Three G11 coolant mixtures, boiling-cooling time comparison.

[D.FYLAKTOS]

Gentlemen, i don't have the proper equipment to do the experiment so i am asking if a fellow Skodian member knows Chemistry far better than me.

let's say that we have G11 antifreeze and 4 big boiling tubes-flasks or 4 big glass cans and inside there is:

In 1st pure distilled water, in 2nd distilled water and 20% antifreeze, in 3rd distilled water and 30% antifreeze and in 4th distilled water and 50% antifreeze.

 

We turn slowly the same heat source below to all 4 tubes-flasks (or glass cans), here is an example

 

 

We measure by clock:

 

1) the time that each mixture will reach the 100 °C (then we remove it)

2) the time that each mixture after the 100 °C  will cool till environment temperature.

 

I don't care which of the 2nd,3rd,4rth will reach it's maximum point, i care only till 100 °C.

According to your knowledge and experience what could be the results?

Which of the 4 will reach the preset temperature first and which of 4 of them will cool faster?

 

 

[Ootohere]

I know nothing about science, but i do know that a cars coolant system has a pressurised system for the Coolant / antifreeze / anti corrosion liquid. 

This raises the temperature at which the liquid boils. 

 

When i ran V8,s on LPG i used Water Wetter, So when i ran remapped Twincharger TSI,s i did the same. 

 

 

Edited 19 March by Rooted

[Breezy_Pete]

Pure water will have the highest heat capacity,  so will boil slowest for a given heat input.

[nta16]

You've covered this subject in depth previously, also that a coolant does more than just protection from freezing or boiling, and various combinations to use as a coolant.

[D.FYLAKTOS]

10 hours ago, nta16 said:

You've covered this subject in depth previously,

 

First time asking that specific question, it's not about the role of antifreeze etc.

It's crucial to know which of the 20-30-50% mixtures will reach the 100 'C first.

[Ootohere]

@D.FYLAKTOS  Why.

 

Is it not normally around 90*oC that the coolant is usually required to get up to for efficiency of keeping the engine oil at around 90*oc and bringing it back down around 90*oC.

Engine oil being a coolant as well as whatever coolant is used. 

[D.FYLAKTOS]

@Rooted actually it's not 100 'C but around 92 'C, at this point (reading the red needle) my thermostat opens for 1st time.

Has to do whith my Cold starts process, i think that the less antifreeze excists the more time needs to reach that point but other members maybe know better.

I am on a trip now, when i return home i want to change the percentage of the G11 in my current coolant as an experiment.

[Ootohere]

You have lost me.     Do you ever just drive the car?

 

Stick the thermostat in a pot and heat the water and measure the temp accurately. 

Use the correct thrmostat.

 

You just use the strength / ratio of Anto-freeze / coolant relevant to the location, climate etc. 

Do not use Anti-freeze if the Ambient temperature is not going to be getting as low as the freezing point of H20.

But if you are leaving in the Coolant / anti corrosion liquid all year and you get freezing weather you better have Anti-freeze in the system, or expect core plugs to be doing their job. 

 

Much cheapness.

Good for checking coolant, & good for engine oil temps just put down the dipstick tube. 

Edited 20 March by Rooted

[Papez]

Water has heat capacity 4.186J/gK, ethylene glycol, used in antifreeze, 2.42J/gK. No need to experiment, you can do the math.

Just make proper mixture for your weather conditions. There's really no point in trying to slightly reduce heat capacity of 4l of water, when you need to heat up 80kilos of metal.

 

 

Also, I think that facelift Felicia uses G12, not G11.

Edited 20 March by Papez

[nta16]

Yes that stuff was covered in previous thread(s) not necessarily the exact figures but certainly the principles.

 

Coolant, antifreeze, additives in and can be added, accuracy of thermostat number starting to open and fully open, accuracy of water gauge and bias range, oil, which G number, all covered IIRC.

 

Might not have covered possible efficient temperatures of different engines but we leave that to the German engineers to sort for us and all their designed systems on the car.

 

[D.FYLAKTOS]

1 hour ago, Papez said:

There's really no point in trying to slightly reduce heat capacity of 4l of water, when you need to heat up 80kilos of metal.

 

 

Also, I think that facelift Felicia uses G12, not G11.

 

For me which combination will reach first the 92 'C matters.

