And we’re off
That’s it now , I am off to Wilkinson’s to bulk buy popcorn and buy a crate of Hobgoblin , I have a feeling this thread will get heated , and it’s a bank holiday weekend .
I predict a thread lock by Monday night .
All we need is interjection by Carryfast .
UKtramp:
yourhavingalarf:
Short answer, yes, a fridge can freeze chilled stuff. Just as well as it can ripen bananas at +15.This is exactly why you shouldn’t pay any attention to just anyone… Stick something in your fridge at home at 4 degrees and see how long it takes you to freeze it.
Complete and utter rubbish.
Our fridge at home can and does quite easily freeze stuff that is inadvertently placed in contact with where the chilled air enters the cabinet, despite the temperature everywhere else in there being a uniform 4 degrees C.
yourhavingalarf:
You’re a fridge engineer…You say?
Set the fridge trailer to minus 27 degrees C and put a strawbwerry in it and see what happens to it.
Complete and utter rubbish you collosal dumb [zb].
Set anything to minus 27 and it will freeze, who is disputing that?? I don’t think you read the question correctly, you say I am dumb.
Roymondo:
Our fridge at home can and does quite easily freeze stuff that is inadvertently placed in contact with where the chilled air enters the cabinet, despite the temperature everywhere else in there being a uniform 4 degrees C.
You are referring to a domestic fridge which cools by taking the air from the freezer compartment which is totally different to the way a reefer or any industrial refrigeration system works. A temp of +4deg changes the hydrogen molecules in water base products making the crystals heavy and this is known as hydrogen fusion which is the first steps to freezing. Your fridge at home is blowing air for short periods at already freezing temps at the intake and why you can freeze produce by accident if placed for long periods at this point.
UKtramp:
Roymondo:
Our fridge at home can and does quite easily freeze stuff that is inadvertently placed in contact with where the chilled air enters the cabinet, despite the temperature everywhere else in there being a uniform 4 degrees C.You are referring to a domestic fridge which cools by taking the air from the freezer compartment which is totally different to the way a reefer or any industrial refrigeration system works. A temp of +4deg changes the hydrogen molecules in water base products making the crystals heavy and this is known as hydrogen fusion which is the first steps to freezing. Your fridge at home is blowing air for short periods at already freezing temps at the intake and why you can freeze produce by accident if placed for long periods at this point.
Absolutely correct. This “hydrogen fusion” process produces enough energy to power the `fridge, and give us endless energy into the green future.
UKtramp:
Roymondo:
Our fridge at home can and does quite easily freeze stuff that is inadvertently placed in contact with where the chilled air enters the cabinet, despite the temperature everywhere else in there being a uniform 4 degrees C.You are referring to a domestic fridge which cools by taking the air from the freezer compartment which is totally different to the way a reefer or any industrial refrigeration system works. A temp of +4deg changes the hydrogen molecules in water base products making the crystals heavy and this is known as hydrogen fusion which is the first steps to freezing. Your fridge at home is blowing air for short periods at already freezing temps at the intake and why you can freeze produce by accident if placed for long periods at this point.
Perhaps you could remind us who wrote “Stick something in your fridge at home at 4 degrees and see how long it takes you to freeze it. Complete and utter rubbish.”
Hydrogen fusion?? You really are something special…
Franglais:
Absolutely correct. This “hydrogen fusion” process produces enough energy to power the `fridge, and give us endless energy into the green future.
[/quote]
Actually not sure if you are in the know or you are taking the mick, but it’s funny as what you are saying is actually correct. We will see the next generation of fuels using hydrogen technology and yes energy at the moment is testing out hydrogen plants. I suspect that you are in the know as too much of a coincidence that you would be as accurate in your description.
Roymondo:
Hydrogen fusion?? You really are something special…
Yes I agree, the phenomenon is known as hydrogen bonding at +4.0C otherwise termed hydrogen fusion. Your possibly confusing nuclear reactors and fusion that you may be aware of. In the fridge world, hydrogen bonding is our bread and butter. Also why lakes etc, freeze from the top and not from the bottom. And why in the deepest winter when lakes are frozen over the fish do not freeze as the water at the bottom is kept at 4.0C due to hydrogen bonding in the water. Refrigeration is quite a fascinating subject.
Yes, I think we can agree that you are indeed something special.
