you doing RUH?

[@ВладимирФомин-х4р]

А что за патрон он вначале использует?

[@tntomega]

how its work without expansion valve?

[@davegeorge7094]

It does not work because compressed gas needs to be condensed in a coil b4 that capillary coiled tube that act as TVX valve. You see my comments.

[@tntomega]

@@davegeorge7094 so..... its fake?

[@Diamond_Chocobo]

freaking cool. doesnt a heat pump work both ways though? once you reverse the flow the coils on top of the fan should star freezing up right?

[@guyonthecouch007]

Thought you were using crazy glue at first, lol.

[@AnandSaprasert]

Secret Refrigerant?

[@seabournewolf2298]

with slight modification you can add ac to a doll house

[@supermegajaime]

Did I miss the part where the piping is evacuated of air?

[@ПофигистЯ-с4ц]

Укажите пожалуйста тип компрессора используемого в устройстве и где он используется...?

[@popovvlabimir7719]

можете забыть, это фейк.

[@ПофигистЯ-с4ц]

@@popovvlabimir7719 Я Вам такой фейк за пол часа соберу и работать будет не хуже... Если у Вас руки из задницы растут или ума не хватает это не значит что на ютубе сплошные фейки...

[@ПофигистЯ-с4ц]

@@popovvlabimir7719 Не говорите что мне нужно делать и я не скажу куда Вам нужно пойти...

[@ПофигистЯ-с4ц]

@@popovvlabimir7719 Не говорите что мне нужно делать и я не скажу куда Вам нужно пойти...

[@Chevchev2]

¡Hola! Esperaba ver al final del vídeo cómo enfriabas una cerveza, jajaja. Si el serpentín grande no sirve para eso, perdona mi ignorancia, no le encuentro más utilidad al experimento que la científica, dado que el tubo que se congela no hace función de enfriar nada, al estilo de una nevera. A pesar de todo, muy interesante y muy bien montado. Gracias.

[@TheStigma]

EDIT: I'm inclined to believe this is a fake after seeing that this is apparently a popular thing to fake on youtube for some strange reason. Lots of videos on the same topic that are clearly using airpumps or other things that can't possibly work. Most of them are much more obvious than this, but they are all so similar in format I have to assume this is no different given the very unconventional setup. Nice build. is that a tiny compressor? Never seen that formfactor before. I think you will have problems long term with gas-permeation in all plastic parts and seals, and slowly lose refrigerant. Full-copper construction would solve this, but this is harder to make everything fit. Shouldn't there be a radiator or at least coil on the cold side if the purpose is air conditioning? Or is this just a demonstration of the basic principles? I think a good option to look for in a DIY heatpump is to make a water-chiller. That is the same basic setup, but a plate heat exchanger on the cold side instead of the usual radiator. The cold water can be lead outside via small holes in normal insulated plastic water piping to a big radiator (you can usually source cheap if you look around). Plate exchanger can also be scavenged often..Not as high efficiency as a direct gas-loop, but quite good - and way more flexible in placement, installation and future servicing when you don't have professional tools and parts.

[@TheStigma]

@@sw6188 It is possible to make do without a vacuum. You can purge the existing air with refrigerant, close, then pressurize - assuming you make valves necessary for a purge. This is a bit hacky solution, and if not done exactly right it will impact performance or even cause damage to the compressor over time. The U-bend in the expansion valve is probably there was a part of the adjustment mechanism, providing an alternate more restrictive route when almost closed. This adjustment is usually to tune the system to provide a good balance between more expansion (lower temp) and more flow (higher heat capacity). This looks like a non-standard and truncated system that only has the minimum parts required. Maybe more to show the principle than to be a practical machine. It looks at least plausible to me - but I'm not a HVAC specialist.

[@BangkokBubonaglia]

@@TheStigma Thank you for that. I was trying to figure out the purpose of that U pipe. Your explanation makes sense.

[@TheStigma]

I'm inclined to believe this is a fake after seeing that this is apparently a popular thing to fake on youtube for some strange reason. Lots of videos on the same topic that are clearly using airpumps or other things that can't possibly work. Most of them are much more obvious than this, but they are all so similar in format I have to assume this is no different given the very unconventional setup.

[@jjcooler65]

You should really vacuum up the moisture and air first it would run much more efficiently

[@douglasheld]

This is such a weird hodgepodge of connector sizes and incorrectly joined materials. Is it just an excuse to buy a bunch of components?

