Might be a fun topic to talk about: heat mode. There are just a crazy amount of techs that dont understand heat mode properly and how important gas temperature is and how important insulation of the hot line is and how distance can severely affect efficiency due to the temperature drop/loss over longer runs like above 30ish ft.
Great talk and excellent contribution on HVAC. Thank you. I would like to take this opportunity to ask about a doubt regarding the pressure in the condenser. How is the saturation pressure adjusted to the outside temperature? Is it automatic?
Could u please discuss it again using PV, TS & pressure enthalpy diagrams placed in 3 different columns and psychrometric charts And actually show how u used them to predicted compressor failure or some other impending failures or incidents. Also, when u mention variables like enthalpy, entropy, pressure, temperature, density please always mention if it is for ambience or the refrigerant. Thank u
Ashworth college pressure empathy charts were the first things we had to learn.1 year later me not no shite about p.e charts lol.The square represents the metering device,the compressor,the evaporator and the condenser.
Professor! Why is there dome shape in PH or PE chart why not any other shape? What does this signifies and where from the construction of this starts and where it ends?
When a turbo -expander is used in place of a expansion valve, it's then closer to a right trapezoid. The adiabatic expansion is closer to isentropic expansion.
Line ( dome line) represents saturated liquid or saturated vapor? and everything within the dome is also saturated liquid or saturated vapor? And Left & right of the dome is sub cooled liquid and super heated vapor respectively? Please verify? Thank u
People say you must make sure the refrigerant is fully vapor before entering the compressor or else it will damage the compressor. But I cannot find any video about how to determine the state of the refrigerant. 😢
It would be interesting to see a sensitivity analysis of values that would result in resolution power of this system method. If modeling changes are possible then different compression technologies could potentially evaluated for performance.
I know this is a little off topic however, if you have a heat pump condenser with an orfice and an evaporator with a TXV will the system work at all, or bad idea? thank you for your response.
You are referring to a heat pump system. Correct? Yes it can work. He is referring to having a fixed orifice metering for heating mode and txv for cooling. * By the way. In heat pumps the coils are referred to as indoor and outdoor. Because, they change(condenser/evaporator) from indoor to outdoor depending on which mode(heating or cooling) the equipment is operating in.
Are you telling me you've never come across residential equipment designed this way? It is somewhat a common design depending on what part of the country the system is designed to operate in
Question: Eugene mentioned that you could actually take enough measurements only at the compressor/condenser unit and that would be sufficient to do the analysis. However, he says that you need to know the evaporator outlet temperature. To me, and to be accurate, it would seem that you would have to actually go to the actual evaporator and measure its outlet temperature right there? So I don’t understand how you can do all of this at the compressor/condenser unit outside.
@@UA-camCommunists So, even if the line traverses an area whereby it could pick up heat, due the whole suction-side being at a uniform pressure, you can then say (based on the refrigerant-type) that the evaporator must be the PT temperature? Thanks Jason for your reply! 😃
Just think......Willis Carrier understood all this 100 years ago. I don't claim to fully understand psychometrics, general understanding...yes.....on these guys level....no way. Stuff still baffles me.
The compression process in the refrigeration cycle is NOT reversible. (Not isentropic.) The isentropic efficiency of residential compressors runs between 70 to 80%. To have a reversible isentropic process would violate the 2nd Law. You find out the isentropic compression efficiency from the manufacturer. Then you plot your compression line leaning towards the right to a higher temperature than where the isentropic line intersects. But it is all good stuff for the tech to pick up. 😀 Following the isentropic line doesn't hurt anything - just makes that frenchy Sadi Carnot choke in his grave.
hi pressure enthalpy chart is proof that 150psi is far better for evaporator performance than 220psi [when I talk psi I mean temperature ] in the R134a automotive . A second condenser is often needed . The lower the psi the lower the temp but also the higher the % of liquid by 10--20% if u read the chart correct .[ flash gas ] Real world is I can get R134a at 150--160psi , Any engine Rpm on a 110---120f day . Vent temp 42-47 f [thermostat setting ] and low temp operates cycles 22--35 psi . Sight glass installed 100% full. I regularly achieve this with mobile plant / machinery being all other parts are working properly ie cabin insulation , tinted glass correct evap size .
He may be a good author, but he is not a dynamic speaker. Falling sleep is easy with this speaker. Pod casts may not be his best method. Maybe straight lecture at a whiteboard is more helpful , where he can organize his thoughts better . Podcasts inherently allow one jump around a lot easier to jump off the Rails ! Good luck.
Best in the business.
Best HVAC professor ever. Prof. Silberstein made theory very easy and made class enjoyable. I was lucky to spend 2 1/2 years with him.
5 minutes in and I already know this is going to be good content and Eugene sold another book.
Might be a fun topic to talk about: heat mode. There are just a crazy amount of techs that dont understand heat mode properly and how important gas temperature is and how important insulation of the hot line is and how distance can severely affect efficiency due to the temperature drop/loss over longer runs like above 30ish ft.
I agree! Cause I’m one of them!
Great talk and excellent contribution on HVAC. Thank you. I would like to take this opportunity to ask about a doubt regarding the pressure in the condenser. How is the saturation pressure adjusted to the outside temperature? Is it automatic?
I ordered the book....Can't wait to get it...You should create a field app.
