how to observe refrigerant in household refrigerator

[newbieeng]

Hi everyone,
I want to investigate refrigerant flow in a household refrigerator and learn its quality in evaporator and condensers. But it seems to me too difficult and I do not know any method for it. Is there someone could help me on this hardship? And is there any kind of paper or engineer, scientist, etc. you know about working on this kind of study? Is there any equipment that make able to measure of quality of the refrigerant?

[Vampyreguy]

http://www.dynatempintl.com/pdf/ARI7002006.pdf

[cascader]

Think"Mass spectrometer"

[newbieeng]

Think"Mass spectrometer"

thank you cascader,

but mass spectrometer works on samples of elements. All I need is to observe the refrigerant simultaneously while the refrigerator works. Thanks again.

[stonewallred]

Get exposed to radioactive material and develop super powers I guess.
You could theoretically make glass tubes that could stand the pressures, but the heat transfer would not be very good.

[newbieeng]

Get exposed to radioactive material and develop super powers I guess.
You could theoretically make glass tubes that could stand the pressures, but the heat transfer would not be very good.

Glass tubes make me just able to see refrigerant inside the tube. It is not possible to calculate its quality inside it by using glass tubes. My aim is to calculate its quality while the cycle on. I have never thought about radioactive materials to inside it and I have not any idea about them. Could you inform about it to me? How can I observe these radioactive materials inside allumina or copper tubes and in which way can I determine amounts of liquid and vapor? Do you have any idea? And thank you very much for your interest also your help.

[mspanky]

Is there any equipment that make able to measure of quality of the refrigerant?

Quality as in chemically or physical state? Find a pressure/temperature chart and make the necessary measurements.

[Eeyess]

I would say with temp press chart and monitor superheat n subcool. Also take temps at every predetermined length.

[Fabrk8r]

newbieeng, define "quality" as you used it in your original post.

I am getting the impression that what you are asking is "how do i know what state the refrigerant is in (such as gas or liquid) in each component of the unit I am working on?"

Am I correct? If that is what you want to know, then you don't have to physically see the refrigerant to know it's state. As was said by mspanky, a temperature/pressure chart will tell you whether the refrigerant is in a gaseous or liquid state by using the correct refrigeration gauges.

If you are concerned with the actual quality of the refrigerant, then you would have to take a sample and have it analyzed. Seeing the refrigerant won't tell you if it's contaminated, although sometimes you can tell by the odor if there has been a problem within the system.

[newbieeng]

newbieeng, define "quality" as you used it in your original post.

I am getting the impression that what you are asking is "how do i know what state the refrigerant is in (such as gas or liquid) in each component of the unit I am working on?"

Am I correct? If that is what you want to know, then you don't have to physically see the refrigerant to know it's state. As was said by mspanky, a temperature/pressure chart will tell you whether the refrigerant is in a gaseous or liquid state by using the correct refrigeration gauges.

If you are concerned with the actual quality of the refrigerant, then you would have to take a sample and have it analyzed. Seeing the refrigerant won't tell you if it's contaminated, although sometimes you can tell by the odor if there has been a problem within the system.

Thanks for your interest Fabrk8r. That I wanted to mean with "Quality" is that mass of liquid phase of refrigerant divided by the total mass of it (mixture). I am not interested in the refrigerant's state, I want its real properties, qualitatively. You are right about charts, with the data provided by tranducers we can obtain its phase, quality, in shortly its thermophysical properties but in reality, it does not fit the actual one. In the system there are a lot of losses. Flow characterization during the system on seems impossible using that kind of implementations (using transducers of temperature & pressure). My aim is to explain its characterisation simultaneously, without cut-off the system. Some methods for measurement of mass does not fit in that way. Thanks.

[Fabrk8r]

with the data provided by tranducers we can obtain its phase, quality, in shortly its thermophysical properties but in reality, it does not fit the actual one. That right there is Greek to me (I don't understand)

In the system there are a lot of losses. I can agree with this statement.

