How does an Automotive A/C System work: Part 1 Capillary TXV System

[@Ray-n5z7q]

Wow! I am a retired master tech/ shop owner and this is one of the best training videos I've ever seen. The animation added to the video content is amazing. Thanks for taking the time to publish such an amazing educational video. I've been doing this for 21 years and wish i had something like this when i started in automotive AC systems.

[@joakimahillyard6886]

Thank you so much for these videos. They cover everything that no one else has been able to organize and explain in a suitable manner. Keep teaching your great.

[@francisdsa6790]

Professor thankful for your efforts to teaching the easiest way to learn the a c system appreciate 👌👍🙏💐💐💐💐💐

[@thisoldjeepcj5]

Very good explanation. Thanks for publishing this.

[@junnelcaballero6515]

you are an angel. thank u for sharing your knowledge

[@LumosMx]

Wow, very well done! Thank you

[@jesseruiz2337]

These videos are very helpful, thanks for sharing.

[@sepabz5342]

Awesome video thanks for making it

[@d46512]

Does the capillary tube read temperature or pressure? At time 17:45 you said psi. The relationship between temperature and pressure would depend on the charge level and other factors?

[@ProfessorPentane]

You are correct, the capillary tube senses temperature that changes the pressure in the tube causing the TXV to move. Sometimes I get so into my presentation-, my speaking is getting ahead of the thinking. Sorry for any confusion. PP

[@d46512]

@@ProfessorPentane it’s all making sense after watching your AC theory videos. I forgot that saturation temperature is close to pressure with automotive refrigerants. Thanks so much Prof Norman.

[@jasoncatledge1857]

Where can I get this file or program, this would make teaching my students so much easier in addition to me drawing on the board and the consolabs we have. Great stuff!

[@ProfessorPentane]

Hi Jason, Sorry but I can not share this file. I have used this video by playing it while turning the sound off during a mobile class in which I had a computer failure. It worked fairly good and I was able to stop and start the video as needed. I also made this video so I would have this animation forever. I had some great animations on flash and lost all of them when flash no longer worked. Good luck, PP

[@jasoncatledge1857]

@@ProfessorPentane no worries, I’m a new instructor coming from the dealership after 20 years or so. Teaching yourself is one thing but teaching young minds is totally different and foreign. Thanks anyways

[@sivucit]

In residential system we use thermocouple on both suction and discharge line and measure the values to derive eventually super heat. Is there a reason why that method is not used.

[@endurofan9854]

strength and volume maybe, residencial AC are always 4x or more bigher than what the car have

[@greazeman6279]

Good day sir what would be a problem if the senario is 50-60 psi suction side and the discharge line is normal 175 -200psi at the first start of the compressor the temp is ok(40-45 psi suction)then after few minutes the engine is running the suction side will read 50-60 psi still the discharge is normal.thank you hope you can answer my query.

[@endurofan9854]

perhaps the idle is too low and the condenser is too hot, on idle it should'nt reach 200, it should reach that if reved up. to 2k rpm or more

[@abolajibayo4358]

Gracias

[@7soulcraft7]

Sir you seem to be confused. Capillary tube metering and TXV are not the same. Not even close. Cap tubes and fixed orifice devices are just that, delta P, fixed capacity. TXV is a constant modulation, metering device. The sensing bulb in mechanical contact with the suction line has a small charge of the same refrigerant which expands/contracts with temperature ( heat). This action moves, in the power head, a bellows/needle valve orifice to modulate/meter wet vapor refrigerant into the evaporator coil in accordance with the suction gas temperature. From compressor disharge ( high side), hot gas eneters the condensing coil and emerges as a subcooled liquid, hence condenses the refrigerant by means of heat transfer/removal. The subcooled liquid is routed to the metering device ( TXV, orifice tube, etc). Accumulator/dryer/strainers are judiciously placed in the circuit to: remove moisture, strain/capture particulates, prevent liquid slugging the compressor. Orifices being cap tube, TXV, orifice tube shall always be fitted with and inlet strainer. Evaporatopr absorbes heat energy, condenser rejects heat energy. Change of state occurs as such: Condenser - hot gas to subcooled liquid. Evaporator - wet saturated vapor boils completely to superheated gas. Refrigerant is the heat transfer fluid A. The air stream is the heat transfer fluid B1 and B2. B1 is the cabin air blower forced over the evaporatpor coil fin tube surface exchanging sensible and latent heat (moisture,humidity). B2 is the outdoor air passing over/thru the condenser coil fin tube surface. Refrigerant is oil soluble & moves throughout the entire circuit. This is the vapor cycle in a nutshell.