Great video Bryan, Thank you for bringing all this out to the trade. Thanks again.
thank you.
I ordered the book today on Amazon.
Could u please discuss it again using PV, TS & pressure enthalpy diagrams placed in 3 different columns and psychrometric charts
And actually show how u used them to predicted compressor failure or some other impending failures or incidents.
Also, when u mention variables like enthalpy, entropy, pressure, temperature, density please always mention if it is for ambience or the refrigerant.
Thank u
Ashworth college pressure empathy charts were the first things we had to learn.1 year later me not no shite about p.e charts lol.The square represents the metering device,the compressor,the evaporator and the condenser.
Best professor ever!!! #SCC. You are the man Gene!
Pretty sure we where in the same classes 2011-2012ish
Professor!
Why is there dome shape in PH or PE chart why not any other shape?
What does this signifies and where from the construction of this starts and where it ends?
When a turbo
-expander is used in place of a expansion valve, it's then closer to a right trapezoid. The adiabatic expansion is closer to isentropic expansion.
Kids solve those Rubic cubes without even looking at the cube.
As stated "Entropy is reversibility in case of Reciprocating compressor" what in case of other compressors?
Nice sir, regards from india
Line ( dome line) represents saturated liquid or saturated vapor?
and
everything within the dome is also saturated liquid or saturated vapor?
And
Left & right of the dome is sub cooled liquid and super heated vapor respectively?
Please verify?
Thank u
People say you must make sure the refrigerant is fully vapor before entering the compressor or else it will damage the compressor. But I cannot find any video about how to determine the state of the refrigerant. 😢
Yeah PE charts are cool and all but this guy is rocking Cornrows… and that’s really cool
This is fascinating
It would be interesting to see a sensitivity analysis of values that would result in resolution power of this system method. If modeling changes are possible then different compression technologies could potentially evaluated for performance.
Is this excel spreadsheet available?
I know this is a little off topic however, if you have a heat pump condenser with an orfice and an evaporator with a TXV will the system work at all, or bad idea? thank you for your response.
What did you just say
that setup does not make sense.
You are referring to a heat pump system. Correct? Yes it can work.
He is referring to having a fixed orifice metering for heating mode and txv for cooling.
* By the way. In heat pumps the coils are referred to as indoor and outdoor. Because, they change(condenser/evaporator) from indoor to outdoor depending on which mode(heating or cooling) the equipment is operating in.
@@billmabrey3828 a orifice would be extremely bad for efficiency and severly limits its operational range.
Are you telling me you've never come across residential equipment designed this way? It is somewhat a common design depending on what part of the country the system is designed to operate in
Question: Eugene mentioned that you could actually take enough measurements only at the compressor/condenser unit and that would be sufficient to do the analysis. However, he says that you need to know the evaporator outlet temperature. To me, and to be accurate, it would seem that you would have to actually go to the actual evaporator and measure its outlet temperature right there?
So I don’t understand how you can do all of this at the compressor/condenser unit outside.
Well the low side suction goes outside to the compressor ,there's your evap measurements.
@@UA-camCommunists So, even if the line traverses an area whereby it could pick up heat, due the whole suction-side being at a uniform pressure, you can then say (based on the refrigerant-type) that the evaporator must be the PT temperature?
Thanks Jason for your reply! 😃
@@SpinStar1956 I will defer your question to someone more advanced than me,good luck!
@@SpinStar1956 measuring the suction outside would be ok imo. You’d be getting true suction superheat (inc line set heat gains)
What is the difference between thermal efficiency and coefficient of performance?
Just think......Willis Carrier understood all this 100 years ago. I don't claim to fully understand psychometrics, general understanding...yes.....on these guys level....no way. Stuff still baffles me.
he understood the principle, not the intracacies.
Can you talk about oil trap?
I have An early copy of PEWOT in blue binding from SCCC Brentwood, 2008
The compression process in the refrigeration cycle is NOT reversible. (Not isentropic.) The isentropic efficiency of residential compressors runs between 70 to 80%. To have a reversible isentropic process would violate the 2nd Law. You find out the isentropic compression efficiency from the manufacturer. Then you plot your compression line leaning towards the right to a higher temperature than where the isentropic line intersects. But it is all good stuff for the tech to pick up. 😀 Following the isentropic line doesn't hurt anything - just makes that frenchy Sadi Carnot choke in his grave.
hi pressure enthalpy chart is proof that 150psi is far better for evaporator performance than 220psi [when I talk psi I mean temperature ] in the R134a automotive . A second condenser is often needed . The lower the psi the lower the temp but also the higher the % of liquid by 10--20% if u read the chart correct .[ flash gas ] Real world is I can get R134a at 150--160psi , Any engine Rpm on a 110---120f day . Vent temp 42-47 f [thermostat setting ] and low temp operates cycles 22--35 psi . Sight glass installed 100% full.
I regularly achieve this with mobile plant / machinery being all other parts are working properly ie cabin insulation , tinted glass correct evap size .
Holy smokes.
I understand this guy is very smart but I'm having a hard time taking him seriously with the corn rows.
He may be a good author, but he is not a dynamic speaker. Falling sleep is easy with this speaker. Pod casts may not be his best method. Maybe straight lecture at a whiteboard is more helpful , where he can organize his thoughts better . Podcasts inherently allow one jump around a lot easier to jump off the Rails !
Good luck.