Coolant additives that improve heat transference

wjb said:

I use Peach Tea.
You might think that's ridiculous but bear with me a moment.
I go on a ride. I'm in Death Valley. It's 110 degrees. I run out of gas.
I have a radiator full of Peach Tea to sustain me while I wait for rescue.
If your radiator is filled with an Ethylene Glycol solution will YOU be able to hydrate?
Sometimes this important fact is overshadowed by all this science.

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wjb said:

I use Peach Tea.
You might think that's ridiculous but bear with me a moment.
I go on a ride. I'm in Death Valley. It's 110 degrees. I run out of gas.
I have a radiator full of Peach Tea to sustain me while I wait for rescue.
If your radiator is filled with an Ethylene Glycol solution will YOU be able to hydrate?
Sometimes this important fact is overshadowed by all this science.

Click to expand...

Antek said:

In my C7 Corvette I run this stuff Amazon.com: Red Line (80204) Water Wetter - Coolant Additives - 12 Oz Bottle: Automotive to improve the heat transference from the coolant to the radiator and it works wonders, typically coolant temperatures are 10F+ lower than what they used to be without the additive, I also use it on my VROD but can't say how effective it is as there is no temperature gauge on that bike.

Anyone using anything like this on their R3?

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atomsplitter said:

Actually the temperature is controlled by the flow rate through the radiator. The thermostat opens as the temperature climbs, once fully open it cannot allow anymore flow than what the water pump provides. The radiator is sized to handle the maximum expected heat load of the motor. Therefore to run cooler either get a larger thermostat opening or lower the viscosity (resitance to flow) of the coolant or improve the heat transfer coefficient of the coolant. I would suspect the additive reduces the viscosity so that flow is improved with a smaller thermostat opening. The radiator is simply a heat exchanger with a fixed volume. The mass flow rate increasing through the radiator will exchange more heat since more heat is available to be exchanged. The standard equation is mdot (mass flow rate) times difference in enthalpy (delta h). This takes advantage of the first law of thermodynamics (heat can only flow from a higher source to a lower source), so the equation can be rewritten mdot times delta T (differential temperature).

Ever notice that engine coolant is kinda thick compared to water? That additive is simply an adjuvant that makes the coolant flow better (makes water wetter).

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estoma said:

Problem is that the chemical compatibility between the coolant and now-added water-wetter is not known and therefore poorly understood/appreciated, e.g. the water-wetter might well improvise the coolant's corrosion inhibiting properties or even lead to some more adverse chemical incompatibility, e.g. affecting seal integrity - unbeknown to the owner until some reliability issue surfaces later on - normally at substantial expense. Most, if not all, coolants have inferior heat-transfer properties compared to using pure water, preferably distilled water, of course. However, the downside of using pure water is often clearly illustrated when seeing automobiles with opened hoods on the side of the freeway - invariably with a steaming radiator.

I prefer coolants to maintain engine integrity from their side of the engine and to keep the radiator(s) clean and radiator passages unblocked. If one really needs improved cooling, the best answer is normally a larger radiator or one with a thicker core - as installed by many a Ducati Panigale owner. I strictly stick to OEM coolant 'prescriptions' even though I do not when it comes to oils. And I never use additives. If one needs to add sh1t to your oil or coolant, you are potentially using an inferior oil or coolant. So, consider rather draining it and replacing it with whatever you deem best.

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FE_rex said:

Actually water wetter is a surfactant and inhibits localized boiling in the head near combustion surfaces by altering the surface tension of cooling liquids. It is "chemically" reducing bubble formation due to boiling - the same as adding fluid with a higher boiling point (ethylene glycol). A radiator cap (overall system pressure) and thermostat (increased pressure between pump and thermostat) also reduce boiling albeit from pressure-based suppression.

Reduction of localized boiling insures better heat transfer into the cooling system adjacent to combustion and exhaust areas.

And yes ethylene glycol (EG) fluids do have more viscosity than water, however, the overriding factor is the significantly lower thermal conductivity of EG vs water. I am referring to the ability to conduct heat (energy) in the scientific sense, a thermodynamic intrinsic property of the fluid. What this means is - all things being equal it is harder to make EG change temperature than water.

If your cooling system maintains the engine at the correct temperature, adding additives is unlikely to improve an already optimum thermal situation.

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atomsplitter said:

You are correct as far as surfactant. You may be overlooking added heat exchanger efficiency created by sub-nucleate boiling heat transfer by breaking up the laminate layer of coolant on the heat exchanging surface under high flow conditions The BTU transfer coefficient improves with disruption of this layer since the heat transfer required to turn water into steam is over a thousand BTU's (pressure dependent) per pound mass. The small steam bubbles created collapse as they are swept off the surface of the heat exchanger by the turbulent flow above the laminate layer transferring their heat to the bulk coolant. Sub-nucleate boiling improves heat transfer, however going beyond that regime to film and slug boiling reverses the efficiency gain and heat transfer is reduced leading to bulk boiling. So around high heat transfer areas sub-nucleate boiling is desirable to improve heat transfer. The heat transfer rate is dependent on the coolant type (ability to absorb and transfer heat (a.k.a. specific heat capacity)) the mass flow rate and the difference in temperature between the heat source and the heat sink. The equation is m (mass flow rate) times Cp (specific heat capacity) times delta T (differential temperature).

For example: Cooling with hydrogen is better than cooling with carbon dioxide per pound mass because the specific heat capacity is higher for hydrogen than carbon dioxide per pound mass (why large industrial generators are cooled with H vice CO2). Since all automotive cooling systems are water based (excluding oil coolers) then the heat transfer rate is consistent regardless of size or type of engine since they all use the same coolant (water). The best cooling you could get would be 100% pure demineralized water alone. EG with its additives are used mainly as a corrsion inhibitors (corrosion and corrosion products inhibit heat transfer). and anti-freeze (engine/radiator protection). The EG itself has a specific heat capacity about one half that of water. Therefore to lower the temperature of the engine (heat source) with a fixed volume cooling system you would have to change at least one factor that determines cooling rate, i.e. the specific heat capacity of the coolant, the mass flow rate of the coolant, or increase the differential temperature between heat source and heat sink (in this case lower heat sink temperature). In winter the system is a lot more capable of removing heat than summer simply because the delta T is higher.

Depending on the the specific heat capacity of the additive in question, it might be possible to displace enough EG to improve total heat transfer (since the coolant system is a fixed volume, some water/EG must be removed to add the product in question). If specific heat capacity of the system is unchanged by the additive product in question however, then the only other way of improving the cooling would be an increase in the total mass flow rate (since heat source and sink are unchanged).

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Tripps said:

Very well said by all. Amazing how many very smart people we have on this forum

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Tripps said:

Very well said by all. Amazing how many very smart people we have on this forum

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