[@douglasheld]

Oh, I just realised if you turn on CC, there is text describing the design. Maybe I will watch it again as it doesn't make sense.

[@richardchambers256]

​@douglasheldyes there are captions. In this case it pays to be deaf. 😁

[@dannmann17]

Well, I just subscribed👍🏻🇺🇸

[@spaideman7043]

all viewer fully understood how it works after watching this video with no subtile nor explanation.

[@TomasJknOnYT]

Errrr, I think you connected it wrong way. Your condenser needs to be _after_ the compressor, not before. You have compressor->expansion valve(capiliary)->evaporator->"condenser", but you need compressor->condenser->expansion valve->evaporator. Currently your "condenser" - the thick copper coil on top of the fan is doing _nothing_ and your capiliary plays the role of both condenser and expansion valve...

[@Rafael-i1d1q]

I had doubts at first too, but after reviewing it closely, everything is correct. The system follows the proper sequence: compressor -> condenser -> expansion valve -> evaporator. The thick copper coil on the fan is the condenser, and it's working as it should by cooling and condensing the gas. The capillary tube acts as the expansion valve, lowering the pressure before the evaporator. So, everything is connected correctly!

[@TomasJknOnYT]

​@@Rafael-i1d1q Look at @10:16 capillary is between the compressor and the thick copper cylinder (which must be evaporator as it gets cold - judging by the frost on it). So we have compressor -> capillary (whatever role it plays) -> evaporator. So your statements above are _contradictory_. On one hand you say "The system follows the proper sequence: compressor -> condenser -> expansion valve -> evaporator" and then you say "The capillary tube acts as the expansion valve" implying that capillary is between _condenser_ and _evaporator_; which is directly refuted by the image @10:16, which shows capillary between _compressor_ and _evaporator_

[@Rafael-i1d1q]

@@TomasJknOnYT Let me clarify things in more detail to clear up any misunderstandings. At @10:16 in the video, it's true that the capillary tube is placed after the compressor and, as you correctly pointed out, is connected to the evaporator. However, I was initially referring to the standard operating sequence of such systems, not specifically the setup shown in the video. As for the specific system in the video, there’s a unique configuration that may not be immediately obvious. In this case, condensation could occur through a non-standard setup where the capillary tube manages the flow of refrigerant rather than serving as a traditional condenser in the usual sequence. So yes, this isn't a conventional setup, but the system is functioning properly in its own configuration. It might operate differently from standard examples, which is where the confusion arises.

[@TomasJknOnYT]

@@Rafael-i1d1q mene mene, tekel, upharsin

[@jalokin84]

Вот я тоже не понял последовательность, по видео видно что переделывал несколько раз, к примеру переходная муфта была перевернута при пайке а потом стала как надо, помпу переклеил за кадром чуть сместив её, а по сути трв спаял, но не верю я что помпа умеет в вакуум! Сколько помп в руках крутил и когда подающую трубку зажать то на выходе вообще нет давления, скорее всего потому что клапана резиновые, а должны быть жесткие как сталь, ну и поршень должен ваккум создавать, так что звиздежь это.

[@Skunkhunt_42]

Those push connects gonna leak - need square cuts

[@taurihaidma359]

inside is -5C* and inside is +30C* at the moment

[@SynthRockViking]

How does this magic work even?

[@3dbishkek]

действительно всё работает, я только что попробовал, без помощи науки, только на силе веры получилось запустить!

[@sanijoesoep4455]

i think the pump won't do the tricks. it will stop freezing as soon as liquid in the chamber empty.

[@EngDrewman]

This would have been a great video had you explained what you're doing, but the complete silence leaves a lot of unanswered questions. And, why didn't you evacuate the system before charging it? You're supposed to pull

[@IgnacioVelozo-d4h]

No tiene disipador de calor y nunca podría funcionar

[@kesemoi100]

不思議だな～

[@rollercam351]

Evaporation and compression, who’d of thought? 😂

[@bryanwarmuth6434]

sny time someone starts by saying it's not fake usually means it is

[@АндрейАрулепп]

Все наизнанку, главное работает.

