Franglais:
We’ve had hydrogen fusion, warm gases flowing through both coils, fridges put inside freezers, and now we have dry-ice inside a trailer!
This thread is wonderful!
And you are very much mistaken if you think any different. I may not have explained it all in the terms that you understand. Dry ice fog is the white like smoke that you see (in your terms). Hydrogen bonding is what happens at +4 degrees. A difficult subject matter if you are not a fridge man. It is Hot gas not warm gas that flows through the evap coils on defrost and is also known as a hot gas defrost cycle. It uses the discharge pressure from the compressor and super heats the refrigerant into a super heated vapour that we call hot gas. Fridges put inside of freezers?? Sorry you have lost me there.
A reefer is actually a heat pump as it can heat as well as cool between a range of temperatures. It uses a reversing valve to do this, That’s how you reverse which coils you want to defrost utilising the hot gas. Anything else I can help you with understanding just ask away, I can tell that you view this all as codswallop, however you do not have to get too concerned over the technical issues as you do not need to know about such things. Just set the temp and drive, I think why drivers are no longer trained in reefer operation like they used to be is that of the attitude of drivers nowadays both for the job and possible lack of understanding in the first place. It is a shame really as we did at one time have some really good fridge drivers. Ask anyone who drives a fridge if they see dry ice coming out the back doors when they open them. That is what causes your icing up problem in the reefer. I have tried to explain all of this in very simplicit terms in order to help those that would like a deeper understanding of the reefer other than just set the temp and go. I hope the majority who have read my posts have understood better and lets be honest here, you don’t get taught this stuff anymore so people like me giving out this info is probably as close as you will ever get to any official training. It is all good advice, take it or leave it.
the maoster:
Thank you for taking the time and the patience to answer UKT. I’m gonna bow out now before the inevitable bitchfight. Yeah I know I’m usually involved somewhere along the line but I’m not in the mood for it today.
You are welcome Maoster, you know if I can help out then I will. I expect the ■■■■■ fighting with virtually every post I write, I do like it most of the time but I do put my fridge advice as factual and act in a professional manner as I really would hate to be responsible for anyone to follow bad advice and get temperature issues through me. However I wouldn’t listen to me on any other driving topic as I would find it amusing if I sent someone 50 miles out of their way.
Franglais:
We’ve had hydrogen fusion, warm gases flowing through both coils, fridges put inside freezers, and now we have dry-ice inside a trailer!
This thread is wonderful!
Franglais:
We’ve had hydrogen fusion, warm gases flowing through both coils, fridges put inside freezers, and now we have dry-ice inside a trailer!
This thread is wonderful!
If I use the term dry ice, it is to make easier to visualise what I am saying, everyone knows that dry ice is a white frost fog. Only difference of the composition of dry ice is that dry ice is made up of frozen C02 and what you see coming out of the reefer is actually frozen water droplets which is more like steam than water droplets. That explanation might clear this up for you hopefully. Fridge men commonly use the term dry ice because that is a better term to use to explain the steam, people will always associate steam with hot water vapour rather than being cold and it takes some explaining. Does this make my explanation of dry ice easier to understand? Hope so as I am seriously trying to get a point across rather than to confuse anyone.
AndieHyde:
Around here we obey the laws of thermodynamics.
Andy I have tried my best to explain all of this in the simplest of terms so that it is easier to understand. If there is anything that you want clarifying with anything that I have put across, I honestly mean this, ask me. Whether you believe it or not is absolutely your own decision to make. What would be the point in explaining everything to you using the correct chemical terminology. Would it make any difference, no it wouldn’t. Dry ice is easier to visualise rather than to say steam that comes out of a fridge.
Franglais:
We’ve had hydrogen fusion, warm gases flowing through both coils, fridges put inside freezers, and now we have dry-ice inside a trailer!
This thread is wonderful!