 

Felicia came here with Green (G11), the manual says VW TL 774 C although some put G12 even G13.

[Papez]

Ok, I'll do the math for you.

 

Felicia has 5,6l of coolant. Let's ignore part of coolant that's the radiolator, which doesn't circulate until the thermostat opens.

 

To heat up 5,6l of water by 72K, you'll need 1.69MJ of heat.

 

A -20 mixture is around 35% of glycol.  That means 1.96l of glycol, 3,64l of water. I'll ignore difference in density, it's not that big. You need 342kJ for glycol,  1097kJ for water, that's 1,44MJ total. So total difference is 249kJ.

 

To put that into perspective, the engine block takes around 5,2MJ of heat. So if your engine heats up in 10mins, it's around 10kJ/s of heat going into the engine. So, in this situation, the different coolant makes at most 25s of difference.

[D.FYLAKTOS]

I am in my old parents house far away from mine, i have with me only my phone, no proper equipment or time to do experiments or calculations.

Thank you for your help.

[nta16]

😄  There certainly wasn't Papez's level of detail of detail in previous thread(s).

 

I might be wrong but I have the feeling that there was a general conclusion previously that amy difference would be of no significance, but not spelled out in such a strict way as Papez has now put.

 

[D.FYLAKTOS]

I am on leave, in few days i will return home, i will change the water expansion plastic can and i will raise the antifreeze at least in 40% presentance (now it's 20%) to see if there is an effect in the time that the temperature reach the 92 'C.

Edited 21 March by D.FYLAKTOS

[Thefeliciahacker]

you all take into account the heat capacity yet no one is talking about the thermal conductivity

[D.FYLAKTOS]

11 minutes ago, Thefeliciahacker said:

yet no one is talking about the thermal conductivity

 

You can freely start talking. 

[nta16]

3 hours ago, Thefeliciahacker said:

you all take into account the heat capacity yet no one is talking about the thermal conductivity

Not in this thread but I'm almost sure (never 100% (or 110% if you follow kicky-bally) sure and never sure about remembering correctly) this has been covered in other thread(s) and probably a contribution from your good self but no reason not to repeat anything in this thread for other viewers.  Maths are good and real life/world experiences are good.

 

[D.FYLAKTOS]

Coolants and Their Application

 

https://lairdthermal.com/thermal-technical-library/application-notes/common-coolant-types-and-their-uses-liquid-cooling-systems

 

Water with Ethylene Glycol

 

Cons:

 

• Reduced heat transfer efficiency compared to pure water.

 

 

 

 

[Papez]

22 hours ago, Thefeliciahacker said:

you all take into account the heat capacity yet no one is talking about the thermal conductivity

 

I think that doesn't matter that much, when coolant spreads heat by convention. But I wonder how much lower heat capacity limits heat transfer.

[Warrior193]

27 minutes ago, Papez said:

 

I think that doesn't matter that much, when coolant spreads heat by convention. But I wonder how much lower heat capacity limits heat transfer.

My understanding is that the reduction of heat transfer is significant as glycol concentration increases - but the requirements to raise the coolant boiling point, along with corrosion inhibition and anti-freeze protection also need to be considered.

Edited 23 March by Warrior193
correction

[D.FYLAKTOS]

40 minutes ago, Warrior193 said:

My understanding is that the reduction of heat transfer is significant as glycol concentration increases

 

The 50% concentration mixture from the first turn of the key in the morning (environment temperature) will reach the 92 'C first?

[Warrior193]

I think that you are looking at this the wrong way - the function of the coolant (together with the lubricating oil) is to transfer excess heat away from engine components and prevent them from overheating.

A 50% glycol mix has approximately 20% lower ability (specific heat) to transfer heat away from those components.

Yes the engine may be less efficient for a short period until it reaches normal operating temperature, but the way to achieve this sooner is to restrict coolant (thermostats) and/or air flow (shutters) - not by reducing the specific heat properties of the coolant. 

[D.FYLAKTOS]

14 minutes ago, Warrior193 said:

Yes the engine may be less efficient for a short period until it reaches normal operating temperature, but

 

As we say here "you will pay this later".

In this case (50% mixture) the radiator fan will work more often for example in city traffic compared to 20% in a hot climate?

[Thefeliciahacker]

11 hours ago, D.FYLAKTOS said:

the radiator fan will work more often

so what? if it burns out you change it