[@Ertam06ank]

r600 gaz

[@Jan_Seidel]

Pro tip: First heat the metal to glowing hot so the tin melts when touching the copper

[@francantoin2269]

Pito tubing is normally used to throttle the the refrigerant entering to evaporation chamber, it's a kind of valve but without freezing problems, so why are you using a valve at the other side? No sense Second thing, why use the U shaped copper tube on the evaporating chamber? Perhaps to increase the evaporation chamber surface! Otherwise it's a useless complication.

[@Skunkhunt_42]

Ok, so this is the china tiktok AC. Air pump (compressor) and butane.

[@JunkTech89]

I work in the refrigeration industry this is so stupid 😂😂😂😂😅

[@lotarzi1]

wollte sie herstellen und verkaufen,ist aber schon patentiert.

[@davegeorge7094]

Someone used a vicegrip on the threads, whoops...

[@cetinsogutlu1680]

Amaç ne

[@rebekahfrench5747]

Bit of finesse in the soldering department and a purge of the system to displace the oxygen in said system would go a long way.. all that effort and then cheaped out by going plastic.. for the effort why not all copper and dribbly solder joints..😂😂😂

[@jjtrades7186]

Are you working inside of a chicken coop

[@Rashadrus]

Трубка Ранке(Ranque-Hilsch Effect) - более эффективна и делается дешевле, проще и быстрее.

[@odissey2]

И ещё 5 атмосфер надо откуда-то взять!

[@Rashadrus]

@@odissey2 Это несложно, даже автомобильный компрессор при правильном использовании даст и 5, и 7 атмосфер.

[@odissey2]

@@Rashadrus у меня был такой охладитель (для сварщиков). Поигрался и продал.

[@Rashadrus]

@@odissey2 напрасно... хорошая штука!

[@aarongriego2959]

So he just made an refrigeration system. Ok. The fact he soldered it says he's a honeowner. Does anyone know why professionals braze? Anyone?

[@yannkitson116]

I do on installations where price is a concern, pressfittings can be very expensive if you need a lot of them.

[@jamestyrer907]

That's not the way to solder copper pipe.

[@bryanwarmuth6434]

well seems plausible the only suspect part is these systems are filled under a vacume and i didn't se that which is questionable

[@ОлегИжевск]

не правильный холодильник. компрессор должен быть соединён на входе с испарителем и на выходе с конденсатором. Также и капиллярная трубка- на входе с конденсаторов а на выходе с испарителем. На видео капиллярная трубка соединена с компрессором а исаритель с конденсатором друг за другом. Из блогеров плохие мастера по охлаждающему оборудованию

[@Eldeboradordehamburgesas]

Es interesante la bomba solo mueve líquido no gas, ese de los encendedores trabaja a baja presión por ende usas bomba de líquidos y usas como expasor el tubo aunque el otro sobra un montón 🤣🤣🤣🤣🤣 aun la gente cree que estos vídeos son falsos pero la realidad es que son reales cuando estudias la refrigeración esto solo es un juguete

[@Billydsm100]

se nota que ni te molestaste siquiera en leer algo sobre refrigeración básica. El proceso termodinámico de la extracción de calor por medio de un equipo de refrigeración empieza con la "COMPRESION DE GAS" refrigerante. No te voy a dar el curso, busca información que hay mucha y despues opina.

[@wilsonzhong3315]

噪音巨大

[@Raven76ful]

And is still no use for it, put this into the gaming laptop to cool down the CPU and GPU then I will follow you and copy your invention. In this case is just useless something.

[@Retiredkiwi]

LOL, worst copper assembly job i've ever seen (as a now retired fridgey), those cuts would likely reduce flow by 50% with the huge burrs left on everyone of them, even the capillary tube almost completely blocked, 🤣 using Plastic in extreme cold? 🤪 Glad i just speed looked at a few spots in it, rather than waste any time watching it. But ok, it did make me laugh, if that was the intention.🤔

[@rebekahfrench5747]

Hilarious botch job from start to end.. we call him tail light.. Not bright enough to be a head light..😂😂

[@kk2ak14]

😂

[@Tenko-Kuugen]

わざわざ焼きなまし銅管使ってるんだから、最初からそれだけでコの字配管作れば?

[@vosmoi55vosmoi60]

Р

[@rhumb]

Bonjour, merci pour ce tutoriel très intéressant à réaliser ; pouvez-vous nous donner un lien vers l'achat du high-pressure compresseur… ? Il est difficile à trouver ce type de modèle… Merci à vous…

[@Youcanmarket]

Isn't This Maxwell's Demon?????????