And you are very much mistaken if you think any different. I may not have explained it all in the terms that you understand. Dry ice fog is the white like smoke that you see (in your terms). Hydrogen bonding is what happens at +4 degrees. A difficult subject matter if you are not a fridge man. It is Hot gas not warm gas that flows through the evap coils on defrost and is also known as a hot gas defrost cycle. It uses the discharge pressure from the compressor and super heats the refrigerant into a super heated vapour that we call hot gas. Fridges put inside of freezers?? Sorry you have lost me there.
A reefer is actually a heat pump as it can heat as well as cool between a range of temperatures. It uses a reversing valve to do this, That’s how you reverse which coils you want to defrost utilising the hot gas. Anything else I can help you with understanding just ask away, I can tell that you view this all as codswallop, however you do not have to get too concerned over the technical issues as you do not need to know about such things. Just set the temp and drive, I think why drivers are no longer trained in reefer operation like they used to be is that of the attitude of drivers nowadays both for the job and possible lack of understanding in the first place. It is a shame really as we did at one time have some really good fridge drivers. Ask anyone who drives a fridge if they see dry ice coming out the back doors when they open them. That is what causes your icing up problem in the reefer. I have tried to explain all of this in very simplicit terms in order to help those that would like a deeper understanding of the reefer other than just set the temp and go. I hope the majority who have read my posts have understood better and lets be honest here, you don’t get taught this stuff anymore so people like me giving out this info is probably as close as you will ever get to any official training. It is all good advice, take it or leave it.
Hydrogen bonding does happen at +4C. You mentioned originally hydrogen fusion, which happens inside stars.
.
You stated that
“Hot gas runs through both coils regardless”. How so? Where is the heat being pumped from, and to, if both coils are “hot”?
.
Post #96 also talks of fridges being put in freezers?
.
And dry ice?
Really? Minus 80C inside a fridge trailer?
Maybe… if it was stored inside a freezer plant, otherwise, no.
The “white smoke” which is a term I certainly haven’t reffered to anywhere here, is water vapour.
.
.
As has already been said fridges recirculate the air inside the trailer.
Look at an example of a multi drop fresh load? Load correctly, uniformly chilled to plus 4.
If ambient air enters (loading outside of a cold dock) tipping etc then when the doors are closed again the new ‘warm’ air needs cooling. If not the upper layers of the load would warm up, of course.
To chill the new air the fridge fires up. It will be set to blow out air about +1 or +2 to drag the air down to +4. Since the air inside may be +20 or more, the cooling coil will be well below this temperature. As the air flows over it, any moisture in the air will be frozen on the coil surfaces. This is how icing occurs even with fresh loads.
It is important to understand that fridges (almost all of them anyway) are heat pumps.
The air we are cooling is not getting colder…Stay with me… It is getting less hot.
So in order to keep efficient cooling a layer of ice on the coils will actually act as insulation. (Igloos are warm inside It will prevent warm air giving up heat to the refrigerant inside the coils. Air will blow over an icicle at maybe -2 instead of a coil at -10 or whatever.
That is why defrost is necessary.
If a trailer of fresh is loaded and the doors aren’t opened, then once the moisture is taken out of the air the could will stay clear-ish. If the doors are opened then fresh moist air will be introduced. And this effect is much greater with a part or diminishing load as there will be much greater volumes of air involved.
.
.
Franglais:
We’ve had hydrogen fusion, warm gases flowing through both coils, fridges put inside freezers, and now we have dry-ice inside a trailer!
This thread is wonderful!
And you are very much mistaken if you think any different. I may not have explained it all in the terms that you understand. Dry ice fog is the white like smoke that you see (in your terms). Hydrogen bonding is what happens at +4 degrees. A difficult subject matter if you are not a fridge man. It is Hot gas not warm gas that flows through the evap coils on defrost and is also known as a hot gas defrost cycle. It uses the discharge pressure from the compressor and super heats the refrigerant into a super heated vapour that we call hot gas. Fridges put inside of freezers?? Sorry you have lost me there.