For the OP,
Forget all the temperature experts and statisticians etc etc etc.
and especially all the know-nothings and know-it-all’s above
Fridge transport is very critical, to keep fresh - fresh, frozen - frozen, and even ripen fruit in transit.
If you are loading somewhere, lets say dairy produce, and they want it to be at +2, you’ve been sitting in a lay-by having your break,
turn on the fridge at +2, as long as it’s not next door, by the time you get there, it will be near or as ■■■■ it +2
You have to turn up at the supplier with the fridge at the required temperature,
When you turn up at a supplier, they will check the temperature of the inside of the trailer, if it isn’t low enough, they will not (in theory) load you,
This was your comment:
The scenario is: you load up chilled products, its +25c outside, so no matter what the temperature was in the trailer, by the time its loaded it is +16c inside. Your running temp is supposed to be +4c
Forget the outside temperature, it’s what is inside the reefer that is important
it’s up to you to get to the supplier with a suitable internal temperature,
you can’t just turn up without the fridge running, then think OK i’ll just shove it on -25
so if you’re loading fresh at +2 to +6 turn up with an internal temp within that range
if it’s frozen at -25, turn up with your internal temp at at least -18
edited to add
if it’s frozen at -25, turn up with your internal temp at at least -18
if you want to be loaded straight away, otherwise be prepared for a wait till it is low enough
While appreciate the helpful discussion above i have been probably not quite clear as many of you are missing my point. This was a theoretical question, so forget about the actual figures, they are just an example.
I will try to reword:
What is the actual temperature of the blown in air in comparison to the setpoint?
Priest:
While appreciate the helpful discussion above i have been probably not quite clear as many of you are missing my point. This was a theoretical question, so forget about the actual figures, they are just an example.I will try to reword:
What is the actual temperature of the blown in air in comparison to the setpoint?
It varys. If the fridge is at say +16 and it needs to be +4 the fridge will blow a lot coler than +4 until the thermostat kicks in at +4 then it runs ambient.
So in theory yes you can freeze chilled goods if you loaded the trailer withou it being sat at the actual temperature of said goods.
Thankyou for the question.
In a correctly set up chain, this wouldnt happen, but not everyone does their job right, so it can happen. Only considering single compartment trailers, to keep it simple. Trailers are to move stuff at a steady temperature, not cool the goods down. They should have all their internal surfaces already cooled to the correct product temperature. They operate from air temp sensors, near the roof at various places, if the trailer body is cool the air inside will also be cool. During loading (outside of a proper insulated dock) warmer air could well be introduced. If order to drop the air temp the unit will recirculate and cool the air in the trailer. (It doesnt ■■■■ in exterior air). The air blowing from the unit will be much lower temp than the “set temperature”.
If only the air above the load needs cooling then it wont take long to cool this air. However if the load is actually above the "set temperature" or of the reefer body is too warm before loading then the unit will be blowing freezing air for much longer. This is when damage to the fruit/veg or whatever is more likely to happen. If it is a load of peaches loaded in a field on a summer afternoon in southern Italy, and run at +4 then the top layers of the pallets will be either frost damaged or ready to have sticks put in them to be sold as ice-lollys. . Industrial chilling and freezing plants dont cool down whole loads of goods, the temperature gradient inside a block such as a pallet stacked is too great, they chill or freeze smaller units with large air flows.
.
.
Ice is less dense than liquid water because the hydrogen molecules present form a low energy bond that holds them further aprart than in water.
NOTE. These are bonds between different water (H2O) molecules.
“Hydrogen Fusion” is a sub-atomic process whereby free hydrogen atoms combine to form helium atoms, and huge amounts of energy.
NOTE. This happens at the temperatures and pressures inside stars, such as our own Sun… Not at +4deg C.
NOTE. “Nuclear Fusion” is not “Nuclear Fission”.
Odd isn’t it when someone like me who is an Industrial refrigeration engineer and a consultant in this field that has worked world wide and highly regarded knows a lot less than someone who tows a reefer and is more of an expert. I have designed and worked on some of the most complex refrigeration plants on the planet, +4.0C is a very special temperature in refrigeration and as Franglais has pointed out that hydrogen bonding is in H2O. The human body is made up of 75% water, an awful lot of food stuffs hold water content and so the 4.oC magic number is very relevant.
