Glide, Dew Point, Bubble Point, PT Charts and the Refrigerant Slider App
In this video, we talk about PT charts, saturation, superheat, subcool, glide, dew point, and bubble point and using the Danfoss Refrigerant Slider app. Since this video has been uploaded, the app name has been changed to the Ref Tools app.
The pressure and temperature of a refrigerant are linked at saturation, and we would typically use PT charts to see what the temperature of a refrigerant should be at a given saturation pressure or vice versa. The older refrigerants had a straightforward pressure-temperature relationship, but nowadays, we have a lot of refrigerant blends that complicate the pressure-temperature relationship by introducing glide. When we use refrigerants with glide, we must also use either the dew or bubble point to help us figure out the pressure for a given saturation temperature or vice versa.
The Danfoss Refrigerant Slider/Ref Tools app is a useful tool that replaces your standard PT chart, and it allows you to figure out the corresponding temperatures and pressures on refrigerants with glide. The Refrigerant Slider contains data for most modern refrigerants, even naturals like CO2 and hydrocarbons like R-290. Not to mention, the Refrigerant Slider spares you the trouble of keeping a bunch of PT charts on hand.
Refrigerant that is in the process of boiling or condensing is at saturation; it is a liquid-vapor mixture. When the temperature exceeds the saturation temperature when the refrigerant is boiling, the difference is what we call superheat. Superheated vapor is 100% vapor. On the other hand, when the temperature dips below the saturation temperature when the refrigerant is condensing, that's subcooling. Subcooled liquid is 100% liquid.
The Refrigerant Slider within Ref Tools is available on iPhone and Android smartphones, and you can find it by simply looking up "Danfoss" in the App Store or Google Play Store. Ref Tools should be one of the top apps displayed. Alternatively, you can find the Ref Tools app on your browser of choice by going to danfoss.com/coolapps.
Within the app, you can save refrigerants as favorites so that you can access them quickly without scrolling through several refrigerant options. You can also move the slider with your thumb to select a target saturation pressure and temperature (or you may type those values into the PSI and temperature fields to the right of the slider; if you type in one value, the other will automatically adjust). The Ref Tools app also shows you additional data about each refrigerant, including GWP, ODP, critical temperature, the boiling temperature at atmospheric pressure, tank color, and more information.
You can also use the app to see the pressure-temperature relationship based on dew point or bubble point. When we use PT charts on refrigerants with glide, we must understand exactly what dew point and bubble point are. The dew point marks the first change from vapor to liquid, and the bubble point marks the first change from a liquid to vapor. In the case of a refrigerant like R-407C, the difference between dew and bubble point is significant. If you're using subcooling, you're going to use the bubble point to determine the P-T relationship. If you're using superheat, you'd use dew point. (Remember: bubcooling and dewperheat.)
But the absolute best part of the app is that it's free!
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Пікірлер: 36
NICE JOB ,BRYAN.I LIKE YOUR CLASSES, KEEP UP THE GOOD WORK.
If anybody has a hard time rembering whether to use bubble or Dew on Danfoss slider p/t chart. Just Think “ bubbles “ in a sight glass in a liquid line = Subcooling = When trying to figure out Head Pressure. Good vid !
I'm Korean and your KZread is always the best for me. thank you always thank you
I listen to the Podcast all day, really enjoy what you have created. I needed this.. thanks.
I like your training classes. Good Job
Very relevant lesson, Bryan. Really enjoy your content and I tell as many as I can about HVAC School.
Thank you for sharing your knowledge
Thank you for your teaching
Great info. Thank you Bryan.
Thank you teacher,so easy,so fast,now i know about.
Good stuff as always.
Great video thank you
is there a good explanation why you use bubble point for subcooling when it refers to when the freon changes state to a vapor but the condensor superheat is when it's changing to a liquid? It seems backwards.
@ros879
3 жыл бұрын
I had the same question.
No doubt you are a great teacher but you have to slow down to be the perfect teacher. Thanks
@MR-lg2tr
3 жыл бұрын
You just need to stop being so slow in the head bud. Go back and rewatch if you can't understand it. Not all of us have slow brains like yourself . Grow up
I use to listen to music out back after work , now I listen to HVAC SCHOOL after work
@HVACS
6 жыл бұрын
That is high praise Terry. Thank You.
Bryan, the main thing we struggle with is getting techs to understand when to use the average of the bubble and dew. Can you expand on this video and cover when to use the average?
@MR-nl8xr
6 жыл бұрын
Dallas Fan.👍
Varry nice app essay to use am retired but love it.
Thanks.
If I hooked up my gauges to see if the charge is good, would I refer to the Bubble point temp? I am not calculating superheat, just checking pressures/temps. From my understanding, the bubble point temperature is the point where the refrigerant starts to boil. So if I read 40F Bubble point temp, I know the A/C is working fine (with normal ambient temps of course).
Wow nice.
I deal with r 448 a lot now days. If I want to achieve 25 degrees evaporator, should I go by bubble, or dew ?
Cuando estoy calculando sobrecalentamiento en el evaporador , en que opción debe estar el botón?
What is usually the saturated temp for a 2.5 ton r407c system ambient temp is at 93
The pressure reading is for the high side I'm assuming
3 things happen within the evaporator. Bubble point 1- liquid refrigerant starts to boil at this pressure and temperature Mid point 2- half of the liquid refrigerant has boiled away to a gas. Dew point 3- the last of the liquid refrigerant has boiled away With a higher glide refrigerant say 10°f You could start at a boiling temperature of 18°f and end at dew point temperature of 28°f
@sv6k0a39
9 ай бұрын
Does that mean within the condenser coil, the "Bubble Point" is the point where the last particle of vapor has condensed into a liquid?
@vincentpribish9276
9 ай бұрын
@@sv6k0a39 Correct Any temperature drop after that is called subcooling.
Posted 3 yrs ago! Where've I been???
Wouldn't dew be used in subcool since that's when the refrigerant would be condensing into a liquid
Dont install app PSI to degrees F temps relations are wrong on the app
Wow. That background beat is incredibly distracting and out of place.
Except for the fact you have to agree with all the bullsht permissions!!!!! ITS just RIDICULOUS you have to give access to almost everything in your phone including contact info & lose all privacy to use the apps!!! NO THX!!!