A reefer is actually a heat pump as it can heat as well as cool between a range of temperatures. It uses a reversing valve to do this, That’s how you reverse which coils you want to defrost utilising the hot gas. Anything else I can help you with understanding just ask away, I can tell that you view this all as codswallop, however you do not have to get too concerned over the technical issues as you do not need to know about such things. Just set the temp and drive, I think why drivers are no longer trained in reefer operation like they used to be is that of the attitude of drivers nowadays both for the job and possible lack of understanding in the first place. It is a shame really as we did at one time have some really good fridge drivers. Ask anyone who drives a fridge if they see dry ice coming out the back doors when they open them. That is what causes your icing up problem in the reefer. I have tried to explain all of this in very simplicit terms in order to help those that would like a deeper understanding of the reefer other than just set the temp and go. I hope the majority who have read my posts have understood better and lets be honest here, you don’t get taught this stuff anymore so people like me giving out this info is probably as close as you will ever get to any official training. It is all good advice, take it or leave it.
Hydrogen bonding does happen at +4C. You mentioned originally hydrogen fusion, which happens inside stars.
.
You stated that
“Hot gas runs through both coils regardless”. How so? Where is the heat being pumped from, and to, if both coils are “hot”?
.
Post #96 also talks of fridges being put in freezers?
.
And dry ice?
Really? Minus 80C inside a fridge trailer?
Maybe… if it was stored inside a freezer plant, otherwise, no.
The “white smoke” which is a term I certainly haven’t reffered to anywhere here, is water vapour.
.
.
As has already been said fridges recirculate the air inside the trailer.
Look at an example of a multi drop fresh load? Load correctly, uniformly chilled to plus 4.
If ambient air enters (loading outside of a cold dock) tipping etc then when the doors are closed again the new ‘warm’ air needs cooling. If not the upper layers of the load would warm up, of course.
To chill the new air the fridge fires up. It will be set to blow out air about +1 or +2 to drag the air down to +4. Since the air inside may be +20 or more, the cooling coil will be well below this temperature. As the air flows over it, any moisture in the air will be frozen on the coil surfaces. This is how icing occurs even with fresh loads.
It is important to understand that fridges (almost all of them anyway) are heat pumps.
The air we are cooling is not getting colder…Stay with me… It is getting less hot.
So in order to keep efficient cooling a layer of ice on the coils will actually act as insulation. (Igloos are warm inside It will prevent warm air giving up heat to the refrigerant inside the coils. Air will blow over an icicle at maybe -2 instead of a coil at -10 or whatever.
That is why defrost is necessary.
If a trailer of fresh is loaded and the doors aren’t opened, then once the moisture is taken out of the air the could will stay clear-ish. If the doors are opened then fresh moist air will be introduced. And this effect is much greater with a part or diminishing load as there will be much greater volumes of air involved.
.
.
AndieHyde:
Around here we obey the laws of thermodynamics. [emoji38]
Andy I have tried my best to explain all of this in the simplest of terms so that it is easier to understand. If there is anything that you want clarifying with anything that I have put across, I honestly mean this, ask me. Whether you believe it or not is absolutely your own decision to make. What would be the point in explaining everything to you using the correct chemical terminology. Would it make any difference, no it wouldn’t. Dry ice is easier to visualise rather than to say steam that comes out of a fridge.
Using the correct terminology is never wrong. Especially in any sort of technical, scientific or engineering context.
This isn’t a forum for 5 year kids.
Although it occasionally resembles a playground.
Franglais:
We’ve had hydrogen fusion, warm gases flowing through both coils, fridges put inside freezers, and now we have dry-ice inside a trailer!
This thread is wonderful!
And you are very much mistaken if you think any different. I may not have explained it all in the terms that you understand. Dry ice fog is the white like smoke that you see (in your terms). Hydrogen bonding is what happens at +4 degrees. A difficult subject matter if you are not a fridge man. It is Hot gas not warm gas that flows through the evap coils on defrost and is also known as a hot gas defrost cycle. It uses the discharge pressure from the compressor and super heats the refrigerant into a super heated vapour that we call hot gas. Fridges put inside of freezers?? Sorry you have lost me there.