Flow characterization during the system on seems impossible using that kind of implementations (using transducers of temperature & pressure). My aim is to explain its characterisation simultaneously, without cut-off the system. Some methods for measurement of mass does not fit in that way.
More Greek. Thanks.

I'm sorry, but I don't think I can be of any assistance in this matter.

[jpsmith1cm]

I might be able to hang with you here....

Problem is, I don't think you are going to like my answers.

Determining the mass of liquid refrigerant in the system at any one given time during operation is going to be tricky because it will change as operating conditions change.

I supposed that, if you can measure the ID of the tubing, the length of the tubing, then calculate the density of the refrigerant contained in it, you could come close, but you still have a varying amount contained in the condenser and evaporator as well as variable temperatures.

I don't know of any way to account for these variables, but then again, I'm not the engineer.

[Russ57]

I'm with JP. Weight and density along with temperatures and pressures can provide answers. However in any real system things will be changing all the time. Something like a chiller would be closer to steady state. Thermodynamics, basically being four dimensional, is never easy.

Maybe if we knew what the goals were it would help. Are you an engineer, inventor, student, or scientist?

[nightranger121]

[newbieeng]

I'm with JP. Weight and density along with temperatures and pressures can provide answers. However in any real system things will be changing all the time. Something like a chiller would be closer to steady state. Thermodynamics, basically being four dimensional, is never easy.

Maybe if we knew what the goals were it would help. Are you an engineer, inventor, student, or scientist?

I am a mechanical engineer. I have expressed my aim numerous time under this topic. You can learn it from the 1st thread.

[Paul Bee]

"Troubleshooting and servicing modern air conditioning and refrigeration systems" by John Tomczyk. Mr Tomczyk has a degree in mechanical engineering and his books reflect that. www.powells.com/technicalbooks might be a good place to start.

[newbieeng]

"Troubleshooting and servicing modern air conditioning and refrigeration systems" by John Tomczyk. Mr Tomczyk has a degree in mechanical engineering and his books reflect that. www.powells.com/technicalbooks might be a good place to start.

Thank you

[icemeister]

I understand the concept of "quality" with respect to two-phase refrigerant flow, but what puzzles me here is "why" one would have a need to physically measure this value in an operating system?

Normally, we measure the refrigerant state at the beginning and at the end of the evaporator or the condenser. Those points can easily be measured with pressures and temperatures. The varying quality of the refrigerant in between those points becomes much more problematic to get a reading for, since quality doesn't follow the P/T rules directly.

Perhaps if you divulge the reason one might need to physically take snapshots of a refrigerant's active phase change, we may get a better idea of how we may help.

Are you looking to further cost-reduce a system's heat exchangers...or something to that effect?

[newbieeng]

I understand the concept of "quality" with respect to two-phase refrigerant flow, but what puzzles me here is "why" one would have a need to physically measure this value in an operating system?

Normally, we measure the refrigerant state at the beginning and at the end of the evaporator or the condenser. Those points can easily be measured with pressures and temperatures. The varying quality of the refrigerant in between those points becomes much more problematic to get a reading for, since quality doesn't follow the P/T rules directly.

Perhaps if you divulge the reason one might need to physically take snapshots of a refrigerant's active phase change, we may get a better idea of how we may help.

Are you looking to further cost-reduce a system's heat exchangers...or something to that effect?

My aim is to light the refrigeration system clearly. Up to now design of refrigerators are being made up of by trial and error. My main aim is to change this and obtain a scientific method to design them rather than trial and error. First target is to characterize the flow in the system and in the light of this characterization to design evaporator and condenser respectively.

[stonewallred]

The phase change in the condenser and evaporator is never the same, unless every aspect of it is the same, including the ambient temp crossing the coils, the swirls picked up by the liquid refrigerant as it goes through the tubing, the humidity of the air crossing the coils and even the amount of surface oxidation present on the coils. Any variation will alter the composition of the refrigerant.

I think you are failing to grasp that the condenser and evaporator are the results of years of research and design, not trial and error as you claim. That is why "x" coil must be matched to "y" OD unit, and why each matching is engineered to provide "z" cooling and heating at stated design conditions. Research and design, not some group of engineers trying different matches.