Industrial refrigeration is my field and I can tell you anything you want to know about it. I even posted all of my refrigeration qualifications on here at one time including my gold card status and ammonia handling certs. Cold storage plants do indeed freeze from fresh in large blast freezers holding 20 pallets or more, then placed into the cold storage warehouse set at usually -20. The frozen pallets still hold heat and it takes a lot of energy to hold the huge amounts of pallets frozen.
If you place pallets in the cold storage warehouse at a less temperature than the set temperature then you get problems with imbalance and the compressors work harder than they should work and using huge amounts of energy to pull these pallets down to temp. All depends on the numbers here but it takes aprox 18 hrs to freeze a batch of 20 pallets of meat for example to freeze -18 to the core. Once again this all depends on water and salt content of the produce. I developed a way of freezing meat down to -10 which is the temp needed for factory cutters and slicers to effectively slice frozen meat. Any way carry on regardless with all your own theories, I am sure you will be right in your own ways.
Priest:
Well, i wonder if it is more complicated.I heard rumors someone got a claim as in my scenario the fridge went on full blast and frozen the front pallets. Obviously if you want to drop from +20 to +4 the fastest way is to get -20c air in
I’ve seen “temperature leeching” in the front of a C2 “Frigoblock” chiller, that can be set to +2 on one side (usually right), -25 on the other (Smaller, left hand partition). When you switch the thing off having tipped, by the time you get back to base you see both sides being something like -6… “Ambience”…
There’s no danger of the RHS compartment freezing all the stuff in there - because you’ve already tipped the lot by this point - Right?
You could, in theory end up “freezing some milk” - should the customer reject the load, and you intended returning it to base, except that you ended up freezing it in this scenario…
I’m with Trampy on this tbh, he certainly talks the talk and I’m not confident enough on a subject I know little about to argue with him, I’ve actually watched his YouTube vids so can appreciate his expertise. I only pull a reefer, I know little of the gubbins that go on inside it.
the maoster:
I’m with Trampy on this tbh, he certainly talks the talk and I’m not confident enough on a subject I know little about to argue with him, I’ve actually watched his YouTube vids so can appreciate his expertise. I only pull a reefer, I know little of the gubbins that go on inside it.
Thank you for that Maoster, yes I forgot I shared that with you, actually that video is at the docks in hull which was the biggest cold storage facility in Europe, If there is anything that I know that nobody can argue with me , it’s refrigeration. I offered at one stage on here to do a refrigeration series to help drivers expand their knowledge, try to get any refrigeration courses for free anywhere else, they are expensive for a reason. However once again this was soon scoffed by a certain few on here so why would I bother. I will still contribute to any refrigeration topic on here and answer any questions regardless, members who know better will listen and learn, those who are the know it all types will always fail to learn or hold the incorrect knowledge because they think that they already know it all. When I read some of the comments on here, it really makes me smile and realise why the refrigeration industry is a closed door to only the select few. You would be shocked at how few of us there are who deal in industrial refrigeration and how highly regarded we as British engineers are throughout the world. Refrigeration was developed and pioneered in Scotland and we have remained the leading engineers ever since. Our expertise is something to be proud of, yet very few people even think about refrigeration. My father was one of the all time greats and his published papers are still amongst the most authoritative today. Believe it or not but I am a god in the refrigeration world and that is a fact.
Painful memories of my euro fridge days coming back to haunt me here.I remember loading green grapes in south Italy in the nineties without realising the basic principles of refrigeration,no tuition beforehand 
in go the grapes to a cool temperature set by me in the trailer and 3 days later back in Oxfordshire the entire load had ripened,so no good for the shops as they’d just perish on shelf,so of course they’re rejected outright.(temperature needed a gradual adjustment) 
There’s a lot to know that never gets taught to a professional standard considering this is food.I wasn’t the only offender with ND Fridge either,lots of ‘miscalculations’ abounded including a rear door ice-cream deluge incident, for one unfortunate soul delivering in Portugal.There should be a qualification at some level for this work I always figured,obviously not ADR level grade but maybe a specialist component of the CPC farceathon.
manalishi:
.There should be a qualification at some level for this work I always figured,obviously not ADR level grade but maybe a specialist component of the CPC farceathon.
You’re not wrong there with that statement. The food chain requirement for refrigeration at engineer and storage facility level is very high and scrutinised by auditors regularly, Then the transport side just lets it all down, nothing stopping anyone from driving a reefer which is mindless and the reason why the checks and the paperwork trail at each end have to be so high.