A reefer is actually a heat pump as it can heat as well as cool between a range of temperatures. It uses a reversing valve to do this, That’s how you reverse which coils you want to defrost utilising the hot gas. Anything else I can help you with understanding just ask away, I can tell that you view this all as codswallop, however you do not have to get too concerned over the technical issues as you do not need to know about such things. Just set the temp and drive, I think why drivers are no longer trained in reefer operation like they used to be is that of the attitude of drivers nowadays both for the job and possible lack of understanding in the first place. It is a shame really as we did at one time have some really good fridge drivers. Ask anyone who drives a fridge if they see dry ice coming out the back doors when they open them. That is what causes your icing up problem in the reefer. I have tried to explain all of this in very simplicit terms in order to help those that would like a deeper understanding of the reefer other than just set the temp and go. I hope the majority who have read my posts have understood better and lets be honest here, you don’t get taught this stuff anymore so people like me giving out this info is probably as close as you will ever get to any official training. It is all good advice, take it or leave it.
Hydrogen bonding does happen at +4C. You mentioned originally hydrogen fusion, which happens inside stars.
.
You stated that
“Hot gas runs through both coils regardless”. How so? Where is the heat being pumped from, and to, if both coils are “hot”?
.
Post #96 also talks of fridges being put in freezers?
.
And dry ice?
Really? Minus 80C inside a fridge trailer?
Maybe… if it was stored inside a freezer plant, otherwise, no.
The “white smoke” which is a term I certainly haven’t reffered to anywhere here, is water vapour.
.
.
As has already been said fridges recirculate the air inside the trailer.
Look at an example of a multi drop fresh load? Load correctly, uniformly chilled to plus 4.
If ambient air enters (loading outside of a cold dock) tipping etc then when the doors are closed again the new ‘warm’ air needs cooling. If not the upper layers of the load would warm up, of course.
To chill the new air the fridge fires up. It will be set to blow out air about +1 or +2 to drag the air down to +4. Since the air inside may be +20 or more, the cooling coil will be well below this temperature. As the air flows over it, any moisture in the air will be frozen on the coil surfaces. This is how icing occurs even with fresh loads.
It is important to understand that fridges (almost all of them anyway) are heat pumps.
The air we are cooling is not getting colder…Stay with me… It is getting less hot.
So in order to keep efficient cooling a layer of ice on the coils will actually act as insulation. (Igloos are warm inside It will prevent warm air giving up heat to the refrigerant inside the coils. Air will blow over an icicle at maybe -2 instead of a coil at -10 or whatever.
That is why defrost is necessary.
If a trailer of fresh is loaded and the doors aren’t opened, then once the moisture is taken out of the air the could will stay clear-ish. If the doors are opened then fresh moist air will be introduced. And this effect is much greater with a part or diminishing load as there will be much greater volumes of air involved.
.
.
My meaning of the coils having hot gas in them is from one of two ways, do a defrost and you send hot gas through the evap coils. If your condenser coils ice up you can also send hot gas through those. Not exactly at the same time you say? but in theory you are always going to send the hot gas through both sets of coils as the super heated vapour of the hot gas does not cool and condense immediately after reaching the condenser but rather condenses half way through them but never really completely cools to a sub cooled liquid as the pipework has not got enough length to them. You say most fridges are heat pumps? Not true in the least, a heat pump can cool or freeze and requires a 3 way valve arrangement to enable this. On reefers they are indeed heat pumps but most industrial refrigeration systems are not heat pumps. An amount of frost on the evap coils is actually needed and required but not for insulation purposes. Refrigeration gas can take heat out of minus temperatures very easily with a layer of frost on, the layer of ice or frost stops any flash over occurring and is very helpful as the short runs of pipework would see the compressor with cavitation problems, hence the use of a receiver. it is only when the ice becomes so thick and restricts the airflow that it becomes a problem.
Post #96 also talks of fridges being put in freezers? Still no idea of what you are talking about here.
I will however give you a bit of credit for your explanation but unfortunately it is incorrect but I do acknowledge your understanding. The dry ice I have already posted to you but because of the club that I am in it may be delayed until approved. The dry ice was an analogy for a visual rather than to state what it is, which is actually cold steam. Try explaining that easily, simpler to refer to it as dry ice.
AndieHyde:
Around here we obey the laws of thermodynamics.
Andy I have tried my best to explain all of this in the simplest of terms so that it is easier to understand. If there is anything that you want clarifying with anything that I have put across, I honestly mean this, ask me. Whether you believe it or not is absolutely your own decision to make. What would be the point in explaining everything to you using the correct chemical terminology. Would it make any difference, no it wouldn’t. Dry ice is easier to visualise rather than to say steam that comes out of a fridge.
No need to worry about me, I am a big boy and this isn’t my first time at the rodeo.
In simple terms, I know my nuclear reactions from my nucleation but you keep on digging.
Actually not quite so savage, you have jumped in a bit too quick there in your excitement old bean. But then that is just you isn’t it. Lack of understanding of the subject and acting like a troll. Franglais has put a few pointers that are correct unlike yourself. I think my reply to him covers any misunderstanding.
AndieHyde:
No need to worry about me, I am a big boy and this isn’t my first time at the rodeo.
In simple terms, I know my nuclear reactions from my nucleation but you keep on digging.
I don’t really think you’re the man to match me Andy. The only way you could make me look silly is if I was walking next to you in public.
Franglais:
This isn’t a forum for 5 year kids.
Although it occasionally resembles a playground.
I beg to differ on that Franglais. It nearly always resembles a playground. Anyway regardless, it is good to speak with someone who has a bit of an understanding of the refrigeration cycle. But like you picking out my words and terminology, Likewise I have to do the same with your’s, although I did understand what you meant in the same way as you knew exactly what I meant. In real life if someone describes an analogy of dry ice fog forming, you wouldn’t turn around and make a meal out of it by explaining to them the temp and chemical compounds so that they are actually incorrect, If that were the case, in our workshop we would never get anything done. We would be stood all day telling each other we are incorrect.
UKTramp:
… dry ice flowing out of your trailer and onto the loading bay.
Hi UKT, please feel free to correct me if I’m wrong, but since you mentioned dry ice…
I don’t claim any knowledge of the process, so I looked it up.
Wikipedia has this to say:
Dry ice is easily manufactured. First, gases with a high concentration of carbon dioxide are produced. Such gases can be a byproduct of another process, such as producing ammonia from nitrogen and natural gas, oil refinery activities or large-scale fermentation. Second, the carbon dioxide-rich gas is pressurized and refrigerated until it liquefies. Next, the pressure is reduced. When this occurs some liquid carbon dioxide vaporizes, causing a rapid lowering of temperature of the remaining liquid. As a result, the extreme cold causes the liquid to solidify into a snow-like consistency…
This got me wondering how there’d be the necessary environment and a sufficient amount of pressurised CO2 in the back of a 'fridge trailer to allow proper dry ice to form/escape when somebody opens the doors.
My layman’s understanding of what can be observed is simply that what people think of as dry ice might be more easily explained by saying that the sub-zero temperature inside the 'fridge trailer has frozen very small droplets of the naturally occurring moisture (humidity) found in the air as you later pointed out.
I doubt that anybody would seriously think that you meant ‘actual’ dry ice, but it looked to me that you just used a simplified term, which is much better than turning full ‘Carryfast’ on us.
I’m sure you remember Dave the fun we used to have when purging Co2 tankers and scooping up the dry ice and slipping it into someone’s pocket or cup of tea?
dieseldave:
My layman’s understanding of what can be observed is simply that what people think of as dry ice might be more easily explained by saying that the sub-zero temperature inside the 'fridge trailer has frozen very small droplets of the naturally occurring moisture (humidity) found in the air as you later pointed out.
I doubt that anybody would seriously think that you meant ‘actual’ dry ice, but it looked to me that you just used a simplified term, which is much better than turning full ‘Carryfast’ on us.
Cheers Dave, I was trying my hardest to not do a Carryfast and thought the dry ice terminology was the least text rich format to use. The whole point of giving my time to this thread was purely to help anyone out who might benefit from my loading and defrosting advice. It is good advice and factual. Why I had to get technical with the refrigeration science was actually boring to me so tried to skimp over that as quickly as possible without dwelling on it too much. If anyone wants to start a technical refrigeration thread (which I doubt) I would be more than willing to go into a 10 page explanation on the theory. This wasn’t that thread. I think Maoster got the most from this and a few silent others. Was a good thread up until the usual suspects arrived and tried to get me to bite. No chance, I am a different UKT nowadays.
AndieHyde:
Around here we obey the laws of thermodynamics.
Andy I have tried my best to explain all of this in the simplest of terms so that it is easier to understand. If there is anything that you want clarifying with anything that I have put across, I honestly mean this, ask me. Whether you believe it or not is absolutely your own decision to make. What would be the point in explaining everything to you using the correct chemical terminology. Would it make any difference, no it wouldn’t. Dry ice is easier to visualise rather than to say steam that comes out of a fridge.
Because water vapour is such a difficult concept to understand. Most people are familiar with the “smoking” devices known as vapes. A user blows smoke but nothing burns.
Its witchcraft in league with the devil if you ask me and my limited capacity for understanding.
The reason people keep picking on your posts is because you keep offering up inaccuracies whilst ,metaphorically, strutting around claiming to know everything there is to know. When we boil off your condescending waffle and self proclamation down to its essence, we find the information contained within flawed to various degrees so people, like myself start to poke holes, so instead of being the bigger man and admitting that perhaps your own delivery method might need some addressing, you take the full on attack and belittlement approach .
That brings me to another thought I have been having recently. If you are on premod, then how do so many of your rule 3 violations get through?
Whilst we have all been looking at alternatives of amusement during lockdown, I was so desperate that I found other forums for, and get this, a forum for forum managers…a…
I know, I feel dirty and ashamed too, but one of the reoccurring threads being discussed on the 3 sites I visited was forum managers creating false accounts for the express intentions of increasing traffic utiilising such methods of outspoken controversy,and how widespread such actions are within the industry.
Seems strange you randomly turning up again after limp flounce nearly a year ago.
Why would anyone introduce the idea of “dry ice” when even a child can have the idea of clouds explained to them and the way steam comes out of their mouth on a cold day?
And especially why would a “fridge man” who claims expertise in cold and chill stores as well as fridge transport? Why especially them? Because Carbon Dioxide is really used in that industry and introducing points of misunderstanding defies all logic or common sense that I can see. Imagining a group of competent engineers or mechanics using such loose language is difficult.
…
P.S.
Saying you use the “least text rich format” is classic!
Franglais:
“The defrost cycle of hot gas obviously runs through both sets of coils regardless.”
Fascinating stuff…
Yes it is easily done, just reverse from heat to cool once again a good driver knows this trick, you don’t need to be an engineer to do this. During winter months we often defrost coils with either hot gas or by putting the fridge unit into a deep freeze. This will send super heated gas through the condenser coils.
Franglais:
Why would anyone introduce the idea of “dry ice” when even a child can have the idea of clouds explained to them and the way steam comes out of their mouth on a cold day?
But it isn’t steam that comes out of your mouth (unless you have a very strange metabolism…). It’s not dry ice, nor is it steam - I think youve just out-pedanted yourself
but I’m not in the mood for it today.
